Mechanisms for responses to environmental stress in fruit trees

1.为了分析果树对环境胁迫、高低温、干旱和盐胁迫的适应机制，建立了甜菜碱相关化合物的分析方法。结果，许多果树的根和叶中不含甜菜碱。对柑桔中的脯氨酸甜菜碱进行了测定。随着氮肥处理叶片叶绿素含量的增加，Fv/Fm比值增大。叶绿素含量超过25 ug/cm^2后，Fv/Fm的增加率下降。在柑桔幼苗和无花果、葡萄插枝上施用NaCl后，叶片和根系中Na、Cl含量随盐浓度成比例积累。在盐胁迫下，柑桔根和叶脯氨酸甜菜碱含量增加，根中的含量与盐浓度更接近。研究了不同土壤施氮量和盐胁迫对果树根尖区解剖特征的影响。不施氮处理限制了新根的生长，而施氮处理促进了新根的生长。施氮叶片细胞核呈DAPI染色。盐胁迫导致根冠脱落。盐胁迫下根尖基部细胞大小增大，液泡化增多。5 .几种果树叶片中BuBisCO和热休克蛋白含量随土壤施氮量的增加而积累。观察了菌根与果树根系的共生关系。

1.In order to analyze the adaptation mechanisms to environmental stress, high or low temperatute, drought and salt sttress, in fruit trees, the analytical method of betaine-related compounds was established. As a result, there were no glycine betaine in roots and leaves in many fruit trees. In contrast, proline betaine in citrus was determined.2. Fv/Fm ratio increased with increases in the chlorophyll content of leaves by the application of nitrogen fertilizer. However, the ratio of increase in Fv/Fm decreased when the chlorophyll content exceeded 25 ug/cm^2 in persimmon trees.3. When NaCl applied to seedling of citrus and cuttings of fig and grape, Na and Cl contents in leaves and roots accumulated in proportion to salt concentration. In citrus, proline betaine content in roots and leaves increased by salt stress : the content in the roots was more parallel to salt concentration.4. The effects of different amount of nitrogen applied in the soil and salt stress on the anatomical features of root apex area were observed in several fruit trees. The growth of new roots was limited in non-nitrogen treatment and they increased with nitrogen application. Cell nucleous with DAPI staining was obviously observed in nitrogen applied leaves. Salt stress induced a root cap falling. Cell size in the basal part from root tip with salt stress expanded with more vacuolation.5. The contents of BuBisCO and heat shock protein in the leaves of several fruit trees accumulated with increases of nitrogen application in the soil.6.Symbiotic relationships between mycorhiza and roots of fruit trees were observed.