Photosynthesis and ChlorophyII Fluorescence Characteristics of Simmondsia chinensis (Link.) Schneider in the Arid-hot Valley of Jinshajiang River, China THE EXPERlMENT 0N GROW SEEDLINGS OF SIMM0NDSIA CHINENSIS CHEMICAL COMPOSITION OF JOJOBA OIL INTRODUCED BY YUNNAN Effects of high-temperature stress on physiological characteristics of leaves of Simmondsia Chinensis seedlings from different provenances