Allelopathic Effects of Root Water Extracts of Eucalyptus Urophylla on Photosynthesis Characteristics of Schima superba and Cinnamomum camphora Seedlings

To study the allelopathy effects of eucalyptus urophylla on photosynthesis characteristics of schima superba and cinnamomum canphora seedlings, three concentrations of root extracts(l:6, l:12 and l:24) were prepared with eucalyptus urophylla and used for pot culture experiment on photosynthetic indexes of two species seedlings. Being treated with the root extracts, the change trends of net photosynthetic rate, transpiration rate and stomatal conductance of schima superba were basically the same. The diurnal variations of intercellular CO2 concentrations for all of the treatments of schima superba showed the basal identical trend. The net photosynthetic rate, transpiration rate and stomatal conductance diurnal variation of cinnamomum canphora seedlings treated with the extraction of root had the same trend line as a double-peak curve with the maximum peak at the same time. The diurnal variation of intercellular CO2 concentrations of the treatments at noon was higher than that in the morning and evening. However, the controls of cinnamomum canphora fluctuated in a small concentration range.