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林业科学 ›› 2009, Vol. 12 ›› Issue (6): 45-53.doi: 10.11707/j.1001-7488.20090609

• 论文 • 上一篇    下一篇

新疆额河流域两种野生杨树萌蘖苗叶片的气体交换特性*

刘华1,2 臧润国2 江晓珩3 丁易2 张炜银2 白志强3 郭仲军3   

  1. (1.安徽农业大学林学与园林学院 合肥 230036; 2.中国林业科学研究院森林生态环境与保护研究所国家林业局森林生态与环境重点实验室 北京 100091; 3.新疆林业科学研究院森林生态研究所 乌鲁木齐 830000)
  • 收稿日期:2008-03-18 修回日期:1900-01-01 出版日期:2009-06-25 发布日期:2009-06-25
  • 通讯作者: 臧润国

Leave Gas Exchange Characteristics of Sprout Seedlings of Two PoplarSpecies in the Irtysh River Basin,Xinjiang

Liu Hua1,2,Zang Runguo2,Jiang Xiaoheng3,Ding Yi2,Zhang Weiyin2,Bai Zhiqiang3,Guo Zhongjun3   

  1. (1.School of Forestry & Landscape Architecture,Anhui Agricultural University Hefei 230036;2.Key Laboratory of Forest Ecology and Environment,The State Forestry Administration Institute of Forest Ecology, Environment and Protection,Chinese Academy of Forestry Beijing 100091;3.Institute of Forest Ecology,Xinjiang Academy of Forestry Urumqi 830000)
  • Received:2008-03-18 Revised:1900-01-01 Online:2009-06-25 Published:2009-06-25

摘要:

选择额河流域天然林内苦杨(Populus laurifolia)和银白杨(P. alba)的3个年龄的自然萌蘖更新苗,于2006年的6—8月间利用LI-6400便携式光合仪,测定并分析了2种杨树的光合及相关气体交换特性(光合速率(Pn)、气孔导度(Gs)、气孔限制值(Ls)、蒸腾速率(Tr)及水分利用效率(WUE)等)。结果表明: 6—8月间,2种树木叶片的Gs随月份的变化呈下降趋势。不同年龄的2种杨树苗叶片Gs的日变化基本上表现出单峰和双峰型的趋势。其中,苦杨在6月的Gs日变化为双峰型,7、8月份为单峰型,且均在11:00时左右出现最大Gs值; 银白杨在6和7月Gs的日变化均为双峰型,最大Gs值出现在11:00时和13:00时。选择最大气孔限制时段内15:00时的Ls值进一步比较2种杨树光合生理特性,其中,Tr在6,7月均受Ls的限制,且对苦杨的蒸腾限制性要高于银白杨; 而Pn和WUE均不受Ls的影响。到8月,当苦杨的Ls大于0.3时,其叶片的Pn就受到明显的抑制,而银白杨的叶片由于不耐干旱均已脱落。总体上,苦杨自然萌蘖更新苗要比银白杨对自然干旱的适应性强,这可能是苦杨在额河流域比银白杨自然分布范围广的原因之一。未来气候或人为截流引起进一步干旱后,苦杨可能会比银白杨有更好的适应性。

关键词: 额尔齐斯河, 杨树, 萌蘖苗, 光合生理, 气孔交换

Abstract:

The riparian forest along the Irtysh river watershed, Xinjiang of Northwest China is regarded as an important gene pool for plants in the family Salicaceae. The survival and development of these plants could affect the structure and functions of the natural ecosystems in the river basin. The special environmental characteristics (such as drought, high temperature, and strong light in the growing season) in the river basin area often cause stresses on growth and development of the plants. Our major objectives were: 1) to understand the influence of natural drought stress on ecophysiological characteristics of the natural sprout poplars, 2) to compare the drought resistance of the two natural poplar species in terms of the ecophysiology to explain their distribution difference. We selected three different ages of natural sprout tillers of Populus laurifolia Ledeb. and P. alba Linn. Some stomatal factors such as Gs, Ls, Pn, Tr, and WUE were measured with LI-6400 from June to August in 2006. The results showed that monthly changes of Gs for the two poplar species declined from June to August. The diurnal change curves of G s of the two popular species in three different ages were basically in the form of unimodal or bimodal. The diurnal change curve of Gsfor P. laurifolia was bimodal in June, and was unimodal in July and August. The maximum value of Gs for P. laurifolia all appeared at 11:00 OClock in the day of measurement. The diurnal change curve of Gs for P. alba was bimodal in June and July, and the maximum value of Gs in the day of measurement occurred at 11:00 OClock and 13:00 OClock, respectively. Drought resistance and photosynthesis characteristics of the two popular species were compared by using Ls value at 15:00 OClock when most stomata restriction appeared. Tr of these two species were restricted by Ls in June and July, and the restrictions to P. laurifolia was higher than that to P. alba. Pn and WUE were not affected by Ls in June and July. But in August, when the Ls value of P. laurifoliawas greater than 0.3, Pn was restricted by Ls apparently, while the leaves of P. alba were shed because of the drought stress. This study showed that in general P. laurifolia had stronger adaptability to natural drought stress than P. alba in this region. This may be one of reasons why P. laurifolia has wider distribution areas than P. alba in the Irtysh rive basin areas. We could predict from this study that P. laurifolia will be able to adapt better than P. alba to the further drought caused by both global climate change and anthropogenic water withdraw from the Irtysh river.

Key words: Irtysh river, Poplars, sprouting seedling, photosynthesis, gas exchange