Abstract: With 4 lotus cultivars as materials, the changes in activities of adenosine diphosphoglucose pyrophosphorylase (ADPGPase), starch synthase (SSase) and starch branching enzyme (Q-enzyme) in rhizome during it development and their relationship with starch synthesis were studied. The results showed that peaks of fructose, glucose and total soluble sugar, sucrose content reached at beginning, middle, end stage of rhizome development, respectively. Total starch, amylose and amylopectin content in rhizome increased quickly after middle stage, total starch content reached 11.2% to 12.7% in fresh rhizome at end stage, and 70% of total starch was amylopectin. ADPGPase and SSase activities at the same development stage in different cultivar’s rhizome were obviously different, but Q-enzyme activity had little difference. During rhizome development SSase activity peak appeared earlier than ADPGPase and Q-enzyme at early stage, while ADPGPase and Q-enzyme activity peaks appeared at middle stage. ADPGPase activity at middle stage and SSase activity at early stage were very significantly and significantly correlated with total starch content at end stage in rhizome, co-efficient were 0.9830 and 0.8458,respectively; Q-enzyme activity was significantly correlated with amylopectin content at end stage, with co-efficient 0.7690.

Key words: Nelumbo nucifera Gaertn, Starch, ADPGPase, Starch synthase, Q-enzyme