Gymnosperm reproduction

当花粉使植物胚珠受精时，种子就形成了。种子在人类历史上非常重要：我们消耗或已经消耗的所有卡路里中的三分之二来自胚乳，胚乳是源自被子植物胚囊或雌性配子体的种子组织。裸子植物，如针叶树，也是种子植物，尽管在某些生殖方面更原始。尽管我们通常不吃针叶树种子，但它在加拿大具有至关重要的经济意义，因为我们从道格拉斯冷杉，云杉和松树的森林中获得了巨大的财富。我们了解如何培育树木的形式和生长速度，抗病虫害和木材质量。然而，我们只是最近才开始了解胚珠和种子发育过程中发生的机制。了解授粉，受精和种子发育的基本过程将为我们提供知识，以便在为重新造林生产大量种子时创造更高的效率。由于授粉失败或自花授粉的后果，种子可能无法发育;这种近交胚死亡。针叶树是自由授粉的，不能排除风带给胚珠的任何东西。它们能选择自己的花粉而不是外来花粉吗？它们有什么机制，这种机制的生化基础是什么？花粉-胚珠相互作用包括由胚珠渗出的授粉滴捕获花粉，随后花粉萌发并穿透珠心，以花粉管将雄配子递送到卵中结束。这项拟议的研究计划将调查从授粉到受精的事件。我们将从分子的角度来研究这个问题。我的学生将从事蛋白质分析。例如，花粉滴似乎是一种物种特异性的萌发媒介，它偏爱自己的花粉而不是其他物种的花粉。柏树和雪松的花粉滴在授粉后迅速收缩，这意味着一种主动机制。我们将揭开这个机制。我们还将研究蛋白质组在受精、胚珠发育和卵成熟过程中的变化。这些研究是假设驱动的，将聘请两名博士生。这项工作的影响是实际的，导致更深入地了解对有效管理生殖至关重要的事件。我的工作也可能有助于理解对种子进化至关重要的适应。

When pollen fertilizes a plant ovule, seed is formed. Seed is important in the history of humanity: two-thirds of all calories that we consume or have consumed are from endosperm, which is a seed tissue derived from the angiosperm embryo-sac, or female gametophyte. Gymnosperms, such as conifers, are also seed plants, albeit more primitive in some of their reproductive aspects. Even though we don't commonly eat conifer seed, it is of critical economic importance in Canada, because we derive great wealth from our forests of Douglas-fir, spruce and pines. We understand how to breed trees for form and growth rate, resistance to pests and disease, and for wood quality. However, we are only recently beginning to understand mechanisms that occur during ovule and seed development. Understanding the underlying process of pollination, fertilization and seed development will provide us with the knowledge to create greater efficiencies when it comes to producing abundant seed for reforestation. Seeds can fail to develop because of pollination failure, or because of the consequences of self-pollination; such inbred embryos die. Conifers are open-pollinated and cannot exclude whatever the wind bring to the ovule. Can they select their own pollen over foreign pollen? What mechanisms do they have, and what is the biochemical basis for the mechanism? Pollen-ovule interactions include pollen capture by a pollination drop exuded from the ovule, followed by pollen germination and penetration through the nucellus, ending with the pollen tube's delivery of male gametes into the egg. This proposed program of research will investigate the events from pollination to fertilization. We will study this from a molecular standpoint. My students will be working on protein analysis. Pollination drops, for example, appear to be a sort of species-specific germination media, favouring their own pollen over pollen from other species. Pollination drops of cypress and cedar species retract very quickly after pollination, implying an active mechanism. We will unravel this mechanism. We will also be investigating the changes in proteome during fertilization, ovule development and egg maturation of a variety of evolutionarily significant gymnosperms. The studies are hypothesis-driven and will engage two PhD students. The impact of this work is practical, leading to deeper understanding of events critical for effective management of reproduction. My work is also likely to contribute to understanding of adaptations critical to the evolution of seeds.