Influences of host species on transpiration, photosynthesis, chlorophyll and mineral contents of medicinal hemiparasiteThesium chinenseTurcz
Thesium chinense (Santalaceae) is an obligate root hemiparasite and the whole weed serves as a traditional medicine in China. This paper examined chlorophyll (Chl) concentration, transpiration (E), photosynthesis (Pn), stomatal conductance (g), respiration nighttime (Rd), water use efficiency (WUE), and mineral elements of T. chinense grown with different hosts or without host. The results showed that Chl concentrations, Pn, Pnmax, and WUE of T. chinense grown with host were significantly higher, approximately 1.5–3 folds, than that grown without host. E and g value of T. chinense greatly exceeded that of their hosts during the daytime—they increased about 1.5–3.5 folds (except of Gnaphlium affine) and 1.2–3.0 folds, respectively, while maintaining little higher or equal to their host during night but very much lower than daytime. The WUE value of T. chinense was generally much less than that of their hosts, except Eremochloa ophiuroides. T. chinense grown with hosts had higher concentration of K, P, Cu and K/Ca ratio, and lower Na concentration compared with that without host plants. There were also differences among different host species backgrounds on all examined parameters of T. chinense. We pointed out that Imperata cylindrica, Prunella vulgaris, and Gnaphlium affine were more suitable hosts than E. ophiuroides. As an additional result T. chinense can mostly be independent as for C supply.