Study Of Dodder's Selective Parasitism Between Native Plants And Invasive Humulus Scandens

Biological invasion damages natural community and Eco-System of the invaded habits,which leads to great loss of biodiversity species,and causes great economic loss and ecological problems,even results in health damage of human beings,animals and plants.At present,the methods of controlling biological invasions include manual,physical,chemical,biological,comprehensive means and so on.Biological control is the most effective and greenest control method.It is based on the ecological balance theory between natural enemy and host species to restrain their reproduction and expansion and maintain a new balance in the food chain by introducing natural enemy of the invasive species.However,it is considered that the introduction of natural enemy will lead to a second biological invasion.Accordingly,screening local enemy species to control the invasive plants biologically would be a new direction of biological control.In this study,we wanted to know the influencing factors of dodder selecting hosts between native species and invasive Humulus scandens in a pot experiment.The factors consisted of plant origin(exotic or native),plant density(illumination intensity),biodiversity(species number),water content and the nutrient concentration(carbon-C,nitrogen-N and phosphorous-P).By comparing the parasite number(percentage)of dodder between native plants and invasive plants,we can analysis the major factors influencing dodder's hosts selection.The results indicated that the parasite number of dodder was increasing with both the decline of illumination under plant canopy and the increase of plant N concentrations.However,the parasite number of dodder had no obvious connection with plant origin,biodiversity,water content,C and P concentrations.The results demonstrated that the main influencing factors of dodder's selective parasite were illumination under plant canopy and plant N concentration rather than plant origin,biodiversity,water content,C and P concentrations.Invasive H.scandens formed high-dense single plant or single-dominant community without no or few native plants and with very low illumination under plant canopy in the field,so dodder has no choice but to parasite H.scandens.Based on our results it can be inferred that dodder could parasite and damage native species,accordingly dodder only can be used to control H.scandens when H.scandens forms dense single communities in the field.Although dodder can damage native species when we use dodder to control H.scandens,our study found the factors influencing dodder's host selection,which provides good information for any future study of dodder to bio-control invasive species.