摘要

The present study was carried out to characterize the changing activities of key enzymes during grain filling in two kernel type winter wheat cultivars. Results showed that starch accumulation rate (SAR) and activities of ADP-glucose pyrophosphorylase (AGPase), Soluble starch synthase (SSS), granule-bound starch synthases (GBSS) and starch branching enzyme (SBE) in large kernel types were significantly higher than those in small kernel types. The simulation with Richards' equation showed that it was accumulation duration and SAR that determined the starch accumulation in large kernel types. Compared with small kernel types, plants of large kernel types maintained longer filling duration, higher SAR and greater activities of related enzymes during mid and late grain-filling. These observations suggest stronger sink activities in large kernel types at a later stage of development. Consequently, large kernel types have advantages over the small kernel types in terms of the amount of starch accumulation at mid and late stage.