Mechanisms for responses to environmental stress in fruit trees

1.建立了甜菜碱类化合物的分析方法，分析了果树对高低温、干旱、盐胁迫等环境胁迫的适应机制。结果表明，许多果树根和叶中不含甜菜碱。与此相反，测定了柑橘中脯氨酸甜菜碱的含量.随着施氮量的增加，叶片叶绿素含量增加，Fv/Fm比值增加。叶绿素含量超过25 μ g/cm^2时，Fv/Fm的增加率降低.柑橘幼苗、无花果和葡萄插条在NaCl胁迫下，叶片和根系中Na、Cl含量的积累与盐浓度成正比。盐胁迫使柑橘根和叶中脯氨酸甜菜碱含量增加，根中含量与盐浓度的变化趋势更为平行.研究了不同施氮量和盐胁迫对几种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，施氮处理促进了新根的生长。DAPI染色显示，施氮处理叶片细胞核明显。盐胁迫引起根冠脱落。盐胁迫下，根尖基部细胞体积增大，液泡化增多.几种果树叶片中BuBisCO和热激蛋白的含量随着施氮量的增加而增加。6.菌根与果树根系之间存在共生关系。

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.