盆栽对柑橘叶片光合和叶绿素荧光特性的影响

以杂柑类品种‘天草’为试验材料,研究大田栽培下及不同体积盆栽限根条件下柑橘的光合特性和叶绿素荧光特性。结果表明,在不同光强下大盆栽培柑橘的净光合速率(Pn)、气孔导度(Gs)、胞间CO₂浓度(Ci)及蒸腾速率(Tr)与大田栽培相比均无显著差异；而小盆栽培显著降低了柑橘植株的Pn,Gs及Tr,但Ci无明显变化。大盆栽培会引起植株对高浓度CO₂的利用能力降低,但小盆栽培植株对不同浓度CO2的利用能力都显著低于大田栽培。从叶绿素荧光参数来看,大盆栽培除了导致天线色素转换效率(Fv'/Fm')下降以外,对PSⅡ最大光化学效率(Fv/Fm)、PSⅡ的实际光量子产量(ΦPSⅡ)、PSⅡ的电子传递速率(ETR)、光化学猝灭系数(qP)及非光化学猝灭系数(NPQ)均无显著影响；而小盆栽培导致Fv'/Fm',ΦPSⅡ,ETR显著下降,NPQ显著上升。能量分配分析的结果与光合和叶绿素荧光参数变化相一致。

Effects of pot cultivation on photosynthesis and chlorophyll fluorescence characteristics in leaves of citrus

Under pot and field culture, the photosynthesis and chlorophyll fluorescence characteristics of citrus plants (Tiancao) were studied. The results showed that the net photosynthesis rate (Pn), stomatal conductance (Gs), intercellular CO₂ concentration (Ci) and transpiration rate (Tr) remained unchanged in the plants grown in large pots as compared to those in field at different photosynthetic photo flux density. However, Pn, Gs and Tr of plants cultured in small pots significantly decreased, while Ci unchanged. The capacity for CO₂ utilization reduced only at high concentration under large pot culture, but it significantly declined at all CO₂ concentration under small pot culture in comparison with the control. Maximal efficiency of PSⅡ photochemistry (Fv/Fm), effective PSⅡ quantum yield (ΦPSⅡ), electron transport rate (ETR) and photochemical quenching (qP) as well as non|photochemical quenching (NPQ) of plants under large pot culture showed no significant difference as compared to that in the field except that excitation energy capture efficiency of PSⅡ reaction centers (Fv'/Fm') decreased prominently. However, Fv'/Fm', ΦPSⅡ and ETR markedly decreased and NPQ increased in the plants cultured in small pots, which was consistent with the analysis results of the distribution of excitation energy.