Strategy by latitude? Higher photosynthetic capacity and root mass fraction in northern than southern silver birch (Betula pendula Roth) in uniform growing conditions
| Autor: | Sergei Suprun, Sari Kontunen-Soppela, Sarita Keski-Saari, Antti Tenkanen, Elina Oksanen, Markku Keinänen |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
0106 biological sciences
Biomass (ecology) Provenance Stomatal conductance Physiology Growing season Plant Science 15. Life on land Biology Photosynthesis 010603 evolutionary biology 01 natural sciences Photosynthetic capacity Trees Plant Leaves Horticulture Betula pendula Chlorophyll fluorescence Betula Finland 010606 plant biology & botany |
| Zdroj: | Tree physiology. 41(6) |
| ISSN: | 1758-4469 |
| Popis: | Growth of northern trees is limited by short growing seasons. In multi-year trials, northern trees usually grow less than southern ones but can have higher gas exchange, whereas differences in biomass allocation and its relation to photosynthesis are less known. We characterized silver birch (Betula pendula Roth) provenances from southern (latitude 61°) and northern (latitude 67°) Finland in uniform chamber conditions. In a time-series experiment, we measured traits related to growth, biomass allocation and photosynthesis, and determined gas exchange responses to temperature and light. We found provenance differences in photosynthetic capacity and growth. The northern provenance allocated relatively more to roots, having a higher root mass fraction and lower shoot:root ratio than the southern provenance. On the other hand, the northern provenance had fewer leaves and lower total leaf dry weight (DW) than the southern provenance. The northern provenance attained higher rates of net photosynthesis (Anet) and higher stomatal conductance (gs) in all measured temperatures and higher photosynthesis at the optimum temperature (Aopt) than the southern provenance, but there was no difference in the optimum temperature of photosynthesis (Topt, 18.3 °C for the southern provenance vs 18.9 °C for the northern one). Photosynthetic light response curves showed no between-provenance differences. In a time-series, the northern provenance had higher Anet than the southern provenance, but gs was similar. The northern provenance had higher maximum quantum yield of photosystem II photochemistry (Fv/Fm) than the southern provenance. There were no differences between provenances in height, total plant DW, shoot DW, root DW or shoot mass fraction. Our results suggest that the provenances occupy a common thermal niche, or can at least relatively quickly acclimate to a common growth temperature. Thus, carbon assimilation of these northern trees may not be significantly affected by rising temperatures alone. In an equal photoperiod and optimal conditions, we found different one-season biomass accumulation strategies: southern trees grow with more leaves, while northern trees reach similar total assimilation (total DW, height) with more efficient photosynthetic capacity per leaf area (higher gas exchange, higher Fv/Fm) and relatively more investment in the below-ground fraction of the plant. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|