Effects of Cytokinin, Ethylene, and Abscisic Acid

As with the auxins, there is a vast literature dealing with the effects of gibberel-lins on cell expansion. For detailed discussions the reader is referred to Low (1975) and Jones (1973). Effects of GA on cell expansion in stems were reviewed by Phinney and West (1961). 

The most common effects of cytokinin, ethylene, and abscisic acid on stem and coleoptile cell elongation are inhibitory. They inhibit both auxin-enhanced 

In light-grown hypocotyls of dwarf watermelon seedlings benzyladenine (BA) enhances ethylene production and promotes cell elongation (Loy and Pollard 1977). Prevention of BA-induced ethylene production prevents BA-induced elongation, an indication that ethylene is necessary for BA-induced growth promotion. 

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