Effects Of Heavy Metal Cd On Alien Invasive Plants And Their Resistance To Disease

In recent years, global change has been a hot topic in ecology. Combining with the heavy metal pollution and alien plant invasion, we selected three kinds of widely distributed alien plants(Eupatorium catarium, Eupatorium adenophora and Solidago canadensis) in China, to study their tolerance and accumulation to Cd by adding Cd to the culture. Then E. adenophora which had high tolerance and accumulation to Cd was choosed to study the effects of Cd accumulation on alien plants. The purpose of the study was to explore the relationship between heavy metal pollution and alien plant invasion and to provide new research ideas for the study of the invasion ecology under global change. The main results were as follows:(1) Most alien compositae plants would probably have higher tolerance and accumulation to heavy metals. S. canadensis had higher tolerance to Cd in terms of growth and some physiological indexs and had high accumulation to Cd. At the same time, we found that both E. adenophora and E. catarium had higher tolerance and very high accumulation to Cd(more than 100 mg/kg Cd).(2) E. adenophora had high tolerance and accumulation to Cd. They growed well and there were no lesion on their leaves under 6.25 and 12.5 mg/kg Cd treatment.Furthermore, the roots of E. adenophora growed well and there were no significant differences among different treatments. The root activity decreased with the increase of Cd contents and root ROS increased with the increase of Cd contents. E.adenophora had very high accumulation to Cd(more than 100 mg/kg Cd). What’s more, the shoots and roots of E. adenophora respectively accumulated 543 and 1852mg/kg Cd under 25 mg/kg Cd teratment, which far beyond the critical value of Cd hyperaccumulator(100 mg/kg).(3) Cd accumulation improved the resistance of E. adenophora. In this study, we inoculated Rhizoctonia solani to the leaves of E. adenophora. It was found that the leaves showed element defence after accumulating Cd. The results showed that lesion area of these leaves under Cd treatments were significantly smaller than the control and the lesion area decreased with the increase of Cd contents.