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Hello,
I forward an article from Norman Uphoff. With best wishes for a
SRI-friendly monsoon season!
Andreas Jenny
---
As you all know, one of the most evident differences between
SRI-grown rice plants and conventionally-grown plants, is the root
size, color and general healthy condition. I came across a relevant
article in NATURE this morning, which I will attach. This seems to
shed some more light on what is going on with 'the SRI effect.'
Norman
MORE EVIDENCE ON THE CONTRIBUTION THAT ROOTS MAKE TO PLANT PERFORMANCE
The 10 July 2004 issue of Nature has an article on agricultural biotechnology, subtitled "Genetic technology supports sustainable farming." It reports on research by the USDA Vegetable Laboratory that is trying to determine why tomato plants that are grown on natural, hairy-vetch mulch are healthier -- and yield 20% more -- than the same variety grown on black polyethylene mulch, which also suppresses weeds and conserves moisture, and fed with synthetic fertilizer.
Using a modern genetic technique called CNDA subtraction cloning, described in the article (p. 73), "a number of genes [were identified] that expressed themselves more vigorously in plants grown on hairy-vetch mulch, rather than black plastic. These genes included those involved in photosynthesis, disease resistance, defense against pests, and the assimilation of nitrogen. All of this helps to explain the more vigorous growth of hairy-vetch-mulched plants.
"What is not explained, however, is why those genes express themselves vigorously. But Dr. Matoo has a hypothesis. Among the healthiest parts of the hairy-vetch-grown plants are their roots. These are a source of hormones which affect gene expression. More roots, more hormones, and more expressive genes. One up for sustainability."
MORE EVIDENCE ON THE CONTRIBUTION THAT ROOTS MAKE TO PLANT PERFORMANCE
The 10 July 2004 issue of Nature has an article on agricultural biotechnology, subtitled "Genetic technology supports sustainable farming." It reports on research by the USDA Vegetable Laboratory that is trying to determine why tomato plants that are grown on natural, hairy-vetch mulch are healthier -- and yield 20% more -- than the same variety grown on black polyethylene mulch, which also suppresses weeds and conserves moisture, and fed with synthetic fertilizer.
Using a modern genetic technique called CNDA subtraction cloning, described in the article (p. 73), "a number of genes [were identified] that expressed themselves more vigorously in plants grown on hairy-vetch mulch, rather than black plastic. These genes included those involved in photosynthesis, disease resistance, defense against pests, and the assimilation of nitrogen. All of this helps to explain the more vigorous growth of hairy-vetch-mulched plants.
"What is not explained, however, is why those genes express themselves vigorously. But Dr. Matoo has a hypothesis. Among the healthiest parts of the hairy-vetch-grown plants are their roots. These are a source of hormones which affect gene expression. More roots, more hormones, and more expressive genes. One up for sustainability."
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