biologia plantarum

Biologia plantarum 44:599-601, 2001 | DOI: 10.1023/A:1013711224402

The Response of Nitrate Reductase Activity and Nitrate Assimilation in Maize Roots to Growth Regulators at Acidic pH

N. Shankar¹, S.R. Khan¹, H.S. Srivastava¹

¹ Department of Plant Science, M.J.P. Rohilkhand University, Bareilly-, India

Nitrate and total nitrogen contents, and nitrate reductase (NR) activity of the excised maize roots in buffered or unbuffered nitrate solution (at pH 6.5 or 4.5) as affected by putrescine (PUT), abscisic acid (ABA) and salicylic acid (SA) were investigated. In unbufferred solution, the NR activity was lower at pH 4.5 as compared to that at pH 6.5, but in bufferred solution the activity was higher at lower pH. Supply of 100 µM PUT or 500 µM SA, promoted NR activity and 50 µM ABA inhibited the activity at pH 6.5. However, at pH 4.5, PUT and SA inhibited NR activity and ABA had no effect. In most cases, the increase in NR activity was positively correlated with total organic nitrogen and a negatively with nitrate content. A reverse situation was found when NR activity was inhibited by the growth regulators.

Keywords: abscisic acid; nitrate content; putrescine; salicylic acid

Subjects: abscisic acid; maize; nitrate assimilation and metabolism, phytohormones; pH, nitrate reductase, root; putrescine; root, nitrate reductase, pH; salicylic acid, nitrate reductase, pH; Zea mays

Published: December 1, 2001Show citation