Phenotypic Plasticity Of Solidago Canadensis Populations With Different Geographical Location And Their Responses To Shading And Salt Stress

Phenotypic plasticity has been one of the most importantmechanisms to promote the success of plant invasion. However, theimportant roles of adaptive phenotypic plasticity in the success ofdispersal are still unknown. Solidago canadensis, one of the mostharmful alien invasive plants in China, successfully dispersal from theeastern of China to the north, west and south of China. In this paper,15populations of S. canadensis were collected from the easterncoast of China from north to south and along the Yangtze River Valleyfrom east to west. We conducted two year common gardenexperiemnt to compared the variation and plasticity of phenotypictraits among two years. The response and phenotypic plascity of S.canadensis in response to salt stress and shading stress were alsotested..The results showed that:(1) Salt stress significantly reducedthe biomass, leaves number, plant height, net photosynthetic rate,indicating an adaptive strategy for S. canadensis confronting the saltcondition. And lower leaf number and physiological activity could alsohelp the individuals prevent the water leaving. Only the leaf numberand plant height varied significantly among populations with differentgeographical origins. The phenotypic plasticity, including the number of leaves, proline content, POD activity and transpiration rate, weresignificantly different among populations with different geographicalorigins and the salt tolerance based on aboveground, undergroundand total biomass had significantly negative correlation with theplasticity of leaf number.(2) Shading stress significantly reduced thebiomass and basal diameter, increased the plant height, leaf lengthand width, which indicated that S. canadensis increased contact areaof light and chlorophyâ…¡content for obtaining more luminous energy tomaintain photosynthesis. The lignin content, total phenols contentand total flavonoid content were significantly decreased whichindicated that shading stress reduced the defense capability. Thephenotypic plasticity of different traits in respose to shading stresswere significantly different among populations with differentgeographical origins.(3) The second generation of common gardenhad lower basal diameter, plant height, thousand seed weight, therelative chlorophyâ…¡content and higher leaf length, leaf width, leafarea and the transpiration rate compared with thse in the firstgeneration, indicating an adaptive strategy for S. Canadensis afterincreasing number of plant of limited resource for optimal resourceallocation; The phenotypic plasticity of different traits of commongarden were significantly different among varied populations. Theseresults not only broadened the theoretical system of invasive ecology,but also provided the reference for prevention to the alien invasiveplants, which could provide theory evidences for the management andcontrol of the invasive S. Canadensis.