Study On Characteristic Of Transpiration And Ecological Function Of Familiar Landscape Plants

The experiments in characteristic of transpiration and ecological function with the familiar landscape plants including Berberis thumbergii cv. atropurpurea, Ligustrum vicaryi, Euonymus kiautschovicus Loes., Syringa oblate Lindl., Kerria japonica (L.)DC., Ginkgo biloba L., Sophora japonica L. and Fraxinus chinensis Roxb. were conducted in Beijing, Northern of China, In this research, the transpiration characteristic and correlative ecological function of different landscape plants, dynamics of trunk sap flow of G. biloba were compared and analysed; The relationship between trunk sap flow and environmental factors and the estimable equation of daily sap flow flux during the periods of whole year growth were revealed. The main results are as followed:The sequence of daily average transpiration rate tested plants species was Ligustrum vicaryi＞Fraxinus chinensis Roxb.＞Euonymus kiautschovicus Loes.＞Syringa oblate Lindl.＞Sophora japonica L.＞Ginkgo biloba L.＞Kerria japonica (L.)DC.＞Berberis thumbergii cv. Atropurpurea. Daily transpiration rate fluctuating for both Ginkgo biloba L. and Berberis thumbergii cv. Atropurpurea was relatively stable, which possibly means that these two species had low sensitivity and better capacity of acclimatize themselves to environmental change under the same situation. Ginkgo biloba L., Kerria japonica (L.)DC. and Berberis thumbergii cv. Atropurpurea were 3 low water-consumption speciesThe results also indicated that the leaf water use efficiency (WUE) was ranged as Syringa oblate Lindl.,＞Sophora japonica L.,＞Kerria japonica (L.)DC.,＞Fraxinus chinensis Roxb.,＞Berberis thumbergii cv. Atropurpurea,＞Ginkgo biloba L.,＞Euonymus kiautschovicus Loes.,＞Ligustrum vicaryi.Through the analysis on the change trend of net photosynthesis rate and leaf water use efficiency (WUE) followed the change of transpiration rate, Berberis thumbergii cv. atropurpurea, Ligustrum vicaryi, Euonyrnus kiautschovicus Loes., Syringa oblate Lindl., Kerria japonica (L.)DC., Sophora japonica L. and Fraxinus chinensis Roxb. were likely to have inefficacy water consumption and potential of reducing transpiration.The capability sequence of decreasing air temperature and increasing humidity was Ligustrum vicaryi,＞Fraxinus chinensis Roxb.,＞Euonymus kiautschovicus Loes.,＞Syringa oblate Lindl.,＞Sophora japonica L.,＞Ginkgo biloba L.,＞Kerria japonica (L.)DC.,＞Berberis thumbergii cv. Atropurpurea; the capability sequence of O₂ production and CO₂ absorption per unit leaf area (m²) ranged as Syringa oblate Lindl.,＞Sophora japonica L.,＞Fraxinus chinensis Roxb.,＞Euonymus kiautschovicus Loes.,＞Ligustrum vicaryi,＞Ginkgo biloba L.,＞Kerria japonica (L.)DC.,＞Berberis thumbergii cv. Atropurpurea. So, the suggestion could be gotten that the ecological function among plant species were different, the reasonable plants choose was necessary to urban forestation.The seasonal change trend of sap flow revealed that transpiration flux was the most in Jul., daily sap flow flux could reach around 23L. Daily sap flow flux fluctuating was relatively distinct in May, July and Sep., most distinct in Jul, discrepancy could reach 20L. According to average daily sap flow flux of different growth phases, transpiration flux of Ginkgo biloba L. of 12-years-old was 2580L.Trunk sap flow flux of Ginkgo biloba L. during growing season correlated to the environmental factors and characteristics of plants shape. Air temperature was a steadable influencing factor; the influence of other environmental factors showed quite different during growing periods of Ginkgo biloba L.Stepwise regression analyses revealed that the air temperature was the main factor affecting the sap flow. Stepwise regression equation showed significant different.