Cotyledon Excision and Flowering in Pisum Sativum

Abstract

Investigations of the flowering behaviour of peas led Paton and Barber (1955), Sprent and Barber (1957), and Barber (1959) to propose the presence of a mobile flower-delaying substance, "colysanthin", in cotyledons of late-flowering varieties. Moore (1964, 1965) and Sprent (1966) have recently obtained results consistent with the colysanthin hypothesis. However, the basis for early flowering of other varieties is not clear. Moore (1964) observed significant latening of two early-flowering varieties, Massey and Alaska, following cotyledon excision at 4 days after germination, and Haupt (1952) has reported a slight delay in the early variety Kleine Rheinlanderin when embryos, separated from the cotyledons within 8 hr of soaking the seed, were grown in nutrient culture. In contrast Cruickshank (unpublished data) did not observe any change in flower node of Massey following culture of embryos removed from dry seeds. Paton and Barber (1955) in separate experiments obtained conflicting evidence that a flower-promotive substance was present in Massey cotyledons. In the one experiment in support, only five plants were scored due to the high death rate of plumules following early excision of the cotyledons.