不同淀粉含量玉米籽粒淀粉粒度的分布特性

  【目的】 比较不同淀粉含量玉米籽粒淀粉粒度分布特性，及其与籽粒总淀粉、蛋白质含量和容重的相关性。【方法】选用普通型品种农大108、郑单958和高淀粉型品种费玉3号、郑单18，对成熟期玉米籽粒中淀粉粒的体积、数目和表面积分布进行分析测定。【结果】成熟期玉米籽粒胚乳内淀粉粒的粒径分布范围为0.37—31.5μm，以2μm和15μm为界限，将淀粉粒分为小型、中型和大型三类。淀粉粒的体积和表面积分别表现为双峰和三峰分布，淀粉粒的数目表现为单峰分布，其中小淀粉粒组数目占总数的95%左右；高淀粉玉米小淀粉粒组（＜2μm）和中淀粉粒组（2—15μm）所占体积分数显著高于普通型玉米，而在普通型玉米中，大淀粉粒组（＞15μm）所占的数目、体积和表面积百分比相对较高；籽粒总淀粉含量与0.8—2μm，2—10μm和10—15μm的淀粉粒体积百分比均呈正相关，其中与前两者的相关系数达到显著水平，与其它粒径范围的淀粉粒体积百分比呈负相关；蛋白质含量及籽粒容重与所有粒径范围内的淀粉粒体积百分比无明显相关性。【结论】玉米胚乳淀粉粒数目、体积和表面积分别呈单峰、双峰和三峰曲线变化，高淀粉型玉米小、中型淀粉粒组的体积百分比显著高于普通型玉米。

Starch Granule Size Distribution in Grains of Maize with Different Starch Contents

【Objective】The purpose of this research was to reveal the size-distribution characteristics of starch granules in maize endosperm and to study the relation of starch granule size to grain starch content, protein content and test weight. 【Method】In the present experiment, four maize cultivars (Nongda 108 and Zhengdan 958 as common maize, Feiyu 3 and Zhengdan 18 as high starch maize) were used, and maize grains at mature stage were analyzed to study the changes of number, volume and surface area distribution of starch granules in maize endosperm.【Result】The starch granule in matured grain was 0.37-31.5 μm in diameter. Taking 2 μm and 15 μm as limit, the starch particles were divided into three types: small starch granule group (SSG, ＜2μm), middle starch granule group (MSG, 2-15 μm) and large starch granule group (LSG, ＞15 μm). The distribution frequency showed two-peak curve in starch granule volume, and three-peak curve in starch granule surface area. Maize endosperm had a typical single peak curve in number of starch granule, and the SSG granule accounted for over 95% of the total starch granule. The percent age of volume of SSG and MSG were higher than that of LSG in the high starch maize, but in the common maize, the percent ages of volume, number and surface area of LSG were higher than those in high starch maize. Correlation analysis indicated that the starch content was positively correlated with the volume of 0.8-2 μm (r=0.777, P＜0.05), 2-10 μm (r=0.735, P＜0.05) and 10-15 μm starch granules, but negatively correlated with other size ranges. The content of protein and test weight had no correlation with volume of starch granule with other size ranges.【Conclusion】Maize has a typical single peak curve in number of starch granule, two-peak curve instarch granule volume, and three-peak curve in starch granule surface area. The percent ages of volume of SSG and MSG in the high starch maize were higher than that of common maize significantly.