ABA promotion of ethylene production in anther culture of Brussels sprouts (Brassica oleracea var. gemmifera) and its relevance to embryogenesis

Abstract

Abscisic acid (ABA) inhibited embryogenesis in anther culture of Brussels sprouts. This was accompanied by enhanced ethylene production during the first half of the anther culture period followed by a reduction in ethylene during the latter half, when compared to anthers not treated with ABA. The enhancement of ethylene production by ABA 6 h and 48 h after the start of the culture period was counteracted by the ethylene biosynthesis inhibitor aminoethoxyvinylglycine (AVG). Both AVG and the ethylene antagonist AgNO₃ removed much of the ABA inhibition of embryogenesis, suggesting that at least part of the ABA effect on embryo production is mediated through increased ethylene biosynthesis. ABA promotion of ethylene production was reduced by high temperature: less ethylene evolved from ABA-treated anthers following a 24 h treatment at 35°C than from ABA-treated anthers incubated continuously at 25°C. A high temperature treatment such as this is invariably necessary for embryogenesis in Brussels sprouts anther culture.