2种切花菊不同叶位光合特性的研究

Photosynthetic Characteristics of Leaf Positions of 2 Cut Chrysanthemum Cultivars

为了解2个切花菊品种不同叶位同化能力的差异,比较不同叶位对日光温室栽培条件下光照的适应能力,为设施栽培的生产管理提供理论依据,采用GFS-3000型便携式光合测定系统测定2个切花菊品种‘神马’和‘优香’叶片的光合参数,并拟合其光响应曲线。结果表明,除水分利用效率(WUE)外,‘神马’3个叶位叶片的净光合速率(Pn)、蒸腾速率(Tr)、胞间CO2浓度(Ci)和气孔导度(Gs)平均值均高于‘优香’;但‘优香’不同叶位之间Pn值和WUE值差异较大,上位叶Pn值和WUE值达3.51μmol/(m2·s)和2.47 mmol/(m2·s),分别为下位叶的6.26、8.23倍,说明随着叶龄的增加,‘优香’叶片的光合能力和水分利用效率明显下降。从最大光合速率(Pmax)和光饱和点(LSP)实测值和拟合值的比较看,直角双曲线修正模型对切花菊光响应曲线的拟合效果较好;且2个品种Pmax、表观量子效率(AQE)和LSP值变化趋势一致,即按叶位从上到下逐渐降低。‘优香’不同叶位之间Pmax差异较大,上位叶为下位叶的3倍,这与光合速率的变化趋势一致。‘神马’LSP值和AQE更高,因此对光照条件的适应范围更广,更适用于日光温室栽培。

This study aims to understand the difference of assimilation ability of two cut flower Chrysanthemum cultivars, and to compare the ability of different leaf positions to adapt to sunlight under green housecultivation, thus to provide a theoretical basis for production management in facility cultivation.‘Jingba＇and‘Youxiang＇were measured by GFS-3000 portable photosynthetic system to understand their photosyntheticcharacteristics and the light response curves were fitted. The results showed that the photosyntheticparameters, e.g. the average of net photosynthetic rate（Pn）, transpiration rate（Tr）, intercellular CO2 molefraction（Ci） and stomatal conductance（Gs） of‘Jingba＇were a little higher than that of‘Youxiang＇except water use efficiency（WUE）; but the Pn and WUE of different leaf positions of‘Youxiang＇differed greatly, those ofthe upper leaves were 3.51 μmol/（m^2·s） and 2.47 mmol/（m^2·s）, which were 6.26 times and 8.23 times of thelower leaves, respectively. This suggested that the photosynthetic capacity and water use efficiency of‘Youxiang＇decreased significantly with the increase of the age. According to the maximum net photosyntheticrate（Pmax） and light saturation point（LSP）, the modified rectangular hyperbola fitted the light response curve ofcut flower Chrysanthemum well. The variation tendency of Pmax, apparent quantum efficiency（AQE） and LSP of the 2 cultivars were consistent, gradually decreased from top to bottom of the leaf position. While the Pmaxofdifferent leaf positions of‘Youxiang＇varied remarkably, and had the same tendency as that of Pn. But the LSPand AQE of‘Jingba＇were higher, so it had a broader adaptation to light intensity and was more suitable for sunlight greenhouse cultivation.