The Effect of Two Growth Retardant Chemicals, Cycocel and B-Nine, on Certain Nitrogeneous Components in Barley Seedlings

• Main Author: Kinser, Linda
• Format: Others
• Published: TopSCHOLAR® 1969
• Subjects: Western Kentucky University; Barley; Agriculture; Biology; Life Sciences; Plant Biology; Plant Sciences
• Online Access: http://digitalcommons.wku.edu/theses/1776; http://digitalcommons.wku.edu/cgi/viewcontent.cgi?article=2777&context=theses

Certain chemicals are known to inhibit growth in many plant species. These chemicals possess a common trait, the ability to inhibit stem elongation by suppressing the activity of the subapical meristematic region (11). These growth retardants have been extensively studied during the past several years in an effort to determine the biochemical mechanism responsible for reduction in plant height. The characteristic effect of these chemical retardants on the growth pattern has been described as producing plants with shorter, thicker stems and broader, darker green leaves. Tolbert, however, noted that although plants treated with the plant growth retardant, Cycocel, (2-chloroethyltrimethlammoniumchloride) and some of its related compounds were shorter and exhibited the above characteristics, he also found there was no loss in weight of the treated plants (25). Thus it appears that these chemicals cause growth to be manifested in a manner slightly altered from the normal pattern for that species. In living systems growth can be correlated with an increase in protein content; and since plants must synthesize their own amino acids, the metabolism of nitrogen is a vital factor in determining the rate of growth. Nitrogen is absorbed by the plant in the form of nitrate and must be converted into a usable form (14). The first step of this conversion is accomplished enzymatically by nitrate reductase (2). Although Kahn and Faust (8) have determined the effect of Cycocel on the soluble protein level in barley seedlings, information concerning other aspects of nitrogen metabolism has not been reported in the literature. The purpose of this study was to determine the effects of two growth retardant chemicals, Cycocel and B-Nine (succinic acid 2, 2-dimethylhydrazide), upon the nitrate level, the soluble protein nitrogen content, and the activity of the nitrate reductase enzyme of young barley plants.