雷州半岛尾巨桉人工林生理形态特征对季节性干旱的响应  

Response of Physiological and Morphological Characteristics of Eucalyptus urophylla×E.grandis Plantations to Seasonal Drought in Leizhou Peninsula,China

作　　者：曹昊阳 刘宇升 许宇星[1] 竹万宽[1] 黄润霞 王志超[1] CAO Haoyang;LIU Yusheng;XU Yuxing;ZHU Wankuan;HUANG Runxia;WANG Zhichao(Research Institute of Fast-growing Tree,Chinese Academy of Forestry/National Positioning Observation and Research Station of Eucalypt Plantation Ecosystem,Zhanjiang 524022,Guangdong,China;Nanjing Forestry University,Nanjing 210037,Jiangsu,China)

机构地区：[1]中国林业科学研究院速生树木研究所/广东湛江桉树林生态系统国家定位观测研究站,广东湛江524022 [2]南京林业大学,江苏南京210037

出　　处：《桉树科技》2024年第3期1-9,共9页Eucalypt Science & Technology

基　　金：“十四五”国家重点研发计划项目(2023YFD2201005);广西重点研发计划(桂科AB23026010);广东省林业科技创新项目(2022KJCX020);广东湛江桉树林生态系统国家定位观测研究站运行补助项目(KS2024160017);林业生态监测网络平台运行项目数据采集(2024CG232)。

摘　　要：为明确尾巨桉对季节性干旱的响应,进而为全球气候变化背景下桉树人工林的建设、恢复以及可持续经营管理、水资源高效利用提供数据支持和理论指导,本文以典型季节性干旱胁迫区的尾巨桉人工林为研究对象,通过监测和分析尾巨桉的蒸腾速率、气孔导度、叶片水势和各冠层结构参数的季节变化特征,明确尾巨桉旱雨季间各生理特征和冠层形态方面的差异,从而揭示其应对季节性干旱的生理形态响应。结果表明:尾巨桉旱季的平均蒸腾速率(0.048 cm·min^(-1))显著小于雨季的平均蒸腾速率(0.064 cm·min^(-1)),平均气孔导度变化规律和平均蒸腾速率一致,旱季(0.39mm·s^(-1))显著小于雨季(0.49mm·s^(-1))。尾巨桉旱季的平均黎明前叶片水势为-1.41MPa,平均正午叶片水势为-1.79Mpa,均显著小于雨季(平均黎明前叶片水势-1.17MPa,平均正午叶片水势-1.47MPa),正午与黎明前的水势差旱季平均为0.39MPa,显著大于雨季的平均水势差(0.29MPa)。旱季的叶面积指数(LAI)为1.93,显著小于雨季的2.34,旱季的平均叶倾角(56.34°)和冠层总孔隙度(18.33%)均显著大于雨季(平均叶倾角53.26°,冠层总孔隙度13.85%)。研究结果说明尾巨桉为应对季节性干旱,在冠层形态方面会通过主动的叶运动(增加叶倾角和主动落叶)方式来减小截获的辐射进而降低树体的水分散失;在生理方面,尾巨桉会通过降低冠层气孔导度来降低蒸腾速率从而减少树体的水分散失,同时还通过降低自身水势、增加叶片和土壤之间的水势差来提高其在旱季的吸水和保水能力。This study investigated the response of Eucalyptus urophylla×E.grandis to seasonal drought,aiming to provide data and theoretical guidance for the construction,restoration,and sustainable management of Eucalyptus plantations amid global climate change.This study foucused on E.urophylla×E.grandis plantations in regions experiencing typical seasonal drought stress.By monitoring and analyzing seasonal variations in transpiration rate,stomatal conductance,leaf water potential,and various canopy structural parameters of E.urophylla×E.grandis,seeking to identify differences in physiological traits and canopy morphology between dry and wet seasons.This will help to elucidate the physiological and morphological adaptations of E.urophylla×E.grandis to seasonal drought conditions.Results indicated that the average transpiration rate was significantly lower during the dry season(0.048 cm·min^(-1))compared to the wet season(0.064 cm·min^(-1)).Similarly,average stomatal conductance was reduced significantly in the dry season(0.39 mm·s^(-1))versus the wet season(0.49 mm·s^(-1)).Leaf water potential before dawn is -1.41 MPa during the dry season and -1.79 MPa at noon,both significantly lower than in the wet season(-1.17 MPa before dawn,-1.47 MPa at noon).The midday-to-dawn water potential difference is greater in the dry season(0.39 MPa)compared to the wet season(0.29 MPa).The leaf area index(LAI)is lower in the dry season(1.93)compared to the wet season(2.34).Additionally,leaf angle(56.34°)and canopy porosity(18.33%)are higher in the dry season than in the wet season(leaf angle 53.26°,canopy porosity 13.85%).The study concluded that E.urophylla×E.grandis mitigated seasonal drought effects by reducing radiation interception and water loss through increased leaf angle,leaf drop,and physiological adjustments like decreased stomatal conductance and transpiration rate,while enhancing water uptake and retention by lowering leaf water potential and increasing the water potential difference between leaves and soil.

关 键 词：尾巨桉 季节性干旱 生理特征 冠层结构 

分 类 号：S718[农业科学—林学]