| Puionium Gaertn which belongs to Cruciferae , is distributed in sandy soil of Mongolia altiplano. It is a kind of vegetable with officinal, hygienical, feeding and sand-fixation functions. Two of its species, P.cornutum(L.) Gaertn. and P.dolatum Maxim.var.dolabratum, were studied in this paper. The results showed that there were stomata in both the upper epidermis and the lower epidermis in cotyledon and euphylla, which thickened and belonged to anisocytic type. The stomata make and break showed a two-kurtosis trend in the two species, but the stomata make and break responsed slower in P.cornutum(L.) Gaertn than in P.dolatum Maxim.var.dolabratum. The trend of physiological effect on leaves in vitro were basically the same under different storage conditions, though the changes were slower in the refrigerate treatment compared with room temperature treatment. Physiological and environmental factors had synergetic effects on the photosynthesis processes of the two species. Photosynthetic daily change showed a two-kurtosis trend, with the"photosynthetic noon break"phenomenon. The content of chlorophyll was comparatively high and chlorophyll ratio was low, which guaranteed obvious light adaptation capacity. The light compensation point and the light saturation point were 20μmol·m-2·s-1 and 1200μmol·m-2·s-1 respectively in P.cornutum(L.) Gaertn. while the light compensation point and the light saturation point were 50μmol·m-2·s-1and 1200μmol·m-2·s-1 respectively in P.dolatum Maxim.var.dolabratum, indicating that the available range of light intensity in P.cornutum(L.) Gaertn. was wider than in P.dolatum Maxim.var.dolabratum. The photosynthetic Characteristics of P.cornutum(L.) Gaertn. excelled that of P.dolatum Maxim.var.dolabratum. |
