蕾后期和花前期切花菊品种'神马'不同部位叶片光合作用和叶绿素荧光特性的比较

对蕾后期和花前期切花菊(Chrysanthemum morifolium Ramat.)品种'神马'('Jinba')不同部位叶片光合作用参数日变化、叶绿素荧光参数、光响应曲线及参数进行了研究.结果表明:蕾后期和花前期品种'神马'叶片蒸腾速率(Tr)、气孔导度(Gs)和净光合速率(Pn)的日变化均为单峰曲线,峰值出现在10:00或12:00;胞间CO2浓度(Ci)的日变化则先降低后升高,谷值出现在12:00.蕾后期和花前期品种'神马'叶片Tr、Ci和Gs值的平均值总体上随叶片位置降低而逐渐升高;蕾后期不同部位叶片Pn值的平均值差异较小,花前期叶片Pn值的平均值则随叶片位置降低而逐渐降低.随着叶片位置降低,蕾后期和花前期品种'神马'叶片的初始荧光(Fo)、最大荧光(Fm)、可变荧光(Fv)、表观量子效率(AQE)和最大净光合速率(Pmax)以及蕾后期的暗呼吸速率(Rd)均逐渐降低,而花前期的Rd值以及蕾后期和花前期的光补偿点(LCP)均逐渐升高.随着光合有效辐射(PAR)升高,蕾后期不同部位叶片以及花前期中部叶和下部叶的Pn值呈先急剧升高后趋于平稳的变化趋势,而花前期上部叶的Pn值则呈先急剧升高后逐渐下降的变化趋势.研究结果显示:在切花菊设施栽培过程中适当补充光照可提高切花菊品质.

Comparison on photosynthesis and chlorophyll fluorescence characteristics of leaves in different positions of cultivar'Jinba' of cut chrysanthemum ( Chrysanthemum morifolium) at post-budding and pre-blooming stages

Photosynthetic parameter diurnal changes, chlorophyll fluorescence parameters, and light response curves and parameters of leaves in different positions of cultivar 'Jinba' of cut chrysanthemum (Chrysanthemum morifolium Ramat.) at post-budding and pre-blooming stages were studied. The results show that at post-budding and pre-blooming stages, the diurnal changes in transpiration rate ( Tr ) , stomatal conductance ( Gs) and net photosynthetic rate ( Pn) of leaves of cultivar 'Jinba' all are single peak curves, with the peak values at 10:00 or 12:00, and that in intercellular CO2 concentration ( Ci) decreases at first and then increases, with the valley value at 12:00. In general, the average values of Tr, Ci and Gs of leaves of cultivar 'Jinba' at post-budding and pre-blooming stages increase gradually with decreasing of leaf position. There is a small differences in the average value of Pn of leaves among different leaf positions at post-budding stage, and the average value of Pn of leaves at pre-blooming stage decreases gradually with decreasing of leaf position. With decreasing of leaf position, initial fluorescence ( F o ) , the maximum fluorescence ( F m ) , variable fluorescence ( F v ) , apparent quantum efficiency (AQE) and the maximum net photosynthetic rate (Pmax) of leaves of cultivar 'Jinba' at post-budding and pre-blooming stages, and dark respiration rate ( Rd) at post-budding stage decrease gradually, while Rd value at pre-blooming stage and light compensation point ( LCP ) at post-budding and pre-blooming stages increase gradually. With increasing of photosynthetically active radiation ( PAR), Pn value of leaves in different leaf positions at post-budding stage and that of middle and lower leaves at pre-blooming stage increase sharply at first and then change to be steady, while that of upper leaves at pre-blooming stage increases sharply at first and then decreases gradually. It is suggested that during the facility cultivation process of cut chrysanthemum, appropriate light supplement can enhance quality of cut chrysanthemum.