‘金焰彩栾'与黄山栾树光合特性比较

‘金焰彩栾'是黄山栾树天然黄化突变体,具有较高的观赏价值。为研究‘金焰彩栾'的光合特性,采用光合测定系统对‘金焰彩栾'和黄山栾树(对照)色素含量、生长量、光合作用日变化和光响应曲线进行了测定。结果表明:‘金焰彩栾'的叶绿素a、b,以及总叶绿素和类胡萝卜素含量均大幅减少,其中叶绿素b含量降幅最大。‘金焰彩栾'的生长量、叶面积和比叶重显著低于对照。‘金焰彩栾'净光合速率(Pn)日变化曲线呈单峰,对照呈双峰曲线,两者的峰值大小和出现时间存在差异; 两者的胞间CO2浓度(Ci)日变化均呈先降后升的趋势,且均在上午11:00时达到全天最低值; ‘金焰彩栾'的气孔导度(Gs)显著低于对照; 其气孔限制值(Ls)在7:00―11:00时显著低于对照,在13:00―17:00显著高于对照; 其蒸腾速率(Tr)与对照差异不显著。通过对Pn的相关分析得知,‘金焰彩栾'Pn与Ci、Gs、Tr、Ls等均呈显著或极显著相关关系。‘金焰彩栾'最大净光合速率(Pn, max)显著低于对照,光补偿点(PLCP)显著低于对照,光饱和点(PLSP)显著高于对照,暗呼吸速率(RRd)和表观量子效率(eAQY)均显著低于对照。推测可能由于突变使叶绿素含量减少,进而影响‘金焰彩栾'叶片呈色和生长发育,从而导致‘金焰彩栾'光合速率较黄山栾树降低。
Koelreuteria bipinnata var. integrifoliola‘Jinyan' is a natural yellow mutant of K. bipinnata var. integrifoliola with higher ornamental value. In order to study the photosynthetic characteristics of K. bipinnata var. integrifoliola ‘Jinyan', the pigment content, growth, diurnal variation of photosynthesis and light response curves of ‘Jinyan' and the wild type were determined with photosynthesis system. The results showed that the contents of chlorophyll a, chlorophyll b, total chlorophyll and carotenoids of ‘Jinyan' were significantly reduced compared with the wild type, especially for chlorophyll b. The diurnal variation of net photosynthetic rate(Pn)of ‘Jinyan' showed single curve, and that of the wild type showed bimodal curve. However, the peak values and the peak times of Pn were different. Diurnal variations of intercellular CO2 concentration(Ci)of them showed the same trend that it increased initially and then decreased, reaching the lowest value at 11:00 am. Stomatal conductance(Gs)of ‘Jinyan' was significantly lower than that of the wild type. Stomatal limitation value(Ls)of ‘Jinyan' was significantly lower than that of the wild type from 7: 00 am to 11: 00 am, but higher from 13:00 pm to 17:00 pm. The transpiration rate(Tr)was not significantly different between them. Correlation analysis showed that there were significantly or extremely significant correlation among Pn and Ci, Gs, Tr, Ls of ‘Jinyan'. The maximum net photosynthetic rate(Pn, max)of ‘Jinyan' was significantly lower than that of the wild type. Light compensation point(PLCP)was significantly lower than that of the wild type. Light saturation point(PLSP)was significantly higher than that of the wild type. Dark respiration rate(RRd)and apparent quantum efficiency(eAQY)were significantly lower than that of the wild type. Presumably since the mutation makes the chlorophyll content decreased, thereby affecting ‘Jinyan' leaf coloration and growth, leading to the lower photosynthetic rate