Investigations of root function in fruit trees and application of suitable root conditions

1.研究了水分胁迫对枇杷和桃树幼树叶和根中山梨糖醇生成的影响，以及叶片和根细胞中细胞核和淀粉积累的解剖变化。水分胁迫增加了枇杷叶、根和桃树叶中山梨醇的含量。水分胁迫恢复后，山梨糖醇在根和叶中的含量逐渐下降。对照枇杷新根发育。水分胁迫导致核降解加速，叶肉薄壁和根尖淀粉积累减少。研究了果树新生白根初生木质部分化与根径差异的关系。木质部数量：三叶橙4 ~ 6个，梨3 ~ 7个，葡萄3 ~ 6个，枇杷4 ~ 8个，石榴5 ~ 7个，杨梅3 ~ 7个。梨和葡萄根部木质部脊的数量一般随根径的增加而增加。桃根的木质部脊数为3 ~ 7个。结果表明，施氮植株的粗根数量比不施氮植株的粗根数量增加。在蔷薇科果树中，在靠近内胚层的几层皮质组织中观察到细胞壁向内生长（phii -增厚），这是一种不寻常的次生细胞壁增厚，并在内胚层中观察到Casparian条的发育。在Casparian砂带完成之前，ph -增厚得到了相当大的发展。当从干旱胁迫条件下种植的枇杷根部取样时，观察到与正常条件相比，ph增厚显著发展。干旱条件下枇杷根系皮层phi增厚的发育可能被认为是水分胁迫的一种防御机制。

1.The effects of water stress on the production of sorbitol in the leaves and roots of young loquat and peach trees, as well as anatomical changes to nuclei and starch accumulation in the cells of leaves and roots were investigated. Water stress increased the sorbitol content in the leaves and roots of loquat trees and in the leaves of peach trees. After recovery from water stress, the sorbitol content decreased gradually in roots and leaves. New roots developed in control loquat trees. Water stress resulted in an acceleration of nuclear degradation and a decrease in starch accumulation in the mesophyll parenchyma and in the root tip.2.Primary xylem differentiation in new white roots was examined relative to the difference in root diameter in fruit trees. The number of xylem was 4-6 in trifoliate orange, 3-7 in pear, 3-6 in grape, 4-8 in loquat, 5-7 in pomegranate, and 3-7 in myrica. The number of xylem ridges of the root in pear and grape was generally found to increase with root diameter. The number of xylem ridges ranged from 3-7 in peach roots. These results indicate that the numbers of thick roots having many primary xylem cells increased more in nitrogen fertilized plants than did those in no-nitrogen ones.3.Cell wall ingrowth (phi-thickening), an unusual secondary cell wall thickening, in several layers of cortical tissue adjacent to the endodermis and the development of the Casparian strip within the endodermis were observed in Rosaceae fruit trees. Phi-thickening developed considerably before the completion of Casparian strip. When roots were sampled from trees planted under drought stress conditions in loquat roots, phi-thickening was observed to have developed dramatically compared to normal conditions. The development of phi thickenings of cortex in loquat roots under drought conditions may be regarded as a defense mechanism from water stress.