STUDY ON THE DIFFERENCES IN PHOTOSYNTHETIC CHARACTERISTICS AND LEAF ANATOMICAL STRUCTURE AMONG VARIOUS SPECIES OF ORMOSIA PLANTS

In order to explore the photosynthetic characteristics and leaf anatomical structure of the Ormosia genus, a series of measurements were taken on three endangered species: Ormosia xylocarpa, Ormosia henryi and Ormosia microphylla.These measurements included the light response curve, the CO2 response curve, the leaf anatomical structure, the leaf epidermal characteristics and the chlorophyll content.The aim of this study was to identify the factors influencing plant photosynthesis.Results showed: (1) The three Ormosia species were light-favoring tree species.O. henryi had strong photosynthetic characteristics, and the maximum photosynthetic rate (Pmax) was 15.1354 molms, which was much higher than the other two Ormosia species.Among the three species of Ormosia, O. henryi has the strongest weak light utilization ability and CO2 utilization rate, and O. xylocarpa has a strong CO2 utilization range.(2) Among the three Ormosia species, O. xylocarpa had the thickest leaves, but the thickness of palisade tissue was O. henryi > O. xylocarpa > O. microphylla.(3) The single stomatal area of O. henryi was significantly higher than that of O. xylcarpa and O. microphylla, and the stomatal density of O. xylcarpa was significantly higher than that of O. henryi and O. microphylla.(4) The Chl a of the three Ormosia species was higher than Chl b, which was similar to the results of photosynthetic characteristics.The Chl a, Chl b and Chl (a+b) of O. henryi were significantly higher than those of O. xylocarpa and O. microphylla.The Car content of O. microphylla was significantly lower than that of O. henryi and O. xylocarpa.In conclusion; the leaf microstructure, chlorophyll content and epidermal characteristics of the three Ormosia species are significant importance with regard to their photosynthetic capacity.During the cultivation process, increasing CO2 concentration in the short term can increase the photosynthetic rate of the aforementioned three Ormosia species; in seedling management, appropriate increase in light conditions for Ormosia plants has been demonstrated to facilitate their growth.