A Comparative Study Of Nine Interstocks Apple Drought Resistance

This research takes3 years of cultivated dwarfed inter-stocked apple seedling as experimental material, its cion is Malus domestica Borkh. cv. Nagano Fuji No.2, rootstock is Malus sieversii, inter stocks P22, JM17, SH6, M9T337, Y1, SH40, CG80, B9, SH1 respectively. Treat samples in three different ways: control group(CK)60%-65%, mild water stress(T1)40%-45% and moderate water stress(T2)30%-35%. By researching multiple indicators of dwarfed inter-stocked apples under three different treatment, including external form, photosynthetic parameter, water metabolism, membrane system, Chlorophyll fluorescence parameter and root growth, etc., get to know variation of physiological properties of 9 dwarfed inter-stocked apples under water stress; obtain the function of indicator variation of dwarfed inter-stocked apples under water stress through fuzzy subordinate function, then primarily comprehensively the drought resistance of 9 dwarfed inter-stocked apples, with major results as follows:1、Under drought stress,the dynamical curve of chlorophyll fluorescence in 9 varieties of Malus plant showed an obvious change.original light energy transforming rate(Fv/Fm),and photochemical quenching coefficient(qP)of 9 inter-stocked apple were decreased with prolonging of drought stress time.While Minimal fluorescence(F0) was risen and non-photochemical quenching coefficient(qN) was first increased and then decreased with the strengthening of light water stress.2 、 Under mild water stress, damage index of cion of different inter stocks are low,varieties with inter stocks M9T337, SH40 have lower damaged degree, those with Y1, JM7 have higher damaged degree. Under mild water stress, shoots of coins of inter stocks M9T337 grow obviously more quickly than other those of other inter stocks.Under moderate water stress, shoot growth of SH6、M9T337 decreases more than other varieties, varieties with inter stocks Y1、JM7、P22 have lower damaged degree.3 、 Relative electric conductivity of leaves increases as water stress worsens and lengthens. Under mild and moderate water stress, relative electric conductivity of varieties of Y1, P22 increases more, being higher. The variety of M9T337 has the lowest relative electric conductivity under mild water stress, while under moderate water stress the variety of SH6 has the lowest electric conductivity.4 、 Under water stress, net photosynthetic rate(Pn), stomatal conductance(Gs),transpiration rate(Tr) of dwarfed inter-stocked apples decrease, under mild water stress, they decrease less than they do under moderate water stress. Chlorophyll was first increased and then decreased with the strengthening of light water stress,it is similar to the change of water use efficiency 。 Different inter-stocked apple had different water use efficiency, but light water stress increased the water use efficiency.5、Using subordinate function, make subordinate function analysis on every indicator including form, photosynthetic parameter, water metabolism, membrane system, root growthand Chlorophyll fluorescence parameter, comprehensively assess drought resistance of dwarfed inter stock, with results as follows:Under mild water stress, drought resistance of apples with different inter stock is ranked from weak to strong asY1<JM7<P22<SH40<SH1<CG80<B9<SH6<M9T337.Under moderate water stress, drought resistance of apples with different inter stock is ranked from weak to strong asY1<JM7<P22<B9<SH40<CG80<SH1<M9T337<SH6.