环剥对小金海棠缺铁适应性反应的影响

利用环剥技术研究了液体培养下小金海棠根系缺铁适应性反应的变化情况,结果显示,缺铁条件下小金海棠表现出根际pH值降低及根系Fe3+还原酶活性升高等缺铁适应性反应,而环剥后小金海棠根系的缺铁适应性反应受到抑制,根际pH值与对照相比无显著差异,根系Fe3+还原酶活性也无显著升高。半根供铁植株环剥的试验结果显示,只对缺铁一侧进行环剥则缺铁侧根系无显著的根际酸化和还原酶活性增加等生理变化,但正常供铁一侧根际pH值从第2天开始降低,第6天达到最低。根系Fe3+还原酶活性在处理后第2天有所增加,第6天达到最高值。如对正常供铁一侧根系环剥,则正常供铁一侧根系无显著生理变化,缺铁一侧出现根际pH值降低及根系Fe3+还原酶活性升高等现象。

Effect of girdling on iron-deficiency responses of Malus xiaojinensis in iron-deficient stress

The changes of iron-deficiency responses in roots of the Malus xiaojinensis were studied using girdling techniques under nutrient solution culture.The results showed that compared to the normal iron level(40 μmol/L Fe),M.xiaojinensis had lower rhizosphere pH and higher ferric reductase activity in root under iron deficiency stress(0 μmol/L Fe),but these changes were inhibited by girdling under iron deficiency stress.Furthermore,the side of the split-root plants without iron supply was girdled that the plants had iron-deficienct response of half roots at normal iron level,the rhizosphere pH started to decrease from 2nd day with a minimum on 6th day after iron starvation and the ferric reductase activity in roots started to in-crease on the 2nd day with a maximum on 6th day,too.However,the contrary result appeared if the other side of split-root plants girdled.Based on these results,it is suggested that girdling could prevent the information transmitted between root and shoot.