Effects Of Salinity On Genotypes Of Chinese Bayberry As Ameliorated By Paclobutrazol

Salt stress is one of the most critical factors limiting growth and development of plants.Paclobutrazol(PBZ)is widely used in agriculture because it induces salt stress tolerance in plants.This study was conducted to investigate the effects of PBZ on tolerance of seedlings from two Chinese bayberry genotypes(i.e.Wangdao-WD and Shenhong-SH).The effect of PBZ on salt tolertant of Chinese bayberry genotypes was evaluated by photosynthetic rate(Pn),relative water content(RWC),proline content,total chlorophyll content(Chl(a+b)),activity levels of superoxide dismutase(SOD)and catalase(CAT).Plants were treated with three concentrations of salt(0,0.2%,and 0.4% NaCl)and two concentrations of PBZ solution(0 and 2.0 ?mol L-1).The results obtained are vital because it will provide a basis for selection of salt-tolerant genotypes.The investigation will improve growth of Chinese bayberry,and will promote sustainable use of saline land resources.(1)Applicationof 0.4% NaCl,WD seedlings exhibited less reduction of Pn,RWC,Chl(a+b)and less increase of relative electrolyte conductivity(REC)and malondialdehyde(MDA)than seedlings of SH.Severe salt stress(0.4% NaCl)showed enhanced activities of antioxidant enzymes in WD,but slightly increased SOD and CAT activities in SH.Therefore,WD genotype had higher tolerance to severe salt stress than SH genotype.(2)Application of PBZ has increased RWC,proline content,Chl(a+b)and antioxidant enzymes activity in plants,which facilitated the two Chinese bayberry genotypes to acclimate to salt stress and to increase production of dry matter.It is concluded that Paclobutrazol(PBZ)has ameliorated the negative effects of salt stress in Chinese bayberry seedlings.