Annals of Botany 40: 731-737, 1976
© 1976 Annals of Botany Company
RESEARCH-ARTICLE |
Distribution of 14C Assimilates in the Cowpea (Vigna unguiculata L.) in Relation to Fruit Abscission and Treatment with Benzyladenine
Department of Agricultural Biology, University of Ibadan Ibadan, Nigeria
University of Guelph Guelph, Ontario, Canada
Received: 16 September 1975
The distribution of 14C assimilates from 14C-sucrose was studied in relation to premature fruit abscission in two cowpea cultivars, Adzuki and Mala. In both cultivars most of the radioactivity was recovered in the fruits, constituting 63–85 per cent of the total 14C imported from the fed leaflet. This was followed by the root, leaves and stem in descending order, except that in Mala, import by the stem was greater than that by the leaves. Adzuki imported 56 per cent more 14C than Mala, from the fed leaflet. In Adzuki, which exhibits a relatively low degree of abscission of young fruits, the ratio of 14C accumulated by peduncle 1 (oldest) fruits to that of peduncle 3 (youngest) fruits was 0·31; while in Mala it was 0·61. Ratios of the combined accumulation by peduncles 1 and 2 fruits to peduncle 3 fruits were 0·81 for Adzuki, and 1·88 for Mala. The more mature fruits of Mala thus constituted a more potent sink for 14C assimilates than those of Adzuki.
In Adzuki, benzyladenine treatment of young fruits at each peduncle was not significantly effective in reversing or modifying the normal gradient of assimilates in fruits of different ontogeny. However, in Mala, BA treatment of the youngest fruits caused 43 per cent increase in 14C import, when compared with corresponding fruits of control plants. In Adzuki, BA had no significant effect on total fruit weight, whereas in Mala the weight was increased by about 36 per cent.