庐山不同海拔茶树光合响应差异研究

为明确茶树光合活性和光系统Ⅱ(PSⅡ)的光抑制对海拔梯度的响应规律,以茶树品种庐山本地群体种为材料,观测了庐山5个不同海拔高度茶树叶片的光合气体交换和叶绿素荧光参数。结果表明,叶片厚度、最大净光合速率(Pnmax)、PSⅡ最大相对电子传递速率rETR(Ⅱ)max]、光补偿点(Ic)、光饱和点(Isat)、半饱和光强(Ik)、水分利用效率(WUE)等随海拔升高呈增加趋势,水汽压亏缺(VPD)、气孔导度、蒸腾速率、胞间CO2浓度、暗呼吸速率(Rd)等随海拔升高而呈下降趋势。PSⅡ潜在最大光化学量子产量(Fv/Fm)随海拔升高而增加;PSⅡ非调节性能量耗散量子产量Y(NO)]随海拔升高而降低。PSⅡ实际光化学量子产量Φ(Ⅱ)]、光化学淬灭(qP)、PSⅡ相对电子传递速率rETR(Ⅱ)]均随海拔升高而增加。综上分析,茶树在庐山低海拔处的光合作用和PSⅡ活性显著低于高海拔处,这与低海拔处叶片PSⅡ受到光抑制密切相关。

Different Photosynthetic Responses of Camellia sinensis to Lushan Altitude Gradient

To illustrate the photosynthetic response and photosystem Ⅱ (PSⅡ) photoinhibition of tea leaves to altitudinal gradient, native tea population of Camellia sinensis grown in the cloudy and misty Lushan Mount was measured in terms of photosynthetic gas exchange and chlorophyll fluorescence. Results show that the leaf thickness, maximum photosynthesis rate (Pnmax), maximum relative electron transport rate of PSⅡ rETR(Ⅱ)]max, compensation irradiation (Ic), saturation irradiation (Isat), half saturation irradiation (Ik) and water usage efficiency (WUE) increased with the altitude increased. While vapor pressure deficit (VPD), stomatal conductance, transpiration rate, intercellular CO₂ and dark respiration rate (Rd) displayed an opposite trend. The maximum potential photochemical efficiency of PSⅡ (Fv/Fm) increased while the quantum yield of non-regulated energy dissipation of PSⅡ Y(NO)] decreased with the altitude increased. The effective photochemical quantum yield of PSⅡ Φ(Ⅱ)], photochemical quenching (qP) and relative electron transport rate of PSⅡ rETR(Ⅱ)] all increased at higher altitudes. Overall, tea trees at lower altitudes exhibited decrease of photosynthetic performance compared to those at higher altitudes, due to photoinhibition of PSⅡ.