Wirkung von Kinetin and Abscisinsäure auf die Entwicklung von Lemnaceen-Blütenstandsanlagen in vitro

Abstract

Summary Inflorescence primordia of the short-day plant Lemna paucicostata cultivated in vitro evidence masculinisation, whereas explants of the long-day plant Lemna gibba exhibit feminisation. The influence of different levels of kinetin on the development of the inflorescence primordia was investigated. Comparison of the results obtained shows that low concentrations of kinetin enhance the one-sidedness of the sex expression of the primordia in both species. In explants of the long-day plant concentrations of kinetin promote feminisation, whereas in the short-day plant masculinisation is enhanced. An improved supply of the explants with kinetin leads to a better development of both male and female flower parts. This enhancement of development results in a decrease in the one-sidedness of the sex expression in the explants of both species. Addition of abscisic acid to the agar media also results in a differing effect on the sex expression in both species. Increasing concentrations of abscisic acid reduce stamen development in Lemna gibba to a greater extent than in the case of the control, whereas pistil development in Lemna paucicostata is strongly inhibited. This causes an increase in the one-sidedness of the sex expression of the explants. The results suggest the mode of action of kinetin and of abscisic acid on the development of the explants to be indirect and to find its expression in an activation (kinetin) or a reduction of the activity (ABA) of the other plant hormones at the floral meristem.