摘要:植物比叶面积（SLA）与光合效率的关联性分析，有助于理解植物叶片的光合产物分配与能量分配之间的权衡机制。该研究以秦王川国家湿地公园芦苇（Phragmites australis）种群为研究对象，沿芦苇群落末端至水域边缘分别依次设置：（I：土壤电导率（EC）2.3-2.8 ms/cm）、（Ⅱ：1.8-2.2 ms/cm）、（Ⅲ：0.8-1.5 ms/cm）3个试验样地，研究了秦王川盐沼湿地不同土壤盐分条件下芦苇叶片SLA与光合效率的关系。结果表明：随着土壤盐分含量的降低，湿地群落的高度、地上生物量逐渐增大，密度、光合有效辐射（PAR）呈逐渐减小的趋势；叶面积、株高、净光合速率（P < sub>n）、水分利用效率（WUE）和蒸腾速率（T_r）均呈逐渐增大的趋势，叶厚度逐渐减小，比叶面积呈先增加后减少的变化趋势，叶干重的变化趋势与比叶面积完全相反；芦苇叶片实际光合效率（Y（Ⅱ））、光化学淬灭系数（Q_P）和电子传递速率（ETR）呈先减少后增大的变化趋势，非光化学猝灭系数（NPQ）、调节性能量耗散的量子产额（Y（NPQ））和最大光化学效率（F_v/F_m）呈先增加后减少的变化趋势，非调节性能量耗散的量子产量（Y（NO））呈逐渐增大的变化趋势。在3个样地中，芦苇SLA与Y（Ⅱ）和ETR之间均呈极显著负相关关系（P < 0.01），SMA斜率的绝对值均呈先增大后减少的变化趋势。随土壤含盐量的梯度性变化，芦苇种群适时调整叶片构件模式以改变叶片电子传递速率和实际光化学效率，实现植物光合效率的最大化，反映了盐沼湿地植物的特殊生存策略和叶片构件模式。



Abstract:The analysis of the response of plant specific leaf area (SLA) and photosynthetic efficiency to soil salinity is helpful to understand the balance mechanism between photosynthetic product distribution and energy distribution in plant leaves. This study aims to examine the relationship between specific leaf area and photosynthetic efficiency of Phragmites australis in response to the soil salt gradient. The study area is located in Qinwangchuan National Wetland Park (36.47° N, 103.65° E), Gansu Province, China. The range of the selected site with the area of 100 m×100 m is from the edge to the central of the wetland, where the reed is the single dominant species. There are three sample plots set on the basis of the soil salt content. The results showed that with the soil salt content decreased gradually, the height of the wetland community and the ground biomass presented increasing trend correspondingly, while density, photosynthetic active radiation (PAR), and leaf thickness had the opposite trend. Plant height, leaf area, net photosynthetic rate (P < sub>n), transpiration rate (T_r), and water use efficiency (WUE) increased gradually, and the specific leaf area increased at the beginning and decreased afterwards, and leaf dry weight presented opposite trends compared with SLA. From plot I to plot Ⅲ, with the decreasing of the soil salt content, the effective quantum yield of PSⅡ photochemistry (Y(Ⅱ)), the photochemical quenching (Q_P), and the electron transport rate (ETR) firstly reduced then increased. The non-photochemical quenching (NPQ), the quantum yield of regulatory energy dissipation (Y(NPQ)), and the maximum efficiency of photosystem (PS) Ⅱ photochemistry (F_v/F_m) performed the increased-decreased changing trends. The quantum yield of non-regulatory energy dissipation (Y(NO)) showed increase trend. There were highly significantly negative correlation (P < 0.01) between SLA and Y(Ⅱ), and between SLA and ETR among three plots, and the absolute value of SMA slope firstly increased and then decreased. With the soil salinity gradient changes, the reeds species adjusted blade component model timely by changing ETR and Y(Ⅱ) to maximize plant photosynthetic efficiency, which reflected that the special survival strategy and leaf component model of plants in salt marsh wetland.





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