| The study was carried out by one-year-old potted seedlings ofjojoba(Simmondsia Chinensis(Link) Schneider) from Kehe in Sichuan of China,Phoenix in USA and Condobolin in Australia(represented by Z1,Z2 and Z3 respectively).The characteristics of drought resistance of 3 jojoba provenances were studied by analyzing the regularity for changes of growth,physical and chemical indexes under drought stress,which helped to provide scientific bases for rational cultivation of jojoba and a reference for selecting and brdeeding the jojoba provenance which has comparatively stronger ability in drought resistance.The main results are as following:1.The relative height growth of all the 3 provenances were restrained under drought stress,which showed significant downtrend.2.The LRWC of 3 provenances declined with the aggravation of drought stress,the decrease was Z1＞Z3＞Z2.Soil moisture is the important facto for LRWC.3.The activities of the protecting enzyme System of the 3 provenances had ascended under drought stress.The activity of SOD of Z3 increased the most,the activity of CAT and POD of Z1 increased the most.The content of MDA of Z3 had been ascending under drought stress,there was no appreciable changing trend in Z1 and Z2.4.The content of osmotic regulatory metabolites of the 3 provenances ascended as a whole under drought stress.The increase amount of PRO contents and soluble sugar were: Z1＞Z2＞Z3.5.Net photosynthesize,transpiration rate,stomata conductance,chlorophyll content, energy conversion of PSⅡ,potential activities of PSⅡhave been descending with the degree of soil drought increasing.Pn,Tr,Gs decreased with aggravation of drought stress in the same way:Z3＞Z2＞Z1.The chloropyll content decreased:Z1＞Z3＞Z2.Fv/Fm,Fv/F0 decreased:Z3＞Z1＞Z2.6.The seedling of jojoba of Z3 died firstly,the deathpoint of soil water content is 5.51%～6.26%.There was negative correlation between the deathpoint and the soil moisture.7.Under drought stress,different changes in drought indexes of jojoba seedlings in order to resist adversity.These showed that jojoba had strong drought tolerance. Comprehensive evaluation of drought resistance of jojoba from 3 provenances was given based on principal components analysis and fuzzy subordination function analysisi method. The drought resistance abilities order(from strong to weak) was Kehe in Sichuan of China,Phoenix in USA and Condobolin in Australia.
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