[Comparison of the water consumption characteristics of Eucalyptus and Corymbia clone seedlings and the local indigenous tree species Bischofia javanica].

The water consumption, water consumption rate, net photosynthetic rate (Pn), transpiration rate (Tr) and water use efficiency (WUE) of Eucalyptus urophylla x E. grandis DH33-27, E. urophylla x E. grandis DH32-29, E. grandis H1, Corymbia ptychocarpa and an indigenous tree species Bischofia javanica were studied in normal soil moisture condition. The average daily water consumption of the five tree species was in the order of E. urophylla x E. grandis DH32-29 (188.47 +/- 14. 91) g > E. urophylla x E. grandis DH33-27 (169.27 +/- 16.26) g > E. grandis H1 (118.65 +/- 5.32) g > B. javanica (38.12 +/- 1.46) g > C. ptychocarpa (20.13 +/- 1.72) g, which had obviously positive correlation with the total leaf area of each seedling. The water consumption was mostly in the daytime, which took 90% of the whole day water consumption. The daily change of the water consumption rates of 5 kinds of seedlings followed the curve with one peak at 12:00-14:00. The total water consumption ability of Eucalyptus and Corymbia was higher than that of B. javanica. The water consumption rate of C. ptychocarpa was far higher than that of the other 4 kinds of seedlings, so its large area planting should be given full consideration to this issue. The change in water consumption rate of E. urophylla x E. grandis DH33-27 was mostly impacted by environmental temperature and humidity, because its water consumption rate was the smallest among 4 kinds of Eucalyptus and Corymbia seedlings during the daytime with high temperature and low humidity. The four clone seedlings of Eucalyptus and Corymbia showed higher photosynthetic rates and transpiration rates compared with B. javanica. Two clone seedlings of E. urophylla x E. grandis had better water-saving performance. The WUE of Eucalyptus and Corymbia was higher than that of B. javanica in general, except E. urophylla x E. Grandis DH33-27.