黑沙蒿应对降水变化的木质部与韧皮部协同响应机制  

Synergistic response mechanisms in xylem and phloem of Artemisia ordosica to changes in precipitation

作　　者：张富崇 于明含[1,3,4] 张建玲 王平 丁国栋[1,3,4] 何莹莹 孙慧媛[1,3,4] ZHANG Fu-Chong;YU Ming-Han;ZHANG Jian-Ling;WANG Ping;DING Guo-Dong;HE Ying-Ying;SUN Hui-Yuan(School of Soil and Water Conservation,Beijing Forestry University,Beijing 100083,China;Jixian National Forest Ecosystem Observation and Research Station,Linfen,Shanxi 042200,China;Yanchi Ecology Research Station,Yanchi,Ningxia 751500,China;Key Laboratory of State Forestry and Grassland Administration on Soil and Water Conservation,Beijing Forestry University,Beijing 100083,China)

机构地区：[1]北京林业大学水土保持学院,北京100083 [2]山西吉县森林生态系统国家野外科学观测研究站,山西临汾042200 [3]宁夏盐池毛乌素沙地生态系统国家定位观测研究站,宁夏盐池751500 [4]北京林业大学水土保持国家林业和草原局重点实验室,北京100083

出　　处：《植物生态学报》2024年第7期903-914,共12页Chinese Journal of Plant Ecology

基　　金：中央高校基本科研业务费专项资金(QNTD202303)。

摘　　要：探究不同降水情景下荒漠植物茎干解剖学结构的适应性调节,可以更好地理解未来降水格局变化下荒漠植物水和碳运输间的协调机制。该研究以毛乌素沙地黑沙蒿(Artemisia ordosica)种群为对象,通过野外人工控制降水的方法,模拟半干旱气候区降水变化趋势,设置3个降水量水平(减水30%、自然降水、增水30%)以及2个降水间隔水平(降水间隔5 d、降水间隔15d)开展双因素完全随机实验,测定了黑沙蒿茎木质部与韧皮部解剖结构在不同降水情境下的轴向与径向变异。结果表明:1)在降水改变的情况下,黑沙蒿并未产生更抗栓塞的轴向木质部结构及传导效率更高的轴向韧皮部结构来适应环境;2)降水变化通过改变40–60 cm土层含水率对黑沙蒿的木质部、韧皮部径向解剖性状产生影响。在低水分生境下,黑沙蒿减小导管直径和增大导管壁厚度以保证水分运输的安全性,并且通过增大韧皮部筛管面积来维持韧皮部导度保证碳的有效运输,以此保证黑沙蒿进行正常的生理活动;3)黑沙蒿木质部导管和韧皮部筛管具有等标度的轴向缩放规律,二者协同关联共同维持水力功能,且这种相关关系不受降水变化的影响。该研究表明,黑沙蒿通过改变径向茎干结构而不是轴向结构来适应降水的改变。Aims Investigating the adaptive regulation of stem anatomy in desert plants under different precipitation scenarios will lead to a better understanding of the coordination mechanisms between water and carbon transport in desert plants under future precipitation patterns.Methods In this study,a two-factor completely randomized experiment was conducted to determine the axial and radial variation in the xylem and phloem anatomy of Artemisia ordosica stems under different precipitation conditions by manipulating precipitation in the field in a semi-arid climate zone,with three precipitation treatments in amounts(30%precipitation reduction,natural precipitation and 30%precipitation increase)and two precipitation intervals(5 d precipitation interval and 15 d precipitation interval).Important findings The results indicate:1)Under altered precipitation,A.ordosica did not develop more conductive axial xylem structures and more conductive axial phloem structures to adapt to the changes;2)Precipitation changes affected the radial anatomical traits of xylem and phloem of A.ordosica by altering the moisture content of the 40-60 cm soil layer.Under low moisture habitats,A.ordosica reduced the conduit diameter and increased the conduit wall thickness to ensure the safety of water transport,and maintained the phloem conductivity by increasing the lumen area of phloem sieve cells to ensure the effective transport of carbon,thus ensuring the normal physiological activities of A.ordosica;3)The xylem conduit and phloem lumen of A.ordosica had an equal scaling axial scaling pattern,and the two were synergistically related to each other to maintain the hydraulic function,and this correlation was not affected by changes in precipitation.This study showed that A.ordosica adapted to changes in precipitation by altering the radial stem structure rather than the axial.This study is a valuable addition to the anatomical knowledge of the hydraulic structure of desert shrubs and provides a theoretical basis for future management of vegetation

关 键 词：降水变化 黑沙蒿 木质部 韧皮部 异速生长 

分 类 号：Q948[生物学—植物学]