摘要
通过田间试验,测定了不同生长时期白榆、刺槐纯林及其不同比例混交林[白榆∶刺槐分别为1∶1(1B1C)、1∶2(1B2C)和2∶1(2B1C)]植物叶片的N、P含量、叶绿素(Chl)含量、光合气体交换参数和叶绿素荧光参数的变化.结果表明:5—9月,2种纯林和3种混交林植物叶片N、P含量均呈减小趋势,到植物生长末期,1B2C混交林中刺槐叶片的N含量和白榆叶片的P含量均较其纯林有明显提高;3种混交林中,白榆叶片的叶绿素含量明显高于刺槐,且1B2C混交的白榆叶片Chl值在7月达到最大;3种混交林刺槐和白榆的光合速率(Pn)均大于其纯林,1B2C混交的刺槐叶片Pn在7月达到18.54μmol.m-2.s-1;不同比例混交林刺槐叶片的蒸腾速率和气孔导度均较其纯林有明显改善,为1B2C>1B1C>2B1C.至9月,3种混交林中白榆叶片的PSII电子传递量子效率明显大于纯林;2种纯林与3种混交林叶片光化学淬灭系数差异较小,而纯林的非光化学淬灭系数显著高于1B2C混交林.白榆-刺槐混交林可以显著提高植物叶片的养分含量和光合作用能力,其最优混交比例为1B2C.
A field experiment was conducted to study the leaf N,P,and chlorophyll contents,photosynthetic gas exchange parameters,and chlorophyll fluorescence parameters in pure Ulmus pumila forest,pure Robinia pseudoacacia forest,and U.pumila-R.pseudoacacia mixed forests [1：1（1B1C）,1：2（1B2C）,and 2：1（2B1C）] in different growth periods.From May to September,the plant leaf N and P contents in pure and mixed forests all presented a decreasing trend. By the end of growth period,the leaf N content of U.pumila and the P content of R.pseudoacacia in 1B2C were obviously higher than those in pure forests.In the mixed forests,the chlorophyll content of U.pumila was obviously higher than that of R.pseudoacacia,and the chlorophyll content of U.pumila in 1B2C reached the highest in July.The photosynthetic rate（Pn） of U.pumila and R.pseudoacacia in mixed forests was higher than that in pure forests,and the Pn of R.pseudoacacia in 1B2C reached the highest（18.54 μmol·m-2·s-1） in July.The transpiration rate（Tr） and stomatal conductance（Gs） of R.pseudoacacia in mixed forests were higher than those in pure forests,and the Tr and Gs in mixed forests were in the order of 1B2C1B1C2B1C.In September,the quantum yield of PSII electron transport（ФPSⅡ） of U.pumila in mixed forests was obviously higher than that in pure forest.The photochemical quenching coefficients（qP） of U.pumila and R.pseudoacacia in pure and mixed forests had no significant difference,but the non-photochemical quenching coefficient（NPQ） of the two tree species in 1B2C was significantly lower than that in corresponding pure forests.It was suggested that mixed planting U.pumila and R.pseudoacacia could significantly improve the leaf nutrient contents and photosynthetic capacity of the two tree species,and the optimum mixed ratio of U.pumila and R.pseudoacacia was 1： 2.
出处
《应用生态学报》
CAS
CSCD
北大核心
2010年第9期2228-2234,共7页
Chinese Journal of Applied Ecology
基金
国家林业公益性行业科研专项(200904056)
国家科技支撑计划项目(2006BAD09B04)资助
关键词
白榆
刺槐
混交林
叶片养分含量
光合生理特性
Ulmus pumila
Robinia pseudoacacia
mixed forests
leaf nutrient content
photosynthetic physiological characteristics.
