PDF(Pubmed)
Abstract：
Calcium oxalate (CaOx) crystals are biominerals present in a wide variety of plants. Formation of these crystals is a biomineralization process occurring in vacuoles within specialized cells called crystal idioblasts. This process is dependent on two key components: deprotonated oxalic acid, and calcium ions (Ca2+), and can result in multiple crystal morphologies. Raphides are needle-like CaOx crystals found in various plant organs and tissues. Though their function is highly debated, they can potentially store calcium, sequester heavy metals, protect against herbivory and possibly programmed cell death. The last review of the taxonomic and anatomical distribution of raphides across the plant kingdom dates back to 1980, in a review by Franceschi and Horner, prompting an updated systematic review of raphides in plants. We conduct a broad literature search to record plant taxa and tissue locations containing raphides. We provide an overview of raphide-forming plant taxa, discussing phylogenetic distribution of raphides at the order level, and report on the specific locations of raphides within plants. Our review reveals raphide occurrence has been studied in 33 orders, 76 families and 1305 species, with raphides presence confirmed in 24 orders, 46 families and 797 species. These taxa represented less than 1 % of known species per family. Leaves are the most prominent raphide-containing primary location in all three major angiosperm clades investigated: Eudicots, Magnoliids, and Monocots. Roots are least reported to contain raphides. The collation of such information lays the groundwork to unveil the genetic origin and evolution of raphides in plants, and highlights targets for future studies of the presence and role of plant raphides.
摘要：
草酸钙(CaOx)晶体是存在于多种植物中的生物矿物质。这些晶体的形成是在称为晶体成纤维细胞的专门细胞内的液泡中发生的生物矿化过程。这个过程取决于两个关键组分：去质子化的草酸，和钙离子（Ca2+），并且可以导致多种晶体形态。Raphides是在各种植物器官和组织中发现的针状CaOx晶体。尽管它们的功能备受争议，它们可能会储存钙，螯合重金属，防止食草动物和可能的程序性细胞死亡。在Franceschi和Horner的评论中，对整个植物界raphides的分类和解剖学分布的最后一次评论可以追溯到1980年，促使对植物中的raphides进行更新的系统审查。我们进行了广泛的文献检索，以记录含有raphides的植物分类单元和组织位置。我们提供了形成raphide的植物分类群的概述，在有序水平上讨论了raphides的系统发育分布，并报告植物中raphids的具体位置。我们的评论显示，已经在33个订单中研究了raphide的发生，76科1305种，在24个订单中确认了raphides的存在，46科797种。这些分类单元占每个家庭已知物种的不到1％。在所调查的所有三个主要被子植物进化支中，叶子是最突出的含raphide的主要位置：Eudicots，木兰,和Monocts.据报道，根中含有raphides最少。这些信息的整理为揭示植物中raphides的遗传起源和进化奠定了基础，并强调了未来研究植物raphides的存在和作用的目标。
