1.College of Forestry, Guizhou University,Guiyang 550025,China;2.Guizhou Botanical Garden, Guiyang 550004, China
The endangered plant Oreocharis esquirolii and two species of the same genus including O.elegantissima and O. duyunensis were used to compare the photosynthetic physiological characteristics and anatomical structures of leaves in the same cultivation habitat to study the differences in photosynthetic capacity between O. esquirolii and two species of the same genus.The results showed that Chl a and （Chl a+Chl b） of O. esquirolii was significantly lower than that of the other two kinds of Gesneriaceae （P<0.05）.The results of chlorophyll fluorescence characteristics showed that Fo was significantly higher（P<0.05）， Fv/Fm，Fv/Fo，Y（Ⅱ） and ETR were the smallest among the three plants.During the photosynthetic diurnal process， the Pn of the three plants showed a relatively consistent bimodal curve.The intercellular CO2 concentration trend had a “W” shape， and the stomatal conductance had a downward trend with the passage of time.The transpiration rate had a downward trend， then increased and then decreased with the passage of time， and the three plants all had obvious photosynthetic “napping” phenomenon.Each index showed the lowest characteristic of O. esquirolii.In the photo response， the average Pmax value of O. esquirolii was 2.24 μmol/（m2·s）， which was significantly lower.The average value of Rd and LCP was 1.14 μmol/（m2·s） and 51.85 μmol/（m2·s）， significantly higher than that of the other two plants（P<0.05）.The results of CO2 response curve fitting showed that the vcmax and Jmax of O. esquirolii were 7.6 μmol/（m2·s） and 26.04 μmol/（m2·s）， significantly lower than that of the other two plants（P<0.05）.The results of histological section showed that the upper epidermis and the lower epidermis of O. esquirolii were 37.80 μm and 38.09 μm， higher than that of the other two plants.The PT and ST of O. esquirolii were 40.79 μm and 30.07 μm， significantly lower than that of the other two plants（P<0.05）， which may be related to the long-term adaptation of O. esquirolii to shady and barren habitats.It is indicated that the photosynthetic physiological characteristics of O. esquirolii are overall lower than two species of the same genus including O. elegantissima and O. duyunensis， and its ability to adapt to the light environment and the utilization rate of light energy is relatively weak， which may be one of the main internal factors of the endangered species.
欧明烛,安明态,任启飞,汤升虎,刘芳,马菁华,陈云飞. Comparison of photosynthetic physiological characteristics between endangered plant Oreocharis esquirolii and two species of same genus[J]. Jorunal of Huazhong Agricultural University,2023,42(1):51-59.Copy