Plant News

In the news

2008-11-30T10:03:00.003-06:00

From EurekaAlert!

Introduced parasitoid (Lathrolestes nigricollis) knocks back birch leafminers in the American northeast.
China's "Green Great Wall", a forest shelterbelt running parallel to the Great Wall "could lead to an increase in precipitation by up to 20 percent and decrease the temperature in the area."
High levels of nitrogen in the Seymour Aquifer in Texas makes much of the water unsuitable for human consumption, but could reduce fertiliser addition when used for irrigation.

From Science Daily

Plants moving north as the climate warms may have better defenses than native plants, giving the invaders an edge.
Hybrid vigour in crop plants attributed to "increased expression of genes involved in photosynthesis and starch metabolism in hybrids and polyploids. These genes were expressed at high levels during the day, several-fold increases over their parents."
Non-target insects are affected more by pesticides than by GM crops which express insecticides.

Reconstructing the Sudden Oak Death epidemic

2008-04-17T08:20:00.002-05:00

Biology-blog reports on a study that reconstructs the Sudden Oak Death epidemic in California. The paper is due to be published "early online" later this month in the journal Molecular Ecology.

8000-year-old spruce roots

2008-04-09T02:16:00.004-05:00

Martin Rundkvist talks about some recent discoveries

New research by Leif Kullman at the University of Umeå is just being reported on by the media... no standing trees older than 600 years ... But below ground, the living roots of three trees gave radiocarbon dates at 5,000, 6,000 and 8,000 years BP! The oldest root system thus dates back from the end of the latest glaciation.

Pretty cool stuff. Now here's the interesting question - can someone find something similar in an area that wasn't glaciated? What's the real maximum age for individuals like this?

Update: Reed E. in the comments answers that question (though, sadly, without a reference, so take this with a grain of salt)

While the Norway Spruce is a fine tree, its clonal colonies have nothing on the Quaking Aspen (Populus tremuloides.) There's Pando in Utah, a single clonal colony that is thought to weigh 6,000 tonnes and perhaps as old as 80,000 years.

Posted by: Reed E | April 8, 2008 8:14 PM

Tangled Bank #102

2008-04-02T12:56:00.002-05:00

Tangled Bank #102 is up at Further Thoughts. Berry Go Round #3 was published a week ago at Greg Laden's blog.

Berry Go Round #2

2008-02-28T14:49:00.001-06:00

The second edition of Berry Go Round, the plant-focussed blog carnival, is up at my main blog.

Svalbard Global Seed Vault opens

2008-02-26T10:20:00.003-06:00

The Svalbard Global Seed Vault opened today on a remote island in the Arctic Circle, receiving inaugural shipments of 100 million seeds that originated in over 100 countries. With the deposits ranging from unique varieties of major African and Asian food staples such as maize, rice, wheat, cowpea, and sorghum to European and South American varieties of eggplant, lettuce, barley, and potato, the first deposits into the seed vault represent the most comprehensive and diverse collection of food crop seeds being held anywhere in the world.

The purpose of the repository is to preserve crop genetic diversity. I think it's an important project, but is it really enough?

Source: EurekaAlert!

Additional coverage from the New York Times.

New genetic tools for working with peas

2008-02-26T00:24:00.002-06:00

The pea is one of many important crop species that is unsuited to the Agrobacterium-based genetic modification techniques that are commonly used to work with crops. Researchers, reporting in the open access journal Genome Biology have now discovered the first high-throughput forward and reverse genetics tool for the pea (Pisum sativum), could have major benefits for crop breeders around the world..

Researchers from the INRA Plant Genomics Research Unit at Evry, and the INRA Grain Legumes Research Unit at Bretenières, both in France, both in France developed a high-quality genetic reference collection of Pisum sativum mutants within the European Grain Legumes Integrated Project. Abdelhafid Bendahmane and colleagues used plants from an early-flowering garden pea cultivar, Caméor, to create a mutant population, which they then systematically phenotyped for use in both forward and reverse genetics studies.

Source: EurekaAlert!

Composting to fight climate change?

2008-02-26T00:17:00.003-06:00

From EurekaAlert!

Applying organic fertilizers, such as those resulting from composting, to agricultural land could increase the amount of carbon stored in these soils and contribute significantly to the reduction of greenhouse gas emissions, according to new research published in a special issue of Waste Management & Research (Special issue published today by SAGE).
Carbon sequestration in soil has been recognized by the Intergovernmental Panel on Climate Change and the European Commission as one of the possible measures through which greenhouse gas emissions can be mitigated.

One estimate of the potential value of this approach – which assumed that 20% of the surface of agricultural land in the EU could be used as a sink for carbon – suggested it could constitute about 8.6% of the total EU emission-reduction objective.

“An increase of just 0.15% in organic carbon in arable soils in a country like Italy would effectively imply the sequestration of the same amount of carbon within soil that is currently released into the atmosphere in a period of one year through the use of fossil fuels,” write Enzo Favoino and Dominic Hogg, authors of the paper.

The number - 0.15% - seems small, but this is deceptive - it's still an awful lot of carbon. I'd be more interested in the mechanics of how they're going to get this done...but that would probably require actually reading the journal. The press release addresses an important point

However, capitalizing on this potential climate-change mitigation measure is not a simple task. The issue is complicated by the fact that industrial farming techniques mean agriculture is actually depleting carbon from soil, thus reducing its capacity to act as a carbon sink.

but answers this by saying

According to Hogg and Favoino, this loss of carbon sink capacity is not permanent. Composting can contribute in a positive way to the twin objectives of restoring soil quality and sequestering carbon in soils. Applications of organic matter (in the form of organic fertilizers) can lead either to a build-up of soil organic carbon over time, or a reduction in the rate at which organic matter is depleted from soils. In either case, the overall quantity of organic matter in soils will be higher than using no organic fertilizer.

Let us hope it's that simple.

Draft corn genome

2008-02-26T00:10:00.003-06:00

A team of scientists led by Washington University in St. Louis has begun to unlock the genetic secrets of corn, a crop vital to U.S. agriculture. The researchers have completed a working draft of the corn genome, an accomplishment that should accelerate efforts to develop better crop varieties to meet society's growing demands for food, livestock feed and fuel....
The genetic blueprint will be announced on Thursday, Feb. 28, by the project's leader, Richard K. Wilson, Ph.D., director of Washington University's Genome Sequencing Center, at the 50th Annual Maize Genetics Conference in Washington, D.C.

Source: EurekaAlert!

Related: from Iowa State University News Service: Iowa State researchers help piece together the corn genome's first draft

Also, from PhysOrg.com

Invasive plant journal launched

2008-02-22T00:34:00.000-06:00

The Weed Science Society of America has launched a new journal, Invasive Plant Science and Management. The first issue is expected in the first quarter of 2008. The society is soliciting articles in:

[T]he biology and ecology of invasive plants in rangeland, parkland, prairie, pasture, preserve, urban, wildland, forestry, riparian, wetland, aquatic, recreational, rights-of-way, and other non-crop settings; genetics of invasive plants; social, ecological, and economic impacts of invasive plants; design, efficacy, and integration of control tools; land restoration and rehabilitation; effects of management on soil, air, water, and wildlife; scholarship in education, extension, and outreach methods and resources; technology and product reports; mapping and remote sensing, inventory and monitoring; technology transfer tools; and regulatory issues.

A guardian of grasses

2008-02-07T08:03:00.000-06:00

Anoop Sindhu and colleagues report on a gene that may have played a key role in the evolution of grasses. The gene, Hm1, provides resistance against Cochliobolus carbonumrace 1 (CCR1), a fungus that is capable of attacking and killing corn at any stage of its development (images of CCR1 infection). While CCR1 is only known to affect corn, the gene Hm1 and its relatives are present throughout the grass family, but are absent from other lineages.

CCR1 is only known as a disease in Zea mays, but the Hm1 family of genes throughout the grass family. Sindhu and colleagues silenced the corresponding gene in barley. This resulted in barley that was susceptible to CCR1. The fungus is able to invade susceptible grasses through the production of Helminthosporium carbonum* (HC) toxin. The ability of Hm1 and related genes to resist CCR1 comes from an enzyme known as HC-toxinreductase (HCTR), which detoxifies HCTR.

A phylogenetic analysis of the Hm1-gene family showed that they were monophyletic - they all shared a common ancestor. Since it is present throughout the grass family, but is absent from all other groups of plants, it appears that the gene shares its origin with the grass family. This lead the authors to conclude that:

The maintenance of HCTR gene function in maize and barley, coupledwith the unique phylogenetic position of the Hm1 gene (withno closely related orthologs in eudicots), suggests that Hm1may have played a critical role in the evolution of most ofour cereal crops. Given the devastating potential of CCR1 tokill susceptible corn, it is likely that this fungus or itsancestral form would have threatened the existence of grasses,or at least severely constrained their geographical distribution,had Hm1 not evolved to detoxify HC toxin. Thus, it seems likelythat Hm1 served as a guardian of the grass family, allowingit to survive, thrive, and evolve into crops that feed the world.

*Helminthosporium carbonum is the asexual form of Cochliobolus carbonum. Since fungi are classified on the basis of their sexual structure, fungi whose fruiting bodies are unknown often end up being described as distinct species.

Sindhu, A., Chintamanani, S., Brandt, A.S., Zanis, M., Scofield, S.R., Johal, G.S. (2008). A guardian of grasses: Specific origin and conservation of a unique disease-resistance gene in the grass lineage. Proceeding of the National Academy of Sciences USA, 105(5), 1762-1767. DOI: 10.1073/pnas.0711406105 Open Access

Onions without tears

2008-02-06T23:31:00.000-06:00

Using gene silencing, researchers in New Zealand's Crop and Food research institute were able to make onions that don't make you cry when you cut them.

Source: PhysOrg.com

Eat your carrots - you need the calcium

2008-02-06T22:51:00.000-06:00

Food science tends to focus on improving the nutritional quality of foods, but rarely does it look at how these "improved" foods affect human (or animal) health. A group of researchers from Texas A&M University and Baylor College of Medicine looked at whether enriched calcium in foods was actually used by the body. They had previously engineered carrots which had twice the normal level of calcium. In a paper published in the Proceeding of the National Academy of Sciences USA, they looked at the fate of this calcium in the body. By using labelled calcium they were able to observe its eventual fate. Their conclusion:

In a cross-over study of 15 male and 15 female adults, we found that when people were fed sCAX1 and control carrots, total calcium absorption per 100 g of carrots was 41% ± 2% higher in sCAX1 carrots. Both the mice and human feeding studies demonstrate increased calcium absorption from sCAX1-expressing carrots compared with controls. These results demonstrate an alternative means of fortifying vegetables with bioavailable calcium.

Morris,Jay, Hawthorne,Keli M., Hotze, Tim, Abrams Steven A., and Hirschi*, Kendal D. 2008. Nutritional impact of elevated calcium transport activity in carrots. Proceeding of the National Academy of Sciences USA 105(5):1431-1435 DOI:10.1073/pnas.0709005105

Is it really organic?

2008-02-01T23:54:00.001-06:00

It can be difficult to determine whether something is really organic. How can you tell if a producer is calling food organic that isn't? While most persticides are likely to leave residues that could be tested for, fertilisers are more difficult to detect. One possibility is to look for differences in the ratios of stable isotopes of nitrogen - nitrogen. Spanish scientists Francisco del Amora, Joaquín Navarroa and Pedro Aparicio decided to see if they could tell the difference between organic and conventionally grown crops on the basis of nitrogen isotope ratios. They concluded that it was possible to detect fertiliser use.

Agencies for organic farming certification require techniques to verify the organic nature of the N fertilizers applied to crops. Results show that significant differences have been found between organic and not fully organic practices. Thus, this study demonstrates that with N-isotopic techniques it is possible to discriminate the use of chemical fertilizers in the organic production of sweet peppers with respect to strictly nonorganic crops. Further studies including the effects of different soils characteristics, climate, and biotic or abiotic stress could be useful in determining the proper interval of ¹⁵N/¹⁴N ratio to exclude nonorganic fertilization practices.

del Amora,F.M., Navarroa J., and Aparicio, P.M. 2008. Isotopic Discrimination as a Tool for Organic Farming Certification in Sweet Pepper.

Internationally Important Algal Habitats

2008-01-31T12:49:00.000-06:00

Fifteen locations in Britain have been identified as internationally important based on their algal flora.

Among the 15 locations listed is a freshwater area in Cornwall near St. Just that has 100 species of algae, two of which are classified as rare. Another important area is a coastal site at Lundy Island off Devon with 300 species of algae.

Source: PhysOrg.com

Immune systems in plants

2008-01-31T12:41:00.000-06:00

In a review article due to be published in the journal Developmental & Comparative Immunology John M. McDowell and Stacey A. Simona looked at "plant-pathogen interface" and found notable similarities and differences between the molecular immune responses of plants and (metazoan) animals. They concluded that

It now seems clear that plants and animals have independently adopted many of the same protein modules for immune surveillance. Many interesting mechanistic and evolutionary parallels are evident upon comparison of immune surveillance in plants and animals, and we look forward to productive, “cross-species” dialog between animal and plant immunologists in the years to come.

McDowell, J.M. and Simona, S.A. 2008. Molecular diversity at the plant–pathogen interface. Developmental & Comparative Immunology doi:10.1016/j.dci.2007.11.005

Insecticidal compounds in plants

2008-01-30T14:24:00.000-06:00

Several members of three plants families - the Rubiaceae, Violaceae and Cucurbitaceae- produce cyclotides, cyclic mini-peptides made up of 28-37 amino acids arranged in a circular configuration. These compounds are very stable and have attracted the attention of pharmaceutical companies. Because these peptides lack free amino and carboxyl ends, they cannot be broken down by proteases. The compounds appear to act primarily as insecticides. In an article published in the January 29 issue of PNAS, Barbara Barbeta and colleagues investigated the role of these compounds on the larvae of lepidopterans (butterflies and moths). The compounds damaged the cells of the midgut of Helicoverpa armigera larvae, which severely stunted their growth (image from Wikipedia; see license details).

Barbeta, B.L., Marshall, A.T., Gillon, A.D., Craik, D.J., and Anderson, M.A. 2008. Plant cyclotides disrupt epithelial cells in the midgut of lepidopteran larvae. Proceedings of the National Academy of Sciences USA 105(4):1221-1225 DOI:10.1073/pnas.0710338104

Tropical Plant Biology journal launched

2008-01-30T12:52:00.000-06:00

Springer is launching a new journal Tropical Plant Biology. This first issue is due in March 2008. According to the press release, the journal will:

[R]eport on significant advances in all aspects of tropical plant biology as well as applications towards genetic diversity and crop improvement."

Tropical Plant Biology will cover the most rapidly advancing aspects of tropical plant biology including physiology, evolution, development, cellular and molecular biology, cytology, genetics, genomics, comparative genomics, genomic ecology and molecular breeding. It will publish articles of original research as well as review articles. Occasional special issues focused on a single tropical crop species or breakthrough will also be published. The information in this journal will guide efforts to increase the productivity and quality of tropical plants and preserve the world’s plant diversity.

The journal will be edited by Paul H. Moore of the International Consortium for Sugarcane Biotechnology and and Ray Ming of the Department of Plant Biology, University of Illinois at Urbana-Champaign, both of whom focus on tropical crops.

Plastid evolution

2008-01-29T23:48:00.001-06:00

A forthcoming paper in the Annual Review of Plant Biology looks really interesting: Plastid Evolution. Written by Sven Gould, Ross Waller and Geoffrey McFadden of the University of Melbourne, it looks really promising. From the abstract:

We review the origins, integration, and functions of the different plastid types with special emphasis on their biochemical abilities, transfer of genes to the host, and the back supply of proteins to the endosymbiont.

Gould, S.B., Waller, R.F. and McFadden, G.I. 2008. Plastid Evolution. Annual Review of Plant Biology 59

Interactions between Bt crops and mycorrhizal fungi

2008-01-29T17:49:00.001-06:00

In the February issue of Acta Agriculturae Scandinavica, Section B - Soil & Plant Science Liu Wenke and Du Lianfeng raise the question of whether Bt transgenic crops pose a threat to soil microorganisms, especially arbuscular mycorrhizal fungi. From the paper's abstract

Bt transgenic crops may affect AMF in many ways during their life with regard to the temporal-spatial relevance between the occurrence of Bt proteins and fungal symbiotic development of AMF. This may lead to an unwelcome surprise with regard to specific abundance and diversity of AMF when Bt transgenic crops are planted continuously. It is concluded that interactions between AMF and Bt transgenic crops at individual and community level are a new urgent soil ecological issue. Some evidence about Bt transgenic crop effects on AMF revealed by recent articles are summarized, and research prospects are highlighted in the paper.

Wenke, Liu and Du Lianfeng. 2008. Interactions between Bt transgenic crops and arbuscular mycorrhizal fungi: a new urgent issue of soil ecology in agroecosystems. Acta Agriculturae Scandinavica, Section B - Soil & Plant Science 58 (2) 187 - 192 DOI:10.1080/09064710701478339

Ecological Dimensions of Biofuels Conference

2008-01-29T14:10:00.000-06:00

The Ecological Society of America is sponsoring a conference on the Ecological Dimensions of Biofuels in Washington DC on March 10. Registration for the conference closes February 21. The conference website frames the issue:

Production of fuels from plants and agricultural and forestry wastes can reduce both society’s dependence on fossil fuels and net emissions of atmospheric carbon dioxide, the major contributor to global warming. Expanded use of this bioenergy requires assuring that its production and consumption are truly sustainable. This conference will explore the ecological dimensions of biofuels production and will identify management strategies and research opportunities to ensure their sustainability.

Some of the best writing on this issue can be found at Mike Palmer’s blog Low-Impact, High-Diversity Biofuels. Mike Palmer is an ecology professor at Oklahoma State University.

Predicting plant invasions

2008-01-29T14:07:00.000-06:00

In trying to identify potential invaders, most people tend to look for classic weeds. Species which mature quickly and produce large quantities of readily dispersed seed seem to be ideal candidates for invasion. However, actual studies of invasive species have shown them to be highly idiosyncratic - a non-native species that is invasive in one context may be benign in another context. In a paper published in the January issue of the Journal of Ecology, Angela Moles, Monica Gruber and Stephen Bonser have proposed a new framework for trying to identify potentially invasive plant species. [more]

Pitcher plant gives up its secret

2008-01-29T13:56:00.000-06:00

Pitcher plants use digestive enzymes to break down insects and use them as a nitrogen source. In a paper published in the Journal of Proteome Research, Naoya Hatano and Tatsuro Hamada used proteomic analysis to identify the full suite of enzymes that are present in pitcher fluid of Nepenthes alata. In addition to enzymes which break down proteins (which had been previously isolated) they found several proteins believed to inhibit bacterial growth.

Source: PhysOrg.com

Algae for food, fertiliser and fuel

2008-01-29T13:48:00.000-06:00

A profile of the Laboratory for Algae Research & Biotechnology (LARB) at Arizona State University’s Polytechnic Campus talks about the potential for algae for use as food, fertiliser and biofuel. Algae is being seen as a potential biofuel that does not compete with food for agricultural land. It can also be grown using agricultural wastes as a nitrogen source.

It sounds like a really interesting idea. Hopefully it won't be a cure that's worse than the disease...

Source: PhysOrg.com

Biocontrol for Australian invasive?

2008-01-29T13:41:00.000-06:00

Boneseed (Chrysanthemoides monilifera subsp. monilifera), one of Australia's "20 Weeds of National Significance" is the target of a biocontrol study using a rust fungus, Endophyllum osteospermi, that attacks it in its native range in southern Africa. The study is a collaboration between CSIRO in Australia and the Plant Protection Research Institute in Stellenbosch, South Africa.

Source: PhysOrg.com

Plant fungus affects sex ratios in parasitic wasp

2008-01-26T00:01:00.000-06:00

From PhysOrg.com

The study, recently published in the Proceedings of the Royal Society B, focused on the fungus (Podosphaera plantaginis), the plant (Plantago lanceolata), the checkerspot caterpillar (Melitaea cinxia) and the parasitoid wasp (Cotesia melitaearum) that share habitat in Åland, Finland.

The fungal endophyte alters leaf chemistry in the host plant. This slows the growth rate in Melitaea cinxia caterpillars that feed of the plant. The parasitoid wasp lays its eggs on the caterpillar; like other parasitoids, the wasp larvae gradually consume the still-living host. When the female wasp lays her eggs on caterpillars feeding on Podosphaera plantaginis plants, she ends up producing twice as many female as male offspring. A skewed sex ratio improves the success of these wasps in the fragmented habitat in which they live.

Preserving Salem College's Herbarium

2008-01-20T00:22:00.000-06:00

When Jennifer Cruse Sanders took over Salem College's Herbarium in 2005 it had been closed since 1980. In that time it collections - some dating back to the 1820s - had suffered from neglect and tobacco beetle attack. Now, with Cruse Sanders moving to a job at the Atlanta Botanical Gardens, and her student assistant, Kristian Jones graduating, there is concern about the future of the collection.

[David Bare, Winston-Salem Journal]

A remarkable new palm from Madagascar

2008-01-17T13:44:00.000-06:00

As a result of its long isolation, Madagascar has unique biota. Although it is best known for its lemurs, Madagascar’s palm flora is both diverse and distinctive. In 1995 Dransfield and Beentje recognised 170 species of palms from Madagascar, 164 of which were found only in Madagascar. Since then another 7 species have been described, with another 20 apparently awaiting description. Most of these new species have been found in the eastern wet areas. The western part of the island is drier, and has a much less diverse palm flora. However, an entirely new genus has been discovered in the western dry region - one that is so large and distinctive that the BBC reports it can be seen in satellite images. A description of this new species, Tahina spectabilis was published in the January issue of the Botanical Journal of the Linnean Society.

Tahina, which means “blessed” or “to be protected” in Malagasy (and is also the name of the daughter of the Metz family, Anne-Tahina), is a remarkable tree. It is one of the largest palms in Madagascar, growing 10 m tall (20 m according to the BBC article) with stem diameter of 50 cm. It is also hapaxanthic - it reproduces just once in its lifetime and them dies. As a result of this, it puts all of its resources into flowering, producing a 4-m tall inflorescence. (You can see an image of it here.) [more...]

Baylor honours Steve Davis

2008-01-17T13:37:00.000-06:00

Pepperdine plant ecologist Steve Davis received Baylor University's Robert Foster Cherry Award for Great Teaching. The $200,000 Cherry Award is the only national teaching award presented by a college or university. Having seen Davis speak, I can attest that he's an engaging speaker who really manages to convey ideas well. Although it was several years ago, I remember his talk (on chaparral fire ecology) vividly.

Mooney and Raven honoured

2008-01-17T13:30:00.000-06:00

The Mexican Fundación BBVA Award for Scientific Research in Ecology and Conservation Biology went to Peter Raven (Missouri Botanical Garden) and Harold Mooney (Stanford), two on the most eminent plant biologists. Raven is systematist, while Mooney is known for his work in ecophysiology and global change biology.

Effects of access trails in long-term research plots

2008-01-14T09:18:00.000-06:00

In a forthcoming paper in the journal Biotropica,¹ Liza Comita and Gregory Goldsmith “sought to quantify the significance and spatial extent of research trail impacts on the structure and dynamics of the seedling layer in the 50-ha permanent forest dynamics plot on Barro Colorado Island (BCI), Panama”. This site is very heavily used:

The number of people working within the 50-ha plot on any given work day ranges from six to 12, with up to 20 people present in the plot during the main census of trees, which occurs every 5 yr.

While seedling densities were (unsurprisingly) significantly lower on trails, they were significantly higher within 5 m of the trails. Seedling recruitment showed a similar trend, but the differences were not statistically significant. Between 5 and 20 m from the trails seedling densities were lower than the average for the plot, and recruitment was significantly lower. [more]

Using OpenID for comments

2007-12-04T08:31:00.000-06:00

I added the option of using OpenIDs to comment on this blog, per phydeaux3's blog post. So it should now be possible to leave comments using AOL/AIM, LiveJournal, TypeKey, WordPress or other OpenID logins.

Phydeaux3 also has instructions on how to alter the settings on to allow this on Blogger.

This week

2007-11-16T11:05:00.000-06:00

This week in Science

Hurricane Katrina's Carbon Footprint on U.S. Gulf Coast Forests - Jeffrey Q. Chambers et al. found that "[s]patially explicit forest disturbance maps coupledwith extrapolation models predicted mortality and severe structuraldamage to ~320 million large trees totaling 105 teragrams ofcarbon, representing 50 to 140% of the net annual U.S. foresttree carbon sink"

This week in Proceedings of the National Academy of Sciences USA

A protein key to plant virus transmission at the tip of the insect vector stylet - Marilyne Uzest et al. "report evidence for the existence,precise location, and chemical nature of the first receptorfor a noncirculative virus, cauliflower mosaic virus, in itsinsect vector".
Impacts of plant diversity on biomass production increase through time because of species complementarity - Bradley J. Cardinale et al. found that polycultures outperformed monocultures 79% of the time, but that "only 12%of all experiments do diverse polycultures achieve greater biomassthan their single most productive species". While "a positivenet effect of diversity that is no greater than the most productivespecies has been interpreted as evidence for selection effects... [they] show thatalthough productive species do indeed contribute to diversityeffects, these contributions are equaled or exceeded by speciescomplementarity".
Conifer ovulate cones accumulate pollen principally by simple impaction - James E. Cresswell et al. reports that "ovulate cones [in many pine species] structurallyresemble a turbine, which has been widely interpreted as anadaptation for improving pollination by producing complex aerodynamiceffects...[but they] found noevidence that turbine-like aerodynamics made a significant contributionto pollen accumulation, which instead occurred primarily bysimple impaction."
ATM regulates the length of individual telomere tracts in Arabidopsis - Laurent Vespa et al.
Different mechanisms for phytoalexin induction by pathogen and wound signals in Medicago truncatula - Marina Naoumkina et al.
Temporal and spatial activation of caspase-like enzymes induced by self-incompatibility in Papaver pollen - Maurice Bosch and Vernonica E. Franklin-Tong
Tyrosine-sulfated glycopeptide involved in cellular proliferation and expansion in Arabidopsis - Yukari Amano et al.
Identification of acyltransferases required for cutin biosynthesis and production of cutin with suberin-like monomers - Yonghua Li et al. report on the discovery of two enzymes essential for cutin biosynthesis in Arabidopsis.

What's new

2007-11-08T14:54:00.001-06:00

Since I called this blog Plant News, I am going to try something new - posting links to new papers related to plant biology in major journals (Science, Nature, etc.) This first posting will focus in part on last weeks articles.

This week in Nature:

Stability of organic carbon in deep soil layers controlled by fresh carbon supply - Sébastien Fontaine et al. found that "in the absence of fresh organic carbon, an essential source of energy for soil microbes, the stability of organic carbon in deep soil layers is maintained".

Last week in Science:

A High-Resolution Root Spatiotemporal Map Reveals Dominant Expression Patterns - Siobhan M. Brady et al. present "microarray expressionprofiles of a high-resolution set of developmental time pointswithin a single Arabidopsis root and a comprehensive map ofnearly all root cell types"

Current issue of PLOS Biology

A Novel Snf2 Protein Maintains trans-Generational Regulatory States Established by Paramutation in Maize - Christopher J. Hale et al.

Water repulsion off montane forest leaves

2007-10-29T09:37:00.001-05:00

A study published in the November issue of the journal Biotropica looks at the ability of trees in tropical montane forests to repel water from their leaves. Holder hypothesised that trees in montane forests should be better at repelling water than trees from drier environments - dry forests in Guatemala and a semiarid grassland-foothills ecotone in Colorado. However, he found montane forest trees were less able to repel water than dry forest or temperate grassland-foothill species. Holder suggested that the increased wettability of the montane forest species may be driven by their coating of epiphylls (plant and other organisms growing on the leaf surface), while increased ability to shed water may be selected for in dry environments because it may help channel water to the roots of the plants in arid environments.

Holder, Curtis D. 2007. Leaf Water Repellency as an Adaptation to Tropical Montane Cloud Forest Environments. Biotropica 39 (6), 767-770. doi:10.1111/j.1744-7429.2007.00303.x

[Read the rest of my post Like water off the back of a duck]

Poor showing for fall colours

2007-10-22T22:18:00.000-05:00

Warmer weather has been blamed for less than impressive Fall foliage in New England. According to Dave Gram, writing in the Buffalo News:

Forested hillsides usually riotous with reds, oranges and yellows have shown their colors only grudgingly in recent years, with many trees going straight from the dull green of late summer to the rust-brown of late fall with barely a stop at a brighter hue.
"It's nothing like it used to be," said University of Vermont plant biologist Tom Vogelmann, a Vermont native.
He says autumn has become too warm to elicit New England's richest colors.

While I'm no expert on this, the idea seems intuitively appealing. Brilliant Fall colours are a feature of the Great Lakes region - down here, leave tend to go from green to brown, often with only the slightest nod to yellows and reds. Unfortunately, "intuitively appealing" arguments can be misleading - after all, many people are attracted to creationism for just that reason.

It shouldn't be too difficult to answer the question of whether there is a correlation between Fall colours and climate change. The more interesting question is why there is such a correlation, why might drive such a change. The Gram article attempts to address this:

Warming climate affects trees in several ways.
Colors emerge on leaves in the fall, when the green chlorophyll that has dominated all spring and summer breaks down.
The process begins when shorter days signal leaves to form a layer at the base of their stems that cuts off the flow of water and nutrients. But in order to hasten the decline of chlorophyll, cold nights are needed.
In addition, warmer autumns and winters have been friendly to fungi that attack some trees, particularly the red and sugar maples that provide the most dazzling colors.
"The leaves fall off without ever becoming orange or yellow or red. They just go from green to brown," said Barry Rock, a forestry professor at the University of New Hampshire.

So where do the pigments come from? Why do the plants produce these pigments? While I didn't know the answer to that question, it didn't cross my mind that this was in any way a mystery. Turns out that it is a mystery. There are several hypotheses, including

to attract fruit-dispersing birds (this only works for species with bird-disperse fruit and is, at best, an incomplete explanation; Hoch et al. 2001)
anti-herbivore or anti-microbial defenses
protection against drought or freezing tolerance
protection against photoinhibition that might otherwise interfere with the recovery of nutrients from leaves (Holopainen and Peltonen 2002)
as a means of signaling to aphids that a tree has invested heavily in chemical defenses (Hamilton and Brown 2001)

If Fall pigments play a protective role, it's reasonable to suggest that a shortened period of leaf senescence (triggered by a warmer Fall) might lead to reduced production of these compounds. It is, as I said before, an interesting story. Sadly, it seems like it's still just that - a story.
------------

Hoch, W. A., Zeldin, E. L. and Mccown, B. H.. 2001. Physiological significance of anthocyanins during autumnal leaf senescence. –Tree Physiol. 21: 1–8.
Holopainen, J. K. and Peltonen, P. 2002. Bright autumn colours of deciduous trees attract aphids: nutrient retranslocation hypothesis.Oikos 99 (1), 184–188.
Hamilton, W. D. and Brown, S. P. 2001. Autumns tree colours as a handicap signal. –Proc. R. Soc. Lond. B Biol. Sci. 268: 1489–1493.

Human impacts on pre-Columbian tropical forests

2007-10-19T07:43:00.000-05:00

When European naturalists first visited the New World Tropics they saw vast forests that seemed untouched by humans. While indigenous people often lived in these forests, their populations were small. This led to a perception of tropical forests as primeval, “virgin” forests. In the last few decades, this perception has changed - large areas now covered by mature forests have a history of cultivation. In many cases, “primeval” forests are less than 500 years old.

La Selva biological station in Costa Rica is one of the premier research stations for Neotropical biology. Prior to archaeological study of the site, much of it was assumed to be free of human influence. However, the discovery of pre-Columbian artefacts led to the discovery that the site had been occupied at least 3000 years ago. Charcoal was more abundant in alluvial terraces (flatter areas with deeper, more fertile soil) and less abundant in the less fertile upland soils. A chronology, established by Sol (2000)*, divided the La Selva into four archaeological phases: La Cabaña 1000 – 1550 CE; La Selva 500 – 1000 CE; El Bosque 300 BCE– 500 CE; La Montaña 1500 –300 BCE.

To better understand the history of the site, Lisa Kennedy of Virginia Tech and Sally Horn of the University of Tennessee, Knoxville, undertook a study of sediment cores extracted from the Cantarra swamp*, a 0.5 ha wetland dominated by perennial herbs. They used pollen, charcoal and macrofossils to reconstruct the environmental history of the site. Wetlands are frequently used to reconstruct vegetation histories. As sediments accumulate in bodies of water, plant pollen, fern spores and charcoal fragments are trapped. Pollen coats are extremely tough, and decay takes place very slowly in waterlogged soils. If the vegetation surrounding the site changes, different types of pollen will be deposited into the site. Someone with the patience to sort through these cores can observe thousands of years of history in a few metres of sediment.

[Read the rest of the post]

Sol, C., R. F. 2000. Asentamientos prehispánicos en la Reserva Biológica La Selva, Sarapiquí, Costa Rica: Sistemas de explotación de recursos naturales en un bosque tropical lluvioso. Licenciatura thesis, School of Anthropology and Sociology, University of Costa Rica.
Lisa M. Kennedy, Sally P. Horn. A Late Holocene Pollen and Charcoal Record from La Selva Biological Station, Costa Rica. Biotropica (OnlineEarly Articles). doi:10.1111/j.1744-7429.2007.00334.x

Indian fruit genebank threatened

2007-10-09T07:15:00.000-05:00

Jeremy at Agricultural Biodiversity Weblog reports that the government of Jharkand State in India plans to bulldoze the field genebanks of the Horticulture and Agro Forestry Research Programme in order to build housing for Members of Parliament and Members of the Legislative Assembly.

According to a story in the The Indian Express, the plan will take 288 acres of HARP's land, including 88 acres of Farm 2, and will destroy

5253 plants of different varieties of mango and litchi, 6,500 trees more than 30 years old, eight greenhouse nurseries, each with 4000-5000 plants of guava and jackfruit and a gene bank developed over 20 years to have a germplasm base of 239 varieties of mango and litchi.

As the story goes on to say, this goes beyond destroying decades of work - destruction of a gene bank will also hurt regional farmers

Not just that. “The gene bank of these valuable fruit-bearing tress will be destroyed for ever. It will seriously affect horticulture prospects of the farmers in this belt,” says HARP’s Principal Scientist Shivendra Kumar.

Not only is this a political decision, it's a decision being made by the state legislature to benefit state legislators. So it isn't too surprising that they are unmoved by external forces.

This also flies in the face of a letter from Union Agriculture Minister Sharad Pawar earlier this year asking Chief Minister Madhu Koda to shelve the plan and instead issue mutation certificate of this land whose title was transferred to the ICAR by the Ranchi Deputy Commissioner in 1976. In 1979, HARP was set up with 100 percent funding by the Union government.

Fighting to save Greene Prairie

2007-10-03T22:26:00.000-05:00

The University of Wisconsin-Madison's Arboretum is famous for its restored prairies. The most famous is the Curtis Prairie, established in the 1930s and 40s. Less well known is the 50-acre Greene Prairie, which was restored almost single-handed by Henry Greene in the 1940s and 50s.

Greene Prairie is currently under threat from Reed Canary Grass (Phalaris arundinacea) a perennial grass native to Eurasia. In North America it is invasive in wet sites; the Wisconsin DNR estimates that it dominates 10% of the state's wetlands. The Greene Prairie initially lacked permanently flooded areas, but runoff from suburban have altered the site. Reed Canary Grass currently dominates 10 acres of the 50-acre site. (Reed Canary Grass at Greene Prairie from: Zedler, J.B. and J. Wilcox. 2005. Interconnected Restoration Challenges: Controlling invasives and reestablishing natives, Arboretum Leaflet 1).

So far, restoration efforts have had limited success. University of Wisconsin-Madison News reports on new efforts to incorporate students in the restoration project.

In the new plan, Arboretum staff will burn the experimental site and apply sethoxydim in the spring. Then, each fall, the ecology students will sow native seeds, survey plant diversity and abundance, and otherwise monitor the project's progress. In keeping with its experimental nature, researchers will review the data carefully each year and make adjustments to the approach as needed.

The team hopes not only to keep reed canary grass from spreading further, but also to push it back eventually toward the south. No matter what the final outcome, however, Herrick has no doubts about the benefits.

"At a time when resources are stretched, we could never, as Arboretum staff, pull off this experiment on our own. So, incorporating the students is a perfect way to do this," he says. "It's an education for them - first and foremost. But we also get to advance restoration ecology research and answer land care questions. It's a win, win, win, all the way around."

Serendipity and the origin of crops

2007-09-28T13:22:00.000-05:00

In Puerto Rican dry forest, one of the most striking dichotomies is between forests dominated by native species and forests dominated by exotic Leucaena leucocephala. Most forests that have regrown on abandoned agricultural land are dominated by Leucaena. The colonisation of these areas by native tree species is slow - either the native species are poor colonisers, or Leucaena resists invasion. Its importance on the landscape and apparent stability made me fascinated with the species.

One of the things which struck me early on was the fact that many published sources listed Leucaena as a native species in Puerto Rico. To me, its behaviour shouted “exotic”, but when I spoke to Liogier at the University of Puerto Rico herbarium (author of the Flora of Puerto Rico) he said that it was probably introduced, but there were no records to say anything conclusive, one way or the other. So I was very happy when I came across Colin Hughes’ Monograph of Leucaena. Based on the diversity of hyperparasitoids Hughes concluded that Leucaena leucocephala was native to Central Mexico. He concluded that the abundant populations in the Yucatan (which often formed pure stands in disturbed areas) were, in fact, introduced. And that was the last I had heard on the subject for almost a decade.

When a post entitled “How domestication happens” popped up on my RSS reader, I was curious. The post was minimal, and I almost didn’t click through to the link. When I did so I was rewarded with a post entitled “Biodiversity, trash heaps and the evolutionary origin of crops” and a picture I recognised instantly as Leucaena leucocephala. The post described a paper published in the Proceedings of the National Academy of Sciences entitled: “Serendipitous backyard hybridization and the origin of crops“.

According to Hughes and coauthors, Leucaena leucocephala is one of several domestic species in central Mexico which are believed to have originated through the hybridisation of related species that were brought together in backyard dumps.

Seeds of 13 species of Leucaena are used for food across S-C Mexico…. Food
use is widespread and intensive in Chiapas, Oaxaca, Puebla, Guerrero, and Morelos and more sporadic further north, but unknown further south despite the availability of native species of Leucaena. Present-day food use varies from gathering of pods from local free-living populations for home consumption to intensive harvesting of commercial quantities from cultivated trees and transportation of seeds to regional markets…. This spectrum of increasing human intervention involves transitions from wild to managed to cultivated, from home consumption to local to wider regional marketing, and from very
local to regional to much wider translocation of species.

[This whole thing forced me to reevaluate Leucaena. While I have always thought of it as “useful” for revegetation and perhaps for animal fodder or green manure, the idea of growing it as a food crop for its pods is alien to me. Even the green pods don’t strike me as “food”.]

In Mexico, there is a continuum of use, from Leucaena cuspidata, which is collected from wild populations and used locally, through L. confertiflora and L. collinsii, which are more widely cultivated and tranlocated, to L. eculenta, L. pallida and L. leucocephala which are intensively cultivated. The pods of these latter species are commercial crops which are distributed to markets several hundred kilometres away.

Five of the 13 species are polyploids, and the authors concluded that they are likely to be allopolyploids (polyploids which originated through the bybridisation of two species) whose origins can be traced to backyard gardens and dumps. The underlying idea is that human activity can bring together species which would not normally encounter one-another in the wild. In the case of Leucaena leucocephala and L. pallida the hybrid origin theory is strengthened by the lack of wild populations of the species.

They go on to point out that this hypothesis is not only plausible for Leucaena, but also for the other two major perennial crops in south-central Mexico, Agave and Opuntia, which show similar trends, but are less thoroughly studied than Leucaena species.

Hughes, Colin E. (1998). Monograph of Leucaena (Leguminosae-Mimosoideae), Systematic Botany Monographs 55:1-244
Hughes, C.E., R. Govindarajulu, A. Robertson, D.L. Filer, S.A. Harris, and C.D. Bailey. 2007. Serendipitous backyard hybridization and the origin of crops. Proceedings of the National Academy of Sciences USA 104:14389-14394.

Wolves bring aspen back to Yellowstone

2007-07-26T23:32:00.000-05:00

Aspen (Populus tremuloides) was a major species in Yellowstone, but over the twentieth century populations declined and there was little regeneration. While elk were initially blamed for this lack of regeneration, changing policies by the Park Service led to a change in this policy:

Until 1968, Park Service officials contended that an unnaturally large elk population, which had built up in Yellowstone during the late 1800s and early 1900s, had severely damaged the park’s northern winter range, including aspen (Populus tremuloides) communities. However, agency biologists now hypothesize that elk and other ungulates in Yellowstone are “naturally regulated,” being resource (food) limited, and that the condition of the ecosystem today is much like it was at park formation (Houston 1982; Despain et al. 1986). Elk influences on Yellowstone’s vegetation are now thought to be “natural” and to represent the “pristine” condition of the park.
According to the Park Service, Yellowstone is not now nor has it ever been
overgrazed, and all previous studies to that effect are wrong (Houston 1982).

[Kay, Charles E. 2001. Long-Term Aspen Exclosures in the Yellowstone Ecosystem. USDA Forest Service Proceedings RMRS-P-18.]

This conclusion was challenged by available evidence. For example, Kay showed the change in herbivore exclosures between 1946, 1963 and 1987 (images from Kay, 2001). The aspen clone is bisected by the exclosure's fence. While the two portions of the clone seem fairly similar in 1963, by 1987 the portion of the clone that was protected from herbivores has spread considerably.

William Ripple and Eric Larsen found* that the aspens had stopped regenerating in 1920, about the same time that wolves were eliminated from Yellowstone. However, there were questions on the role that wolves might play in regulating the elk population.

To this end, Ripple and Robert Beschta** looked at the level of browsing and the height of aspen saplings in areas with and without logs (which can provide cover for wolves). In both upland and riparian sites, aspen saplings were taller when downed logs were present.

The reintroduction of wolves has allowed allowed aspen to return to riparian areas (although not, so far, in upland areas). Willows and cottonwoods also returned - more quickly than the aspen, which are a preferred browse for elk. While populations reductions have played a role, so has the 'ecology of fear'.

*Ripple,W.J., Larsen, E.J., 2000. Historic aspen recruitment, elk, and wolves in northern Yellowstone National Park, USA. Biological Conservation 95, 361–370.
**Ripple, W.J., Beschta, R.L., Restoring Yellowstone’s aspen with wolves, Biological Conservation (2007), doi:10.1016/j.biocon.2007.05.006

Story at Science Daily.

Can organic agriculture sustain current levels of food production?

2007-07-19T10:16:00.000-05:00

A recent report by Ivette Perfecto, Catherine Badgley and others at the University of Michigan suggests the organic agriculture is capable of sustaining or increasing current levels of food production globally.

Organic farming can yield up to three times as much food as conventional farming on the same amount of land—according to new findings which refute the long-standing assumption that organic farming methods cannot produce enough food to feed the global population.

According to the press release, the authors found that organic agriculture, which they define as "practices referred to as sustainable or ecological; that utilize non-synthetic nutrient cycling processes; that exclude or rarely use synthetic pesticides; and sustain or regenerate the soil quality", can maintain current levels of production in developed countries, and as much as triple production in developing countries.

The original article was published in Renewable Agriculture and Food Systems. There's a more detailed review at New Scientist and a two-part story(part 1, part 2) at OrganicAuthority.com.

H/T Meteor Blades at dKos.

Open access in botany journal

2007-06-21T22:57:00.000-05:00

The Journal of Experimental Botany has provided open access to papers if the authors' institutions subscribe to the journal. Other authors who want their papers to be freely accessible will have to pay the full cost of publication which is estimated at £1500/$2800/€2250.

Over the last three years the journal has conducted an experiment in which they made about 30% of their papers freely available. They have found that these papers are more widely cited:

Early indications show that OA publication increases impact as full text downloads are, on average, 17% higher and citations 14% higher than for those publications kept under subscription control.

H/T Chronicle of Higher Education News Blog.

Ceiba pentandra: dispersal, vicariance and press releases

2007-06-18T09:13:00.000-05:00

Ceiba pentandra (the silkcotton, kapok or ceiba tree) has a broad distribution including across the Neotropics and Africa. A cultivated form is grown across a wider range for kapok fibres. The trans-Atlantic distribution of C. pentandra has attracted attention for a long time - based on the fact that there are nine species in the Neotropics and only one in Africa, it has generally been assumed that it is a Neotropical species that dispersed to Africa. How it got there has long been a question.

EurekaAlert! published a press release attributed to the National Science Foundation about a paper published in Molecular Ecology concerning the trans-Altantic distribution of Ceiba pentandra, the silk cotton or kapok tree. The paper* considers three mechanisms by which the species could have come to be present on both sides of the Atlantic: Gondwana vicariance, Boreotropical dispersal (and subsequent vicariance) and long-distance dispersal.

In the case on Gondwana vicariance, the distribution would reflect the fact that South America and Africa were connected (as parts of Gondwana) until 96 million years ago. In the case of Boreotropical dispersal, the species would have colonised Africa about 35 million years ago through a then warmer North America and Europe, only to be lost from those areas as the climate warmed. Both of these would be expected to produce deep divergence between African and South American C. pentandra populations. On the other hand, if long-distance dispersal across the Atlantic took place more recently, the divergence would be smaller.

The paper found evidence for recent dispersal. The authors noted that:

Ceiba pentandra has the weakest phylogeographical structure yet reported for a widespread rainforest tree species. Apart from the cluster of sites in Western Ecuador having a variant psbB-psbF haplotype, there was no cpDNA variation across Mesoamerica, the Amazon basin, and West Africa. In fact, this study found less cpDNA variation across three continents than some rainforest tree species exhibit within putative breeding populations in French Guiana and Brazil (Hamilton 1999b; Dutech et al. 2000; Latouche-Halle et al. 2003) or among sample sites at regional scales in French Guiana and across Mesoamerica (Caron et al. 2000; Cavers et al. 2003).

In this regard, C. pentandra is by no means unique - several other species have been found that have recently crossed the Atlantic, including Symphonia globulifera, which apparently colonised the Americas from Africa.

One thing that bothers me is the press release. It opens with

Celebrated in Buddhist temples and cultivated for its wood and cottony fibers, the kapok tree now is upsetting an idea that biologists have clung to for decades: the notion that African and South American rainforests are similar because the continents were connected 96 million years ago.

It’s obvious that whoever wrote the press release didn’t spend much time looking at the paper. While the issue of Gondwanan roots is considered, it’s by no means a new idea. At the same time, it’s a fairly limited suite of trees that are shared between the two areas, and evidence of recent trans-Atlantic dispersal by a few species does not “[upset] an idea that biologists have clung to for decades”. That’s nonsense.

* Christopher W. Dick, Eldredge Bermingham, Maristerra R. Lemes and Rogerio Gribel. Extreme long-distance dispersal of the lowland tropical rainforest tree Ceiba pentandra L. (Malvaceae) in Africa and the Neotropics. Molecular Ecology (OnlineEarly Articles). doi:10.1111/j.1365-294X.2007.03341.x

H/T Agricultural Biodiversity Weblog.

[Crossposted from my Wordpress blog]

Biofuels

2007-05-19T11:34:00.000-05:00

ScienceDaily has an article today about a new biofuel based on wood chips which can be blended with biodiesel and petroleum diesel. It's based on pyrolysis of wood chips in an oxygen-free environment, and yields charcoal as a waste product. It's supposed to be nearly carbon-neutral (as long as the forests are being replanted), and actually carbon-neutral if the charcoal can be added back to the soil as a fertiliser (presumably since the carbon in charcoal is pretty much out of circulation forever).

Link to the paper is here.

Of course, the thing that pops into my head is the question of how much land is available for growing trees. Will a wood-based biofuel lead to further deforestation - like the Brazilian forests that were cleared to plant Eucalyptus to produce charcoal for an iron smelter? Will it shorten the rotation time on current forest plantations? Will it lead to pressure to convert natural and semi-natural areas to tree monocultures? Will it compete with land for food production? Obviously we can't continue to depend on fossil fuels indefinitely, but alternative fuels seem to raise as many questions as answers.

The impact of farming on biodiversity

2007-01-20T18:03:00.000-06:00

Globally, the demand for food is expected to double by 2050, which could require the conversion of an additional 10 billion hectares of natural ecosystems to cropland. With 37% of the available land already under agriculture, agroecosystems represent an important component of global biodiversity. Since agricultural intensification is usually associated with biodiversity declines, being able to estimate the effects of land use change on biodiversity is an important tool for land management. In the latest issue of Science, Butler et al. were able to use six historical measures of agricultural land use change to successfully explain population changes in 57 bird species over the a forty-year period.

New developments in biofuels

2006-09-08T05:30:00.000-05:00

Syngenta is working on a genetically engineered corn variety which contains amylase, an enzyme required to break starch down into sugars, a necessary step in fermenting corn into ethanol. Monsanto and Pioneer Hi-Bred are looking at ways to develop corn varieties which are better for ethanol production.

Despite this interest, corn is unlikely to meet the fuel needs of the US. Instead of starch, many people are looking to cellulose as a source of feedstock for ethanol production. Ceres and the Noble Foundation are looking at switchgrass in Oklahoma, while Mendel Biotechnology is looking at Miscanthus, a Chinese grass. (Read article)

Plant defense against bacteria

2006-09-08T05:05:00.000-05:00

Usually thought of as unwitting participants in the infection of plants by bacteria, it appears that stomata actually play an active role in fighting bacterial infection. New work by Maeli Melotta and Bill Underwood in the lab of Sheng Yang He at Michigan State University shows that stomata close when bacteria are placed on the leaf surface. However, bacteria which infect plants produce coronatine, a phytotoxin which forces the stomata to open (read press release)

Did pollination evolve before flowers?

2006-09-07T10:23:00.000-05:00

It has generally been assumed that pollination originated with flowering plants. However, a study by Nils Cronberg et al. suggests that the process of having animals act as intermediaries in plant reproduction may have arisen long before flowering plants. Not only do springtails and mites move sperm between antheridia and archaegonia, fertile plants attract five times as many of these microarthropods and do sterile ones. (Read article in Science News, or original paper in Science)

Biologist charged with destroying non-native plants

2006-09-07T08:05:00.000-05:00

Biologist Robert van de Hoek is charged with six misdemeanours for killing non-native plants (a Ficus tree and Myoporum shrubs) in one of the largest coastal wetlands in Southern California

To prosecutors, Robert "Roy" van de Hoek is a vandal with pruning shears. To supporters of native California shrubs and trees, he's a martyr. Once again, he's in court.

"Trimming and landscaping isn't done without authorization from government agencies," said Frank Mateljan of the city attorney's office.

(Read article)

New tallest living thing

2006-09-07T02:41:00.000-05:00

A new contender for the title of "tallest living thing" has been discovered in Redwood National Park near Eureka, California. Standing 378.1 feet (115 m) tall, the Coast Redwood nicknamed Hyperion stands 8 feet (2.4 m) taller than the previous champion, the Stratosphere Giant, in Humboldt Redwoods State Park. (See article)

How to grow plants on Mars

2006-09-06T16:36:00.000-05:00

Plants that could grow on Mars would need to be able to tolerate conditions outside the range experienced by plants on Earth. One source of such genes is extremophiles living in Antarctica and in deep ocean vents. University of North Carolina plant physiologist Wendy Boss and microbiologist Amy Grunden propose that transfering stress-tolerance genes from extremophiles to plants may allow them to grow in Martian conditions (See article).

Barcoding algae

2006-09-06T11:40:00.000-05:00

In a paper in the August issue of the American Journal of Botany, Robba et al. discuss the use of mitochondrial cyctochrome c oxidase subunit 1 (cox1) for barcoding Red alge, which are difficult to indentify solely on the basis of morphology. They found that they were able to discriminate species on this basis, and suggested that it might be a useful tool. (See article)

Miracle tree in Haryana

2006-09-06T07:36:00.000-05:00

While neem is often considered a "miracle tree" for all its useful products, but a neem tree in Jagadhri in Harayana is being seen as miraculous for another reason. The tree is oozing a milk-like substance which people believe will cure them of their ailments. (Read more)

Bt brinjal

2006-09-06T07:30:00.000-05:00

The Indian Genetic Engineering Approval Committee has set up a panel to review health and environmental concerns related to Bt brinjal (otherwise known as eggplant, aubergine or melongene). These crops express genes from the bacterium Bacillus thuringiensis, making them toxic to certain lepidopteran and coleopteran species. (Read more)

Jack Fisher, Botanist

2006-09-06T07:26:00.000-05:00

The St. Petersburg Times has a nice little bio on Jack Fisher of the Fairchild Tropical Botanic Garden. (Read more)

Bringing back extinct plants from herbarium specimens?

2006-09-06T07:17:00.000-05:00

Forgotten inheritance: The 150-year-old herbarium of the University of Namur in Belgium is being catalogued for the first time. Among the discoveries is a specimen of Bromus bromoideus, Brome of the Ardennes, a grass endemic to Belgium which went extinct in the 1930s. The European Native Seed Conservation Network is apparently trying to bring the plant out of extinction using stored seed. The article doesn't make it clear whether they expect to get viable seed from the 1852 specimen. (Read more)

Asian Soybean Rust

2006-09-06T07:09:00.000-05:00

Soybean Rust worries farmers: Despite the title of the article, apparently farmers in Indiana aren't worried about Asian Soybean Rust yet, and it doesn't pose a threat at this point in time. However, there's potential for it to spread north if there is a wet spring and summer in the Gulf states, where Asian Soybean Rust currently exists. (Read more)

Forensic Botany

2006-09-06T07:04:00.000-05:00

A nice little article on Forensic Botany from the Nueces County Record Star.

"Botanical evidence has been used as early as the 1930's but is often not used to its full potential because the area of botany is overlooked by many people," said Galloway. "One of the earliest cases using botanical evidence to solve a crime was the Lindbergh baby kidnapping trial, where a ladder found at the crime scene was traced back to the suspect. One of its rungs was matched with wood found in the suspect's shop. Tool marks found on the wood also corresponded with the suspect's tools."

Corridors and plant species richness

2006-09-06T00:31:00.000-05:00

Corridors Increase Plant Species Richness at Large Scales: The utility of corridors in fragmented landscapes has has been controversial since the 1980s. They became popular elements of landscape management plans, but there is little empirical evidence supporting their utility. A recent study in Science found that:

habitat patches connectedby corridors retain more native plant species than do isolatedpatches, that this difference increases over time, and thatcorridors do not promote invasion by exotic species.

This supports the idea that corridors have conservation value (see Damschen et al.'s paper)

Understanding auxins

2006-09-06T00:18:00.000-05:00

Auxin begins to give up its secrets: While the actions of auxins have been known for over 100 years (Charles and Francis Darwin wrote about its action in 1880), and IAA was identified in the 1930s, it's only within the last few years that researchers are beginning to understand the mechanism of auxin action (read more)

Sea slugs with chloroplasts

2006-09-06T00:00:00.000-05:00

Plant wannabes: Reef-building corals have algal symbionts that help them gain enough energy to build reefs. Certain sea slugs do it too - algal cells or chloroplasts are kept in the digestive glands of the sea slugs, which feed off carbohydrates or lipids produced by photosynthesis. In the latest issue of Science, Elizabeth Pennisi reports on recent recent studies have used molecular techniques to investigate this symbiosis.

Apparently algal cells or chloroplasts can for months in the sea slugs, and one species has acquired algal genes. According to Ingo Burghardt of Ruhr University in Bochum, Germany, the sea slug Phyllodesmium keeps zooxanthellae alive that it gets from the soft corals it eats A slug with algal symbionts can survive 260 days without food. The article also reports on the even more interesting case of Elysia chlorotica which acquires chloroplasts from the alga it feed on as a juvenile. Juveniles which don't acquire chloroplasts don't survive. (see article)

News about plants

2006-09-05T23:54:00.000-05:00

The aim here is to report news related to plant biology.