Studies On Ecophysiology Of An Invasive Species Eupatorium Adenophorum

Laboratory and greenhouse studies were conducted to determine the effect of several environmental factors on seed germination and seedling emergence of Eupatorium adenophorum. Seeds germinated over a range of 10 to 30℃with optimum germination at 25℃. High temperature markedly restricted germination, with no germination occurring at 35℃. E. adenophorum was moderately photoblastic, with 17% germination occurring in the dark. E. adenophorum germinated in a narrow range of pH (5.0 to 7.0). Maximum germination (94%) was observed in distilled water at pH 5.7. Germination decreased with increasing water potential, and germination was totally inhibited at osmotic stress below than -0.7MPa. Germination was greater than 65% at less than 100 mM NaCl concentrations and greater than 10% at 250 mM NaCl, with no germination at 300 mM NaCl. Maximum emergence occurred when seeds were planted on the soil surface. No seedlings emerged when planted 1.5 cm deep. These results suggest that the future range of E. adenophorum in China will be restricted largely to the Yunnan-Guizhou Plateau, which includes major parts of Yunnan and Guizhou provinces, the southwestern part of Sichuan province and the western part of Guangxi province. E. adenophorum also tends to be a sporadic problem in other regions, where the climatic and edaphic conditions are suitable for the seed germination.E. adenophorum is an invasive weed in southwestern China. The activities of several enzymes involved in plant protection against stress were assayed to determine physiological aspects of the E. adenophorum that might render the plant vulnerable to...