文献类型：期刊文献

英文题名：Xylem anatomical and hydraulic traits vary within crown but not respond to water and nitrogen addition in Populus tomentosa

作者：Zhang, Yuwen[1,2,3] Ding, Changjun[4] Liu, Yan[1,2,3] Li, Shan[5] Li, Ximeng[6] Xi, Benye[1,2,3] Duan, Jie[1,7,8]

第一作者：Zhang, Yuwen

通信作者：Xi, BY[1];Duan, J[1]

机构：[1]Beijing Forestry Univ, Key Lab Silviculture & Conservat, Minist Educ, 35 East Qinghua Rd, Beijing 100083, Peoples R China;[2]Beijing Forestry Univ, Key Lab Silviculture & Forest Ecosyst Arid, Beijing, Peoples R China;[3]Beijing Forestry Univ, Semiarid Reg State Forestry & Grassland Adm, Beijing, Peoples R China;[4]Chinese Acad Forestry, Res Inst Forestry, State Key Lab Tree Genet & Breeding, Key Lab Tree Breeding & Cultivat,State Forestry Ad, Beijing, Peoples R China;[5]Shaanxi Univ Sci & Technol, Sch Environm Sci & Engn, Xian, Peoples R China;[6]Minzu Univ China, Coll Life & Environm Sci, Beijing, Peoples R China;[7]Beijing Forestry Univ, Natl Energy R&D Ctr Nonfood Biomass NECB, Beijing, Peoples R China;[8]Int Sci & Technol Cooperat Base Forestry Biomass E, Beijing, Peoples R China

年份：2023

卷号：278

外文期刊名：AGRICULTURAL WATER MANAGEMENT

收录：;EI(收录号：20230413419074);Scopus(收录号：2-s2.0-85146418330);WOS:【SCI-EXPANDED(收录号:WOS:000989225500001)】；

基金：Acknowledgments This research was jointly supported by the National Natural Science Foundation of China (31971640, 31872702) , the National Key Research and Development Program of China [grant number 2021YFD2201203] , and the Fundamental Research Funds for the Central Universities (2021ZY18) . The authors appreciate Hongqing Yang and Yafei Wang for the stand management and field data collection. The authors are also grateful to Jinge Sun and lab colleagues for their assistance during field experiments.

语种：英文

外文关键词：Xylem anatomy; Hydraulic function; Phenotypic plasticity; Irrigation; Fertilization; Canopy position

摘要：Nitrogen (N) and water availability are the two crucial factors confining tree growth and forest productivity. Irrigation, fertilization, and combined fertigation are commonly applied to plantation forests for improving productivity. However, how xylem vasculature responds to these management practices remains poorly un-derstood. Here we investigated the responses of tree growth, xylem anatomical structure, and hydraulics of the upper, middle, and lower canopy branches in a 6-year-old Populus tomentosa plantation subjected to four years of irrigation and fertigation treatments. The results showed that an improvement in tree growth only occurred in the irrigation treatment while the addition of N in fertigation treatments did not have a cumulative effect on tree growth. Most of the xylem anatomical traits, including vessel hydraulic diameter (Dh), vessel density (VD), vessel fraction (VF), double vessel wall thickness (t), potential specific sapwood hydraulic conductivity (Kp), fiber wall to lumen ratio (Tf/Df), vessel wall reinforcement (t/b)2, and wood density (WD) all showed conserved plasticity to long-term irrigation and fertigation, despite different tree growth rate, implying that aboveground biomass accumulation may have decoupled from the branch-level xylem traits. Besides, the alterations of other factors, including stomatal regulation strategy and crown structure with soil water and N availabilities, might better explain the variation in tree growth. In contrast, greater variations in branch xylem traits were detected across canopy layers. The upper canopy showed greater hydraulic safety characterized by narrower and denser vessels, higher cell wall to lumen ratio, and higher wood density compared to the lower canopy, while hydraulic effi-ciency (Kp) remained constant across the crown, thus highlighting the priority of hydraulic safety over efficiency in the construction of branch xylem. Overall, our study revealed the response pattern of P. tomentosa xylem structure to long-term water and N management, which facilitates a comprehensive understanding on the mechanisms underpinning the influence of water and nutrients regulation on the performance of fast-growing tree species' plantations.