Abstract:

The acidity or alkaline soil in many areas of south China is the main abiotic stress for citrus plants. Selection of rootstocks tolerant to high or low pH condition is very important for citrus production. In this study，8 different citrus rootstocks including Shiikuwasha（Citrus depressa Hayata Blanco），Zhuju（C. reticulata Blanco），Shantou Suanju（C. reticulata Blanco），‘Goutou’sour orange（C. aurantium L.），Carrizo Citrange（C. sinensis × Poncirus trifoliata），Ni 8047（C. junos），Daoxian Yeju（C. daoxinensis Blanco）and Niedu Yeju（C. reticulate Blanco）were used as materials to evaluate the acidity and alkaline tolerances and screen for the superior rootstocks with better tolerance. Under acidic and alkaline treatments（pH 3.5 and pH 9.0），the symptoms of plant were observed. Meanwhile，the physiological and biochemical parameters related to the abiotic stresses tolerance such as MDA（malondialdehyde），soluble protein，Pro（proline），SOD（superoxide dismutase），POD（peroxidase）and CAT（catalase）were measured. The clustering and comprehensive subordinate function analysis were performed to evaluate the stresses tolerance. The results indicated that observed symptoms were consistent with the measurements of parameters. The Shantou Suanju，Shiikuwasha and Ni 8047 showed great tolerance to low pH stress（pH 3.5），while Daoxian Yeju and Niedu Yeju were susceptible. Zhuju，‘Goutou’sour orange and Shiikuwasha possessed good adaptability to alkaline condition，while Daoxian Yeju and Niedu Yeju were sensitive. Shiikuwasha demonstrated better tolerance to both high and low pH stresses with great potential to be used as rootstock or breeding material.

Key words: citrus, rootstock, acidity tolerance, alkaline tolerance, comprehensive subordinate function analysis