Distinct seasonal dynamics of responses to elevated CO2 in two understorey grass species differing in shade-tolerance

0518254 - ÚVGZ 2020 RIV US eng J - Journal Article
Holub, Petr - Klem, Karel - Linder, S. - Urban, Otmar
Distinct seasonal dynamics of responses to elevated CO2 in two understorey grass species differing in shade-tolerance.
Ecology and Evolution. Roč. 9, č. 24 (2019), s. 13663-13677. ISSN 2045-7758. E-ISSN 2045-7758
R&D Projects: GA MŠMT(CZ) LO1415; GA MŠMT(CZ) EF16_013/0001609; GA ČR(CZ) GA18-23702S
Research Infrastructure: CzeCOS II - 90061
Institutional support: RVO:86652079
Keywords : photosynthetic responses * interspecific variation * stomatal conductance * growth-response * plant-growth * forest * drought * light * carbon * metaanalysis * Calamagrostis arundinacea * ecological niche * glass domes * light environment * Luzula sylvatica * manipulation experiment * seasonal dynamics
OECD category: Biology (theoretical, mathematical, thermal, cryobiology, biological rhythm), Evolutionary biology
Impact factor: 2.392, year: 2019
Method of publishing: Open access
https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.5738

Understorey plant communities are crucial to maintain species diversity and ecosystem processes including nutrient cycling and regeneration of overstorey trees. Most studies exploring effects of elevated CO2 concentration ([CO2]) in forests have, however, been done on overstorey trees, while understorey communities received only limited attention. The hypothesis that understorey grass species differ in shade-tolerance and development dynamics, and temporally exploit different niches under elevated [CO2], was tested during the fourth year of [CO2] treatment. We assumed stimulated carbon gain by elevated [CO2] even at low light conditions in strongly shade-tolerant Luzula sylvatica, while its stimulation under elevated [CO2] in less shade-tolerant Calamagrostis arundinacea was expected only in early spring when the tree canopy is not fully developed. We found evidence supporting this hypothesis. While elevated [CO2] stimulated photosynthesis in L. sylvatica mainly in the peak of the growing season (by 55%-57% in July and August), even at low light intensities (50 mu mol m(-2) s(-1)), stimulatory effect of [CO2] in C. arundinacea was found mainly under high light intensities (200 mu mol m(-2) s(-1)) at the beginning of the growing season (increase by 171% in May) and gradually declined during the season. Elevated [CO2] also substantially stimulated leaf mass area and root-to-shoot ratio in L. sylvatica, while only insignificant increases were observed in C. arundinacea. Our physiological and morphological analyses indicate that understorey species, differing in shade-tolerance, under elevated [CO2] exploit distinct niches in light environment given by the dynamics of the tree canopy.
Permanent Link: http://hdl.handle.net/11104/0304403