Plant Science

Leaf recycling requires a two-step process

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Science  19 Jun 2015:
Vol. 348, Issue 6241, pp. 1328
DOI: 10.1126/science.348.6241.1328-d

During leaf senescence, plants recycle nutrients and other molecules from unneeded leaves for use by seeds and other new growth. Hormones, including ethylene, regulate this process. Studying the leaves of Arabidopsis plants, Ueda and Kusaba found that those carrying mutations affecting the synthesis of the hormone strigolactone did not curl up and die in the dark as did the leaves of normal plants. Dark-induced leaf senescence required another hormone, strigolactone, which the plant synthesized in the leaves in response to ethylene. Separately, ethylene induced leaf senescence better than strigolactone. But together, they synergized. This multistep process probably preserves leaves when possible, only carrying through to leaf senescence when the stress becomes too much.

Plant Physiol. 10.1104/pp.15.00325 (2015).

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