Li Xiao-ping, Wang Jing-yan, Wang Dong, Hu Ting-xing, Chen Hong-zhi, Gong Wei
Sichuan Province Key Laboratory of Ecological Forestry Engineering, Sichuan Agricultural University, Ya' an 625014, Sichuan, China.
Ying Yong Sheng Tai Xue Bao. 2010 Nov;21(11):2734-41.
Different levels (0, 90, 180, and 270 g per tree) of compound fertilizer containing 15% N, 15% P2O5, and 15% K2O were applied to young Eucalyptus grandis to study the diurnal variations of its leaf stomatal conductance (Gs), intercellular CO2 concentration (Ci), net photosynthesis rate (Pn), transpiration rate (Tr), water use efficiency (WUE), and vapor pressure deficit on leaf surface (Vpdl) as well as the variation of leaf chlorophyll content, aimed to approach the relationships of E. grandis photosynthesis with fertilization and environmental factors. In all treatments, the diurnal variation of Pn presented a single-peak curve, with the peak at 14:00 and not showing midday depression. The Gs, Tr, and Vpdl showed the similar trend with Pn, while the Ci had a minimum value at 14:00. The WUE demonstrated a double-peak curve, with the first and second peak occurred at 10:00 and 14:00, respectively. Comparing with the control, the mean values of Gs, Pn, Tr, WUE, and chlorophyll a, chlorophyll b, and total chlorophyll contents under fertilization increased by 4.6%-15.9%, 7.8%-21.8%, 4.8%-11.6%, 3.2%-8.8%, 15.5%-62.0%, 14.5%-44.5% and 15.3%-57.1%, respectively, and the increment increased with fertilization level. By contrast, the mean values of Ci and VPdl decreased by 14.5%-44.5% and 15.3%-57.1%, respectively, and the decrement increased with fertilization level. The Gs, Pn, and Tr were significantly correlated with air temperature, relative humidity (RH), and photosynthetic active radiation (PAR), and also, the Gs was significantly correlated with Pn and Tr. It was suggested that fertilization could promote E. grandis growth and enhance its WUE and biological carbon sequestration, and air temperature, RH, PAR, and Gs were the main factors causing the diurnal variations of photosynthesis and transpiration of E. grandis.
将含15%氮、15%五氧化二磷和15%氧化钾的复合肥以不同水平（每棵树0、90、180和270克）施用于巨桉幼树，以研究其叶片气孔导度（Gs）、胞间二氧化碳浓度（Ci）、净光合速率（Pn）、蒸腾速率（Tr）、水分利用效率（WUE）和叶片表面蒸汽压亏缺（Vpdl）的日变化以及叶绿素含量的变化，旨在探讨巨桉光合作用与施肥及环境因子之间的关系。在所有处理中，Pn的日变化呈单峰曲线，峰值出现在14:00，未出现中午降低现象。Gs、Tr和Vpdl与Pn呈现相似趋势，而Ci在14:00有最小值。WUE呈双峰曲线，第一个和第二个峰值分别出现在10:00和14:00。与对照相比，施肥处理下Gs、Pn、Tr、WUE以及叶绿素a、叶绿素b和总叶绿素含量的平均值分别增加了4.6% - 15.9%、7.8% - 21.8%、4.8% - 11.6%、3.2% - 8.8%、15.5% - 62.0%、14.5% - 44.5%和15.3% - 57.1%，且增幅随施肥水平增加。相比之下，Ci和VPdl的平均值分别降低了14.5% - 44.5%和15.3% - 57.1%，且降幅随施肥水平增加。Gs、Pn和Tr与气温、相对湿度（RH）和光合有效辐射（PAR）显著相关，并且，Gs与Pn和Tr也显著相关。研究表明，施肥可促进巨桉生长并提高其水分利用效率和生物固碳能力，气温、RH、PAR和Gs是导致巨桉光合作用和蒸腾作用日变化的主要因素。
