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株叶片和根系山梨醇产量的影响，以及叶片和根系细胞核和淀粉积累的解剖学变化。水分胁迫增加了枇杷叶和根以及桃树叶中山梨醇的含量。水分胁迫恢复后，根和叶中山梨醇含量逐渐下降。在对照枇杷树中产生新根。水分胁迫导致细胞核降解加快，叶肉薄壁组织和根尖淀粉积累减少。2.研究了果树新白色根初生木质部分化与根径差异的关系。枳橙子的木质部数目为4-6个，梨为3-7个，葡萄为3-6个，枇杷为4-8个，石榴为5-7个，杨梅为3-7个。梨和葡萄根的木质部脊数一般随根径的增加而增加。桃树根的木质部脊数为3-7条。这些结果表明，施氮植株的粗根中含有许多初生木质部细胞，其数量比不施氮植株的粗根多。3.在蔷薇科果树中，观察到内皮层附近的几层皮层组织中细胞壁向内生长（Φ-增厚），以及内皮层中凯氏带的发育。在凯氏带形成之前，Phi加厚就已相当发育。当根从种植在干旱胁迫条件下的枇杷根的树木取样时，观察到与正常条件相比，Phi增厚显著发展。干旱条件下枇杷根皮层加厚的发生可能是枇杷对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.