Zhang Jun-Jie, Hu Yu-Feng, Zhou Hui, Huang Yu-Bi
College of Life Sciences, Sichuan Agricultural University, Ya'an, Sichuan 625014, China.
Zhi Wu Sheng Li Yu Fen Zi Sheng Wu Xue Xue Bao. 2007 Apr;33(2):123-30.
Amylose, amylopectin and starch dynamic accumulation and key enzymes activities in the grains of 4 maize inbred lines (two high-starch ones and two low-starch ones) were studied. The amounts of amylose, amylopectin and starch in the grains of 4 maize inbred lines increased as sigmoid curves during grain filling period. The changes in amylose, amylopectin and starch accumulation rates followed single-peaked curves, and reached their peaks in the 25-30 days after pollination (DAP). Changes in activities of adenosine diphosphoglucose pyrophosphorylase (ADPG-PPase, EC 2.7.7.27), soluble starch synthase (SSS, EC 2.4.1.21) and starch granule-bound synthase (GBSS, EC 2.4.1.21) in the grains of 4 inbred lines appeared single-peaked curves with the peaks appearing 20-30 DAP. Changes in activities of starch-branching enzyme (Q-enzyme, EC 2.4.1.18) in the grains of high-starch inbred lines appeared single-peaked curves with the peak values at 20 DAP, while the two low-starch inbred lines showed double-peaked curves with the peak values in the 15-20 DAP and 30-35 DAP. There was significant correlation between ADPG-PPase, SSS and GBSS activities. The results indicated that the Q-enzyme had different expression in high- and low-starch maize inbred lines, and verified that ADPG-PPase, SSS and GBSS activities were significantly and positively correlated with amylose, amylopectin and starch accumulation rates.
研究了4个玉米自交系（2个高淀粉自交系和2个低淀粉自交系）籽粒中直链淀粉、支链淀粉和淀粉的动态积累以及关键酶活性。4个玉米自交系籽粒中直链淀粉、支链淀粉和淀粉的含量在灌浆期呈S形曲线增加。直链淀粉、支链淀粉和淀粉积累速率的变化呈单峰曲线，在授粉后25 - 30天达到峰值。4个自交系籽粒中腺苷二磷酸葡萄糖焦磷酸化酶（ADPG-PPase，EC 2.7.7.27）、可溶性淀粉合酶（SSS，EC 2.4.1.21）和淀粉颗粒结合合酶（GBSS，EC 2.4.1.21）活性的变化呈单峰曲线，峰值出现在授粉后20 - 30天。高淀粉自交系籽粒中淀粉分支酶（Q酶，EC 2.4.1.18）活性的变化呈单峰曲线，峰值出现在授粉后20天，而两个低淀粉自交系呈双峰曲线，峰值分别出现在授粉后15 - 20天和30 - 35天。ADPG-PPase、SSS和GBSS活性之间存在显著相关性。结果表明，Q酶在高淀粉和低淀粉玉米自交系中的表达不同，证实了ADPG-PPase、SSS和GBSS活性与直链淀粉、支链淀粉和淀粉积累速率显著正相关。
