Abstract

Rejuvenation refers to the transition from an adult state to a juvenile state. Trunk truncation at the base of the tree can result in tree rejuvenation. However, little is known about the association of rejuvenation with leaf biomass and flavonoid accumulation. The results of this study showed that, compared with control leaves, leaves of renewed Ginkgo biloba shoots were larger, thicker, and more lobed and had higher fresh/dry weights and chlorophyll contents. The leaf biomass per hectare of rejuvenated trees was twofold higher than that of the untruncated controls. Moreover, we observed a marked increase in the accumulation of flavonol glycosides via metabolomic analysis and detected upregulated expression of genes involved in flavonoid biosynthesis, including CHS, FLS, F3’H, DFR, and LAR. Overexpression of GbCHS in ginkgo calli confirmed that GbCHS plays an important role in flavonoid biosynthesis. Interestingly, the contents of gibberellins significantly increased in the rejuvenated leaves. Moreover, exogenous gibberellin treatment significantly increased GbCHS expression and flavonoid contents. Our findings show that truncation can stimulate tree rejuvenation by altering hormone levels, representing an effective and feasible approach for enhancing the biomass and flavonoid content of G. biloba leaves.

中文翻译：

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复壮增加银杏叶生物量和类黄酮积累

摘要

回春是指从成人状态到少年状态的转变。树根处的树干截断可导致树木恢复活力。然而，关于复壮与叶生物量和类黄酮积累的关联知之甚少。本研究结果表明，与对照叶片相比，更新后的银杏新梢叶片更大、更厚、裂片更多，鲜/干重和叶绿素含量更高。每公顷复壮树的叶片生物量是未截断对照的两倍。此外，我们通过代谢组学分析观察到黄酮醇苷的积累显着增加，并检测到参与黄酮生物合成的基因表达上调，包括CHS、FLS、F3'H、DFR和LAR。GbCHS在银杏愈伤组织中的过表达证实了GbCHS在类黄酮生物合成中起重要作用。有趣的是，复壮叶中赤霉素的含量显着增加。此外，外源性赤霉素处理显着增加了GbCHS表达和类黄酮含量。我们的研究结果表明，截断可以通过改变激素水平来刺激树木恢复活力，代表了一种有效且可行的方法来提高银杏叶的生物量和类黄酮含量。