Wang Ning, Ji Hongliang, Li Qiang, Wu Pan, Yi Shijie, Li Hong, Liu Xiao
School of Advanced Agricultural Sciences, Weifang University, 5147 Dongfengdong Road, Weifang, 261061, China.
School of Tropical Medicine, Hainan Medical University, Haikou, 571199, China.
BMC Plant Biol. 2025 Apr 10;25(1):452. doi: 10.1186/s12870-025-06500-2.
Non-structural carbohydrates (NSCs) are vital for plant growth, with their levels influenced by light intensity and seasonal changes. However, research on how varying light conditions due to forest density and seasons affect carbon allocation in new twigs and old branches is scarce. Vitex negundo var. heterophylla is a leading shrub species in the warm temperate zone's shrub layer. In this study, we conducted a detailed sampling of V. negundo var. heterophylla branches, differentiating new twigs and old branches across phenological stages under three densities of Robinia pseudoacacia forests. Our sampling schedule was as follows: March (dormant period), May (sprouting period), July (leaf spreading period), September (flowering and fruiting period), and December (deciduous period). The results showed that the seasonal patterns of carbon allocation in the new twigs and old branches were largely in harmony. The starch concentration in the old branches under the high density was significantly lower than in the other two densities during the growing season, but the NSC concentration in December remained at a high level and did not significantly decrease. These indicated even though the light environment was unfavorable to understory V. negundo var. heterophylla during the growing season, cold tolerance in December was not inhibited. And the concentrations of soluble sugars and starch in the new twigs were typically higher than those found in the old branches. This dynamic suggests a strategic prioritization of resources to fuel the growth and development of the plant during the current year. Findings from this study not only contribute to our understanding of carbon allocation strategies in V. negundo var. heterophylla but also provide critical insights for managing and predicting the resilience of warm temperate shrub ecosystems to environmental change.
非结构性碳水化合物（NSCs）对植物生长至关重要，其含量受光照强度和季节变化影响。然而，关于森林密度和季节导致的光照条件变化如何影响新嫩枝和老枝中碳分配的研究却很少。荆条是暖温带灌木层中的优势灌木物种。在本研究中，我们对荆条的枝条进行了详细采样，区分了在三种刺槐林密度下不同物候阶段的新嫩枝和老枝。我们的采样时间安排如下：3月（休眠期）、5月（萌芽期）、7月（展叶期）、9月（花果期）和12月（落叶期）。结果表明，新嫩枝和老枝中碳分配的季节模式基本一致。在生长季节，高密度下老枝中的淀粉浓度显著低于其他两种密度，但12月时NSC浓度仍保持在较高水平且没有显著下降。这些表明，即使在生长季节林下光照环境对荆条不利，但其12月的耐寒性并未受到抑制。并且新嫩枝中可溶性糖和淀粉的浓度通常高于老枝。这种动态变化表明植物在资源分配上具有战略优先级，以促进当年的生长和发育。本研究结果不仅有助于我们理解荆条的碳分配策略，还为管理和预测暖温带灌木生态系统对环境变化的恢复力提供了关键见解。
