玉米茎秆糖含量的分布

利用手持糖度计(PAL-1)，2年7个时期测定3 种不同基因型玉米茎秆糖含量(Brix %)，以研究玉米不同节间、不同测定时期、不同类型间茎秆糖含量的变化规律。结果表明: (1)从植株基部到顶部各节间糖含量呈现增加趋势，但多以穗位或穗位上下一节间糖含量最高。苏玉16(普通玉米)、05-8(普甜玉米)和扬甜1号(超甜玉米)节间糖含量和节间位置的非线性方程分别为Y = 5.0277 exp(0.020564X - 0.017816X²)、Y = 8.8489exp(0.05949X - 0.006454X²)、Y = 9.6652 exp(0.06944X - 0.009475X²)。(2)随着生育进程的推进，苏玉16(普通玉米)茎秆糖含量表现为低-高-低的变化，而05-8和扬甜1号生育后期茎秆糖含量没有下降反而呈上升趋势，这可能与甜玉米的灌浆特性有关。(3)通过系统分组资料方差分析，3个品种的茎秆糖含量存在极显著差异，且普通玉米＜普甜玉米＜超甜玉米，不同节间、不同测定时期玉米茎秆糖含量差异也达极显著水平。(4)去雌可以显著提高茎秆含糖量，籽粒库容量对茎秆含糖量的分布也有影响。

Distribution of Sugar Content in Corn Stalk

Increasing the sugar content in silage corn stalk will improve the forage quality and palatability, the study on which can provide valuable information for silage corn breeding on stalk high sugar content. Three different genotypes, normal corn "Suyu 16", sweet corn "05-8" and super sweet corn "Yangtian 1", were investigated in this study. The sugar content (Brix values) of corn stalk was evaluated at seven stages using the pocket refractometer PAL-1. Results of two-year experiment were as follows: (1) Sugar content of corn stalk increased with the position of internodes from bottom to top, usually with the highest in ear internode or the internodes immediately above or below it. The relationship between sugar content and internode position varied from different genotypes and were modeled using the following three nonlinear equations: Y = 5.0277 exp(0.020564X- 0.017816X~2) for Suyu 16, Y= 8.8489 exp(0.05949X- 0.006454X~2) for 05-8 and Y= 9.6652 exp(0.06944X- 0.009475X~2) for Yangtian 1, respectively. (2) The stalk sugar content of "Suyu 16" changed in a single peak curve, decreased at late growing stage. However, the stalk sugar content of 05-8 and Yangtian 1 was increased at late growing stage. The difference of stalk sugar content may be related to the grain filling characteristics of the three genotypes. (3) Results of variance analysis of nested design indicated highly significant variation for sugar content of stalk among three corn genotypes, the total sugar content was the highest in super sweet corn, and the second highest in sweet corn. Moreover, sugar contents significantly varied depending on different internodes and different measurement stages. (4) Removing ear resulted in the increased sugar content in corn stalk. Additionally, the kernel sink-potential may influence the accumulation of sugar in corn stalk.