Effect Of Iron-deficiency Stress On Physiological And Biological Characters Of Apple Rootstocks

The varieties of physiology and biology indexes, organic acid exudation and iron uptake kinetics of the tissue cultivated seedlings of SH40, M.xiaojinesis,M.micromalus and M:6, were studied by the method of hydroponics.The main results were as follow:1 It was found that SODase and PODase activity in leaves and roots were related to varieties of surperoxide free radical and malondialdehyde(MDA).Iron-deficiency induced SODase and PODase activity elevation. SODase and PODase activity were tiptop under iron-deficiency stress. M.xiaojinesis>M26>M.micromalus>SH40. MDA and O2- content manifested: M.xiaojinesisM26>M.micromalus>SH4o3 The results of Fe content of different rootstocks showed that Fe content in shoots of M.micromalus and SH40 was lower than that in root, SH40 and M.micromalus was sensitive to iron deficiency and easily manifested chlorisis phenomena, but Fe content in shoots of M.xiaojinesis and M26 was higher than that in root, M.xiaojinesis and M26 was not sensitive to iron deficiency and not easily manifested chlorisis phenomena.4 The organic acid exudation from tips of rootstocks roots was oxalic acid, malonic acid tartaric acid, citric acid, malic acid. Iron deficiency induced citric acid and malic acid exudation from tips of MX, roots. With or without Fe supply the total quantity of organic acid and the proportion of kinds of organic acid were different.5 The iron uptake rates of intact roots for four rootstocks tissue cultivated seedlings were found to Michaelis-Menten curve. Iron absorption Kinetics parameters wereinfluenced by factors including rootstocks species, temperature, iron level. Iron uptake rates and the total of iron absorption were influenced by temperature and iron level. M. xiaojinesishad higher in iron uptake rates, the total of iron absorption and the ability of roots, M26 was placed in the middle, M. micromalus was taken second place, SH40 was lower.