Greenhouse Effect Research Today is a free monthly online journal that collates and summarizes the latest research about Greenhouse Effect, including details on global warming, greenhouse gases, causes, impact.

Brassinosteroids Regulate Grain Filling in Rice.

Wu CY, Trieu A, Radhakrishnan P, Kwok SF, Harris S, Zhang K, Wang J, Wan J, Zhai H, Takatsuto S, Matsumoto S, Fujioka S, Feldmann KA, Pennell RI

Ceres Inc., Thousand Oaks, California 91320.

Genes controlling hormone levels have been used to increase grain yields in wheat (Triticum aestivum) and rice (Oryza sativa). We created transgenic rice plants expressing maize (Zea mays), rice, or Arabidopsis thaliana genes encoding sterol C-22 hydroxylases that control brassinosteroid (BR) hormone levels using a promoter that is active in only the stems, leaves, and roots. The transgenic plants produced more tillers and more seed than wild-type plants. The seed were heavier as well, especially the seed at the bases of the spikes that fill the least. These phenotypic changes brought about 15 to 44% increases in grain yield per plant relative to wild-type plants in greenhouse and field trials. Expression of the Arabidopsis C-22 hydroxylase in the embryos or endosperms themselves had no apparent effect on seed weight. These results suggested that BRs stimulate the flow of assimilate from the source to the sink. Microarray and photosynthesis analysis of transgenic plants revealed evidence of enhanced CO2 assimilation, enlarged glucose pools in the flag leaves, and increased assimilation of glucose to starch in the seed. These results further suggested that BRs stimulate the flow of assimilate. Plants have not been bred directly for seed filling traits, suggesting that genes that control seed filling could be used to further increase grain yield in crop plants.

Published 18 August 2008 in Plant Cell.
Full-text of this article is available online (may require subscription).

Articles on Greenhouse Effect published 15 August 2008:

Smoke invigoration versus inhibition of clouds over the Amazon.   Science, 321(5891): 946-9.

The effect of anthropogenic aerosols on clouds is one of the most important and least understood aspects of human-induced climate change. Small changes in the amount of cloud coverage can produce a climate forcing equivalent in magnitude and opposite in sign to that caused by anthropogenic greenhouse gases, and changes in cloud height can shift the effect of clouds from cooling to warming. Focusing on the Amazon, we show a smooth transition between two opposing effects of aerosols on clouds: ... [Abstract] [Full-text]

Articles on Greenhouse Effect published 11 August 2008:

Soil fertility increases with plant species diversity in a long-term biodiversity experiment.   Oecologia.

Most explanations for the positive effect of plant species diversity on productivity have focused on the efficiency of resource use, implicitly assuming that resource supply is constant. To test this assumption, we grew seedlings of Echinacea purpurea in soil collected beneath 10-year-old, experimental plant communities containing one, two, four, eight, or 16 native grassland species. The results of this greenhouse bioassay challenge the assumption of constant resource supply; we found that ... [Abstract] [Full-text]

Lichens as Biomonitors of Air Quality around a Diamond Mine, Northwest Territories, Canada.   J Environ Qual, 37(5): 1675-84.

Lichens are known to be bioaccumulators of atmospheric pollutants and are abundant in the Canadian arctic. Mining in this region may negatively impact the tundra communities and these impacts may be detected by increased accumulation of heavy metals, greenhouse gas constituents, and organic compounds in lichen tissue. The effect of sampling direction and distance from a diamond mine on bioaccumulation in three lichen species, Flavocetraria nivalis, Flavocetraria cucullata, and Cladina ... [Abstract] [Full-text]

Articles on Greenhouse Effect published 7 August 2008:

The invasive species Alliaria petiolata (garlic mustard) increases soil nutrient availability in northern hardwood-conifer forests.   Oecologia, 157(3): 459-71.

The invasion of non-native plants can alter the diversity and activity of soil microorganisms and nutrient cycling within forests. We used field studies to analyze the impact of a successful invasive groundcover, Alliaria petiolata, on fungal diversity, soil nutrient availability, and pH in five northeastern US forests. We also used laboratory and greenhouse experiments to test three mechanisms by which A. petiolata may alter soil processes: (1) the release of volatile, cyanogenic glucosides ... [Abstract] [Full-text]

Articles on Greenhouse Effect published 30 July 2008:

Impact of biofumigation with solarization on degradation of pesticides and heavy metal accumulation.   J Environ Sci Health B, 43(6): 513-8.

A greenhouse study was conducted to evaluate the effect of biofumigation (with sheep and chicken manure) combined with solarization on the dissipation of pesticides (pyrifenox, DDT and dieldrin), and on soil metals accumulation. The treatments consisted of a control, and soil disinfestations by biofumigation combined with solarization (B+S) for two, four, five, six consecutive years. B+S enhanced the dissipation of pyrifenox with regard to control treatment. Significant differences were not ... [Abstract] [Full-text]

Articles on Greenhouse Effect published 29 July 2008:

Isolation and Symbiotic Characteristics of Two Tn5-Derived Phage-Resistant Bradyrhizobium japonicum Strains that Nodulate Soybean.   Curr Microbiol, 57(3): 212-7.

Using transponson Tn5 mutagenesis, two transconjugants of Bradyrhizobium japonicum with the properties of both phage resistance and ability to induce nodulation were isolated at the frequency of 0.02%. These transconjugants were tested for their symbiotic performance on soybean cv. JS335 under greenhouse and field conditions. Both phage-resistant mutants induced nodules (nod (+)), but the transconjugant B. japonicum E13 was ineffective in nitrogen fixation (fix (-)). Rhizobiophage presence in ... [Abstract] [Full-text]

Chitosan enhances disease resistance in pearl millet against downy mildew caused by Sclerospora graminicola and defence-related enzyme activation.   Pest Manag Sci.

BACKGROUND: The present study investigated the effect of chitosan seed priming on the induction of disease resistance in pearl millet against downy mildew disease caused by Sclerospora graminicola (Sacc.) Schroet.RESULTS: Pearl millet seeds were primed with chitosan at different concentrations: 0.5, 1.5, 2.5 and 3 g kg(-1) seed. Of the different concentrations, 2.5 g kg(-1) was found to be optimum, with enhanced seed germination of 99% and seedling vigour of 1782, whereas the untreated control ... [Abstract] [Full-text]

Articles on Greenhouse Effect published 28 July 2008:

Assessment of chemical, biochemical and ecotoxicological aspects in a mine soil amended with sludge of either urban or industrial origin.   Chemosphere, 72(11): 1774-81.

A greenhouse pot experiment was conducted to evaluate the effect of sewage sludge (SS), of sugar beet sludge (SBS), or of a combination of both, in the remediation of a highly acidic (pH 3.6) metal-contaminated soil, affected by mining activities. The SS was applied at 100 and 200Mgha(-1) (dry weight basis), and the SBS at 7Mgha(-1). All pots were sown with Italian ryegrass (Lolium multiflorum Lam.). After 60d of growth, shoot biomass was quantified and analysed for Cu, Pb and Zn. The ... [Abstract] [Full-text]

© 2005-2008 Greenhouse Effect Research Today. All Rights Reserved.