CO_2质量浓度对沈阳市银杏生长及光合固碳能力的影响

Effects of elevated CO_2 on growth and capacity of photosynthetic assimilation of carbon in Ginkgo biloba

以生长在沈阳市区内的银杏为试材,使用开顶箱模拟法对倍增CO2质量浓度(700μmol．mol-1)和正常空气CO2质量浓度(≈350μmol．mol-1)条件下,银杏生长参数、叶面积指数、不同天气中净光合速率日变化进行了初步研究,探讨了高质量浓度CO2对单株银杏光合固碳能力的影响。结果表明:CO2质量浓度增高可以显著提高银杏枝条的生长量和银杏的叶面积指数。经高质量浓度CO2处理后,银杏不同天气下光合速率日变化趋势与对照一致,即晴天为双峰曲线,多云天气为单峰曲线,但净光合速率显著高于对照(P<0．001)。由于净光合速率和叶面积指数升高,高质量浓度CO2也显著提高了单株银杏的固碳释氧能力(P<0．01),晴天比对照提高了119．5％,阴天提高了175．4％。

To study the impact of elevated tropospheric CO2 concentrations on growth and capacity of photosynthetic assimilation of carbon of trees, growth parameters, leaf area index (LAI) and diurnal variation of net photosynthesis rate under different weather were primarily analyzed in leaves of Ginkgo biloba exposed in open-top chambers at either ambient (≈350μmol·mol-1) or elevated (700μmol·mol-1) CO2 concentrations in urban area for a growing season. The results show that elevated CO2 exposure induced, growth parameters, leaf area index and net photosynthesis rate were increased. The diurnal variation of net photosynthesis rate on a fine day revealed two maxima, while single maxima on a cloudy day, which was similar to ambient CO2. As a result, the capacity of photosynthetic assimilation of carbon in Ginkgo biloba was enhanced relatively by 119.5% on fine day, while 175.4% on cloudy day.