桉树无性系和华南乡土树种秋枫苗木耗水特性的比较

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

研究尾巨桉DH33-27、尾巨桉DH32-29、巨桉H1、红冠桉和秋枫5种苗木在正常土壤水分条件下的耗水量、耗水速率、叶片净光合速率(Pn)、蒸腾速率(Tr)和水分利用效率(WUE).结果表明:5种苗木的日平均耗水量大小顺序为:尾巨桉DH32-29(188.47±14.91)g>尾巨桉DH33-27(169.27±16.26)g>巨桉H1(118.65±5.32)g>秋枫(38.12±1.46)g>红冠桉(20.13±1.72)g,耗水量与苗木整株叶面积呈显著正相关.苗木耗水大多集中在白天,白天平均耗水量约为全天平均耗水量的90%.正常土壤水分条件下,5种苗木的耗水速率日变化均呈单峰曲线,峰值出现在12:00—14:00.桉树总体耗水能力强于秋枫.其中,红冠桉的耗水速率远高于其他4种苗木,大面积种植应充分考虑水分问题;尾巨桉DH33-27的耗水速率受环境温湿度影响最大,在白天高温低湿的情况下,其平均耗水速率在4种桉树苗木中最小.与秋枫相比,供试4个桉树无性系均表现出高光合、高蒸腾的特性.2个尾巨桉无性系表现出良好的节水性能.除尾巨桉DH33-27,桉树总体水分利用效率高于秋枫.

The water consumption, water consumption rate, net photosynthetic rate （Pn） , transpi- ration rate （Tr） and water use efficiency （WUE） of Eucalyptus urophylla × E. grandis DH33-27, E. urophylla × 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 ×E. grandis DH32-29 （188.47±14.91） g 〉 E. urophylla × 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×E. grandis DH33-27 was mostly impacted by environ- mental 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 hu- midity. 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 × E. grandis had better water-saving performance. The WUE of Eucalyptus and Corymbia was higher than that ofB. javanica in general, except E. urophylla × E. Grandis DH33-27.