Effect of Some Amino Acids and Sulphur Fertilizers on Growth and Chemical Composition of Iberis amara L. Plant

摘要

TWO field experiments were carried out during 1995/1996 and 1996/1997 seasons to study the response of Iberis amara plant to foliar spray of tryptophan and aspartic acid at 25, 50 and 75 ppm, also, the effect of sulphur fertilizers which were added assoil dressing or foliar spray. Commercial sulphur (99.8% S) was added in soil at three levels of 0.5, 1.0 and 1.5 g/plant, while micron sulphur (70% S) was sprayed at three levels of 1.25, 2.5 and 5.0 g/1. The second part of the study aimed to investigate the effect of seed extracts on cotton leaf worm under laboratory conditions. Spraying I. amara with tryptophan at 75 ppm increased plant height, number of branches, leaves fresh and dry weights, mimber of corymb and corymb fresh weight per plant, total carbohydrates, nitrogen and phosphorus contents. While aspartic acid at 75 ppm increased both yield of fixed oil and total glucosinolates. Spraying I. amara with micron sulphur at 2.5 g/1 stimulated leaves fresh and dry weight. While, sulpher as soil dressing at 1.5 g/plant increased the length of receptacle, number and fresh weight of corymb. Spraying of sulpher at 5.00 g/1 increased total carbohydrates, nitrogen, phosphorus, potassium contents in leaves and total glucosinolates in seeds. Gas liquidchromatographic analysis of the fatty acids revealed that the main fatty acids were heptadecanoic acid (21.48%), caprylic acid (16.65%), and palmitic acid (10.35%). Treating of the first instar larvae of cotton leaf worm with petroleum ether extract of seeds at 5% and 2.5% resulted in mortality percentage of 100% and 97.2%, respectively after 72 hours from feeding. While, acetone extract of seeds gave 100% with both concentrations. As for the fourth instar larvae, the highest concentration (10%) of bothpetroleum ether and acetone extract showed the highest mortality percentage (83.8% and 76.9%, respectively) after 72 hours from application. On the other hand, petroleum ether extract possesses the highest reduction in feeding of larvae at (4th llarvaeinstar).