Senescence and death of plant organs: nutrient recycling and developmental regulation.

Senescence and programmed cell death are important features for plant development. By allowing nutrient recycling and reallocation all along plant life, senescence contributes to the plant survival and the developmental program. This review first presents the concept of senescence in the global whole-plant life story, with an emphasis on the control exerted by flowering. It then focuses on leaf-senescence and its control by hormones, nutrients and development. The role of autophagy and of the Target of Rapamycin (TOR) kinase as potential regulators integrating environmental and endogenous signals, which control cell proliferation, reprogramming and nutrient management, is finally considered. Copyright (c) 2010 Académie des sciences. Published by Elsevier SAS. All rights reserved.