Study On NaCl Stress Tolerance Of Three Kinds Of Shrubs

This experiment through potted method, studied in different concentration treatments of three shrubs-Pyracantha fortuneana (Maxim.) Li,Photinia glabra var. robens and Ligustrumjaponicum Howardii under NaCl stress(0%(CK)、0.3%、0.6%、0.9%) changes of the growth, physiological and biochemical indexes and its response to salt stress,and test data by combining SPSS20.0 method of subordinate function analysis, evaluation of salt resistance of three kinds of shrubs. The results were described as follows:(1) With the increase of NaCl stress concentrations,three kinds of shrubs have different performance:Pyracantha fortuneana under 0.3%,0.6%,0.9% NaCl treatment appear different degrees of yellow, green, dry the phenomenon such as recession, growth potential, high strength under salt stress, and 0.6%and 0.9%in plant dead branches; Photinia glabra var. robens in 0.6% and 0.9% of high strength under salt stress, appearing red spot, leaf blade margin withered; Ligustrumjaponicum privet normal growth.(2) With the NaCl stress concentration and time goes on, the new branch of three kinds of shrub to reduce. Under the same concentration salt stress, Pyracantha fortuneana although can maintain growth rate higher, but the new branch growth rate is fastest decline,and the new branch relative growth decreased most more; Photinia glabra var. robens new branch growth although the slowest, but the new branch relative growth rate decreased speed is the slowest; Ligustrumjaponicum Howardii keep the intermediate position.(3) During NaCl stress, H2O2 and 02=-content of three kinds of shrub leaf was increased with the stress time in general decline, this is anti oxidase system of plants (SOD, CAT, POD, APX) and non enzymatic antioxidant system (AsA, GSH) are positive results. Among them, the contents of SOD, CAT, APX and GSH were rising firstly, but reduced with the time extended that aggravated the damage and revealed low ability of resistance salt in Pyracantha fortuneana, the contents of SOD, CAT and POD were rising last, while the contents of APX, AsA and GSH were rising firstly and then descended, revealed the stronger of resistance salt in Ligustrumjaponicum Howardii, and the same phenomenon as in Photinia glabra var. robens.(4) Under the stress of 0 days, Pyracantha fortuneana each treatment H2O2 were no difference as compared with the control, while 02"-content in low concentration was slightly higher than the CK,02"-content high concentration is far more than CK. In addition, in the 20d, of CK the 02-content reached the highest value, but the maximum value of H2O2 is in the 30d, so 02"-content change fast than H2O2.Thus 02--response is fast than H2O2 under the stress in Pyracantha fortuneana.(5) In the study, we found that APX, ASA and GSH exists dynamic balance under the salt stress. When AsA content is higher, the GSH content is low,.When mass of ASA contents were consumed and reduced by reactive oxygen species, that cannot provide enough energy for the APX and their contents decreased, otherwise the GSH contents were rising, Whereas the GSH were low down. This fully instructions the AsA-GSH system, one of the metabolic pathways between ASA and GSH, play an important role in the damage of Oxidative stress and ROS, and their contents were closely related to the resistance of plant.(6) Through eight indexes of salt tolerance coefficient for subordinate function analysis,the result was that the rank of salt tolerant ability of three species was Ligustrum japonicum Howardii> Photinia glabra var. robens> Pyracantha fortuneana.