Physiological effect of melatonin, IAA and their precursor on quality and quantity of chickpea plants grown under sandy soil conditions

Abstract

The physiological effect of melatonin, IAA and their precursor (tryptophan) as seed priming on quantity and quality of chickpea plants was investigated during two growing seasons of 2013/2014 and 2014/2015 under sandy soil conditions at the Research and Production Station, National Research Centre, Nubaria Province, Behaira Governorate, Egypt. Data show that melatonin treatments showed the most pronounced effect on vegetative growth parameters followed by IAA and tryptophan treatments. The highest significant increase in dry weight of shoot/plant was achieved by melatonin treatments at 0.5 and 1.0mM. Moreover, melatonin treatments at 0.25 and 0.5 mM were the most pronounced treatments caused the highest significant increase in total photosynthetic pigments by 52.18% over control. All applied treatments caused significant increases in seed yield/feddan and its attributes (number of pods and seeds/plant as well as 100seeds weight). IAA treatment at 20mg/l and all melatonin treatments had the most positive effect on increasing seed yield and yield attributes. It was obvious that seed yield/feddan was increased by 113%, 50.6%, 117.6% and 49.6% under the use of 20mg/l IAA, 0.25, 0.50 and 1.0mM melatonin respectively over control. All applied treatments caused significant increase in the nutritional values of the yielded seed (carbohydrate, oil, phenolic compound and antioxidant activity). Melatonin treatment at 0.5mM was the most pronounced treatment, since it caused significant increase in oil content by 44.94%, carbohydrate content by 8.12%, phenolic content by 57.14% and antioxidant activity by 9.41% over control. The results indicate that oil biosynthesis in chickpea seed responded to melatonin treatment more effectively than carbohydrate biosynthesis. Data show that application of tryptophan led to significant increases in the antioxidant activity (as DPPH- radical scavenging capacity) of the yielded seeds as compared with control plant. It is worthy to mention that melatonin treatments were the most pronounced treatments on the quality and quantity of chickpea plant grown under sandy soil conditions.