Leaflet Movement of Robinia pseudoacacia in Response to a Changing Light Environment  

作　　者：Cheng-Cheng Liu Clive V. J. Welham Xian-Qiang Zhang Ren-Qing Wang 

机构地区：[1]Institute of Ecology and Biodiversity, School of Life Sciences, Shandong University, Jinan 250100, China [2]Forest Ecosystem Management Simulation Group, Department of Forest Sciences, University of British Columbia, Vancouver, BC V6T 1Z4, Canada

出　　处：《Journal of Integrative Plant Biology》2007年第4期419-424,共6页植物学报（英文版）

基　　金：Supported by the National Natural Science Foundation of China （39870129）, PhD Program Foundation of Ministry of Education of China （20030422030）, and the National Natural Science Foundation of Shandong Province （Z2003D05）.Acknowledgements The authors sincerely thank Dr Xue-Cong Liu, Zhi-Guo Zhang and Shu-Ping Zhang for technical support, and Jiang Liu, L Chen, and Da-Ning Li for help in field experiment.

摘　　要：Diurnal and nocturnal leaflet movement of black locust （Robinia pseudoacacia L.） was investigated under three light schemes： 100% natural irradiance, 50% shading, and 90% shading. Changes in leaf mid-vein angle were described by measurements of two planes： （i） β, the angle formed by the bottom of the petiolule and its relation to the horizontal plane; and （ii） θ, the angle between the petiolule and the main leaflet vein. The two highest light regimens had a significant effect on β. Variation in β tends to make the leaflet more erect, thereby minimizing any negative impact of high irradiance on leaf lamina. Light-dark rhythms induced variation in θ （termed nyctinastic movement）. Nyctinastic movement is important during the low light levels experienced by leaflets in early morning and late afternoon. At low light levels, the leaflet stopped nyctinastic movement and θ was fixed at an angle that may have enabled the leaf lamina to maximize light interception. After the light-dark cycle was reestablished, nyctinastic movement was restored. Taken together, our results suggest that irradiance induces variation in β leading to diurnal leaflet movement （diaheliotropism）, whereas the light-dark cycle influences θ, which results in nocturnal leaflet movement. Both angles are important for describing patterns of leaf movement in R. pseudocacia.Diurnal and nocturnal leaflet movement of black locust （Robinia pseudoacacia L.） was investigated under three light schemes： 100% natural irradiance, 50% shading, and 90% shading. Changes in leaf mid-vein angle were described by measurements of two planes： （i） β, the angle formed by the bottom of the petiolule and its relation to the horizontal plane; and （ii） θ, the angle between the petiolule and the main leaflet vein. The two highest light regimens had a significant effect on β. Variation in β tends to make the leaflet more erect, thereby minimizing any negative impact of high irradiance on leaf lamina. Light-dark rhythms induced variation in θ （termed nyctinastic movement）. Nyctinastic movement is important during the low light levels experienced by leaflets in early morning and late afternoon. At low light levels, the leaflet stopped nyctinastic movement and θ was fixed at an angle that may have enabled the leaf lamina to maximize light interception. After the light-dark cycle was reestablished, nyctinastic movement was restored. Taken together, our results suggest that irradiance induces variation in β leading to diurnal leaflet movement （diaheliotropism）, whereas the light-dark cycle influences θ, which results in nocturnal leaflet movement. Both angles are important for describing patterns of leaf movement in R. pseudocacia.

关 键 词：heliotropism leaflet movement mid-vein angle nyctinastic movement Robinia pseudoacacia 

分 类 号：Q945.7[生物学—植物学] S792.27[农业科学—林木遗传育种]