Physiology of post-pollination exudate production in Acacia

Abstract

Marginson, R., Sedgley, M. and Knox, R. B. 1985. Physiology of post-pollination exudate production in Acacia-J. exp. Bot. 36: 1660-1668.Stigmas of A. wattsiana produced 1260 nl of secretion by 90 min after pollination. The optimum temperature for post-pollination secretion in A. baileyana, A. brownii and A. iteaphylla was 20°C. Both self and cross intraspecific, interspecific and intergeneric pollinations produced a similar positive response in A. iteaphylla and A. baileyana. In all cases aged pollen was as effective as fresh pollen despite reduced fluorescence in the fluorescein diacetate test. Live yeast cells, fixed chicken erythrocytes, glass beads, talc and Biogel P150 did not stimulate secretion, nor did pollen which had been washed in water or ethanol despite high retention of viability in some cases Pollen diffusates dried on to glass beads produced a positive response in A. iteaphylla and A. gracifolia. Intraspecific and interspecific pollinations involving fresh Acacia pollen resulted in pollen germination on the stigma and pollen tube growth in the style of A. iteaphylla and A. baileyana. In contrast washed pollen failed to germinate and pollen germination and tube growth were reduced at 35 °C as compared with 20 °C. © 1985 Oxford University Press.