陕西渭北旱源土壤—植物—大气连续作中水分运转规律的研究──Ⅲ．生态和生理环境对叶片气孔阻力的影响

在整个生长季内，研究了陕西渭北旱源冬小麦叶气孔阻力与生态和生理因子的关系。结果表明，气孔阻力与大气温度、相对湿度和大气水势及叶温均呈二次曲线相关；与土壤水势呈直线正相关；与叶水势呈指数函数相关；当光量子通量密度小于１５２３μｍｏｌ·ｍ－２·ｓ－１时．气孔阻力与之呈幂函数相关，当光量子通量密度大于１５２３μｍｏｌ·ｍ－２·ｓ－１时，气孔阻力与之呈指数函数相关，此时气孔正处于“午休”期间。试验给出了冬小麦叶气孔阻力与各因素之间的现象模型。通过主要生态因子（气温、光量子通量密度、大气水势和相对湿度）对气孔阻力作用的综合分析表明，在陕西渭北旱塬，诸生态因子对冬小麦叶气孔阻力的重要性依次为大气水势、相对湿度、光量子通量密度和气温。并对其它影响气孔阻力的因素进行了讨论。

陕西渭北旱源土壤—植物—大气连续体中水分运转规律的研究──Ⅱ．生态和生理环境对植物叶水势的影响

在整个生长季内，研究了陕西渭北旱塬冬小麦叶水势与生态因子及叶温的关系。结果表明，冬小麦叶水势与气温呈直线正相关，与光量子通量密度呈二次曲线相关，与大气水势和相对湿度呈Ｓ型曲线相关，与土壤水势和叶温呈指数函数相关，并给出了冬小麦叶水势与各因素之间的现象学模型。通过主要生态因子（气温、光量子通量密度、大气水势和相对湿度）对叶水势作用的综合分析表明，在陕西渭北旱塬，诸生态因子对冬小麦叶水势的重要性依次为气温、大气水势、相对湿度和光量子通量密度。

On the Theory of Harmonious Co-existence between Man and Nature by Marx and Engels

Marx and Engles believed that man and nature develop harmoniously, when the activities of man constitute the content of nature, which is changed constantly because of the activities of man. Marx and Engles also pointed out the duality of the conquest, change and influence exerted on nature by man. On one hand, it can improve people’s living conditions and make people free from the enslavement of the nature. On the other hand, it may also lead to excessively snatching and wrecking nature, then make the deterioration of the environment and ecology out of balance. They also, from the technical angle of ecology, put forward the concrete measures to realize the harmonious symbiosis of man and nature in the development of economy. They also believed that only when socialism or communism is realized, can the conciliation of mankind and nature be realized finally. Marx and Engle’s theory of harmonious symbiosis of man and nature is of great theoretical directive significance for us to insist on the scientific development view.