【摘要】 <正> 用叶绿体直接研究干旱对光合作用的不利影响、不仅可排除气孔及扩散阻力等许多干扰因素,而且还可以研究干旱对光合碳还原各反应步骤不同的危害程度。过去发现,干旱胁迫导致间质酸化,是光合率下降的主要原因。施用弱碱化剂如NH₄Cl则可克服干旱对光合作用的不利影响。高等植物叶片及藻类植物在干旱条件下所表现的间质或细胞质酸化反应与叶绿体相同。这便为农作物施用弱碱化剂以克服干旱的不利影响奠定了基更多还原

【Abstract】 The direct study of the unfavourable effect of water stress upon photosynthesis by means of chlorophyll can not only get rid of the interference factors of stroma and diffusion resistanee but also probe into the different steps and degrees of harmfulness caused by water stress to photosynthesis carbon reduction reaetion. It was found that water stress led to stroma acidification, which was the principal reason for reducing photosynthesis.Application of weak alkali-agents such as NH₄CI can overcome the unfavourable effect of water stress on photosynthesis.The reaction of stroma or cytoplasmic acidification of higher plant leaves and algae under stress is similar to that of chlorophyll,This has laid a good foundation for the application of weak alkali-agents to crops so as to get rid of the unfavourable effect caused by droughts. As far as the research approach was concerned,the direct control of soil moisture regime cost much time and energy and could not obtain the required indexes. The solution culture has now been adopted, and various osmosis agents with no or little sideeffects are being used to regulate osmosis and study tho response of crops to osmosis stress. On the basis of which in incorporation with field test, a lot of labour power, material resources, time and weak alkali-agents can be saved. This is really a great help to agricultural scientific research in the rainfed areas.更多还原