{'fraction_non_alphanumeric': 0.01872175597159458, 'fraction_numerical': 0.003873466752743706, 'mean_word_length': 5.326530612244898, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Correlations between photosynthetic heat tolerance and leaf anatomy and climatic niche in Asian mangrove trees.

Photosynthetic heat tolerance (PHT ) is a key predictor of plant response to climate change. Mangroves are an ecologically and economically important coastal plant community that comprise of trees growing at their physiological limits. Mangroves are currently impacted by global warming, and yet, the PHT of mangrove trees is poorly understood. In this study, we provided the first assessment of PHT in 13 Asian mangrove species, based on the critical temperature that causes the initial damage (TCrit ) and the temperature that causes 50% of the damage (T50 ) in photosystem II. We tested the hypotheses that the PHT in mangroves is (i) correlated with climatic niche and leaf traits, and (ii) higher than in plants from other tropical ecosystems. Our results demonstrated the correlations between PHT and multiple key climatic variables, the palisade to spongy mesophyll ratio and leaf area. The two most heat-sensitive species were Kandelia obovata and Avicennia marina. Our study also revealed that mangrove trees showed high heat tolerance as compared to plants from other tropical ecosystems. The high PHT in mangroves thus demonstrated evolutionary conservativeness in heat tolerance and highlighted the need for integrative and comparative studies on thermoregulatory traits and climatic niche in order to understand the physiological response of mangrove trees to climate change-driven heat waves and rising global temperature.