Elevated CO2 causes different growth stimulation, water- and nitrogen-use efficiencies, and leaf ultrastructure responses in two conifer species under intra- and interspecific competition

Abstract

The continuously increasing atmospheric carbon dioxide concentration ([CO2]) has substantial effects on plant growth, and on the composition and structure of forests. However, how plants respond to elevated [CO2] (e[CO2]) under intra- and interspecific competition has been largely overlooked. In this study, we employed Abies faxoniana Rehder & Wilson and Picea purpurea Mast. seedlings to explore the effects of e[CO2] (700 p.p.m.) and plant–plant competition on plant growth, physiological and morphological traits, and leaf ultrastructure. We found that e[CO2] stimulated plant growth, photosynthesis and nonstructural carbohydrates (NSC), affected morphological traits and leaf ultrastructure, and enhanced water- and nitrogen (N)- use efficiencies in A. faxoniana and P. purpurea. Under interspecific competition and e[CO2], P. purpurea showed a higher biomass accumulation, photosynthetic capacity and rate of ectomycorrhizal infection, and higher water- and N-use efficiencies compared with A. faxoniana. However, under intraspecific competition and e[CO2], the two conifers showed no differences in biomass accumulation, photosynthetic capacity, and water- and N-use efficiencies. In addition, under interspecific competition and e[CO2], A. faxoniana exhibited higher NSC levels in leaves as well as more frequent and greater starch granules, which may indicate carbohydrate limitation. Consequently, we concluded that under interspecific competition, P. purpurea possesses a positive growth and adjustment strategy (e.g. a higher photosynthetic capacity and rate of ectomycorrhizal infection, and higher water- and N-use efficiencies), while A. faxoniana likely suffers from carbohydrate limitation to cope with rising [CO2]. Our study highlights that plant–plant competition should be taken into consideration when assessing the impact of rising [CO2] on the plant growth and physiological performance.

Antagonist Temperature Variation Affects the Photosynthetic Parameters and Secondary Metabolites of Ocimum basilicum L. and Salvia officinalis L.

“…Plants are very vulnerable to climate change effects [ 10 , 11 ], such as changes in temperature [ 1 , 2 , 5 ], water status (drought, flooding) [ 12 ], rising atmospheric CO 2 concentration [ 13 , 14 , 15 ], the attacks of herbivores [ 16 , 17 , 18 , 19 ] and pathogens [ 16 , 20 , 21 ]. Among these climate change effects, increased temperatures negatively impact plant development and crop production [ 1 , 11 , 22 ].…”

The plant response to high CO2 levels is heritable and orchestrated by DNA methylation

“…Across the plant kingdom, an enhanced growth response and larger shoot mass are found when C3 plants are subjected to increased levels of CO 2 (reviewed in Kimball, 2016). Plants produce larger organs such as leaves, often outpacing the growth of ambient CO 2 ‐grown control plants (Yiotis et al ., 2020; Yu et al ., 2021; Hu et al ., 2022). The known mechanism for this increase in growth is the higher efficiency of carbon assimilation during C3 photosynthesis (Tomimatsu & Tang, 2016).…”

Interacting Effects of CO2, Temperature, and Nitrogen Supply on Photosynthetic, Root Growth, and Nitrogen Allocation of Strawberry at the Fruiting Stage

“…Elevated CO 2 is an environmental factor that could affect the yields and nutritional quality of plants [1][2][3]. It has been proved that elevated CO 2 could reduce stomatal conductance and transpiration to improve water use efficiency [4,5], as well as decrease the activity of key enzymes in the photosynthetic carbon reduction cycle and non-photochemical quenching of fluorescence (NPQ) for improving nutrient use efficiency [6,7]. Even at low N-concentration, elevated CO 2 could enhance the photosynthesis rate [8].…”