【作者】 陈崇；

【导师】 李吉跃；

【作者基本信息】 北京林业大学 ， 森林培育， 2008， 硕士

【摘要】 城市树种作为城市森林生态系统的重要组成部分,在城市生态环境的保护中起着非常重要的作用。但同时这些树种存在着耗水量过大、对于涵养水源和城市水资源利用有着难以调和的矛盾等问题。本文针对此问题,选择北京市5种园林绿化树种进行研究,比较不同种类植物光合能力和水分利用效率的差别,为北京市园林植物的选择和栽培管理提供了理论依据。结论如下:1.通过对5种绿化树种光合速率动态变化及环境影响因子的研究发现,在整个生长季节,银杏、绦柳和碧桃的净光合速率日变化主要呈双峰曲线,即具有“光合午休”现象,只有在个别月份(银杏:10月;绦柳:9月、10月;碧桃:5月)呈单峰曲线;针叶树种雪松和灌木金银木净光合速率日变化呈单峰曲线。从各树种达到补偿和饱和,以及受强光抑制的情况来看,从阳性到阴性依次为:绦柳>碧桃>银杏>雪松>金银木,其光合补偿点依次为49.90μmol?m-2?s-1、43.50μmol?m-2?s-1、29.182μmol?m-2?s-1、23.09μmol?m-2?s-1、12.497μmol?m-2?s-1。碧桃是5个树种中最喜光的,属阳性树种,而雪松的耐阴性最强。影响5个树种光合速率动态变化的主要因子为光合有效辐射、空气温度,空气相对湿度、气孔导度及气孔限制值。2.对5种绿化树种蒸腾速率进行分析发现,在整个生长季节,各树种蒸腾速率日变化与净光合速率日变化趋势一致,且平均蒸腾速率碧桃(4.83μmolH2O?m-2?s-1)>银杏( 3.20μmolH2O?m-2?s-1 ) >金银木( 2.74μmolH2O?m-2?s-1 ) >雪松(2.57μmolH2O?m-2?s-1)>绦柳(2.24μmolH2O?m-2?s-1)。这说明蒸腾速率与净光合速率的变化密切相关。3.将5种绿化树种的平均水分利用效率进行比较,5月份水分利用效率的大小排列是:绦柳(3.41μmolCO2?mol-1H2O)>碧桃(2.07μmolCO2?mol-1H2O)>雪松( 2.06μmolCO2?mol-1H2O ) >银杏( 2.02μmolCO2?mol-1H2O ) >金银木(1.55μmolCO2?mol-1H2O);6月份是:绦柳(2.06μmolCO2?mol-1H2O)>金银木( 1.83μmolCO2?mol-1H2O ) >雪松( 1.76μmolCO2?mol-1H2O ) >银杏(1.46μmolCO2?mol-1H2O)>碧桃(1.01μmolCO2?mol-1H2O);7月份是:雪松( 1.80μmolCO2?mol-1H2O ) >绦柳( 1.64μmolCO2?mol-1H2O ) >银杏( 1.36μmolCO2?mol-1H2O ) >金银木( 1.20μmolCO2?mol-1H2O ) >碧桃(1.15μmolCO2?mol-1H2O);8月份是:金银木(1.82μmolCO2?mol-1H2O)>碧桃( 1.65μmolCO2?mol-1H2O ) >绦柳( 1.61μmolCO2?mol-1H2O ) >银杏(1.34μmolCO2?mol-1H2O)>雪松(1.13μmolCO2?mol-1H2O);9月份是:绦柳( 2.57μmolCO2?mol-1H2O ) >雪松( 2.22μmolCO2?mol-1H2O ) >金银木( 2.08μmolCO2?mol-1H2O ) >银杏( 1.48μmolCO2?mol-1H2O ) >碧桃(1.29μmolCO2?mol-1H2O);10月份是:绦柳(3.26μmolCO2?mol-1H2O)>银杏( 1.96μmolCO2?mol-1H2O ) >碧桃( 1.81μmolCO2?mol-1H2O ) >雪松(1.45μmolCO2?mol-1H2O)>金银木(1.38μmolCO2?mol-1H2O)。在整个生长季节,绦柳的平均水分利用效率最大,因此其对土壤水分的利用最大,最适合在北方缺水地区绿化栽培;其余树种水分利用效率在各月份变化不一致,应根据环境条件选择合适的树种栽植。通过上述结论可以看出,在北京水资源紧缺且气候干燥的环境条件下,阳性树种碧桃和绦柳的光合能力、水分利用效率较高,最适宜绿化种植,银杏次之,而耐阴性较强的金银木和雪松其光合能力相对较弱,水分利用效率也不高,不适宜作为北方绿化树种,可以适当减少其种植比例。更多还原

【Abstract】 The urban trees play a very vital role in the protection of ecological enviroment as an important component in the forest ecosystems of city. But at same time these trees have so many problems, such as excessive water consumption, water conservation and the urban water resources use, and the contradictions are difficult to reconcile.5 kinds of virescence trees have been choosed for study in this paper in order to deal with these issues. Compred with the photosynthesis ability and water use efficiency of different trees, the theory basis for choice of Beijing ornamental plant and the cultivation management is provided. The results as follows,1. By the research on the daily change of the net photosynthetic rate and relation of Pn and its influencing factors, the conclusion was elicited. During the whole growth seasons, the daily change of Pn on Ginkgo biloba, Salix matsudana cv. Pendula and Prunus persica was bimodal curve mainly and midday rest depression appears. The turns were Salix matsudana cv. Pendula > Prunus persica > Gingko biloba > Cedrusde odara > Lonicera maackii from positive to negative by the analysis of compensation and saturation and the situation when suppressed by glare. The photosynthetic compensation points were 49.90μmol?m-2?s-1, 43.50μmol?m-2?s-1, 29.182μmol?m-2?s-1, 23.09μmol?m-2?s-1, 12.497μmol?m-2?s-1 in order. But in some special months, these trees are unimodal curve. Cedrusde odara and Lonicera maackii assume the unimodal curve. As a eutropic plant, Prunus persica is most positive, but the shade tolerance of Cedrusde odar is strongest. The main factors of affecting daily change of Pn on 5 trees are PAR, Ta, RH, Gs and Ls.2. Carried the analysis of daily change on Tr and relation on Tr and its influencing factors, the results are followed. During the growth season, the daily change of Tr is same with daily change of Pn. The average transpiration rate was Prunus persica (4.83μmolH2O?m-2?s-1) > Gingko biloba (3.20μmolH2O?m-2?s-1) > Lonicera maackii (2.74μmolH2O?m-2?s-1) > Cedrusde odara(2.57μmolH2O?m-2?s-1) > Salix matsudana cv. Pendula (2.24μmolH2O?m-2?s-1). This shows that Tr related with the change of Pn.3. In may, the WUE was Salix matsudana cv. Pendula(3.41μmolCO2?mol-1H2O)> Prunus persica( 2.07μmolCO2?mol-1H2O ) >Cedrusde odara ( 2.06μmolCO2?mol-1H2O ) >Ginkgo biloba(2.02μmolCO2?mol-1H2O)> Lonicera maackii(1.55μmolCO2?mol-1H2O). In June, Salix matsudana cv. Pendula(2.06μmolCO2?mol-1H2O)> Lonicera maackii(1.83μmolCO2?mol-1H2O)> Cedrusde odara(1.76μmolCO2?mol-1H2O)>Ginkgo biloba(1.46μmolCO2?mol-1H2O)>Prunus persica(1.01μmolCO2?mol-1H2O). In July, Cedrusde odara(1.80μmolCO2?mol-1H2O)>Salix matsudana cv. Pendula(1.64μmolCO2?mol-1H2O)>Ginkgo biloba(1.36μmolCO2?mol-1H2O)> Lonicera maacki(i1.20μmolCO2?mol-1H2O)>Prunus persica(1.15μmolCO2?mol-1H2O). In August, Lonicera maackii(1.82μmolCO2?mol-1H2O)>Prunus persica(1.65μmolCO2?mol-1H2O)> Salix matsudana cv. Pendula(1.61μmolCO2?mol-1H2O)>Ginkgo biloba(1.34μmolCO2?mol-1H2O)> Cedrusde odara ( 1.13μmolCO2?mol-1H2O ) . In September, Salix matsudana cv. Pendula(2.57μmolCO2?mol-1H2O)>Cedrusde odara(2.22μmolCO2?mol-1H2O)> Lonicera maackii( 2.08μmolCO2?mol-1H2O ) > Ginkgo biloba ( 1.48μmolCO2?mol-1H2O ) >Prunus persica(1.29μmolCO2?mol-1H2O). In October, Salix matsudana cv. Pendula(3.26μmolCO2?mol-1H2O)>Ginkgo biloba(1.96μmolCO2?mol-1H2O)>Prunus persica(1.81μmolCO2?mol-1H2O)>Cedrusde odara(1.45μmolCO2?mol-1H2O)> Lonicera maackii(1.38μmolCO2?mol-1H2O).Carries on the comparison of average water use efficiency on 5 trees, the results are followed. WUE of Salix matsudana cv. Pendula is highest, so it absorbs the most soil water and suits for cultured in north area. The WUE daily changes of other trees are different among all months. Appropriate cultured trees should be choosed according to the environmental condition. As a result, Prunus persica and Salix matsudana cv. Pendula are the most appropriate trees which are fit to Beijing because of the high Pn and WUE. The ability of Gingko biloba is weaker. The Pn and WUE of Lonicera maackii and Cedrusde odara are lower than others, so they would not be choosed as landscaping trees in north.更多还原