Details

Autor(en) / Beteiligte

• Slot, Martijn
• Cala, Daniela
• Aranda, Jorge
• Virgo, Aurelio
• Michaletz, Sean T.
• Winter, Klaus

Titel

Leaf heat tolerance of 147 tropical forest species varies with elevation and leaf functional traits, but not with phylogeny

Ist Teil von

• Plant, cell and environment, 2021-07, Vol.44 (7), p.2414-2427

Ort / Verlag

Chichester, UK: John Wiley & Sons, Ltd

Erscheinungsjahr

2021

Quelle

Wiley Online Library Journals Frontfile Complete

Beschreibungen/Notizen

• Exceeding thermal thresholds causes irreversible damage and ultimately loss of leaves. The lowland tropics are among the warmest forested biomes, but little is known about heat tolerance of tropical forest plants. We surveyed leaf heat tolerance of sun‐exposed leaves from 147 tropical lowland and pre‐montane forest species by determining the temperatures at which potential photosystem II efficiency based on chlorophyll a fluorescence started to decrease (TCrit) and had decreased by 50% (T50). TCrit averaged 46.7°C (5th–95th percentile: 43.5°C–49.7°C) and T50 averaged 49.9°C (47.8°C–52.5°C). Heat tolerance partially adjusted to site temperature; TCrit and T50 decreased with elevation by 0.40°C and 0.26°C per 100 m, respectively, while mean annual temperature decreased by 0.63°C per 100 m. The phylogenetic signal in heat tolerance was weak, suggesting that heat tolerance is more strongly controlled by environment than by evolutionary legacies. TCrit increased with the estimated thermal time constant of the leaves, indicating that species with thermally buffered leaves maintain higher heat tolerance. Among lowland species, T50 increased with leaf mass per area, suggesting that in species with structurally more costly leaves the risk of leaf loss during hot spells is reduced. These results provide insight in variation in heat tolerance at local and regional scales. To determine the variation in leaf heat tolerance and investigate what explains such variation, we measured heat tolerance traits for 147 plant species of tropical lowland and pre‐montane forests in Panama. Variation in heat tolerance was related to elevation and leaf traits associated with leaf thermoregulation and leaf construction costs, but not to phylogenetic relatedness of the species.