Morpho-Anatomy of the Gynoecium and Fruit in Three Ornamental Members of Campanuloideae (Campanulaceae)

Roksolana Andreychuk,Anastasiya Odintsova,Barbara Łotocka

doi:10.5586/aa.7415

Abstract

Abstract Gynoecium and fruit micromorphology and anatomy were studied using light microscopy in three species of Campanuloideae belonging to the tribes Cyanantheae ( Platycodon grandiflorus ), Wahlenbergieae ( Jasione montana ), and Campanuleae ( Adenophora liliifolia ) of the native and cultivated flora of Ukraine, to elucidate structural adaptations for fruit dehiscence. The studied species differed in flower/fruit orientation, carpel number, ovary insertion, and capsule-opening position, and the information provided a background for the discovery of common anatomical features influencing fruit dehiscence. In the studied species, the synascidiate and symplicate zones in the ovary and prominent placentae were found to be located near the mid-region of the ovary. The distinct innervation of the ovary wall and ovules was described. In P. grandiflorus , the septa and fruit wall contained a lignified parenchyma in a subepidermal position, while in J. montana and A. liliifolia , lignification was observed only in proximal portions of the septa, above the placenta ( J. montana ), or was noted as a narrow strand from the ovary base to the mid-region, called “axicorn” ( A. liliifolia ). In all the studied species, unlignified endocarpium was detected. The semi-inferior capsule of P. grandiflorus has been defined as a capsule of the Forsythia -type, with a sclerenchymatous layer in the inner zone of the mesocarpium. In J. montana and A. liliifolia , a new histogenetic type of capsule is described as Campanula -type, without lignified layers in the fruit wall and with lignified tissue in the septa, which enabled dehiscence. Our study proposed for the first time the classification of the capsules found in the studied species based on the development of openings in the superior or inferior regions of the fruits. The upright fruits of P. grandiflorus and J. montana reveal incomplete dorsiventral dehiscence in the superior region of the fruit, while dehiscence of pendent fruits of A. liliifolia is hippocrepiform-septifragal interlocular and occurs in the inferior region of the fruit at its base, as revealed previously in Campanula latifolia fruit.

Highlights

According to the most recently reported data ( e Angiosperm Phylogeny Group, 2016; Lammers, 2007), the family Campanulaceae Juss. includes the following five subfamilies: Campanuloideae Burnett, Cyphioideae
E ovary of P. grandiflorus was observed to be semi-inferior, 1 cm in length and 1 cm in diameter, obconic, and presented with the following two regions: the superior one was situated between the insertion of the calyx lobes and the style base, which exhibited the form of a pentahedral pyramid (Figure 1B,C), and the inferior region was situated between the insertion of the calyx lobes and the ovary base
Dimerous gynoecium occurred in J. montana, where it corresponded with the general level of flower reduction in a condensed pseudanthium (Lammers, 2007; Sales et al, 2004). e other characters correlated with this reduction include the small size of the flowers and the dissected corolla. e trimerous gynoecium in A. liliifolia is typical for Campanula-related genera and all members of Campanuloideae (Lammers, 2007)

Summary

Introduction

According to the most recently reported data ( e Angiosperm Phylogeny Group, 2016; Lammers, 2007), the family Campanulaceae Juss. includes the following five subfamilies: Campanuloideae Burnett, Cyphioideae Includes the following five subfamilies: Campanuloideae Burnett, Cyphioideae DC.) Walp., Cyphocarpoideae Miers., Lobelioideae Burnett, and Nemacladoideae Lammers [see Cosner et al (2004) and Takhtajan (2009) for another views]. In Campanuloideae, the following three tribes are distinguished: Cyanantheae Meisner, Wahlenbergieae. Tribe Cyanantheae is a sister clade to the joint clade of Wahlenbergieae and Campanuleae, but the relations within clades remain unresolved (Yoo et al, 2018). E genus Jasione with a capitate pseudanthium and small reduced flowers (Sales et al, 2004) occupies an isolated position in Campanuloideae, and is placed either in the Campanuleae tribe (Cosner et al, 2004; Eddie et al, 2003) or in the Wahlenbergieae tribe (Roquet et al, 2009) One of them corresponds to the first tribe, and the second one is considered as the alliance of the second and third tribes (Cosner et al, 2004; Eddie et al, 2003). e genus Jasione with a capitate pseudanthium and small reduced flowers (Sales et al, 2004) occupies an isolated position in Campanuloideae, and is placed either in the Campanuleae tribe (Cosner et al, 2004; Eddie et al, 2003) or in the Wahlenbergieae tribe (Roquet et al, 2009)

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