摘要
以桑树(Morus alba)为材料,研究了桑树叶片气体交换参数的日变化对不同p H模拟酸雨的响应特点,旨在揭示酸雨对植物光合生产力的影响机制。结果表明,无酸雨处理(CK)的桑树叶片净光合速率的日变化,出现明显的"光合午休"现象,而模拟酸雨处理却明显提高了桑树叶片午休期间的净光合速率。在"光合午休"期间,CK的气孔导度和气孔限制值下降,而胞间CO2浓度升高,经相关性分析,此时净光合速率与胞间CO2浓度呈显著负相关(P<0.01),说明此时净光合速率下降可能是由CO2同化受到抑制导致的,而各模拟酸雨处理下的相应参数的变化趋势与CK相同,其中胞间CO2浓度低于CK,而气孔导度值高于CK,说明模拟酸雨处理可促进桑树叶片光合午休期间的气孔开度和CO2同化。大气温度与蒸腾速率、叶面饱和水汽压亏缺均呈显著正相关,而与大气相对湿度呈显著负相关,在光合午休期间,大气相对湿度接近全天最低值,说明桑树叶片CO2同化受到抑制的主要原因在于水分的匮乏,p H≥4.5模拟酸雨各处理的蒸腾速率、气孔限制值和叶面饱和水汽压亏缺都高于CK,而水分利用效率与CK差异不显著(P>0.05),说明模拟酸雨可促进桑树叶片光合作用过程的水分供应。p H 3.5模拟酸雨处理的光合日同化量、日均净光合速率和气孔导度均显著低于CK(P<0.05),而p H 4.5和p H 5.6处理中的相应参数值均高于CK。以上结果说明,p H≥4.5的模拟酸雨对桑树光合作用具有明显促进作用,在酸雨轻度污染区域,可将桑树作为退耕还林和园林绿化植物用以吸收大气中的SO2或氮氧化物,以适应或减轻大气酸雨污染。
In the present study,the response characteristics of gas exchange parameters for the diurnal variation of the mulberry leaf to simulated acid rain with different p H have been studied to reveal the mechanism and the effects of simulated acid rain on plant photosynthetic productivity. The results showed that net photosynthesis rate（ Pn）present obviously photosynthetic depression at midday in treatment of CK（ no acid rain）,while three treatments of simulated acid rain could increase Pnat midday. During photosynthetic noon-break,stomatal conductance（ Gs）and stomatal limitation value（ Ls） decreased,but the intercellular CO2concentration（ Ci） increased,the results of correlation analysis showed that Pnand Ciwas significantly negative correlation,which indicated that CO2 assimilation have been inhibited. The corresponding parameters under acid rain treatments showed similar change trends with CK excepted with that the Ciwas lower than that of CK,and Gswas higher than CK,indicating that the simulated acid rain treatments could promote stomatal opening and CO2 assimilation of mulberry leaf during midday depression. Atmospheric temperature（ T） significantly positively correlated with leaf saturation water vapor pressure deficit（ Vpdl） and transpiration rate（ Tr）,respectively. However,there was significant negative correlation between T and atmospheric relative humidity（ RH）. Meanwhile,the value of RH was near the minimum value during midday depression of photosynthesis,which indicated that CO2 assimilation inhibition most come from water shortage. While Tr,Gsand Lsin treatments of simulated acid rain with p H≥4. 5 were higher than that of CK,and the water use efficiency（ WUE） in simulated acid rain had no significant difference with CK which indicated that simulated acid rain could promote mulberry leaf intercellular water supplying. In treatments of simulated acid rain with p H 3. 5,the photosynthetic assimilation total（ PT）,average Pnand Gswere significantly lower than that
出处
《草业科学》
CAS
CSCD
北大核心
2015年第11期1862-1870,共9页
Pratacultural Science
基金
东北林业大学大学生创新训练项目(20141022516)
国家青年基金(31300506)
黑龙江省自然科学基金重点项目(ZD201105)
国家林业局国家级项目(2010G29
2011G32)
东北林业大学学术名师支持计划
关键词
光合日变化
光合午休
光抑制
大气污染
diurnal variation of photosynthesis
photosynthetic noon-break
photoinhibition
atmospheric contamination
