title: Sexual competition affects biomass partitioning, carbon-nutrient balance, Cd allocation and ultrastructure of Populus cathayana females and males exposed to Cd stress.
abstract: Although increasing attention has been paid to plant adaptation to soil heavy metal contamination, competition and neighbor effects have been largely overlooked, especially in dioecious plants. In this study, we investigated growth as well as biochemical and ultrastructural responses of Populus cathayana Rehder females and males to cadmium (Cd) stress under different sexual competition patterns. The results showed that competition significantly affects biomass partitioning, photosynthetic capacity, leaf and root ultrastructure, Cd accumulation, the contents of polyphenols, and structural and nonstructural carbohydrates. Compared with single-sex cultivation, plants of opposite sexes exposed to sexual competition accumulated more Cd in tissues and their growth was more strongly inhibited, indicating enhanced Cd toxicity under sexual competition. Under intrasexual competition, females showed greater Cd accumulation, more serious damage at the ultrastructural level and greater reduction in physiological activity than under intersexual competition, while males performed better under intrasexual competition than under intersexual competition. Males improved the female microenvironment by greater Cd uptake and lower resource consumption under intersexual competition. These results demonstrate that the sex of neighbor plants and competition affect sexual differences in growth and in key physiological processes under Cd stress. The asymmetry of sexual competition highlighted here might regulate population structure, and spatial segregation and phytoremediation potential of both sexes in P. cathayana growing in heavy metal-contaminated soils.
authors.affiliation: Ecological Security and Protection Key Laboratory of Sichuan Province, Mianyang Normal University, Mianyang 621000, China.|Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Chen
authors.affiliation: Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China.
authors.forename: Baoli
authors.initials: B
authors.lastname: Duan
authors.affiliation: School of Life Sciences, Southwest University of Science and Technology, Mianyang 621010, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Xu
authors.affiliation: Department of Agricultural Sciences, Viikki Plant Science Centre, P.O. Box 27, FI-00014 University of Helsinki, Finland.
authors.forename: Helena
authors.initials: H
authors.lastname: Korpelainen
authors.affiliation: Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, 51014 Tartu, Estonia.
authors.forename: Ülo
authors.initials: Ü
authors.lastname: Niinemets
authors.affiliation: The Nurturing Station for the State Key Laboratory of Subtropical Silviculture, Zhejiang A & F University, Lin'an 311300, Zhejiang, China licy@zafu.edu.cn.
authors.forename: Chunyang
authors.initials: C
authors.lastname: Li
mesh_terms: D000222:Adaptation, Physiological; D018533:Biomass; D002104:Cadmium / Q000378:metabolism*; D002244:Carbon / Q000378:metabolism; D017753:Ecosystem; D063245:Plant Development; D032107:Populus / Q000378:metabolism* / Q000648:ultrastructure; D012098:Reproduction; D013312:Stress, Physiological; D014197:Trees / Q000378:metabolism* / Q000648:ultrastructure; D014874:Water Pollutants, Chemical / Q000378:metabolism
chemical_list: D014874:Water Pollutants, Chemical; D002104:Cadmium; D002244:Carbon
keywords: Cd accumulation; carbohydrates; dioecy