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ISSUE 2176 Thursday 10 May 2001

Pruning may deprive plant of its wisdom
By Roger Highfield, Science Editor

WHEN a gardener prunes a plant he may inadvertently deprive it of valuable information to help it grow, research on the best-studied plant has shown.

Thale cress, a diminutive relative of the mustard plant, is the first plant to have its genetic code laid bare. Now the army of scientists studying the weed has found that old leaves pass their wisdom down to their juniors, a mechanism that is likely to be at work in all plants.

Writing in today's issue of Nature, Janice Lake, Prof Ian Woodward and colleagues at the University of Sheffield report that mature leaves of the weed pass on signals about the level of light and carbon dioxide to developing leaves on the same plant.

The youngsters alter the way the plant's genetic code is read to adjust the number of their stomata - the pores in the leaves that are crucial for photosynthesis and water balance - to fine tune its ability to grow in that particular environment.

By placing leaves in different levels of carbon dioxide and light, the team showed that the make-up of a young leaf matched the environment of older ones rather than its own.

Prof Woodward said it might be best to leave the fully expanded leaves near the growing tip of a plant intact so they could pass on their wisdom.

-- Anonymous, May 09, 2001