2个油茶品种及6个近缘种的光合特性日变化规律

为了筛选油茶近缘种高光效种质资源,从而为培育油茶新品种提供优质材料,以2个普通油茶品种(‘湘林1’与‘湘林97’)和6个近缘种(博白大果油茶、越南油茶、浙江红山茶、溆浦大红山茶、攸县油茶、滇山茶)为试验材料,对其叶片的净光合速率、蒸腾速率、胞间CO2浓度、气孔导度、水分利用效率等光合参数进行了测定和分析。观测结果表明:滇山茶、攸县油茶、越南油茶、博白大果油茶和‘湘林1’与‘湘林97’叶片的净光合速率均呈“单峰”曲线的变化趋势,其气孔导度和蒸腾速率亦均呈“单峰”曲线的变化趋势,而其胞间CO2浓度却呈“V”型曲线的变化趋势;浙江红山茶和溆浦大红山茶的净光合速率均呈“双峰”曲线的变化趋势,其气孔导度呈“平稳”型曲线的变化趋势,胞间CO2浓度呈“W”型曲线的变化趋势,蒸腾速率呈“单峰”曲线的变化趋势,说明其均存在光合“午休现象”。相关性分析结果表明:净光合速率与气孔导度呈极显著正相关(P<0.01),与水分利用效率呈显著正相关(P<0.05);气孔导度与水分利用效率呈极显著正相关(P<0.01)。主成分分析结果表明:从5个光合参数中提取了特征根>1的主成分2个,其累计贡献率为83.545%;主成分1(F1)中净光合速率、气孔导度和水分利用效率的累计正向贡献率最多,主成分(F2)中蒸腾速率的累计正向贡献率最多;根据综合评价结果可知,2个普通油茶品种及6个近缘种的光合效率由高到低依次为:油茶‘湘林1’>滇山茶>油茶‘湘林97’>攸县油茶>博白大果油茶>越南油茶>溆浦大红山茶>浙江红山茶。

Diurnal variation regulations of photosynthetic characteristics in two Camellia oleifera cultivars and six related C. oleifera species

In order to select some high light-efficiency germplasm resources in Camellia oleifera, and to provide some high-quality materials for cultivating new C. oleifera cultivars, using two C. oleifera cultivars (‘XL1’ and ‘XL97’) and six related species (C. gigantocarpa, C. vietnamensis, C. chekiangoleosa, C. magniflora, C. yuhsienensis, C. reticulata) as test materials, some indexes were determined and analyzed, including net photosynthetic rate, transpiration rate, intercellular CO2 concentration, stomatal conductance, water use efficiency and so on. The results of observation and determination showed that, change trends of net photosynthetic rates in C. gigantocarpa, C. vietnamensis, C. yuhsienensis and C. reticulata and two C. oleifera cultivars were single-peak curves, those of their stomatal conductance and transpiration rates also were single-peak curves, but those of their intercellular CO2 concentrations were V-shape curves. Change trends of net photosynthetic rates in C. chekiangoleosa and C. magniflora were double-peak curves, stomatal conductances were stable, those of intercellular CO2 concentrations were W-shape curves, and those of transpiration rates were singlepeak curve, so lunch break phenomena existed in their photosynthesis. The results of correlation analysis showed that: net photosynthetic rate was very significant positive correlated with stomatal conductance (P < 0.01), and significant positive correlated with water use efficiency (P < 0.05). Stomatal conductance was very significant positive correlated with water use efficiency (P < 0.01). The results of principle component analysis showed that, two principal components with eigenvalue over one were extracted from five photosynthetic parameters, and their cumulative contribution rate reached 83.545%. Cumulative positive contribution rate of net photosynthetic rate, stomatal conductance and water use efficiency in the first principal component (F1) was the largest, that of transpiration rate in the second principal component (F2) was the largest. Based on the results of comprehensive evaluation and photosynthetic efficiency from high to low, order of the two C. oleifera cultivars and six related species was C. oleifera ‘XL1’, C. reticulata, C. oleifera ‘XL97’, C. yuhsienensis, C. gigantocarpa, C. vietnamensis, C. magniflora, C. chekiangoleosa.