晋西黄土区刺槐蒸腾、光合与水分利用的试验研究

Study on Robinia pseudoscacia L.Transpiration, Photosynthesis and Water Use Efficiency

针对黄土地区造林成活率不高,保存率低的情况,就黄土高原的主要造林树种—刺槐的各种生理过程(如蒸腾、光合、气孔导度)的内在规律与环境因子的影响(如光合有效辐射)进行分析研究,以水分合理高效利用为切入点,通过研究气孔行为与蒸腾和光合之间的关系,得到一系列的临界值:从光合有效辐射入手,蒸腾与光合和光合有效辐射之间均呈抛物线关系,在光合有效辐射大于882 um o l/(m2.s)时实施措施,既可大大减小蒸腾,又可改善光合;光合与蒸腾的非线性关系可用抛物线方程表述,其中光合速率最高时的蒸腾速率为临界值,超出此值即为奢侈蒸腾;综合分析光合速率、蒸腾速率与气孔导度之间的关系,当气孔导度大于0.35 um o l/(m2.s)时,适时提高气孔阻力并抑制蒸腾的措施,既节约水分又促进光合。通过对临界值的分析的,得到黄土高原地区抗旱造林的一些新的方法。

In order to improve the condition of low survival rate of forestation,the inherence law of physiological of Robinia pseudoscacia L., for example： transpiration rate, photosynthesis rate, stoma conductance, and their affecting environment factors were discussed in view of increasing the plant water use efficiency ,such as：photosynthetic active radiation. Through studying the relationship between both transpiration and stomatic behavior and photosynthesis and stomatic behavior,a series of critical values were obtained. The experimental results showed that there was a parabola relationship between both photosynthesis and photosynthetic active radiation and transpiration and photosynthetic active radiation. It is possible that the measures should be taken to prevent transpiration and improve photosynthesis when the photosynthetic active radiation exceeded 882 umol/（m^2·s）; and there was a parabola relationship between photosynthesis and transpiration. The transpiration at the maximum photosynthesis was a critical value,above which ,transpiration was the luxurious part. It is possible that the measures for increasing stomatic resistance and preventing transpiration could save water, and improve photosynthesis and yield as well. From the analyses of the critical values,new methods for loess area forestation could he got.