Leaf development is affected by different amounts of light, leading to structural and physiological gradients. Young leaves are normally more sensitive to high light levels, which may trigger different strategies for light protection. On this basis, the objective of the current study was to determine strategies used by young (1st node, red), in transition (2nd node, starting to become green, and 4th node, almost all green) and mature (6th node, green) leaves of Eugenia uniflora L. (Myrtaceae) to deal with light. Young leaves showed less structural protection from light, which improved after the 2nd node. The reddish colour of young E. uniflora leaves is mainly due the greater production of photoprotective pigments, mainly anthocyanins, although the chlorophyll/carotenoid ratio showed some contribution by the carotenoids. Reactive oxygen species were homogeneously distributed in the young leaves, turning to malondialdehyde only in older leaves. The lower structural protection from light and physiological immaturity of young E. uniflora leaves lead to photoinhibition and reduced quantum yield during at times of highest light intensity of the day, causing lower efficiency in electron transport. The E. uniflora case clarifies the occurrence of different defence strategies against light exposure according to leaf developmental stages.

叶片发育受不同光量的影响，导致结构和生理梯度。幼叶通常对高光水平更敏感，这可能会触发不同的光保护策略。在此基础上，本研究的目标是确定年轻（第一个节点，红色）、过渡中（第二个节点，开始变成绿色，第四个节点，几乎全是绿色）和成熟（第 6 个节点，绿色）使用的策略。 ) Eugenia uniflora L. (桃金娘科) 的叶子处理光。幼叶对光的结构保护较少，在第 2 个节后有所改善。年轻E. uniflora的红色叶子主要是由于光保护色素的产生较多，主要是花青素，尽管叶绿素/类胡萝卜素的比例显示类胡萝卜素有一些贡献。活性氧均匀分布在幼叶中，仅在老叶中转化为丙二醛。E. uniflora幼叶对光的较低结构保护和生理不成熟导致光抑制和在一天中最高光强度时降低量子产率，导致电子传输效率降低。在E.叶草案阐明根据叶的发育阶段对曝光的不同防御策略的发生。