posted on 2024-11-18, 15:09authored byInaugural addresses
Inaugural lecture--Faculty of Botany, Rand Afrikaans University, 7 August 1974@@Senescence of plant tissues, or phytogerontology, is the decline in, and eventual cessation of, the functional abilities shown by mature cells, tissues, organs or organisms. It is a complex process and several hypotheses have been proposed which, however, only consider some aspects of senescence. The hypotheses may be grouped in the following categories:
I. Hypotheses which emphasize endogenous factors such as progressive and irreversible changes in chemical and cellular constituents.
2. Hypotheses based on exogenous factors including temperature, water and light.
3. Hypotheses involving genetic factors.
A specialised form of senescence includes the ripening of fruits and vegetables, as well as the decline of cut flowers after picking. This is associated with changes in subcellular morphology and biochemistry which can be accelerated or retarded by environmental conditions such as available nutrients, water, temperature
or light. Increasing knowledge about senescence will eventually lead to the development of effective preservatives, the importance of which cannot be over-emphasized. The specific
stimulus which initiates the process of deterioration is still unknown and intensive research on this aspect is absolutely necessary.