Effect Of Iron Deficiency Stress On Physiological Characteristics Of Five Kinds Of Apple Rootstock Seedlings

In order to select out the ideal rootstock cultivars suitable for high resistant cultivation of apple to iron deficiency. This study selected several common apple rootstocks as the research materials, and combined the method of hydroponic nutrient solution culture, sand culture with field planting, and determined the physiological indexes in chlorophyll content, active iron content, total iron content of different apple rootstock, and combined with the growth status of different apple rootstock on the southern border, and screened out strong anti-deficiency apple rootstocks.1.In filed experiments. Malus Xiaojinensis Cheng et Jiang and Malus micromalus Makino manifested performance resistance to iron deficiency. No chlorosis symptom was not found in its leaves when it was grown in the southern calcareous soil with p H=8.53. In contrast, severe chlorosis was found in the contrast apple rootstock Malus sieverii Roem grown under the same soil conditions. its leaf chlorophyll content was significantly lower than that of Malus Xiaojinensis Cheng et Jiang and Malus micromalus Makino seedlings. Resistance to iron deficiency of Malus Xiaojinensis Cheng et Jiang and Malus micromalus Makino leaf active iron content was higher than Malus sieverii Roem. but chlorosis leaf total iron content of Malus sieverii Roem is higher than Malus micromalus Makino.2.The experimental results of physiology laboratory showed that: Iron deficiency leads to the chlorophyll content decreased of each apple rootstock seedlings. Malus.robusta Rehd rootstock seedlings affected most, with minimal Malus micromalus Makino affected. Under iron stress, rhizosphere acidification ability of different apple rootstock in different. Root Fe3+ reeducates activity of 4 kinds of apple rootstock seedlings compared with the corresponding add iron treatment significantly increased and the increase degree was Malus micromalus Makino>Malus.hupehensis Rehd>Malus sieverii Roem>Malus robusta Rehd.Malus sieverii Roem, Malus micromalus Makino and Malus robusta Rehd rhizosphere acidification was significantly stronger than contral treatments when the iron stress reached two weeks. Until 12 week, Malus.robusta Rehd and Malus micromalus Makino rhizosphere acidification capacity remains stronger than Malus sieverii Roem and Malus hupehensis Rehd.3.The technique of sand culture-adding nutrient solution regularly is suited to cultivate apple or pear seedlings under laboratory conditions. In the study of plant minimal element deficiency, river sand is better than quartz sand theoretically. In the pretreatment of medium, it was very necessary to leaching sand tested with diluted acid. The measures such as selecting seedlings with appropriate age, expand sample space and prolong the developmental period of seedlings were benefited to improve the efficiency of the study of mineral nutrition of fruit trees.