Study On Photosynthetic Characteristics Of Different Camellia Clones At Growth Of Seedlings

The relative chlorophyll content of forty different Camellia oleifera clones were measured and ranked in Camellia germplasm repository of National Forest Farm of Tongkou of Minhou county in Fujian, and12clones were selected which had higher relative chlorophyll content. The selected12different Camellia oleifera clones from Fujian, Jiangxi, Zhejiang provinces as test material, their photosynthetic characteristics and daily variation process were studied. Photosynthetic and fluorescence parameters were studied with LCPro+portable photosynthesis analyzer system in July and August2013. Diurnal variation of photosynthetic physiological indexes%diurnal variation of the chlorophyll fluorescence, the correlation between main photosynthetic indicators and physiological and ecological factors and the relationship between the chlorophyll fluorescence parameters of12different Camellia oleifera clones were studied, with the aim of selecting fine and adaptable Camellia oleifera clones and providing scientific bases for choosing the excellent varieties and high photosynthetic efficiency and providing a reference for improving photosynthetic capacity and productivity. The results were as follows:(1)12clones with the SPAD value of relatively high were selected:O65-8、DN5、DN6、 PN3、PN6、PN7、QN6、Changing4、Changlin20, Changlin21、Changlin23、Changlin53.(2) The diurnal variation of Pn of12different Camellia oleifera clones showed two forms of a single-peak curve and double-peak curve. The maximum of net photosynthetic rates of different Camellia oleifera clones from high to low in turn was:O65-8>Changlin23>Changlin4>DN6> DN5>Changlin20>PN6>Changlin53>PN7>Changlin21>PN3>QN6. Cluster analysis showed that Changlin23and Changlin4Camellia oleifera clones from Fenyi county, Jiangxi were more adaptable to photosynthesis in high temperature and strong light conditions, the clone had stronger utilization of light energy.(3)The clone of Changlin53、Changlin21、PN6、PN7、Changlin20、DN5、QN6and Changlin21had strong adaptability to high temperature by increasing transpiration rate and reduce leaf temperature. Changlin23、Changlin4、Changlin21and PN6had strong drought resistance because of high water use efficiency. The diurnal variation of Ci and the diurnal variation of Pn had opposite trend. The diurnal variation of Ci presented "U" curve. Ci of Changlin53、QN6、PN7、 O65-8were high, showing they had strong ability to use weak light. Different Camellia oleifera clones had different adaptability to different environmental conditions, so it was suitable for choosing suitable varieties for different environment according to different clones to achieve the purpose of right kind of trees planted the right place.(4)The main environmental factors which effected on the diurnal variation of Pn of12different Camellia oleifera clones were PAR and RH. And the main physiological factors was Cond and next was Tr through the relevant analysis. Pn and Ci were negative correlation level, which was further illustrate the noon of intercellular CO2concentration was low and the Pn value was falling, which were caused by the tomatal factors. The main environmental factors which effected on the diurnal variation of Tr of different Camellia oleifera clones were PAR and the main physiological factors was Cond.(5)The response of light show that different clones have different light use range. QN6、 DN6、 Changlin20and PN7not only have high light saturation point, but also has lower light compensation point. Show the clones have very widely light intensity using range. Both can better adapt to the strong light environment and can adapt to a low light environment. Changlin53、 PN6、DN5are opposite that they are more suitable for planting in shade shaded environment of part time. The apparent quantum efficiency of PN7is significantly larger than the other clones. And its maximum net photosynthetic rates (Pn) of is highest. It is Indicate that the photosynthetic potential of PN7is greater than other clones, and has stronger photosynthesis ability and better use of weak light environment.(6)Photosynthetic CO2response curves showed that CO2compensation point range from30.09μmol·mol-1to124.52μmol·mol-1, and saturation point range from1535to1860μmol·mol-1. Among them, DN6had a wide range of CO2available, followed by Changlin23、PN6、PN3. The low CO2compensation point was one of indicators of Camellia optimal selection and breeding high-yielding varieties. These clones, including PN3、Changlin23、Changlin20、DN6, were relatively ideal clones. CE of Changlin20and Changlin23were significantly greater than the other clones, indicating that the two clones had stronger ability that using low CO2concentrations than other clones.(7)The study of chlorophyll fluorescence parameters showed that there were divisity about photosynthetic performance between different Camellia oleifera clones. Diurnal variation showed that PSII potential activity and PSII original light energy conversion efficiency of PN6、DN5、 Changlin4、Changlin21and Changlin53were higher than other Camellia oleifera clones and the light inhibition were also lighter, photosynthetic performance were better at the same time. ETR of PN6、O65-8、DN5、Changlin23、 Changlin53were high, so their ability to adapt to glare, anti-stress capability and the ability to recover after stress were significantly better than the other clones. Changlin53、QN6、PN6、PN3、Changlin21、Changlin23had a strong ability of self-protection to response to light damage because of their high heat dissipation levels.