Instituto de Ciencias Agropecuarias del Litoral, Universidad Nacional del Litoral, Consejo Nacional de Investigaciones Científicas Y Técnicas, Kreder 2805, Esperanza, Santa Fe, Argentina.
Facultad de Ciencias Agrarias, Universidad Nacional del Litoral, Esperanza, Santa Fe, Argentina.
Protoplasma. 2022 Jan;259(1):141-153. doi: 10.1007/s00709-021-01649-7. Epub 2021 Apr 27.
In the present work, we study the ovule, seed, and fruit development in six Bulbostylis species in order to characterize the genus in a comparative approach and to identify the characteristics that can be used in taxonomy and phylogeny. Flowers and fruits at different developmental stages were analyzed using LM and SEM after processing according to standard techniques. The species studied have the following: anatropous and bitegmic ovules, weak crassinucellar ovules, obturator of integumentary origin, monosporic embryo sac of the Polygonum type, nuclear endosperm, hypostase formation, seed coat formed by tanniferous endotegmen and exotesta, and Bulbostylis-type embryo. On the other hand, the pericarp development constitutes the main variation within Bulbostylis since the cells of the exocarp may or may not present starch grains, and their inner periclinal walls may be slightly or deeply concave depending on the degree of development of the mesocarp sclereids. In a taxonomic context, the results herein obtained are in conflict with studies which suggest infrageneric groupings based on fruit micromorphology, and also with the relationship among the Bulbostylis species based on molecular analysis. This work contributes to a better understanding of the reproductive anatomy and embryology in Bulbostylis, and reveals the first insights about the origin of multiple embryos in Cyperaceae. Given the frequent presence of polyembryony in Bulbostylis, and the poor mention of this condition in the family, this work highlights an aspect in the anatomy of Cyperaceae that must be re-explored.
在本工作中，我们研究了六个 Bulbostylis 物种的胚珠、种子和果实发育，以便通过比较方法对属进行特征描述，并确定可用于分类学和系统发育学的特征。采用 LM 和 SEM 对经过标准技术处理的不同发育阶段的花和果实进行分析。所研究的物种具有以下特征：倒生和双珠被胚珠、弱厚珠心胚珠、珠被起源的封闭器、Polygonum 型单孢子胚囊、核胚乳、基细胞形成、由单宁内珠被和外珠被组成的种皮以及 Bulbostylis 型胚。另一方面，果皮的发育是 Bulbostylis 内部的主要变异，因为外果皮细胞可能含有或不含有淀粉粒，其内壁的垂周壁可能略微或深深地凹陷，这取决于中果皮石细胞的发育程度。在分类学背景下，本文获得的结果与基于果实微形态学的属下分组研究以及基于分子分析的 Bulbostylis 种间关系相冲突。这项工作有助于更好地理解 Bulbostylis 的生殖解剖学和胚胎学，并揭示了 Cyperaceae 中多胚起源的初步见解。鉴于 Bulbostylis 中多胚的频繁出现，以及该条件在该科中提及较少，这项工作突出了 Cyperaceae 解剖学中必须重新探索的一个方面。
