北京市七种园林树种叶水势动态特征及其影响因素分析

Analysis on Dynamic Characteristics and Influencing Factors of Leaf Water Potential of Seven Landscape Tree Species in Beijing

以北京市常见7种园林绿化树种白皮松(Pinus bungeana)、侧柏(Platycladus orientalis)、桧柏(Sabina chinensis)、沙地柏(Sabina vulgaris)、银杏(Ginkgo biloba)、栾树(Koelreuteria paniculata)和国槐(Sophora japonica)为试材,采用盆栽控制法,研究7种园林树种叶水势的动态特征及影响因素,明确植物水分亏缺状态和抗旱机理,以期为北京市园林绿化树种的选择提供参考依据。结果表明:在良好水分供应处理下,桧柏、白皮松、沙地柏、侧柏、银杏和国槐幼树叶水势日变化呈早晚高、正午低的变化趋势。栾树叶水势于12:00—14:00出现短暂回升,而后逐渐升高,与其它树种叶水势日变化趋势存在极显著差异(P<0.01)。常绿树种幼树叶水势日变幅均显著低于落叶树种(P<0.05)。分析绿化树种与气象因子间相关关系发现,该研究中的常绿、落叶树种叶水势与太阳辐射量、大气温度呈极显著负相关(P<0.01),而与大气相对湿度呈极显著正相关(P<0.01)。影响不同绿化树种叶水势变化的主导气象因子存在种间特异性,即桧柏、侧柏、国槐叶水势主要受大气相对湿度影响调控,而白皮松、沙地柏、银杏和栾树叶水势的主导影响因子为大气温度。

Seven common landscape tree species of Pinus bungeana,Platycladus orientalis,Sabina chinensis,Sabina vulgaris,Ginkgo biloba,Koelreuteria paniculata,and Sophora japonica were used as experimental materials to study the dynamic characteristics and influencing factors of leaf water potential of seven landscape tree species by pot control method,in order to clarify the water deficit status and drought resistance mechanisms of plants and provide reference for the selection of landscape tree species in Beijing.The results showed that under good water supply treatment,the diurnal variations in leaf water potential of S.chinensis,P.bungeana,S.vulgaris,P.orientalis,G.biloba,and S.japonicaall presented a trend of high in the morning and evening,and low at noon.There was a very significant difference in the diurnal variation trend of K.paniculataand other tree species(P<0.01).Its leaf water potential rose briefly from 12:00 to 14:00,and then increased again with time.The daily variation of leaf water potential of evergreen tree species was significantly lower than that of deciduous tree species(P<0.05).The monthly change in leaf water potential of each experimental tree species from July to October showed a gradual upward trend.The leaf water potential with sufficient soil water content was significantly negatively correlated with solar radiation and atmospheric temperature(P<0.01),and positively correlated with atmospheric relative humidity(P<0.01).There was no significant difference in the degree of influence of solar radiation on leaf water potential between different tree species.The impacts of atmospheric temperature on the leaf water potential of S.japonica and P.bungeanais were stronger than that of other tree species.P.orientalis,G.bilobaand K.paniculata were more susceptible to atmospheric relative humidity than other tree species.The main meteorological factor that affected the changes in leaf water potential of S.chinensis,P.orientalis,and S.japonica was atmospheric relative humidity,while the atmospheric temperature was the dominant meteorological factor functioning leaf water potential of P.bungeana,S.vulgaris,G.biloba,and K.paniculata.