Abstract
The authors study the role of abcisic acid (ABA) in higher plants growing under low nitrogen environment. We have already reported that, by the application of ABA in low nitrogen conditions, chlorophyll was preserved in cucumber plants, and amino acid and protein contents were increased.
To know the role of ABA in early stages of nitrogen assimilation in cucumber plants growing under low nitrogen conditions, activities of nitrate and nitrite reductase, and the contents of nitrate, nitrite and ammonium were investigated. ABA increased activities of nitrate and nitrite reductase in cucumber plants under low nitrogen conditions. ABA increased nitrate content in all organs, and nitrite and ammonium contents in aerial parts. These results suggest that ABA has important roles for growth and development of cucumber plants under low nitrogen conditions due to the absorption of nitrate and an abundant supply of ammonium by increasing nitrate and nitrite reductase activities.
