Study On The Drought Resistence Of Newly Introduced Apple Dwarf Rootstocks

Dwarfing rootstocks can dwarf trees, make trees early fruit and have high yield, improvefruit quality and increase economic benefits. Dwarfing close planting cultivation has becomethe trend of the development of apple production. Since the roots of dwarfing rootstockresistance is poor, combined the resistance strong base rootstock and dwarfing inter-stock ispublic applied in production. This paper aims at screening out of drought-resistant rootstockscombination, to lay the foundation of selecting parents in hybridization breeding andcultivation utilization of rootstock in production.Research the strong drought-resistance of the stocks, which would be the basis forcultivation and utilization of production and cross breeding of select parents.4apple drawingstocks (F1、F2、F3、F4)which were introduced from French, and M26(No.5) which is one ofthe most widely used in agricultural production at present as inter-stocks, and Malusprunifolia(Willd.)Borkh who was growled two-year old as scion variety, and Fuji,Nagafu2had been grafted on the inter-stocks. Potted experiments were used to study on the changes indrought index, the appearance of morphological and physiological and anatomical structure ofcontinuous soil drought stress and natural growth. The method of membership functions wasused to analyze drought resistance of the5combinations of apple rootstocks, and obtained thefollowing results:1. With increased levels of drought stress,5combinations showed different droughtsymptoms of apparition. The growth was inhibited, and it was most notable in thick branchesand stem diameter. The survival rates are differences between the5combinations afterdehydration.2. Under drought conditions the5combinations of some physiological indexes hadchanged, the relative water content decreased, and water saturation deficit is rising, membranepermeability and proline as the stress increased showed an upward trend; overall trend ofprotective enzyme for the high after the fall, and it showed significant differences between the5combinations; with the degree of drought increased chlorophyll a, chlorophyll b showed anupward trend, carotene showed a downward trend, which is slightly different from previousstudies.3. When reached moderate moisture duress10d,20d,35d, photosynthesis of5combinations were measured. The net photosynthetic rate, transpiration rate and stomatal conductance of the5combinations all significantly decreased compared with the control,intercellular CO2concentration is higher than in the control, indicating that photosynthesis isinhibited. When reached moderate moisture duress20d, daily variation of photosynthesis of5combinations were measured.Found that the treatment of5combinations had photosynthesisand transpiration in morning when tempratrer is low and light is weak.4. Leaf anatomical structure of5combinations which were not grafted Fuji-Nagafu2had been studied on in2010. The thickness of the upper and lower epidermis, leaf thickness,palisade tissue thickness, spongy tissue thickness and palisade tissue and spongy tissue ratio,tightness of leaf palisade tissue structure, looseness of leaf sponge tissue structure weremeasured. The method of membership function was used to analyze drought resistancecomprehensive of the5combinations, results consistent with the results of morphology andphysiology of2011. However, the results of anatomical structure of2011are not consistentwith the results of morphological and the physiological indicators, it may indicating thatanatomical structure of the same scion can not be identified as the basis for droughtresistance.5. The morphological characters, physiological, anatomical structure, photosynthesisrelated indicators were analyzed respectively by the method of membership function, theorder of drought resistance of the5combinations is:4>1>5>2>3.