Photosynthetic Characteristics of Camellia oleifera Clones at Different Growth Phases

The photosynthetic characteristics of three Camellia oleifera clones, i.e., XL67, XL1, and CK at different annual growth phases including the new shoot growing stage, fruit developing stage, fruit maturing stage, flowering stage,and dormant stage were studied. The results showed that there were two types of Pn diurnal variation curves of C. oleifera clones with single peak and double peaks respectively. There was significant differences in Pn among the three clones, that the Pn value of XL67 was significantly higher than that of XL1 and CK. It was showed that the highest transpiration rate of the three clones occurred at the fruit growth stage, while the lowest transpiration rate happened at the dormant stage. The average light compensation point of XL67, XL1, CK was 51.4 μmol/(m2·s), 52 μmol/(m2·s), and 51.8 μmol/(m2·s). The average light saturation point of XL67, XL1, CK was 570 μmol/(m2·s), 552 μmol/(m2·s), and 521 μmol/(m2·s), respectively. The study showed that stomatal conductivity and Ci were the major physioecological factors which influenced on Pn of XL67, XL1 and CK, among which the Pn index of XL1 and CK was mainly influenced by PAR.