In Vitro Selection Of Mutants Resistant To Autotoxicity Apple Rootstock And Studies On Their Resistance Mechanisms

Apple rootstocks were decisive in apple autotoxicity tolerance. Screening and breeding autotoxicity tolerant mutants could improve apple autotoxicity tolerant ability. Recently tissue culture and mutagenesis technique were used in screening autotoxicity tolerant mutant successful in many crops. But the mutant's reality was often doubtful, because it might not be genotype. So it is the most important to identify the genotype of the mutants.This experiment was use to five kinds of phenolic acids`s contents like phloridzin were tested from different orchard soil area in this experiment; This experiment took the begonia varieties ---Malus micromalus and dwarfing rootstock as the tested varieties, and used the 98% phloridzin as the stress material,in order to screen meristem-tip that growing better to further training through setting five different concentration gradient material in the medium to stress the hitom meristem-tip.We cultivate the resistance in vitro shoot after screen and the wild type of in vitro shoot, and took the inoculation in medium without phloridzin as control . we studied the plant`s growth, differentiation, Physiological and biochemical aspects between the resistant mutant and wild-type plants regenerated plant.The result showed that:1 It was that the phloridzin and p-hydroxybenzoic acid contents in the orchard soil were related from the old of fruit trees in orchard.2 Determined the selection pressure that using phloridzin as the stress screening material resistance in ordre to screening of resistant mutants,the result is Malus micromalus variety is 3g / L,and M26 variety is 2g / L.3 It can incresed the resistance for phloridzin of shoot on the continuous culture medium contens phloridzin. The survival rate of adventitious buds of two kinds of resistant cultivars were improved in the continous culture press.The differentiating capbility of the resistense shoot is lower than the control but higher than the wild-type after cultured on the medium With phloridzin.4 The resistant plant height, root length, fresh weight and other growth parameters were significantly higher than the wild type In phloridzin stress. Resistance analysis showed that the capbility of against phloridzin of transgenic is better than wild-type plantlets. Chosen out of two pairs of phloridzin resistance to shoot B-1 and M-1, further molecular identification and study its physical resistance.5 The protective enzyme activity,permeability regulation and the root activity was not significantly different physiological and biochemical indexes between CK treatment's B-1, M-1 and wild-type. Mutants of the protective enzyme treatment was significantly higher than the wild type in phloridzin stress which deal with the most significant difference in 4th day. The MDA contents of Mutation treated was significantly lower than wild-type processing, and handling of PRO accumulation of mutations was significantly higher than the wild-type deal. The root activity of mutant treatment was significantly higher than wild-type deal.6 Of the level of DNA molecules were exist differences between mutant plants and wild-type plants, but which of these polymorphisms and anti-phloridzin related needs further identification.