The Effect of Environment Temperature of Plants on the Physicochemical Properties of Their Starches

Abstract

Two aspects of experiments, in vivo and in vitro, are described in this review. In in vitro experiments, the crystallization of starch was studied on some model systems using amylodex-trin. The results suggested that the crystalline structure of a starch granule was dependent on external temperature and microenvironment of cellular location developing a starch granule and it was in keeping with results of the follwing in vivo experiments. In in vivo experiments , the temperature of soybean seedlings, potato tubers, sweet potato roots and rice ears was controlled at constant during starch accumulation period using some devices. The following changes were noted in respective starches by elevation of environment temperature. (1) Pasting temperature decreased considerably in all the test series. (2) Maximum viscosity (amylogram) decreased in potato and sweet potato, increased in rice and was approximately constant in soybean seedlings (cotyledon). (3) a-Amylase susceptibility of raw granules and (4) content of bound phosphate were decreased. (5) Amylose content was decreased appreciably in rice and slightly in soybean seedling hypocotyls and was constant in potato and soybean seedling cotyledons. (6) Crystalline type shifted from B or C type toward A type in soybean seedlings and sweet potato and was constant in potato (B type) and rice (A type). From these results, a new day-night rhythm structure in a native starch granule was suggested and relations of the structure to the property were discussed .