Longevity of Plant Organs: Internal Factors Controlling Abscission

Publisher Website
Google Scholar
Abstract
One of the most obvious conclusions from this detailed survey of selected areas of the abscission literature is that more exchange of viewpoints and approaches between the different groups is necessary. The workers on Coleus need to use both the isolation techniques of the bean workers and the chromatographic techniques of the fruit investigators, and the bean workers would benefit from more quantitative work on the native controlling substances in the intact plant. In all systems investigated, however, auxin is clearly involved in the normal control of abscission.. In Coleus, the genus which has been most investigated, there is as much quantitative evidence that auxin is the normal controlling factor as exists for any other hormonally controlled phenomenon in plants, with the possible exception of growth. The abscission of bean leaves is not so clearly normally controlled by endogenous auxin. It is at present impossible to judge to what extent the gaps in the evidence for bean abscission reflect the different interests of the bean investigators and to what extent they reflect a more complex auxin system for the control of abscission. As was said by one of the few researchers who has studied the abscission of both genera, "Im allgemeinen ist Phaseplus im Vergleich zu Coleus ein viel undankbareres Objekt" [Mai]. Since Coleus was initially selected for abscission studies because of the unusual regularity of its normal abscission, it may well be that the early investigators were also unwittingly selecting for an unusually simple system of auxin-controlled abscission. Only future research can tellus if this is so.