%0 Journal Article %A Sheng-Bo SHI %A Hui-Mei LI %A Xue-Ying WANG %A Xiang-Guo YUE %A Wen-Hua XU %A Gui-Chen CHEN %T COMPARATIVE STUDIES OF PHOTOSYNTHETIC CHARACTERISTICS IN TYPICAL ALPINE PLANTS OF THE QINGHAI-TIBET PLATEAU %D 2006 %R 10.17521/cjpe.2006.0006 %J Chinese Journal of Plant Ecology %P 40-46 %V 30 %N 1 %X

The photosynthetic characteristics of three medicinal alpine plants, Rheum tanguticum, Anisodus tanguticus and Gentiana straminea, were studied and compared to a low land species, Isatis indigotica. The response of net photosynthesis rate (Pn) to intercellular CO2 concentrations (Ci) and photon flux density (PFD) was determined using a LI-6400 photosynthesis system. The photosynthetic pigments and UV-B-absorbing compounds also were determined in the four species in order to evaluate differences in their photosynthetic characteristics. The results indicated that the three alpine plants had relatively low photosynthetic quantum yields (AQY) as compared to the low land species of I. indigotica, and AQY, carboxylation efficiency (CE) and photorespiratory rate (Rp) were the lowest in R. tanguticum. However, Pn did not respond strongly to changes in PFD, which may be due to the high concentration of photosynthetic pigments and UV-B-absorbing compounds in the leaves. Similar to R. tanguticum, the alpine plant G. straminea also had higher contents of UV-B-absorbing compounds, chlorophyll and carotenoids, but its Rp was higher and Pn was limited by stomatal conductance in response to PFD and Pn was lower. The photosynthetic characteristics of the alpine species, A. tanguticus, was similar to the low land species, I. indigotica, both of which had a high AQY and CE. These results indicated that although there were some differences among the three alpine species, no corresponding characteristics appeared in photosynthetic advancements. The response of Pn to Ci exhibited Pi regeneration limitations after reaching full CO2 saturation. The changes of Rp in the four species were similar to that of maximum Pn in photosynthetic Ci response.

%U https://www.plant-ecology.com/EN/10.17521/cjpe.2006.0006