向日葵花期叶片蒸腾特性时空变化及其与环境因子的相关性研究

Temporal and spatial variations in transpiration of sunflower leaves in blooming period and its correlation with environmental factors

向日葵叶片在盛花期的蒸腾特性研究结果表明:向日葵不同叶位的蒸腾作用明显不同,最高峰出现在中上部位叶片,最大值是12叶位,为23.44μE(H2O)·m-2·s-1。一天中最高峰时间在12∶30,不同叶位的蒸腾速度的日变化均呈单峰曲线,环境因子对蒸腾作用的影响不是单一的直接作用,并且每种因子对蒸腾作用的影响在日变化中明显不同。早8∶30光量子通量密度和叶片温度与蒸腾作用均呈极显著正相关,相对湿度在早8∶30和上午10∶30都呈极显著正相关,其他时间均呈不显著正相关。在上午10∶30和14∶30时,光量子通量密度与蒸腾作用呈负相关,中午12∶30和晚上18∶30呈不显著正相关;叶片温度在上午10∶30与蒸腾作用呈负相关外,其他时间均呈不显著正相关。

The studied results of the transpiration characteristics of sunflower leaves in blooming period showed that the transpiration at different leaf positions of sunflower was obviously distinct, and the peak appeared in the leaves from the middle to up at 12∶30 in a day, with the highest value of 23.44μE(H2O)·m-2·s-1 at the 12th leaf, and daily changes of transpiration rate at different leaves appeared single peak curves. The influences of environmental factors on transpiration were comprehensive and the impact of each factor on transpiration was obviously different in daily change. Both photons flux density and leaf temperature had significant positive correlation with transpiration at 8∶30 am, but relative humidity had significant positive correlation with transpiration at 8∶30 am or at 10∶30 am, and at any other time they were not significantly correlated. Photons flux density were negatively correlated with transpiration at 10∶30 am or at 14∶30 pm, but at 12∶30 pm or 18∶30 pm, there was no significant correlation except that leaf temperature was negatively correlated with transpiration at 10∶30 am, they were not significantly correlated at any other time.