Nectary structure and function in relation to angiosperm reproductive success: Developmental and evolutionary perspectives

蜜腺是分泌花蜜的植物腺体，花蜜是一种富含碳水化合物的溶液，但也含有较低浓度的其他溶质。 尽管是小而神秘的，蜜腺是非常重要的生态促进植物和生物之间的有益的相互作用，在加拿大和国际上的环境。 花蜜腺通常位于战略位置，导致访问者接触花药（产生花粉的器官）和柱头（花粉接收地点，授粉发生）。 因此，当访花动物如蜜蜂和其他昆虫从花蜜中采集花蜜作为重要的食物来源时，互利关系就会发生，最终导致种子和果实。 我们日常饮食的主要部分可以直接归因于昆虫授粉，因此蜜腺。 有些花的基部甚至有刺，管状的延伸部分隐藏了花蜜，只有舌头足够长的动物才能获得花蜜。对于一种极其有益的物种，蜜蜂（Apis mellifera）来说，花蜜是加拿大和世界各地一种高价值商品的前身-蜂蜜。蜜腺的研究需要显微镜。 每个蜜腺通常有三个结构组成部分：一个表皮（一层覆盖细胞），几个亚表皮层的腺细胞，加上一个维管供应（管道）。 我们将调查这三个组成部分，通过寻找细胞生长和发育的机制，导致有关蜜腺的形式和功能的新知识，在进化的背景下。 我们将研究I）产蜜花距，它的独特之处在于其尖端形成分叉（如字母Y）。 有趣的是，蜂鸟和某些昆虫的舌头是分叉的。 利用光学、共聚焦显微镜和扫描电子显微镜，我们将在整个发育过程中放大骨刺的细胞，以确定这些Y分支的骨刺是如何发育的。 此外，使用牙齿印模材料，以定期的间隔施加到相同的，活的骨刺，甚至将允许我们跟踪表皮细胞的个别文件，因为他们分裂和伸长; II）植物管道的糖传导形式称为韧皮部，将在各种花蜜腺中进行检查，我们已经发现了伴随细胞的差异，将到达的糖作为花蜜分泌到外部的特殊细胞。 此外，我们将调查花蜜腺的一个非常大的家庭，菊科，扩大我们的发现韧皮部形成在表皮，一个独特的发生在植物中;和III）奇怪的不育花称为“无性型”突变体从几个物种形成蜜腺-有时仍然功能-在他们的花瓣和萼片。 我们将比较这些突变体和正常植物的蜜腺结构和花蜜生产，以了解更多关于在授粉甚至不能发生时仍然存在的花蜜腺的起源。

Nectaries are plant glands that secrete nectar, a solution rich in carbohydrates but also containing other solutes at lower concentrations. Despite being small and cryptic, nectaries are extremely important ecologically for fostering beneficial interactions between plants and organisms in their environment, both in Canada and internationally. Floral nectaries typically reside in strategic locations leading to the visitor's contact of anthers (pollen-producing organs) and stigmas (pollen-receiving sites, where pollination occurs). Thus, mutualistic relationships occur when flower-visiting animals such as bees and other insects gather nectar as an important food source from floral nectaries, leading eventually to seed and fruit set. Major parts of our daily diets can be attributed directly to pollination by insects, and hence to nectaries. Some flower bases even possess spurs, tubular extensions that conceal nectar available only to animals with sufficient tongue length to attain it. And for an extremely beneficial species, the honey bee (Apis mellifera), nectar is the precursor of a highly valued commodity in Canada and worldwide - honey.***The study of nectaries requires microscopy. Each nectary typically has three structural components: an epidermis (a layer of covering cells), several subepidermal layers of glandular cells, plus a vascular supply (plumbing). We shall investigate these three components by searching for mechanisms of cellular growth and development leading to new knowledge about nectary form and function, in an evolutionary context. We shall study I) nectar-yielding floral spurs which are unique by the formation of a bifurcation (like the letter Y) at their tip. Interestingly, hummingbirds and certain insects have bifurcated tongues. Using light, confocal, and scanning-electron microscopy, we shall magnify the cells of spurs throughout their development, to determine how these Y-branched spurs develop. Also, use of a dental impression material applied at regular intervals to the same, living spur will even allow us to trace individual files of epidermal cells as they divide and elongate; II) the sugar-conducting form of plant plumbing called phloem will be examined in a variety of floral nectaries in which we have already discovered differences in companion cells, special cells that unload arriving sugar to be secreted externally as nectar. Also, we shall survey floral nectaries of a very large family, the Asteraceae, to expand our discovery of phloem that forms in the epidermis, a unique occurrence in plants; and III) strange sterile flowers called "agamous type" mutants from several species which form nectaries - sometimes still functional - amidst their petals and sepals. We shall compare nectary structure and nectar production in these mutant and normal plants, to learn more about the origin of floral nectaries still present when pollination cannot even occur.**