摘要
研究了田间大豆及盆栽大豆光合速率与气孔导度等生理指标的日变化情况,并分析了土壤温度和土壤含水量的日变化对光合日变化的影响。结果表明,田间大豆及盆栽大豆的光合都能产生午休,但田间大豆午休程度要比盆栽大豆轻得多。造成这种现象的原因是盆栽大豆根系紧靠盆壁生长,一天中土壤水分大幅度下降及中午时过高的土温严重影响大豆根系对水分的吸收及其它的生理活动。该实验结果还表明,一天中土壤水分大幅度下降及土温过高可以加重大豆的光合午休,但不是造成午休的主要原因。
The diurnal variations of photosynthesis and stomatal conductance and other physiological indexes were studied in pot cultured soybcan and field cultured soybean.The effect of diurnal variations of soil water content and soil temperature on the diurnal variation of photosynthesis were also studied. The midday depression of photosynthesis was found in field cultured soybean as well as in pot cultured soybean,but the extent of midday depression of photosynthesis in field cultured soybean was much lower than that in pot cultured soybean.The main causes of this performance could be ascribed to that the roots of pot cultured soybean was growing close against the pot wall,the great depression of pot soil water content during the course of the day and the excesively high temperature of soil at the noon time stronly influenced the uptake of water by soybean roots and other metablism of soybean roots.The results of this experiment also indicated that although the deficiet of soil water content and the high temperature of soil during the course of the day could intensify the midday depression of photosynthesis,they were not the main causes of midday depression of photosynthesis.
关键词
大豆
光合变化
土壤水分
soybean
diurnal variation of photosynthesis
midday depression of photosynthesis
soil water content
