Effects of Light Intensity on Photosynthetic Physiological Char-acteristics and Biomass of Three Yellow Camellia Species
Camellia perpetua,C.flavida and C.tunghinensis belong to Theaceae,Camellia and Camellia Sect.Chrysantha.They are the second-class national key protected wild plants.The distribution range of these three species is narrow,and the wild resources are on the verge of extinction.Exploring their adaptabili-ty to different light environments and finding the light intensity suitable for their growth can provide a theo-retical basis for the artificial breeding,population restoration and ex-situ protection of these three yellow Ca-mellia species,and can also provide a partial explanation for the reasons for the habitat differences of their wild populations.This study used 3-year-old cuttings of the three yellow Camellia species as experimental materials and used artificial shading methods to study the effects of different light intensities(8％,20％,45％,100％)on their photosynthetic physiological characteristics and biomass.The results showed that:(1)The three yellow Camellia species had higher maximum net photosynthetic rate(P max),Apparent Quan-tum Yield(AQY),maximum fluorescence(F m),maximum photochemical efficiency(Fv/Fm),actual photo-chemical efficiency(ΦPS Ⅱ)and photosynthetic Electron Transfer Rate(ETR)under low light conditions(8％and 20％light intensity),indicating that they had better adaptability to low light environment.(2)The Pmax of C.perpetua remained at a high level under 45％light intensity,and the Light Saturation Point(LSP)showed an increasing trend with the increase of light intensity.However,the Pmax and LSP of C.fflavida and C.tunghinensis increased first and then decreased with the increase of light intensity,and both reached the maximum at 20％light intensity.(3)With the increase of light intensity,the contents of total chlorophyll(Chl),chlorophyll a(Chl a),Chlorophyll b(Chl b),and carotenoid(Car)in the three yellow Camellia spe-cies leaves decreased,Car/Chl values increased,and Chl a/Chl b values first decreased and then increased.(4)With the increase of light intensity,the root,stem,leaf biomass and total biomass of the three yellow Ca-mellia species increased first and then decreased.Among them,the total biomass of the C.perpetua was the highest at 45％light intensity,while the C.flavida and C.tunghinensis were the highest at 20％light inten-sity.In summary,C.perpetua is more tolerant to strong light,followed by C.flavida,and C.tunghinensis is the weakest.C.perpetua prefers a medium light environment(45％light intensity),while C.flavida and C.tunghinensis prefer a medium to low light environment(20％light intensity).The photosynthetic charac-teristics of the three yellow Camellia species are consistent with the characteristics of the light environment of the wild population.
万方数据
维普
