浙北地区常见绿化树种光合固碳特征

高固碳能力的树种选择是营造优质碳汇林,发展碳汇林业的重要基础工作.以浙北地区常见的30种造林绿化树种为研究材料,利用LI-6400便携式光合测定仪,测定树木光合日变化及不同光强梯度下光合作用的光响应特性,并根据实验观测值进行计算,对30个树种的日净固碳量和光合生理拟合参数进行Ward法聚类分析和因子分析.结果表明:香樟的固碳量最大((11.374±1.020) g·m-2·d-1),其次为碧桃、垂柳、石栎、无患子,固碳量最小的为红叶李((2.178±0.605) g·m-2·d-1),香樟和红叶李的日净固碳量有极显著差异(P＜0.01)；树木的生理特性指标分析进一步反映了树种在浙北地区生长适应性及固碳能力大小,同时,根据树木的生理特性指标进行因子分析和聚类分析的结果,香樟、碧桃在浙北地区生长适应性较好,其次为无患子、垂柳、女贞等；根据树种固碳量及生理指标综合测定分析,建议在浙北地区造林绿化中可以优先选用香樟、碧桃、垂柳、无患子、石栎、女贞这些树种.

The photosynthetic carbon fixation characteristics of common tree species in northern Zhejiang

Development of carbon sequestration forestry has made the species choice of high carbon sequestration capacity an important measure for planting superior quality carbon sink forests. The photosynthetic rate, light saturation point, light compensation point, maximum net photosynthetic rate, apparent quantum efficiency and other physiological indicators can be used to reflect the characteristics of carbon fixation and assimilation of CO₂ capacity. This research selected thirty common afforestation tree species in northern Zhejiang province as the research materials. They are Ginkgo biloba L., Taxodium distichum (L.) Rich, Podocarpus nagi (Thunb.) Kuntze, Populus euramevicana, Salix babylonica L., Zelkova schneideriana (Hand.) Mazz, Celtis julianae Schneid., Magnolia grandiflora L., Magnolia denudate Desr., Michelia chapensis Dandy, Michelia maudiae Dunn, Liriodendron chinense (Hemsl.) Sarg, Cinnamonum campora (L.) Prels, Machilus pauhol kanehira, Amygdalus persica var. persica f. Duplex, Prunus cerasifera f. Atropurpurea, Cerasus yedoensis, Photinia×fraseri Dress 'Red Robin', Albizia julibrissin Durazz., Choerospondias axillaris, Acer buergerianum Miq, Ilex chinensis Sims, Sapindus mukorossi Gaertn, Koelreuteria integrifoliola Merr., Diospyros glaucifolia, Osmanthus fragrans, Ligustrum lucidum, Liquidambar formosana Hance, Elaeocarpus glabripetalus Merr., and Lithocarpus glaber. A portable LI-6400 photosynthesis apparatus is used to measure the photosynthetic diurnal variation and the responses of photosynthesis to different light intensities in the tested tree species. Ward cluster analysis was used to analyze the net sequestered carbon of 30 tree species, and both factor analysis and Ward cluster analysis were used to examine the fitting physiological parameters of photosynthesis. The results showed that Cinnamonum campora (L.) Pres has the highest carbon fixation ((11.374±1.020) g·m^-2·d^-1), followed by Amygdalus persica var. persica f. duplex, Salix babylonica L., Lithocarpus glaber, Sapindus mukorossi Gaertn and others, and Prunus cerasifera f. atropurpurea has the lowest ((2.178±0.605) g·m^-2·d^-1). Cinnamonum campora (L.) Prels. has significantly higher net sequestered carbon (P<0.05) than Prunus cerasifera f. Atropurpurea. The physiological characteristics of these trees further reflect their growth adaptability and carbon sequestration capacity in northern Zhejiang province. According to the results of factor analysis and Ward cluster analysis, Cinnamonum campora (L.) Prels. and Amygdalus persica var. persica f. duplex have better growth adaptability, followed by Sapindus mukorossi Gaertn, Salix babylonica L., Ligustrum lucidum. Therefore, these tree species are recommended for afforestation in northern Zhejiang. Because plant photosynthesis is a complex physiological process, the photosynthetic physiological indicators only show the characteristics of tree species in one aspect, and do not represent the pros and cons of the species. The conclusion obtained from comprehensive multi-index and cluster analysis is consistent with that from diurnal net carbon sequestration analysis, implying that the integrated indicators of physiological parameters can better reflect the relative inferiority of the carbon sequestration capacity. On the view of optimal afforestation tree configuration, more research is needed to combine photosynthesis and regional growth and adaptability of species and to improve their photosynthetic capacities.