Mature pollen germinates rapidly on the stigma, extending its pollen tube to deliver sperm cells to the ovule for fertilization. The success of this process is an important factor that limits output. The flavonoid content increased significantly during pollen germination and pollen tube growth, which suggests it may play an important role in these processes. However, the specific mechanism of this involvement has been little researched. Our previous research found that hyperoside can prolong the flowering period of Abelmoschus esculentus (okra), but its specific mechanism is still unclear. Therefore, in this study, we focused on the effect of hyperoside in regulating the actin-depolymerizing factor (ADF), which further affects the germination and growth of pollen. We found that hyperoside can prolong the effective pollination period of okra by 2–3-fold and promote the growth of pollen tubes in the style. Then, we used Nicotiana benthamiana cells as a research system and found that hyperoside accelerates the depolymerization of intercellular microfilaments. Hyperoside can promote pollen germination and pollen tube elongation in vitro. Moreover, AeADF1 was identified out of all AeADF genes as being highly expressed in pollen tubes in response to hyperoside. In addition, hyperoside promoted AeADF1-mediated microfilament dissipation according to microfilament severing experiments in vitro. In the pollen tube, the gene expression of AeADF1 was reduced to 1/5 by oligonucleotide transfection. The decrease in the expression level of AeADF1 partially reduced the promoting effect of hyperoside on pollen germination and pollen tube growth. This research provides new research directions for flavonoids in reproductive development.

中文翻译：

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金丝桃苷通过调节肌动蛋白解聚因子1对秋葵微丝的解聚作用促进花粉管生长

成熟的花粉在柱头上迅速发芽，伸出花粉管，将精子细胞输送到胚珠受精。这个过程的成功是限制产量的一个重要因素。在花粉萌发和花粉管生长过程中黄酮类化合物含量显着增加，这表明它可能在这些过程中发挥重要作用。然而，这种参与的具体机制却鲜有研究。我们之前的研究发现金丝桃苷可以延长花期南芥（秋葵），但其具体机​​制尚不清楚。因此，在本研究中，我们重点研究金丝桃苷对肌动蛋白解聚因子（ADF）的调节作用，进一步影响花粉的萌发和生长。我们发现金丝桃苷可以将秋葵的有效授粉期延长2-3倍，并促进花柱中花粉管的生长。然后，我们用本氏烟草细胞作为研究系统，发现金丝桃苷加速细胞间微丝的解聚。金丝桃苷在体外能促进花粉萌发和花粉管伸长。而且，AeADF1被识别出所有AeADF基因在花粉管中高度表达以响应金丝桃苷。此外，根据体外微丝切断实验，金丝桃苷促进了 AeADF1 介导的微丝消散。在花粉管中，基因表达AeADF1寡核苷酸转染降低至 1/5。表达水平的下降AeADF1部分降低金丝桃苷对花粉萌发和花粉管生长的促进作用。本研究为黄酮在生殖发育中的研究提供了新的研究方向。