摘要:
以元谋县金沙江干热河谷区14个树种为试材，探讨了干季（3月）、干热季（5月）和湿润季（10月）典型晴天里各树种水分利用效率日动态规律，以揭示极端干热生境条件下供试树种水分利用效率的动态特征，并展开比较分析，结合它们在当地的实际表现，讨论了其适应性和应用前景。结果表明：供试树种水分利用效率在不同季节均可划分为高、中、低3种类别，同一树种在不同季节所属的类别具有较大差别，在季节性干热胁迫鲜明的干热河谷，供试树种水分利用效率的日动态响应机制具有明显的季节效应。在干季转向干热季阶段，干热胁迫的加深明显促进了WUE日变化峰值的提前出现，亦使WUE更早地受到抑制而下降；在干热季转向湿润季阶段，供试树种水分利用效率日变化峰值延后，部分树种水分利用效率“午睡”现象消失，印楝、新银合欢、苏门答腊金合欢及木豆水分利用效率提高较大，在湿润季节里获得较高的光合生产力，从而增强树种在干热河谷区的存活能力。在干热季和湿润季同时具有较高或中等水分利用效率的树种有余甘子、山毛豆、车桑子、小桐子和山合欢等5个树种。
Abstract:
In order to reveal the dynamic characteristics of water-use efficiency of major tree species for vegetation restoration under the condition of extremely dry and hot environment in the dry-hot valleys of the Jinsha River, Yuanmou County, we compared the water-use efficiency of 14 natural tree species on typical sunny days during the dry season (March), dry-hot season (May) and wet season (October).Combining the practical growth conditions, the adaptability and application of the tested tree species were analyzed.The water-use efficiency of tree species in different seasons all could be divided into three classifications, i.e. high, medium and low water-use efficiency.The classification of some tree species varied among different seasons.The dynamic response mechanism of daily water-use efficiency displayed significant seasonal effects in the dry-hot river valleys with obvious seasonal dry-hot stress.When growth environment varied from dry in March to dry and hot in May,the peak value of daily water-use efficiency occurred earlier and the water-use efficiency declinded earlier under intensified dry-hot stress.During the stage from dry-hot season to wet season,the peaks of daily water-use efficiency presented at a relatively later time;the phenomenon of “midday depression” of some tree species vanished; the water-use efficiency of Azadirachta indica (A.) Juss, Leucaena glauca (L.) Benth., Acacia glauca (L.) Moelichl and Cajanus cajan (L.) Millsp. got improved greatly,indicating that these tree species had a higher photosynthesis capability under the condition of enough water supply,which was beneficial for their survival during the wet season in the dry-hot river valley.Five other tree species,Phyllanthus emblica L., Dodonaea viscosa L., Tephrosia candida DC., Jatropha curcas L. and Albizia kalkora (Roxb.) Prain,presented relatively high or medium water-use efficiency both during the dry-hot season and wet season.
百度学术
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