title: Germination shifts of C3 and C4 species under simulated global warming scenario.
abstract: Research efforts around the world have been increasingly devoted to investigating changes in C3 and C4 species' abundance or distribution with global warming, as they provide important insight into carbon fluxes and linked biogeochemical cycles. However, changes in the early life stage (e.g. germination) of C3 and C4 species in response to global warming, particularly with respect to asymmetric warming, have received less attention. We investigated germination percentage and rate of C3 and C4 species under asymmetric (+3/+6°C at day/night) and symmetric warming (+5/+5°C at day/night), simulated by alternating temperatures. A thermal time model was used to calculate germination base temperature and thermal time constant. Two additional alternating temperature regimes were used to test temperature metrics effect. The germination percentage and rate increased continuously for C4 species, but increased and then decreased with temperature for C3 species under both symmetric and asymmetric warming. Compared to asymmetric warming, symmetric warming significantly overestimated the speed of germination percentage change with temperature for C4 species. Among the temperature metrics (minimum, maximum, diurnal temperature range and average temperature), maximum temperature was most correlated with germination of C4 species. Our results indicate that global warming may favour germination of C4 species, at least for the C4 species studied in this work. The divergent effects of asymmetric and symmetric warming on plant germination also deserve more attention in future studies.
authors.affiliation: Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China.
authors.forename: Hongxiang
authors.initials: H
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Yu
authors.affiliation: Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China.
authors.forename: Yingxin
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Graham Centre for Agricultural Innovation, Wagga Wagga, New South Wales, Australia.
authors.forename: Wei
authors.initials: W
authors.lastname: Zheng
authors.affiliation: Animal Science and Technology College, Jilin Agricultural University, Changchun, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Tian
authors.affiliation: College of Environment and Resources, Dalian Nationalities University, Dalian, China.
authors.forename: Yantao
authors.initials: Y
authors.lastname: Song
authors.affiliation: Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China; Graham Centre for Agricultural Innovation, Wagga Wagga, New South Wales, Australia.
authors.forename: Guangdi
authors.initials: G
authors.lastname: Li
authors.affiliation: Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China.
authors.forename: Daowei
authors.initials: D
authors.lastname: Zhou
mesh_terms: D002681:China; D003198:Computer Simulation; D018525:Germination; D057232:Global Warming; D019684:Magnoliopsida / Q000254:growth & development*; D008954:Models, Biological; D063148:Plant Dispersal; D013696:Temperature