Key message

Low number of pistillate flowers in the tung tree is a major factor causing the low yield of tung fruits.

Abstract

The tung tree (Vernicia fordii Hemsl.), an economically important woody oil plant, produces excellent fast-drying oil from the seeds which has been used as a protective finish on projects and surfaces for centuries. Knowledge of sex determination and flower development of tung trees is helpful for high-yield cultivation and breeding of new elite cultivars. However, studies on tung flower biology and ontogeny are still lacking. Here, we reported a comprehensive study of the flower biology and ontogeny of the tung tree, focusing on flower cycle, flower morphology and flower development. The inflorescence phenophases of monoecious tung trees were divided into 12 pivotal stages and used as a unique timeline to reference the events registered throughout the flower cycle. Histological studies on sporogenesis and gametogenesis were also conducted. Meanwhile, all the unique events throughout flower cycle were linked together to show the correlation between inflorescence development phenophases, pistillate and staminate flower stages and its embryological development. Tung trees in our plantation were grouped into three major types, i.e., monoecious, gynoecious and androecious trees which produced different number of fruits in each inflorescence. We propose that low number of pistillate flowers in the tung tree is a major factor causing the low yield of tung fruits, and that any measures increasing the number of pistillate flowers would effectively improve the yield of tung fruits.

中文翻译：

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桐树的花生物学和个体发育（Vernicia fordii Hemsl。）

关键信息

桐树中雌蕊花的数量少是导致桐果产量低的主要因素。

抽象

桐树（Vernicia fordiiHemsl。，一种经济上重要的木本油料植物，从种子中产生极佳的速干油，这些油已被用作项目和地面上的保护层，已有数百年历史了。桐树的性别决定和花发育的知识有助于高产栽培和新优良品种的育种。然而，仍然缺乏关于桐花生物学和个体发育的研究。在这里，我们报道了桐树的花生物学和个体发育的综合研究，重点是花的周期，花的形态和花的发育。雌雄同株的桐树的开花期被划分为12个关键阶段，并被用作唯一的时间轴来引用整个花周期中记录的事件。还进行了孢子发生和配子发生的组织学研究。与此同时，将整个花周期中所有独特的事件联系在一起，以显示花序发育的表相，雌蕊和雄蕊花期与其胚胎发育之间的相关性。我们的人工林中的桐树分为三种主要类型，即雌雄同株，雌雄同株和雄雄同株，它们在每个花序中产生不同数量的果实。我们认为桐树中雌蕊花的数量少是导致桐果产量低的主要因素，任何增加雌蕊花数量的措施都将有效地提高桐果的产量。我们的人工林中的桐树分为三种主要类型，即雌雄同株，雌雄同株和雄雄同株，它们在每个花序中产生不同数量的果实。我们认为桐树中雌蕊花的数量少是导致桐果产量低的主要因素，任何增加雌蕊花数量的措施都将有效地提高桐果的产量。我们的人工林中的桐树分为三种主要类型，即雌雄同株，雌雄同株和雄雄同株，它们在每个花序中产生不同数量的果实。我们认为桐树中雌蕊花的数量少是导致桐果产量低的主要因素，任何增加雌蕊花数量的措施都将有效地提高桐果的产量。