Major nutrient reserves in seeds of Cicer arietinum, patterns of their depletions from the cotyledons and coincidental gains in biomass of growing seedling in response to selective organectomy

Selective organectomy in young seedlings of Cicer arietinum has provided a unique approach to investigate a variety of growth correlative phenomena that are manifested through axillary bud differentiation and branch growth. The present study was aimed at gaining better insight of the regulatory influence exerted by the cotyledons on the overall growth pattern. Here the modified seedling system has been employed to investigate the nutritional contributions of the cotyledons by analyzing the available storage reserves, the temporal pattern of their depletions, and coincidental gains in biomass during seedling establishment. The retained cotyledons appear to play a significant role in the subsistence of the seedlings. It was observed that increment in seedling biomass did not always match with the cotyledonary depletions accompanying seedling growth. The quantitative difference in terms of gross biomass ratio of net seedling gains to cotyledonary depletion, over a 4-week growth period, was significantly negative for the first two weeks, becoming positive thereafter. The transition of these ratios from negative to positive is indicative of a reducing cotyledonary contribution towards seedling growth. The transition was delayed by one week upon complete deshooting due to deferred onset of fresh growth in the form of axillary branches in such cases. Although the two major cotyledonary mobilizable polymers i.e. starch and soluble proteins had an initial pool size, respectively, of 39.48 and 20.14% of dry seed weight, these were utilised to more or less similar extent (93%).