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荒漠短命植物异喙菊的小花异形性及繁殖特性 被引量:8
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作者 吉乃提汗.马木提 成小军 谭敦炎 《生物多样性》 CAS CSCD 北大核心 2018年第5期498-509,共12页
异喙菊(Heteracia szovitsii)是分布于新疆北部荒漠、具短寿命花和多态果实的菊科一年生短命植物。本文对该物种的开花式样和花部特征以及繁育系统与昆虫传粉特性进行了研究,以期明确其头状花序中小花的形态差异及其与多态果实间的关系... 异喙菊(Heteracia szovitsii)是分布于新疆北部荒漠、具短寿命花和多态果实的菊科一年生短命植物。本文对该物种的开花式样和花部特征以及繁育系统与昆虫传粉特性进行了研究,以期明确其头状花序中小花的形态差异及其与多态果实间的关系、揭示其在短的花寿命内的繁殖特性。结果表明:该物种头状花序中发育成多态果实的3类小花在数量、冠毛的有无以及舌片长/宽、子房宽、花柱裂片长和子房喙长之间均存在不同程度的差异,且3类小花冠毛的有无以及子房宽和喙长与多态果实的形态一致,说明多态果实的数量与形态在小花发育过程中就已完成分化。花序中的小花每天集中在上午开放,使花序在功能上犹如一朵花,可快速增大花展示和对传粉者的吸引,以使异交在开花后短时间内完成;3类小花的自花花粉均可在花柱裂片上萌发并长出花粉管,说明该物种自交亲和。3类小花不去雄套袋后均能结实,且自然授粉后的结实率显著高于不去雄套袋的,说明该物种能自主自花授粉,且异花授粉促进了结实。3类小花通过雄性先熟以及次级花粉呈现中的泵/刷机制,将花粉呈现在花柱上部和未展开的柱头裂片外侧刷状毛上以及裂片顶端,延长了花粉呈现(雄性阶段)持续的时间,减少了花内雌雄功能间的干扰,有利于传粉者异花传粉,提高了雄/雌性适合度;同时,柱头裂片展开时可将自花花粉落置到裂片上,以完成自主自花授粉。主要传粉者六显甜花蜂(Halictus sexnotatulus)的访花时间与花序开放时间、花粉活力最高期和柱头最佳授粉期高度吻合,有利于雄性阶段花粉的输出以及雌性阶段柱头接受花粉,保障授粉在开花后短时间内快速有效地完成以及异交成功。在新疆北部荒漠的春季环境中,具短寿命花的异喙菊既可在低温多风导致传粉者不足或活动受限时,通过快速自主自花授粉及自交亲和机制来提供繁殖保障,也可在传粉者活动正常时,通过集中开花、雄性先熟及次级花粉呈现等机制来快速完成异交,提高雌/雄性及后代的适合度。 展开更多
关键词 Heteracia szovitsii 异形小 短寿命花 自主自授粉 次级粉呈现 传粉
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Beasts of the Devil, Perishables, and the Natura Morta
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作者 Gregory Chan 《Journal of Literature and Art Studies》 2013年第6期391-394,共4页
Bugs have long embodied that from which we seek protection. Whether a mild irritant (a "fly in the ointment"), a costly pest to gardeners ("bug of W"), or a destructive force of Biblical proportions (a swarm ... Bugs have long embodied that from which we seek protection. Whether a mild irritant (a "fly in the ointment"), a costly pest to gardeners ("bug of W"), or a destructive force of Biblical proportions (a swarm of locusts), bugs are nature's warning of approaching death. This paper investigates the natura morta canvas during the Golden Age of Dutch art, focusing on how these symbols of natural evil work to enliven the visual rhetoric of the still-life as they invite spiritual contemplation. In religious-themed art, we intuitively recognize these morbid creatures as symbols of decay encroaching on domestic scenes filled with food and cut flowers. Emphasizing the short life of these perishables, bugs embody a classic tension and its dichotomous variations: the corporeal vs. the spiritual, earth vs. heaven, and sin vs. redemption. Though ostensibly a peripheral feature of the natura morta, bugs are a decidedly central motif that reflects the viewer's struggle with sin: Is it repellent, attractive, or repellently attractive? This study will concern the visual rhetoric of flies, dragonflies, and bees in the works of Osias Beert, Ambrosius Bosschaert, and Georg Flegel, with an emphasis on the beasts of the devil as icons of Dutch art. 展开更多
关键词 still-life Dutch paintings religious art DEATH
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