Senescence: Is It Universal or Not?

Both demographic and physiological senescence have been demonstrated to occur in various organisms. However, indeterminate growers, such as some animals and most perennial plants, seem to escape the wear and tear of aging. Indeed, most angiosperms show no signs of senescence, and both negligible and negative senescence (improved physiological performance with aging) have been reported in perennial plants growing in their natural habitat. In this opinion article, I review recent developments in the study of senescence in perennial plants and propose that continuous growth prevents senescence. I also address the question whether senescence is a universal process.