Effects of light intensity and wind speed on transpiration rate of potted Eucalyptus saplings

In order to investigate the effects of light intensity，wind speed and leaf age on transpiration of potted Eucalyptus saplings，Eucalyptus saplings transpiration rate were observed with pot experiments，in which light intensity and wind speed were controlled. Meteorological factors were monitored simultaneously. The results showed that: transpiration rate of Eucalyptus increased as the light intensity enhancing. When the light intensity was more than 720 μmol/m2·s，the transpiration rate began to decline. The peak value emerged in different periods under different light intensities. The times of peak value emerging were mainly affected by light intensity. The peak values were 0.018 g/cm2·h to 0.024 g/cm2·h when light intensities ranged from 500 μmol/m2·s to 720 μmol/m2·s. The transpiration of young leaves were easy restrained by strong light，but for the old leaves，the transpiration were restrained under low light level. No significant change was found in the influence of wind speed on Eucalyptus saplings transpiration under the conditions of low air temperature and low tree transpiration rate. Positive correlations were found between the vapor pressure deficit，light intensity，air temperature and the Eucalyptus saplings transpiration rate. There was a negative correlation between air humidity and transpiration rates.