Resistance Evaluation And Response Of Crabapple Seedlings Under Drought And Rehydration And NaCl Solution Stress

Crabapple is a kind of resources of apple(Malus spp.) and its a popular ornamental trees,we can enjoy the flowers and fruits. Most types of crabapples are also can be root stock for apples and excellent ornamental trees. In the field of beautifying the environment, being cultivation of ornamental plants and fruits, it has important value on research and application.Various types of crabapples germplasm resources are rich in our country, but the adaptability of environment is different from different types. The seedlings of 9 types of crabapples were used as experimental materials. Analyzed the photosynthesis indicators: net photosynthesis rate(Pn), transpiration rate(Tr), water use efficiency(WUE) of leaves, physiological indexes:Pro, MDA, root activity, leaves cell viability, analyzed the production of H2O2, O2-by dyeing technology and observed the directly reflect changes in the external morphology of damage index under the natural soil drought and rehydration and different concentrations of Na Cl solution stress. Extract the important indicators of drought-resistant and salt tolerance by using principal component analysis. Using weighted membership function value to do the fuzzy comprehensive evaluation of all types of crabapples` drought-resistant and salt tolerance. In order to filter a strong drought-resistance and salt tolerance to be a good root stock material. Provide the reference for the drought and saline-alkali land. The main results are as follows:(1) Under drought stress, Malus ‘Radiant' and M. ‘Hongfen' can hold high Pn, WUE and Chl,stable Ci and Gs. They can restore even more than the original state after rehydration and hold stable content of Pro, MDA and high root activity and leaves cell viability. They can adjust the drought-resistant ability and maintain a good state after rehydration, they are drought-resistant relatively strong types. M. pinyiensis and M. pinyiensis Dwarfed damaged seriously, they are difficult to maintain normal photosynthesis in severe drought;M.micromalus is not sensitive for drought stress which has low indexes and cannot adjust timely. Its a drought-resistant relatively weak type. Other types of crabapples are intermediate type.(2) Sort all types of crabapples by drought-resistant ability, it can be divided into four categories: M. ‘Hongfen' and M.‘Red Jade' are the type of highest drought-resistant ability;M. ‘Radiant', M. ‘Hongyan', M. ‘Purple Prince' and M. ‘Sugar Tyme' are the type of high drought-resistant ability; M. pinyiensis Dwarfed and M. pinyiensis are the type of medium drought-resistant ability; M.micromalus is the type of low drought-resistant ability.(3) Under different concentrations of Na Cl solution stress, M. pinyiensis Dwarfed, M.pinyiensis and M.‘Red Jade' are can hold high Pn, WUE and Chl, stable Ci and Gs. They can hold stable content of Pro, MDA and high root activity. They are salt tolerance relatively strong types. M. ‘Radiant', M. ‘Hongfen', M. ‘Hongyan' and M. ‘Sugar Tyme'damaged seriously, indexes declined obviously and have the low leaves cell viability.They are salt tolerance relatively weak type. Other types of crabapples are intermediate type.(4) Sort all types of crabapples by salt tolerance ability, it can be divided into four categories:M. pinyiensis Dwarfed and M.‘Red Jade' are the type of highest salt tolerance ability; M.pinyiensis and M. ‘Purple Prince' are the type of high salt tolerance ability; M. ‘Hongfen'and M. ‘Radiant' are the type of medium salt tolerance ability; M. ‘Sugar Tyme', M.micromalus and M. ‘Hongyan' is the type of low salt tolerance ability.(5) Synthesize the drought-resistant ability and salt tolerance ability, choose the crabapple which with high drought-resistant ability and salt tolerance ability. M. ‘Red Jade' is the type of highest drought-resistant ability and salt tolerance ability; M. ‘Purple Prince' is the type of high drought-resistant ability and salt tolerance ability.(6) In this study, I choose eight indicators which can reflect accurate drought-resistant ability and salt tolerance ability. They are WUE, Pn, root activity leaves, cell viability, Pro, MDA and the injury index of stress which can improve test efficiency and accurately.