ABSTRACT
As plants (or individual organs) age, they undergo degenerative changes which impair their vital functions, limit growth, and eventually cause death (12,18,23,25,38). In many crop plants, this degeneration seems too sudden to represent a simple time-dependent accrual of lesions induced by the environment. Instead the physiological deterioration seems to be controlled by internal factors, a process which has been termed senescence (12,25). Many crop plants, particularly soybeans, die as their fruit mature and are therefore limited to one reproductive phase, a life cycle pattern called monocarpy (9,25,26,38). The senescence phase of a monocarpic life cycle has been termed monocarpic senescence (26) to distinguish it from other patterns of senescence (12). The fact that monocarpic senescence may begin while the fruit are still developing suggests that it may limit the productive capacity of these plants, and that problem will be the primary thrust of this paper. Although soybeans will be emphasized here, it should be noted that monocarpic senescence in some other species may differ a bit from soybeans (23,25,26).
