| The Camellia oleifera in Hainan is in good quality and tea oil has a unique fragrance, it is called’Hill grapefruit oil’in the local, which has long history of cultivation. The Camellia oleifera in Hainan is short supply in the market and has great development potential. In order to promote the healthy development of Camellia oleifera industry in Hainan, select a variety of high efficiency of photosynthesis for the local climate and environment and provide theoretical basis for the work of provenence selection and comprehensive evaluation, LI-6400 portable photosynthesis system was used to study the photosynthesis of Camellia clones in hainan:’Hainan 2’,’hainan 6’,’Hainan 9’,’Hainan 18’and’hainan 19’Under field conditions. This research studied diurnal variation of photosynthesis and environmental factors of five cultivars of Camellia clones in Hainan, comparison of chlorophyll content and chlorophyll fluorescence; the response of photosynthesis to light intensity and CO2 concentration; and study the discipline of photosynthesis under net natural state. The main findings are as follows:1. By comparing photosynthesis diurnal variation of Camellia oleifera in Hainan found that under net natural state, the photosynthetic active radiation (PAR) and air temperature were single-peak curve, and it reached to the highest by 1421 μmolm-2-s1 and 37.7℃ at 13:00; relative humidity of atmosphere and atmospheric CO2 concentration is irregular U-shaped, and it came to the lowest by 47% at 13:00 while the air CO2 concentration came to the lowest by 376 μmol at 15:00.2. Net photosynthetic rate of’Hainan 2’changed as single peak curve, while other four kinds of clones in the diurnal variation of net photosynthetic rate were double-peak curve, the peak appear at 9:00 am or at 15:00 pm, in the diurnal variation of net photosynthetic rate in the order from hight to low are as follows:’Hainan 19’5.50 μmolm-2s-1>’Hainan 18’5.02 μmolm-2s-1>’Hainan 9’4.68 μmolm-2s-1’Hainan 2’4.06 μmolm-2s-1>’Hainan 6’3.84 μmolm-2s-1, and it is the same as transpiration rate; in the diurnal variation of stomatal conductance of’Hainan 18’and’Hainan 2’was single-peak curve, while’Hainan 9’、’Hainan 19’ and ’Hainan 6’ had same change as net photosynthetic rate; all of the five kinds of camellia clones in the diurnal variation of intercellar CO2 concentration(Ci) were irregular U-shaped. Among the physiological factors, transpiration rate(Tr),stomatal conductance (Gs),and intercellular CO2 concentration(Cj) were the major factors that influenced the variations of net photosynthetic rate(Pn) of the five kinds of camellia clones, and luminous strength(PAR) was one key ecological factors that influenced the variations of Pn.3. The light saturation points of the five kinds of Camellia clones were 1408 μmolm-22s-1-1523 μmolm-2s-1,the light compensation points was bewteen 19.65 μmolm-2s-1 and 36.37 μmolm-2s-1,the apparent quantum efficiency were 0.0307-0.0455. Data therefore showed that the leaves of Camellia. had the higher utilization efficiency on weak light and strong light. Camellia was sun plants.4. The CO2 saturation points of the five kinds of camellia clones were 1008 μmolm-2s-1-1328 μmolm-2s-1, the CO2 compensation points was bewteen 78.4 μmolm-2s-1 and 96.6μmolm-2s-1,the carboxylation efficiency were 0.053-0.095. The CO2 compensation point is high, consistent with the photosynthetic characteristics of C3 plants.5. The maximum photochemical efficiency(Fv/Fm),ΦPSⅡ, Fv/Fo, ETR and qP of ’Hainan 19’ was the highest in five clones, while Fo and NPQ was the lowest; The maximum photochemical efficiency(Fv/Fm),ΦPSⅡ, Fv/Fo, ETR and qP of ’Hainan 6’ was the lowest in five clones, while Fo and NPQ was the highest; The other three clones between ’Hainan 19’ and ’Hainan 6’... |
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