SO_2湿沉降对桑树叶片的形态和其利用光能的影响  

Effect of SO_2wet deposition on morphology and light energy utilization in mulberry leaves

作　　者：王月 李学鹏 彭鸿旭 朱义勇[1] 张秀丽[1] 孙广玉[1] 

机构地区：[1]东北林业大学生命科学学院,黑龙江哈尔滨150040

出　　处：《草业科学》2017年第10期2080-2089,共10页Pratacultural Science

基　　金：中央高校基本科研业务费专项资金(2572017CA21);黑龙江省青年科学基金(QC2016018);国家自然科学基金(C160704)

摘　　要：以桑树(Morus alba)为材料,用亚硫酸钠和亚硫酸氢钠的混合溶液模拟SO_2湿沉降,探讨SO_2湿沉降对桑树叶片光合特性的影响。结果表明,与清水对照(CK)相比,100mmol·L^(-1) SO_2湿沉降明显伤害了桑树叶片,表现出叶片失绿发黄、边缘焦枯、含水量下降,细胞皱缩且边缘模糊,气孔数量减少,叶片最大净光合速率显著下降(P<0.05)。在50mmol·L^(-1) SO_2胁迫下,桑树幼苗表现出一定的抗性,叶片边缘略呈焦枯状态,叶色浓绿,内部细胞体积减小,密度增大,气孔数量增多,最大净光合速率下降,光呼吸速率、蒸腾速率和水分利用效率增加。说明桑树叶片可通过调整叶片结构,降低呼吸消耗和增大光呼吸及蒸腾速率来适应50mmol·L^(-1) SO_2胁迫。两种浓度SO_2处理的叶绿素荧光与光强的响应参数变化趋势相似,差异不显著(P>0.05),当光强大于400μmol·mol^(-1)时,实际光化学效率、光化学淬灭系数和电子传递速率随着光强的增加而显著降低(P<0.05),非光化学淬灭系数和非光化学淬灭值均显著增加(P<0.05)。说明SO_2湿沉降降低了桑树叶片净光合速率,增强了呼吸消耗,促使叶片早衰。桑树可通过调整叶片自身结构、增加热耗散和提高水分利用效率等多种途径适应SO_2胁迫,且对低浓度SO_2胁迫表现出抗性。In order to explore the effects of SO2 wet deposition on the photosynthetic characteristics of leaves of mulberry seedlings, we exposed leaves to simulated SO2 wet deposition treatments. Two SO2 concentrations （100 and 50 mmol · L-1） were applied. The results showed that compared to 0 mmol · L-1 SO2 wet deposition （CK）, the 100 mmol · L-1 treatment clearly damaged mulberry leaves. A wide range of effects were present in treated leaveschlorosis; leaf blade edges withering; cell shrinkage; indistinct cell edges; decreased stomatal numbers; decreased leaf water content; reduced maximum net photosynthetic rate; significantly reduced light compensation point and light saturation point; and significantly high rates of dark respiration, photorespira- tion, and transpiration. Overall, light use efficiency by the mulberry leaves was reduced by the 100 mmol · L-1 SO2 treatment. In mulberry leaves treated with 50 mmol · L-1 SO2, the following effects were seen= leaf blade margins were slightly withered; cell volumes were less than those in leaves treated with 100 mmol · L-1 SO2 ; leaves were dark green; leaf water content decreased slightly; cell volume decreased, but cell density increased; stomatal numbers increased; light compensation point, light saturation point, dark respiration, CO2 compensation point, and water use efficiency decreased; the maximum net photosynthetic rate decreased; however, photorespiration and transpiration rates increased. We conclude that the mulberry could adjust to the treatment by reducing respiration consumption and increasing photorespiration and transpiration rates to adapt to the 50 mmol · L-1 SO2 stress. The curve parameters of chlorophyll fluorescence in response to light were similar between the two SO2 concentrations stress. The actual photochemical efficiency, photochemical quenching coefficient, and electron transfer rate decreased with the increase in light intensity; these values were significantly lower than those of CK in photon flux density conditions over 400

关 键 词：SO2污染 桑树 扫描电镜 响应曲线 光饱和点 CO2补偿点 光呼吸 

分 类 号：S888.2[农业科学—特种经济动物饲养]