Morphogenesis of fruits in Gladiolus imbricatus and Iris sibirica (Iridaceae)

Abstract

Based on light microscopy investigation of fruits and seeds in Gladiolus imbricatus and Iris sibiriса, new data on morphogenesis and histogenesis of the pericarp and seed coat development have been revealed. The inner ovary structure, vascular system and fruit dehiscence were also studied. The ovary of the studied species has trilocular basal part and unilocular upper part with incomplete septae. The vascular system in both species is composed of three dorsal veins and three septal veins. The dorsal veins are each divided into three vascular bundles radially whereas the septal veins are also each divided into three bundles but tangentially. Vascular supply of ovules is provided by septal veins in the central column. In both species, the floral tube falls down with adnate stamens and style at the beginning of fruit ripening. For both species, a dorsiventral (valvate) type of fruit dehiscence is characteristic; however, in I. sibiriса, a dorsal (fissuricidal) type, in which valvae are connected at the center, top and base of the capsule, occurs as well. According to our data, capsule in both species belongs to the Lilium-type, with lignified endocarpium. In G. imbricatus, we observed early tissues differentiation in the pericarp as well as earlier and faster dorsal slits formation. The seed coat in G. imbricаtus is of endotestal type, while in I. sibirica-of exotestal type. Highly specialized features of the seed coat in G. imbricatus are the following: wing formation by outer integument, few-layered mesotesta and destruction of cellular structure of the inner integument. The obtained data complement our previously suggested consideration about more pronounced morphological adaptations for dissemination of fruits and seeds in G. imbricatus. In this article, we confirm the high level of adaptiveness of fruits and seeds in the anatomy and histogenesis of the pericarp and seed coat in G. imbricatus to external conditions.

Micromorphology and anatomy of fruit in Iris pseudacorus L.

“…The interior structure of the fruiting ovary in I. pseudacorus is characterized by the appearance of three zones. However, the synascidiate zone is short and sterile, contrary to I. sibirica (Skrypec & Odintsova, 2020). The appearance of synascidiate and symplicate zones in the ovary (but without entitling these zones) was clearly illustrated by Van Tieghem (1871) for I. lutescens Lam.…”

“…In both species, the size of the fruit depends on the number of seeds inside; seeds are located horizontally from the very base to the top of the locule (Skrypec & Odintsova, 2015). After anthesis, the floral tube falls out with an accrescent style in both species (Skrypec & Odintsova, 2020). However, in I. pseudacorus seeds arrangement is uniseriate, contrary to the biseriate arrangement in I. sibirica and many other Iris species (Rodionenko, 1961); dorsal grooves are visible in the green fruit, and slits are complete (arise from the top to base of fruit) contrary to I. sibirica, where grooves are not detectable and slits are mostly short (Skrypec & Odintsova, 2014).…”

“…Iris L. is the most species-rich genus in the family Iridaceae, being treated morphologically for taxonomic purposes, mainly from the flower and vegetative morphology (Fomin & Bordzilovskyi, 1950;Goldblatt et al, 1998;Wilson, 2006;Sennikov et al, 2023). However, fruit structure in this genus, especially with the application of anatomical techniques, was poorly studied (Rodionenko, 1961;Gritsenko, 2020;Skrypec & Odintsova, 2020). For the whole Iridaceae family, the fruit was defined as a syncarpous inferior trilocular multi-seeded capsule with loculicidal dehiscence (Goldblatt et al, 1998).…”

Micromorphology and Anatomy of the Flowers in Clivia spp. and Scadoxus multiflorus (Haemantheae, Amaryllidaceae)

“…e morphological and anatomical features of the flower in Asparagales are being studied to explain the appearance of some features of the flower and fruit (Odintsova & Fishchuk, 2017;Skrypec & Odintsova, 2020). One such feature is the organization of the flower vascular system.…”

Comparative flower morphology of Agapanthus africanus and A. praecox (Amaryllidaceae)

“…The integration of data from molecular phylogenetics and evolutionary comparative flower morphology is a promising direction for the construction of modern evolutionary taxonomy. The study of micromorphology and vascular anatomy of monocotyledonous flowers and fruits is a modern direction in the study of evolutionary morphology (Odintsova & Fishchuk, 2017;Skrypec & Odintsova, 2020). Molecular-phylogenetic reconstructions of the subfamily Agapanthaceae have been carried out by many scientists Pires et al (2006), Seberg et al (2012), Chase et al (2016).…”