摘要： 研究了大豆在开花期、结荚期和鼓粒期的光合日变化及叶片中淀粉和可溶性糖含量的日变化。结果表明,结荚期和鼓粒期大豆的光合作用有午休产生,而在开花期没有发现午休现象。但是在这三个不同生育期中叶片的可溶性糖和淀粉含量的日变化却表现出相同的趋势,它们的变化与大豆光合午休之间没有必然联系。用去荚和去叶方法改变大豆植株库源比后,对大豆光合午休产生与否没有影响。实验结果表明,大豆叶片中碳水化合物的累积不是造成光合午休的原因。

关键词: 大豆, 光合日变化, 光合产物累积, 光合午休

Abstract: The diurnal variation of photosynthesis and concentration of starch and soluble sugar in soybean leaves were studied at the flowering, podsetting and seedfilling stages. The midday depression of photosynthesis was observed at the podsetting and seedfilling stages but not at the flowering stage. However, the same trend of the diurnal variation of the concentration of starch and soluble sugar in soybean leaves occurred in those three different stages.There was no definite correlation between the diurnal variation of photosynthales and midday depression of photosynthesis. Changes in the source/ sink ratio, caused by defoliation or pod removal, had no effect on the occurrance of the midday depression of photosynthesis. Results indicated that the accumulation of photosynthates in soybean leaves did not cause the midday depession of photosynthesis.

Key words: Soybean, Diurnal variation of photosynthesis, Accumlation of photosynthates, Midday depression of photosynthesis