淹水胁迫对星花玉兰及其品种光合特性的影响

Effects of Flooding Stress on Photosynthetic Characteristics of Yulania stellata and Its Cultivars

为探究星花玉兰(Yulania stellata)光合生理特性对淹水胁迫的响应规律,采用双套盆法对星花玉兰及其4个品种进行淹水处理,测定不同淹水时间叶绿素含量、比叶面积、光合参数和叶绿素荧光参数的变化。结果表明:①在淹水胁迫下,各品种叶绿素a、叶绿素b和总叶绿素变化趋势基本一致,‘皮鲁埃特’和‘菊花’未出现显著性变化,星花玉兰、‘贝蒂’和‘朱迪’呈下降趋势。②各品种的净光合速率(Pn)呈下降趋势,处理组最大净光合速率(P_(nmax))与光饱和点(L_(SP))均显著低于对照组;‘菊花’和‘皮鲁埃特’的暗呼吸速率(R_(d))为处理组高于对照组,而‘贝蒂’、‘朱迪’和星花玉兰的Rd在淹水处理后显著降低,光合产物消耗减少。③各品种星花玉兰的最大光化学量子产量(F_(v)/F_(m))均为下降趋势。‘皮鲁埃特’与‘朱迪’有效光化学量子产量(Φ_(PSⅡ))在淹水胁迫下整体下降幅度较小,分别为8.4%和24.7%;‘菊花’、‘贝蒂’和星花玉兰则下降幅度较大,分别为76.7%、85.7%和64.6%。淹水胁迫影响星花玉兰及其品种光合特性,不同品种有差异,除‘贝蒂’外其余4个星花玉兰品种在处理前7 d时光合作用正常进行,‘皮鲁埃特’具有较强的光合能力和涝害适应能力。研究结果可为筛选适应南方湿涝地区或易积水地区栽植的星花玉兰品种提供理论依据。

In order to clarify the response rules of photosynthetic and physiological characteristics of Yulania stellata to flooding stress,the double-pot method was used to Y.stellata and its 4 cultivars by flooding.The changes in chlorophyll content,specific leaf area,photosynthetic parameters and chlorophyll fluorescence parameters after different flooded days were measured respectively.The results showed that the changing trends of chlorophyll a,chlorophyll b and total chlorophyll were slightly different under flooding stress,and there were no significant changes in Y.‘(Mag’s)Piroutte’and Y.stellata‘Chrysanthemiflora’,while Y‘.Bety’,Y.stellata and Y‘.Judy’showed a downward trend respectively.The net photosynthetic rate(Pn)showed a downward trend,and the maximum net photosynthetic rate(P_(nmax))and light saturation point(LCP)of the treatment groups were significantly lower than those of the control group respectively.The dark respiration rate(Rd)of Y.stellata‘Chrysanthemiflora’and Y.‘(Mag’s)Piroutte’of the treatment group was higher than that of the control group.The Rd of Y.‘Bety’,Y.stellata and Y.‘Judy’were significantly reduced after flooding treatment to reduce the consumption of photosynthetic products respectively.The effective photochemical quantum yields(Φ_(PSⅡ))of Y.‘(Mag’s)Piroutte’and Y.‘Judy’decreased by 8.4%and 24.7%under flooding stress;Y.stellata‘Chrysanthemiflora’,Y‘.Bety’and Y.stellata decreased significantly,respectively 76.7%,85.7%and 64.6%.The maximum photochemical quantum yield(Fv/Fm)of each cultivar of Y.stellata.had a downward trend.The photosynthetic characteristics of Y.stellata and its cultivars were affected by flooding stress,but different cultivars had differences.Except for Y‘.Bety’,the Photosynthesis of the other 4 Y.stellata cultivars performed normally during the 7 d before treatment;Y.‘(Mag’s)Piroutte’had strong photosynthetic capacity and waterlogging adaptability.The results provid a theoretical basis for the selection of Y.stellata cultivars suitable for planting in wet and waterlogged areas in southern China.