Chloroplast Pigments, Free and Bound Amino Acids, Activities of Protease and Peroxidase during Development and Senescence of Attached Nodal Leaves of Cajanus cajan L.

摘要

Biochemical analyses of total chlorophylls, carotenoids, total soluble proteins, peroxidase activity, individual and total free amino acids, and protein-bound amino acids were carried out with tagged 5th and 7th nodal leaves of Cajanus cajan L. cv. UPAS-120 when plants were 140 days old. Estimations were conducted at 0, 7,14, 21, 28, 35 and 42 days after tagging. Developing and mature leaf stages of both the nodes were characterized by a gradual increase in the chloroplast pigments and proteins whereas a decline was registered at the senescent phase. Young leaves were characterized by low level of protease activity but considerably higher activity was recorded with maturity and progress of leaf senescence. However, peroxidase activity steadily increased in all stages. Total free and protein and bound amino acids displayed different distribution patterns with leaf maturation. Free amino acids showed an increment at the onset of senescence whereas protein and bound amino acids decreased as leaf entered into senescent phase. The concentrations of protein-bound amino acids were much higher than free amino acids in both the nodal leaves. Leaves from both the nodes exhibited similarity in having faster degradation of chlorophylls than carotenoids aftermaturity and gradual increment in protease activity throughout the stages of development and senescence. The decline in the total protein amino acids in 5th nodal leaves was more marked than 7th nodal leaves.