The effect of environmental temperature on distribution of unit chains of rice amylopectin

The effects of environmental temperature during the early development of seeds on the structural characteristics of the endosperm starch were investigated using near-isogenic lines of rice plants (Taichung 65, waxy), grown under temperature controlled conditions. High performance gel permeation chromatography (HPLC) demonstrated that Pseudomonas isoamylase-debranched amylopectins of rice plants grown at lower temperature (25 degrees C) contain increased amounts of short chains and decreased amounts of long chains as compared with amylopectins obtained from rice plants grown at higher temperature (30 degrees C). By high performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) of isoamylase-debranched amylopectins it was detected that the amount of unit chains with degree of polymerization (DP) 6 and 11-13, in the amylopectin of rice plants grown at lower temperature (25 degrees C) had significantly increased and the amount of unit chains with DP 8, 22-24 and 29 had significantly decreased, as compared with the amylopectin of rice plants grown at higher temperature (30 degrees C). It was confirmed that the environmental temperature between 5 and 10 d after pollination strongly influenced the structure characteristics of the endosperm starch of rice plants.