干热河谷区3个种源余甘子的光响应曲线特性研究

Light Response Curve of Photosynthesis of Three Phyllanthus emblica Provenances in Dry-hot Valley of Jinsha River

以云南干热河谷区3个种源余甘子幼苗为研究对象,利用Li-6400 XT便携式光合作用测定系统测定其不同光合参数,并绘制相应光响应曲线,比较了不同种源余甘子光合特性差异。结果表明:在低光合有效辐射(PAR)条件下,3个种源余甘子净光合速率(Pn)差异较小,随着PAR升高3个种源余甘子表现出较大差异。3个种源余甘子气孔导度(Gs)和蒸腾速率(Tr)在低PAR范围内迅速上升,随着PAR升高呈缓慢上升或下降趋势。3个种源余甘子胞间CO 2浓度(Ci)呈先急速下降后趋于平稳的变化趋势;水分利用效率(WUE)呈现先上升后趋于平缓再下降的总体趋势。直角双曲线修正模型能较好地拟合不同种源余甘子Pn的光响应曲线,决定系数(R^2)在0.9982~0.9994之间。种源20180907-1的LSP、LCP及Pn,max均相对较高,利用强光的能力较强;种源20180907-2的LSP中等,LCP及Pn,max均较低,表观量子效率(α)较高,对弱光的利用能力较强,且WUE较高,抗旱能力较强;种源20180907-3的LSP、LCP均为中等,对强光的利用能力中等。

In order to study the difference of photosynthetic characteristics among Phyllanthus emblica L.provenances,the photosynthetic parameters were measured by a LI-6400XT portable photosynthesis system,and the corresponding light response curves were drawn for three wild Phyllanthus emblica L.provenances seedlings in the dry-hot valley area of Jinsha River.The results showed that the differences of net photosynthetic rate(Pn)among three Phyllanthus emblica L.provenances were not distinct under the condition of low photosynthetically active radiation(PAR).However,with the increase of PAR,great differences in Pn among three Phyllanthus emblica L.provenances appeared.The light response curves of stomatal conductance(Gs)and transpiration rate(Tr)of three Phyllanthus emblica L.provenances were basically the same,rising rapidly in the low PAR range and slowly rising or falling with the increase of PAR.The light response curves of intercellular CO2 concentration(Ci)among three Phyllanthus emblica L.provenances showed a trend of rapid decline first and then stabilized,while the light response curves of water use efficiency(WUE)showed an overall trend of rising first and then stabilizing and finally declining.The modified rectangular hyperbolic model was applicable to fitting the Pn-PAR curve of different Phyllanthus emblica L.provenances,with the determination coefficient(R^2)between 0.9982 and 0.9994.Provenance 20180907-1 had strong ability to utilize strong light with a higher LSP,LCP,and maximum net photosynthetic rate(Pn,max).Provenance 20180907-2 had strong weak light utilization and drought resistance with a medium LSP,lower LCP,lower Pn,max,higher apparent quantum efficiency(α)and higher WUE.Provenance 20180907-3 had medium ability to utilize strong light because LSPand LCPwere both medium.