Biochemical Changes during Different Stages of Growth in terms of Seed Size of Kabuli Chickpea (Cicer arietinum L.)

Total soluble sugar and total starch in leaves and stem increased from vegetative to pod initiation stage in all the genotypes of different seed size, but the contents were significantly higher in large-seeded genotypes at pod initiation stage. Soluble protein and total nitrogen in leaves and stem increased from vegetative stage till flower initiation and then declined owing to mobilization of nitrogen from vegetative tissue to the sink (seed) and the content of soluble protein and total nitrogen was also found to be higher in leaves of large-seeded genotypes. The levels of total soluble sugar, total starch and total soluble protein increased up to 20 DAF in podwall followed by a decline thereafter. Higher total soluble sugars and total starch was observed in podwall of large-seeded genotypes till 20 DAF as compared to small and mediumseeded genotypes, which indicates better capacity of podwall to acts as a major sink for assimilates and afterwards it became a source for the developing sinks. In developing seeds, the levels of these reserves increased towards the maturity and were more in large-seeded genotypes as compared to medium and small seeded categories indicating higher sink strength of large-seeded genotypes. Nitrate reductase activity in leaves decreased towards the maturity in all the chickpea genotypes varying in seed size and was found to be higher in large-seeded than in medium and smallseeded genotypes. Acid invertase activity was higher in podwall of small-seeded genotypes at 10 DAF as compared to medium and large-seeded genotypes and thereafter it decreased. However, in large-seeded genotypes, the invertase activity in podwall was higher at 20 and 30 DAF. The activity of invertase decreased in developing seeds towards maturity, and large-seeded genotypes maintained higher activity initially. The activity of sucrose synthase declined in small and medium-seeded genotypes after 20 DAF, while it continued to increase in developing seeds of large-seeded genotypes indicating that large seeds maintained storage activity for the longer duration that ultimately increased the seed size.