树干高压注射铁肥矫正苹果失绿症及其机理

Application of iron fertilizer by use high-pressure trunk-injection to remedy the iron deficiency chlorosis in apple trees and its mechanism

利用N-Fe、邻二氮杂菲铁和 59Fe作为铁源,以3-8年生富士／八棱海棠为试材进行主干强力高压注射试验。结果表明,铁肥树干强力高压注射,主要以二价铁(Fe2+)沿中央木质部的导管运输,大部分向下运输,使铁在根中大量贮存;向上运输较少,运输速度为每小时数百厘米,矫正缺铁失绿症的速度比根系输液慢,但由于根中贮存大量的铁,持效期较长。主干强力高压注射产生肥害的机理是先使吸收根中毒,然后导致叶片枯萎,提高注射部位,提高注射液浓度和减少注射的用药量,可以防止或减轻肥害的产生。

Iron fertilizer can not satisfactorily correct chlorosis when fertilized in the soil, as Fe2+ in the fertilizer is easily oxidized into Fe3+ in the soil. High-pressure trunk-injection of iron fertilizer was reported to be effective to correct chlorosis, but the mechanism involved was unknown. The objective of this paper was to better understand the mechanism of correcting chlorosis with iron fertilizer by using high-pressure trunk-injection method.The experiments were carried out with apple (Malus pumila, cultivar Fuji) during the year 2000-2002 at experimental station of Quzhou of China Agricultural University and in the Yongnian county of Hebei province. The N - Fe, O-phenanthroline-Fe and 59Fe were injected through the tree trunk. The results indicated that Fe2+ was transported along the central xylem, and most of Fe2+ was stored in roots due to the difficulties in root to shoot transportation of Fe2+ . Regreening in iron deficiency chlorosis trees was slower but the effect of correcting iron deficiency chlorosis lasted longer when iron fertilizer was injected than was root-supplied.