A comparative approach to understanding the ovule, seed, and fruit development in Bulbostylis (Cyperaceae: Cyperoideae: Abildgaardieae)

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.

Yielding to the image: How phenotyping reproductive growth can assist crop improvement and production

Reproductive organs are the main reason we grow and harvest most plant species as crops, yet they receive less attention from phenotyping due to their complexity and inaccessibility for analysis. This review highlights recent progress towards the quantitative high-throughput phenotyping of reproductive development, focusing on three impactful areas that are pivotal for plant breeding and crop production. First, we look at phenotyping phenology, summarizing the indirect and direct approaches that are available. This is essential for analysis of genotype by environment, and to enable effective management interpretation and agronomy and physiological interventions. Second, we look at pollen development and production, in addition to anther characteristics, these are critical points of vulnerability for yield loss when stress occurs before and during flowering, and are of particular interest for hybrid technology development. Third, we elaborate on phenotyping yield components, indirectly or directly during the season, with a numerical or growth related approach and post-harvest processing. Finally, we summarise the opportunities and challenges ahead for phenotyping reproductive growth and their feasibility and impact, with emphasis on plant breeding applications and targeted yield increases.