Bases moleculares de la senescencia

MOLECULAR BASIS OF SENESCENCE

















Santiago May 6, 2011




















SUMMARY

The senescence of the plants is a process with is present indifferent stages of the development of this. Its principal function may be viewed of different point of view, since although the plant trying to get rid of all those organs that are not needed at anygiven time and recovery all the nutrients in them to be exported to storage organs or growing zone or in the case of fruits accumulate there, exist also those senescence that are necessary fordifferentiation of some tissue that complied a temporal function and requires a differentiation to meet its final function. We can divide different types of senescence in a monocarpicsenescence side is where the process culminating in the death of the whole plant, and Polycarp where organs have a limited lifespan as leaves and flowers, and the death of these does not imply death of the completeindividual. Senescence is a fully regulated process. Endogenous factors such as age of the plant, reproductive development and levels of various growth regulators regulate senescence through five importanthormones in the first place are those that inhibit senescence, auxin, cytokinins and gibberellins and that promote such as abscisic acid and ethylene. Environmental factors inducedifferent types of stress and the plant to protect dispenses with some structures. This strongly suggests that genes involved in these processes may have an impact upon the control of senescence. The most studied senescence isthe photosynthetic organ. The first sign of senescence on leaves begins with a decrease in photosynthetic rate, followed by catabolism of macromolecules mainly chlorophyll also begin to catabolizemembrane lipids, proteins and RNA. All these molecules will result in different products of hydrolysis, with ammonia and nitrogen the most important; these should be combined with amino acids to...