青藏高原几个主要环境因子对植物的生理效应

Effects of Several Environmental Factors on Plant Physiology in Qinghai-Xizang Plateau

青藏高原作物生育期间的太阳辐射及其强度 ,均高于我国内地 ,而且短波辐射比例大 ,光照时间长 ,不仅直接影响植物的光合作用、呼吸作用等重要代谢过程 ,而且不同光质对高原植物植株的生长高度、根系的萌生发育、叶绿素含量以及碳水化合物、蛋白质、脂肪等贮藏物质的积累等方面都有不同的影响。昼夜温差大这一环境特点与高原作物高产之间的关系尚存争议 ,但对作物的品质确实具有明显的影响作用。在高海拔、低气压 (低 CO2 含量、低 O2 含量 )条件下 ,植物表现出光合作用光饱和点升高、光补偿点降低、适温偏低 ,暗呼吸速率较低等特点 ,因而有利于植物充分利用光能 ,也有利于植物体内干物质的积累 ,而且高海拔对植物体内不同代谢成分的形成具有不同的影响作用。虽然青藏高原的多个环境因子 ,如太阳强辐射、蓝紫光成分多、昼夜温差大等 ,对高原小麦的高产来说不可缺少 ,但平均气温较低导致的高原地区小麦生育期明显延长是其干物质产量和籽粒产量高于平原地区的主要原因。

This paper briefly summarized the effects on plant physiology of several main environmental factors in Qinghai-Xizang Plateau, such as plentiful solar radiation, great temperature range, high elevation and low air pressure. The total quantity and intensity of solar radiation are both higher in Qinghai-Xizang Plateau than in lowlands during crop development. And the content of short-wavelength radiation is higher, the duration of illumination is longer too. Not only can these characteristics directly affect some important metabolic processes, such as photosynthesis and respiration, but also different light quality has different influence on growing length of plant shoot, development of root, content of chlorophyll, and accumulation of carbohydrates, protein and fat, etc. Although there is some controversy about the relationship of great temperature range to high yield of plateau crop, high temperature range can distinctly influence the quality of crop, as some researches indicated that the content of protein or carbohydrate of crop is positively related to the temperature range during crop development. Under the condition of high elevation, low air pressure(low CO\-2 density and low O\-2 density), plant always shows the increasing of light saturation point, the decreasing of light compensation point, the falling of adaptive temperature of photosynthesis and the lowered rate of dark respiration etc. So plateau plant can fully utilize light energy and accumulate more dry matters. Furthermore, high elevation can affect the forming of different metabolic products in plant. This paper also systematically analyzed the reason of high yield of plateau crop(Wheat). Although the other environmental factors such as intense solar radiation, high content of blue violet light, great temperature range etc are indispensable, the elongation of crop developmental duration caused by low annual average temperature is the main reason for high yield of dry matters and grains in plateau region. Lastly, this paper made some suggestions to the future development of the study of plant physiology in Qinghai-Xizang Plateau.