摘要： Apoptosis or programmed cell death (PCD) is known for defense and developmental mechanisms. A remarkable overlap has been suggested between the hallmarks of PCD in plants and animals in spite of identification of very few regulatory proteins or protein domains conserved across all eukaryotic PCD forms. The features like chromatin condensation, nuclear DNA fragmentation, and participation of caspase like proteases in plant PCD appear to be similar across the board and in conformity with the process in metazoans as well. Transgenic expression of mammalian anti- and proapoptotic proteins in plants influence the regulatory pathways of cell death activation and suppression, indicating the existence of functional counterparts of such genes in plants, several of which have now been cloned and characterized to various extents, suggesting that despite differences, there may be a fair level of functional similarity between the mechanistic components of plant and animal apoptosis. The overall review of the available data pertaining to mechanism of PCD in plants is at best inclined to support an ancestral relationship with animal apoptosis rather than any common regulational strategies. Besides, as far as germ cell apoptosis is concerned, ‘Abortive Apoptosis’ is a theory that still requires much scientific evidence to be considered valid. Because of naturally occurring processes within the spermatozoa that mimic somatic cell apoptosis, many believe that this theory requires additional evidence. Oxidative Stress Oxidative stress upon spermatozoa is induced by an increase in the amount of reactive oxygen species (ROS) that are present in the fluids filling the male genital tract.
