Abstract:

Pot culture experiments were conducted to investigate the characteristics of growth and water use of Robinia pseudoacacia under different soil water conditions,which were suitable soil water condition, medium soil water stress and serious soil water stress. The results showed that R. pseudoacacia leaf water potential, leaf relative water content, mean rate of shoot growth, photosynthetic rate and water use efficiency (WUE) of single leaf all decreased significantly with decreasing of soil moisture. In whole growth season, R. pseudoacacia shoot grew and yielded quickly mainly from April to June. Total water consumption and biomass of R. pseudoacacia under suitable soil water condition were all the highest, yet water use efficiency was the highest under medium soil water stress. The monthly highest water consumption, the daily highest water consumption and the time that the daily highest water consumption appeared of R. pseudoacacia were different under the three soil water conditions. The date of the daily highest water consumption under medium and serious soil water stress was about a month later than that under suitable soil water condition, and the monthly water consumption of R. pseudoacacia all reached its peak in July under three soil water conditions.In growth season, R. pseudoacacia showed a single peak in photosynthetic rate and transpiration rate in the diurnal variation, except a pronounced midday depression in July. R. pseudoacacia had characteristics of high water consumption and high drought resistance, and was not fit to be massively planted over vast area in some water shorten regions in Loess Plateau, but only fit for some slope condition such as shady slopes and gaps, where soil water condition was more favorable.

Key words: Robinia pseudoacacia, Water consumption, Soil water conditions, Growth