Which plant trait explains the variations in relative growth rate and its response to elevated carbon dioxide concentration among Arabidopsis thaliana ecotypes derived from a variety of habitats?
Elevated atmospheric carbon dioxide (CO2) concentration ([CO2]) enhances plant growth, but this enhancement varies considerably. It is still uncertain which plant traits are quantitatively related to the variation in plant growth. To identify the traits responsible, we developed a growth analysis model that included primary parameters associated with morphology, nitrogen (N) use, and leaf and root activities. We analysed the vegetative growth of 44 ecotypes of Arabidopsis thaliana L. grown at ambient and elevated [CO2] (800 μmol mol−1). The 44 ecotypes were selected such that they were derived from various altitudes and latitudes. Relative growth rate (RGR; growth rate per unit plant mass) and its response to [CO2] varied by 1.5- and 1.7-fold among ecotypes, respectively. The variation in RGR at both [CO2]s was mainly explained by the variation in leaf N productivity (LNP; growth rate per leaf N),which was strongly related to photosynthetic N use efficiency (PNUE). The variation in the response of RGR to [CO2] was also explained by the variation in the response of LNP to [CO2]. Genomic analyses indicated that there was no phylogenetic constraint on inter-ecotype variation in the CO2 response of RGR or LNP. We conclude that the significant variation in plant growth and its response to [CO2] among ecotypes reflects the variation in N use for photosynthesis among ecotypes, and that the response of PNUE to CO2 is an important target for predicting and/or breeding plants that have high growth rates at elevated [CO2].
KeywordsGas exchange measurement Growth analysis Natural variation Relative growth rate Genomic analysis
We thank members of the Laboratory of Plant Ecology and Functional ecology at Tohoku University for their support in the plant growth analysis. This work was supported by a Grant-in-Aid for Young Scientists (S) (no. 20677001), a Grant-in-Aid for Scientific Research on Innovative Areas (no. 21114009), the Global COE program (J03), and CREST to K. Hi.
Author contribution statement
R. O. and H. O. conducted the experiments. R. O., H. O. and K. Ha. analysed data. K. Ha. was responsible for the genomic analysis. K. Hi. designed and supervised the research. R. O. and K. Hi. wrote the manuscript. All authors read and approved the manuscript.
- Hewitt EJ, Smith TA (1975) Plant mineral nutrition. The English University, LondonGoogle Scholar
- Hunt R (1978) Plant growth analysis. Stud Biol 96:67Google Scholar
- Meehl GA et al (2007) Global climate projections. In: Solomon S, Qin D, Manning M, Chen Z, Marquis M, Averyt KB, Tignor M, Miller HL (eds) Climate change 2007: the physical science basis. Contribution of Working Group I to the fourth assessment report of the Intergovernmental Panel on Climate Change. Cambridge University, New YorkGoogle Scholar
- van der Werf A, Vannuenen M, Visser AJ, Lambers H (1993a) Contribution of physiological and morphological plant traits to a species competitive ability at high and low nitrogen supply–a hypothesis for inherently fast-growing and slow-growing monocotyledonous species. Oecologia 94:434–440CrossRefGoogle Scholar