较高的茎秆糖含量有助于提高青贮玉米的饲料品质和适口性。本研究以YXD053和98A-04两个茎秆高糖自交系及Y6-1茎秆低糖自交系为材料。于2013年和2014年通过对玉米雄穗始花后棒三叶面积及其光合参数和茎秆糖含量的多期测定,分析玉米棒三叶光合性状对玉米茎秆糖含量的影响。结果表明：3个自交系茎秆糖含量在雄穗始花期基本一致,雄穗始花后21天,茎秆糖含量差异最大。不同茎秆糖含量玉米自交系光合参数特征明显,与茎秆低糖自交系Y6-1相比,茎秆高糖自交系YXD053和98A-04光合速率下降缓慢,有较长的高光合功能持续期；且在籽粒发育后期有较高的光合速率。茎秆低糖自交系Y6-1胞间CO2浓度及蒸腾速率高于茎秆高糖自交系YXD053和98A-04。气孔导度及叶面积对茎秆糖含量的影响在2个茎秆高糖自交系之间表现不一致。在玉米籽粒生长发育后期,棒三叶高光合速率及较长的高光合功能持续期是茎秆高糖的生理基础,乳熟期棒三叶光合速率可以作为茎秆糖含量的一个选择指标。研究结果为选育茎秆高糖青贮玉米提供了理论依据。
英文摘要:
The stalk sugar content in silage maize plays an important role in improving its forage quality and palatability. In this study, we reported effect of photosynthetic characters of three ear leaves on stalk sugar content in maize. Two inbred lines with high stalk sugar content YXD053and 98A-04 and one inbred line with low stalk sugar content Y6-1 were used to measure stalk sugar content and photosynthetic characters of three ear leaves in 2013 and 2014, respectively. For three inbred lines, the stalk sugar content were nearly equal at tassel flowering stage, the largest difference was at 21 day after tassel flowering. Compared with the low stalk sugar content inbred lines Y6-1, photosynthetic rate (Pn) of two inbred lines with high stalk sugar content YXD053 and 98A-04 had a higher value and decreased slowly, and the Pn high value duration of its was longer, especially at the last sampling stages (21 day after tassel flowering). The inbred lines Y6-1with low stalk sugar is higher than the high stalk sugar inbred lines YXD053 and 98A-04 in intercellular CO2 concentration and transpiration rate. In influences of stomatal conductance and leaf area to stalk sugar content, the two inbred lines with high stalk sugar perform inconsistently. The high Pn and longer Pn high value duration of three ear leaves in the latter growth stage (milk stage) was physiological basis of high stalk sugar content in maize. The photosynthetic rate of three ear leaves at milk stage might be used as an alternative indicator in high stalk sugar content maize breeding programs.
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