不同密度对大豆生理特性的影响

Effect of Different Density on the Soybean Physiological Characteristics

为确定大豆高产栽培合理密度,以长农18大豆为试验材料,研究了不同密度对大豆生理特性的影响。结果表明:叶绿素含量变化均呈现先升高后降低的趋势,光合速率呈现双峰曲线变化,出现了两次光合高峰值。蒸腾速率、气孔导度由V4期的最大值逐渐降低到R7期的最小值。单株干物质积累量呈"S"形曲线的变化,在R7期达到最大值。种植密度对叶绿素含量的影响是,从V4之后到R7期之前表现出明显差异,低密度的叶绿素含量高于高密度的叶绿素含量,在一定密度范围内,随着种植密度的增加光合速率降低,胞间CO2浓度升高,群体叶面积指数变大,单株干物质积累量逐渐减少。蒸腾速率和气孔导度变化趋势基本相同,随着种植密度的降低蒸腾速率升高、气孔导度变大。

For the purpose ot detining reasonable density,the etiect oI different density on the soybean physio- logical characteristics with Changnong 18 as test materials was studied. The results showed that chlorophyll content changes were all increasing at first and then decreasing, photosynthetic rate present diauxie curve chan- ges,appeared twice photosynthetic peak values. Transpiration rate and stomatal conductance value from the maximum of V4 period gradually reduced to the minimum of R7. The accumulation of dry matter yield presented a ＂S＂ shape curve change,and at R7 reached maximum. The effect of planting density on the chlorophyll content was as follows： from V4 to R7 period showed obvious difference,chlorophyll content of low density was higher than that of high density,in a certain density range,with the increase of planting density, photosynthetic rate reduced,the intercellular CO2 concentration increased,group leaf area index increased,the accumulation of dry matter yield decreased. The transpiration rate and stomatal conductance change trend were the same, with the reduction of planting density,transpiration rate rised and stomatal conductance got big.