Sokoloff Dmitry D, Malyshkina Raisa A, Remizowa Margarita V, Rudall Paula J, Fomichev Constantin I, Fesenko Aleksey N, Fesenko Ivan N, Logacheva Maria D
Biological Faculty, Lomonosov Moscow State University, Moscow, Russia.
Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, United Kingdom.
Front Plant Sci. 2023 Jan 12;13:1081981. doi: 10.3389/fpls.2022.1081981. eCollection 2022.
Understanding the complex inflorescence architecture and developmental morphology of common buckwheat () is crucial for crop yield. However, most published descriptions of early flower and inflorescence development in Polygonaceae are based on light microscopy and often documented by line drawings. In and many other Polygonaceae, an important inflorescence module is the thyrse, in which the primary axis never terminates in a flower and lateral cymes (monochasia) produce successively developing flowers of several orders. Each flower of a cyme is enclosed together with the next-order flower by a bilobed sheathing bract-like structure of controversial morphological nature.
We explored patterns of flower structure and arrangement in buckwheat and its wild relatives, using comparative morphology, scanning electron microscopy and X-ray microtomography.
Our data support interpretation of the sheathing bract as two congenitally fused phyllomes (prophylls), one of which subtends a next-order flower. In , a homeotic mutant of , the bilobed sheathing bract-like organ acquires tepal-like features and is sometimes replaced by two distinct phyllomes. Wild representatives of (ssp. ) and most cultivars of common buckwheat possess an indeterminate growth type with lateral thyrses produced successively on the primary inflorescence axis until cessation of growth. In contrast, determinate cultivars of develop a terminal thyrse after producing lateral thyrses. In contrast to , the occurrence of a terminal thyrse does not guarantee a determinate growth pattern in . The number of lateral thyrses produced before the terminal thyrse on the main axis of varies from zero to c. 19.
The nine stages of early flower development formally recognized here and our outline of basic terminology will facilitate more standardized and readily comparable descriptions in subsequent research on buckwheat biology. Non-trivial relative arrangements of tepals and bracteoles in and some other Polygonaceae require investigation using refined approaches to mathematical modelling of flower development. Our data on inflorescence morphology and development suggest contrasting evolutionary patterns in the two main cultivated species of buckwheat, and . The genus offers an excellent opportunity for evo-devo studies related to inflorescence architecture.
了解普通荞麦（）复杂的花序结构和发育形态对于作物产量至关重要。然而，大多数已发表的蓼科早期花和花序发育的描述基于光学显微镜，且常以线条图记录。在和许多其他蓼科植物中，一个重要的花序模块是聚伞圆锥花序，其中主轴从不以花结束，侧生聚伞花序（单歧聚伞花序）依次产生多个发育阶段的花。聚伞花序的每朵花与下一级花一起被一个形态性质有争议的二裂鞘状苞片结构所包围。
我们利用比较形态学、扫描电子显微镜和X射线显微断层扫描技术，探索了荞麦及其野生近缘种的花结构和排列模式。
我们的数据支持将鞘状苞片解释为两个先天性融合的叶状体（先出叶），其中一个叶状体托着下一级花。在的一个同源异型突变体中，二裂鞘状苞片样器官获得了花被片样特征，有时被两个不同的叶状体所取代。（亚种）的野生代表种和大多数普通荞麦品种具有无限生长类型，在初级花序轴上依次产生侧生聚伞圆锥花序，直至生长停止。相比之下，的有限生长品种在产生侧生聚伞圆锥花序后发育出顶生聚伞圆锥花序。与不同，顶生聚伞圆锥花序的出现并不能保证的有限生长模式。在主轴上顶生聚伞圆锥花序之前产生的侧生聚伞圆锥花序数量从零到约19个不等。
这里正式确认的早期花发育的九个阶段以及我们的基本术语概述将有助于在后续荞麦生物学研究中进行更标准化和更易于比较的描述。在和一些其他蓼科植物中，花被片和小苞片的非平凡相对排列需要使用精细的花发育数学建模方法进行研究。我们关于花序形态和发育的数据表明，荞麦的两个主要栽培种和的进化模式形成对比。属为与花序结构相关的进化发育研究提供了绝佳机会。
