Zhai De-Li, Xu Jian-Chu
Center for Mountain Futures, Kunming Institute of Botany, Kunming 650201, Yunnan, China.
Institute of Environment and Ecology, School of the Environment and Safety Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang, 212013, Jiangsu Province, China.
Plant Divers. 2022 Jan 22;45(1):98-103. doi: 10.1016/j.pld.2022.01.003. eCollection 2023 Jan.
The leaf phenology of trees has received particular attention for its crucial role in the global water and carbon balances, ecosystem, and species distribution. However, current studies on leaf phenology have mainly focused on temperate trees, while few studies including tropical trees. Little attention has been paid to globally extensive industrial plantations. Rubber plantations are important to both the local and global economies. In this study, we investigated the legacy effects of defoliation phenology on the following year's leaf flushing, leaf disease, and also latex yield of rubber trees, an economically important tree to local people and the world. Results show that extended duration of defoliation increased the subsequent duration of refoliation and rates of infection by powdery mildew disease, but led to reduced latex yield in March. This legacy effect of rubber defoliation may relate to the carbohydrate reserved in the trees. A longer duration of defoliation would consume more reserved carbohydrates, reducing available reserves for disease defense and latex production. Extended duration of defoliation period was associated with either a lower temperature before the cessation of latex tapping in October-November and/or a higher temperature after the cessation of latex tapping in December-January. Leaf falling signals the end of photosynthetic activities in deciduous trees. Thus, the leaf falling phenology will impact ecological processes involving rubber trees. Our findings indicated that the inclusion of defoliation periods in future rubber trees' research, will be crucial to furthering our understanding of leaf flushing, powdery mildew disease, and latex yield.
树木的叶片物候因其在全球水分和碳平衡、生态系统及物种分布中的关键作用而受到特别关注。然而，目前关于叶片物候的研究主要集中在温带树木，涉及热带树木的研究较少。全球广泛分布的人工林很少受到关注。橡胶种植园对当地和全球经济都很重要。在本研究中，我们调查了落叶物候对次年橡胶树叶片萌发、叶部病害以及乳胶产量的遗留效应，橡胶树对当地人和世界来说都是一种具有重要经济价值的树木。结果表明，落叶持续时间延长会增加随后的再叶化持续时间和白粉病感染率，但会导致3月份乳胶产量下降。橡胶落叶的这种遗留效应可能与树木中储存的碳水化合物有关。落叶持续时间越长，消耗的储存碳水化合物就越多，从而减少了用于病害防御和乳胶生产的可用储备。落叶期延长与10 - 11月停止割胶前温度较低和/或12 - 1月停止割胶后温度较高有关。落叶标志着落叶树木光合作用活动的结束。因此，落叶物候将影响涉及橡胶树的生态过程。我们的研究结果表明，在未来橡胶树的研究中纳入落叶期，对于加深我们对叶片萌发、白粉病和乳胶产量的理解至关重要。
