Study On The Invasive Characteristics Of Solanum Rostratum Dunal.

Solanum rostratum Dunal.was adopted as the study objective.Wild field investigation,electron microscope-based observation of ultra-structure,cultural dish filter paper method,photosynthesis system-based measurement and other methods were used to study distribution range of S.rostratum Dunal.in Inner Mongolia,ultra-structure of pistil and stamen,germination of seeds and photosynthetic features in different growth periods,aiming to identify invasion and harm of S.rostratum Dunal.in Inner Mongolia and to reveal its invasion-related features.Major study results are as follows.(1)It was indicated by field investigation that S.rostratum Dunal.had gradually expanded on the basis of its original distribution range and showed increased harms.By October 2016,S.rostratum Dunal.was majorly distributed in 5 Banner counties,3 cities and several villages in four league cities in Inner Mongolia,such as Jinshan development zone in Hohhot city,Jinqiao development zone and Soil left banner in Hohhot,Bairin West Banner county and Arhorchin Banner in Chifeng city,urban streets of XiLinhot city in XiLin Gol League city,and Right Tumete banner and Guyang county in Baotou city.Invasion habitats include roadside,farmland,forest edge,scrap heap,disturbed area,river bed,green belt,and areas inside and outside peasant households.Among the districts,S.rostratum Dunal.was distributed most extensively and presented most severe harms in Chifeng city,including 7sumus of Bairin West Banner and 7 villages/counties and villages in Arhorchin Banner county.Jinshan development zone of Hohhot city ranked the second position and S.rostratum Dunal.has expanded to Jinchuan culture square.(2)It was indicated by ultra-structure of S.rostratum Dunal.that the chapiters ware incurved internally and their surface was composed of long stripped cells,which extended to its top and formed mastoid-like papules.Thechapiters were long and thin;the epidermis cells were stripped with numerous glandular hairs.The shapes of large and small stamens were similar and stripped;the stamens were separated by connective and incurved internally;they were composed of stripped and irregular cells.Epidermis cells of a small stamen anther were compact and arranged in a regular basis;the surface showed relatively large and a high amount of strumae.Epidermis cells of a small stamen anther were loosely arranged,and the surface showed less strumae than a small stamen.Its anther showed porous dehiscence.It was observed at the conjunction between anther and filament that the surface of filament showed mild cutinization.(3)According to S.rostratum Dunal.germination experiments under different temperatures,different collection period and different storage conditions,it was indicated that optimal germination temperature range for S.rostratum Dunal.seeds was 20?-30?,and the germination effect is the best at 30 ?;the optimal storage method was outdoor storage.As S.rostratum Dunal.seeds grown in Inner Mongolia are completed matured during the first10 days of October,manual removal before October can effectively hinder its further expansion.(4)The photosynthenic features of S.rostratum Dunal.during different growth stages are as follows.The net photosynthetic rate shows a changing trend of rising to declining with a peak during its flowering period and a lowest level during seeding period.The leave light compensation point of S.rostratum Dunal.is 46-84 ?mol·m-2·s-1,the light saturation point is 950.79-1210.10 ?mol·m-2·s-1,the apparent quantum yield is 0.0152-0.020?mol·m-2·s-1,CO2 compensation point is 78.515-120?mol·mol-1,and CO2 saturation point is 766-956 ?mol·mol-1.The range of carboxylation efficiency is 0.042-0.057 ?mol·mol-1.It is indicated that S.rostratum Dunal.shows a strong adaptability to strong light and a low utilization rate of weak light.It is a light-demanding plant.The relatively high carboxylation efficiency indicated that S.rostratum Dunal.shows high CO2 utilization performance under a condition of low CO2 concentration,which is the physiological basis forsuccessful invasion of S.rostratum Dunal.