果树体内铁的再利用研究

Iron deficiency chlorosis, resulting in reducing yield and decreasing the quality of crops, is still an important problem in the world. However there is not an efficient method to be applied to crops for remeding Iron deficiency chlorosis. Influence of N fertilizer form on iron absorption and distribution, iron storage and re-utilization, grafting method and ringing or girding on iron absorption and distribution were studied in fruit trees. Moreover Iron content in different organs were determined in mature apple trees and different methods were compared for remeding iron deficiency chlorosis in fruit trees. The following progress were obtained: 1)Fruit trees, as a perennial plant, can store iron in their trunk and scaffold limbs, and re-utilize iron when they are in iron deficiency; 2)Applying N fertilizer with the N form effected iron absorption. The root ability of absorbing iron under NH+ nutrition was stronger than the roots under NO3_,and NH+ fertilizer was favorable in re-utilizing iron; 3)New technology, using red O-phenanthrolin-Fe was obtained to trace iron absorption and distribution for fruit trees. The different mechanisms of iron utilization and distribution of fruit trees were shown with this new technology: Fe2+ was absorbed and transported along xylem near cambium to stem, leaves and main vein when iron fertilizer was root-inserted while Fe2+ was transported along the central xylem to roots and stored in roots under high-pressure trunk-injection, and this is why death of trees are observed sometimes under Fe fertilization with the high-pressure trunk-injection method. 4)Iron content in different organs were studied in mature apple trees and influence of grafting method and ringing or girding were obtained on iron absorption, transport and distribution in fruit trees. 5)Different results for remeding iron deficiency chlorosis in fruit trees were obtained with different methods of Fe fertilization. Fe fertilizer by root-inserted gave the best result to remeding iron deficiency chlorosis for leaves as compared with the other methods such as soil applying of Fe fertilizer, high-pressure trunk-injection method and leaf application. 6)A new method for remeding iron deficiency chlorosis was obtained with applying Kan-Dibao in soil. Soil applying Kan-Dibao had a good effect to remeding leaf iron deficiency chlorosis. The pH and the content of salt cultivation layer of soil decreased significantly while the content of chlorophyll in leaves increased significantly (double or three times higher than that in the leaves from control trees) after applying Kan-Dibao,

果树缺铁失绿症是全球性植物营养突出问题之一。本项目旨在研究果树体内铁再利用的机制和途径，包括铁肥施用方式、时期对铁在树体内贮藏的影响；非活性铁与活性铁之间的转化及内在规律；铁胁迫时体内质外体铁和铁蛋白的反应规律与调控；农艺措施在铁胁迫时诱导铁活化的作用。探索提高植物体内铁再利用途径，为根治果树缺铁失绿提供理论和实践依据。