Abstract Light adaptability is a major driver of succession and evolution in natural forest plant communities. However, the relationship between plants and light is contradictory; light provides energy for plant growth, but excessive light negatively affects plant growth. To reveal the pattern of plant adaptation to diurnal variation in light, photoprotection strategies were analyzed in young and mature leaves of six dominant species at two successional stages. Mature leaves of both mid- and late-successional dominant species exhibited a higher net photosynthetic rate (Pn) than young leaves. In particular, the mature leaves of the mid-successional tree species had higher high-light tolerance because of a higher Pn, water use efficiency (WUE) and electron transfer rate (ETR). In contrast, the mature leaves of the late-successional tree species had a higher restoration ability after high-light stress because of higher thermal energy dissipation and faster stomatal regulation. Young leaves of both the mid- and late-successional dominant species exhibited a higher photoprotection capability than mature leaves. The young leaves of the mid-successional tree species had higher high-light tolerance because of their highest WUE and anthocyanin/chlorophyll (Anth/Chl) and higher flavonoid/chlorophyll (Flav/Chl), total phenolics/chlorophyll (Phen/Chl) and total antioxidant capacity/chlorophyll (TAC/Chl) ratios. The young leaves of the late-successional tree species had a stronger restoration ability due to highest Flav/Chl, Phen/Chl, and TAC/Chl ratios and a higher moisture content and non-photochemical quenching coefficient (qN, NPQ). This study shows that in a high-light environment, when leaves are at the same developmental stage, mid-successional tree species better tolerate high-light, while late-successional tree species have a greater restoration ability after high-light stress.

中文翻译：

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夏季高光环境下中后期优势树种的不同光保护策略

摘要 光适应性是天然林植物群落演替和进化的主要驱动力。然而，植物与光的关系是矛盾的；光为植物生长提供能量，但过多的光会对植物生长产生负面影响。为了揭示植物对光照昼夜变化的适应模式，在两个演替阶段对六个优势物种的幼叶和成熟叶进行了光保护策略分析。中后期优势种的成熟叶表现出比幼叶更高的净光合速率（Pn）。特别是，中演替树种的成熟叶片由于具有较高的 Pn、水分利用效率 (WUE) 和电子转移率 (ETR)，因此具有更高的耐光性。相比之下，晚演树种的成熟叶片在强光胁迫下具有更高的恢复能力，因为其热能耗散更高，气孔调节更快。中后期优势种的幼叶比成熟叶表现出更高的光保护能力。中演替树种的幼叶由于其WUE和花青素/叶绿素(Anth/Chl)和较高的黄酮/叶绿素(Flav/Chl)、总酚/叶绿素(Phen/Chl)，具有较高的耐光性和总抗氧化能力/叶绿素 (TAC/Chl) 比率。Flav/Chl、Phen/Chl、TAC/Chl比值最高，水分含量和非光化学猝灭系数（qN，NPQ）较高，晚演树种的幼叶具有较强的恢复能力。