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| Transpiration characteristics of major tree species for soil and water conservation in Loess Plateau |
| Zhou Xiaoxin1,Zhang Jianjun1,2,Li Yitao1 |
| 1.College of Soil and Water Conservation,Beijing Forestry University;2.Key Lab.of Soil & Water Conservation and Desertification Combating,Ministry of Education: 100083,Beijing,China |
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Abstract Leaf water conservation capacity,daily changes of transpiration rate and leaf water potential of Populus davidiana,Robinia pseudoacacia,Pinus tabulaeformis and Platycladus orientalis were studied by using precision Electronic Balance with the accuracy of 0.001 g and Dew Point Microvokmeter.The results show that the descending order of the leaf water conservation capacity of four tree species is Populus davidiana,Robinia pseudoacacia,Pinus tabulaeformis,Platycladus orientalis,and it took 19 h、41 h、49 h and 77 h respectively before the leaf-weight did not decrease in natural condition.The descending order of the average transpiration rate is: Populus davidiana(0.616 mmol/(m2·s)),Robinia pseudoacacia(0.605 mmol/(m2·s)),Pinus tabulaeformis(0.318 mmol/(m2·s)),Platycladus orientalis(0.270 mmol/(m2·s)),and the daily maximum transpiration rate in the following descending order: Populus davidiana(1.196mmol/(m2·s)),Robinia pseudoacacia(1.190 mmol/(m2·s)),Pinus tabulaeformis(0.723mmol/(m2·s)),Platycladus orientalis(0.704 mol/(m2·s)).The diurnal variation of leaf water potential was a waveform curve with the highest in the early morning,the lowest at noon and significant recovery in the afternoon,and its daily variation amplitude is in the following order: Robinia pseudoacacia is the largest,while Pinus tabulaeformis is the smallest,and Populus davidiana,Platycladus orientalis are in the middle.Leaf water potential and transpiration rate are negatively related,and the relationship between them can be fitted by logarithmic curve.Daily transpiring water consumption amount(by 12h/d) on unit leaf area(by 1 cm2) of the four tree species is in the following descending order: Populus davidiana(0.48 mm),Robinia pseudoacacia(0.47 mm)>Pinus tabulaeformis(0.25 mm),Platycladus orientalis(0.21 mm).
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Received: 12 January 2009
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