Inferences on gynoecium evolution in<i>Xyris</i>(Xyridaceae, Poales) based on floral anatomy and development

Nardi, Kaire de Oliveira; Campbell, Lisa M.; Oriani, Aline

doi:10.1093/botlinnean/boab031

Cited by 4 publications

(6 citation statements)

References 30 publications

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“…In Acorus , the placentae are hanging from the cross-zone into the ovary locules. In Xyris , the ovules have their micropyles facing the style, they are attached more or less basally and occupy the upper surface of an area corresponding to the fused septae in the gynoecium centre (placentation is columnar in some species) [ 63 , 64 , 65 , 66 ]. In general, carpels with fertile (syn)ascidiate zone are characteristically rare in the grade of lilioid monocots ( Figure 2 and Figure 3 ).…”

Section: Resultsmentioning

confidence: 99%

Patterns of Carpel Structure, Development, and Evolution in Monocots

Remizowa,

Sokoloff

2023

Plants

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The phenomenon of heterochrony, or shifts in the relative timing of ontogenetic events, is important for understanding many aspects of plant evolution, including applied issues such as crop yield. In this paper, we review heterochronic shifts in the evolution of an important floral organ, the carpel. The carpels, being ovule-bearing organs, facilitate fertilisation, seed, and fruit formation. It is the carpel that provides the key character of flowering plants, angiospermy. In many angiosperms, a carpel has two zones: proximal ascidiate and distal plicate. When carpels are free (apocarpous gynoecium), the plicate zone has a ventral slit where carpel margins meet and fuse during ontogeny; the ascidiate zone is sac-like from inception and has no ventral slit. When carpels are united in a syncarpous gynoecium, a synascidiate zone has as many locules as carpels, whereas a symplicate zone is unilocular, at least early in ontogeny. In ontogeny, either the (syn)ascidiate or (sym)plicate zone is first to initiate. The two developmental patterns are called early and late peltation, respectively. In extreme cases, either the (sym)plicate or (syn)ascidiate zone is completely lacking. Here, we discuss the diversity of carpel structure and development in a well-defined clade of angiosperms, the monocotyledons. We conclude that the common ancestor of monocots had carpels with both zones and late peltation. This result was found irrespective of the use of the plastid or nuclear phylogeny. Early peltation generally correlates with ovules belonging to the (syn)ascidiate zone, whereas late peltation is found mostly in monocots with a fertile (sym)plicate zone.

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Section: Resultsmentioning

confidence: 99%

Patterns of Carpel Structure, Development, and Evolution in Monocots

Remizowa,

Sokoloff

2023

Plants

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“…However, species of Rapateaceae demonstrate contrasting carpel zone fertility and placentation at the level of subfamily. Among other Poales, such variability with respect to ovule insertion, either in the plicate or ascidiate carpel zone, is also found in Xyridaceae Nardi et al, 2021) and Bromeliaceae (Bernardello et al, 1991;Sajo et al, 2004). In Bromeliaceae, it is accompanied by variation in ovary position.…”

Section: Gynoecium Construction: Carpel Fusion and Ovule Attachmentmentioning

confidence: 93%

“…Such simultaneous initiation of numerous organs requires more space and meristematic material, leaving only a small area for gynoecium inception. Among Poales, common petal-stamen primordia have been reported for Xyridaceae (Remizowa et al, 2012;Nardi et al, 2021) and Eriocaulaceae (Stützel, 1984;Silva et al, 2016;Sokoloff et al, 2020). Simultaneous organ initiation but with separate primordia is also found in Rapateaceae.…”

Section: Floral Ontogenymentioning

confidence: 97%

“…A plicate zone allows insertion of more ovules (Doyle and Endress, 2000;Endress and Doyle, 2009) which means increased seed set. Gynoecia with numerous ovules inserted in a plicate carpel zone and often unilocular ovary are characteristic of biotically (insect or bird) pollinated families, including some Xyridaceae Remizowa et al, 2012;Nardi et al, 2021), Mayacaceae (De Carvalho et al, 2009;Oriani and Scatena, 2019), some Bromeliaceae (Bernardello et al, 1991;Sajo et al, 2004), and also some wind-pollinated Juncaceae Shamrov et al, 2012). Xyridaceae and Mayacaceae differ from Rapateaceae by their orthotropous ovules and Bromeliaceae by the presence of septal nectaries and variable ovary position.…”

Section: Gynoecium Construction: Carpel Fusion and Ovule Attachmentmentioning

confidence: 99%

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Flower and Spikelet Construction in Rapateaceae (Poales)

et al. 2022

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The family Rapateaceae represents an early-divergent lineage of Poales with biotically pollinated showy flowers. We investigate developmental morphology and anatomy in all three subfamilies and five tribes of Rapateaceae to distinguish between contrasting hypotheses on spikelet morphology and to address questions on the presence of nectaries and gynoecium structure. We support an interpretation of the partial inflorescence (commonly termed spikelet), as a uniaxial system composed of a terminal flower and numerous empty phyllomes. A terminal flower in an inflorescence unit is an autapomorphic feature of Rapateaceae. The gynoecium consists of synascidiate, symplicate, and usually asymplicate zones, with gynoecium formation encompassing congenital and often also postgenital fusions between carpels. Species of Rapateaceae differ in the relative lengths of the gynoecial zones, the presence or absence of postgenital fusion between the carpels and placentation in the ascidiate or plicate carpel zones. In contrast with previous reports, septal nectaries are lacking in all species. The bird-pollinated tribe Schoenocephalieae is characterized by congenital syncarpy; it displays an unusual type of gynoecial (non-septal) nectary represented by a secretory epidermis at the gynoecium base.

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“…Therefore to overcome this computation challenge, in case of families with more than two types of placentation, we referred to the literature to find out which placentation types is ancestral or derived in that family. For example, in Xyridaceae the axile is the ancestral placentation whereas basal, free central, and parietal are derived types (Nardi et al, 2021). Thus, we used axile as the primary placentation type for Xyridaceae in our analysis.…”

Section: Placentation and Associated Trait Data Collectionmentioning

confidence: 99%

The Evolution of Placentation in Flowering Plants: A Possible Role for Kin Selection

Shivaprakash¹,

Bawa²

2022

Front. Ecol. Evol.

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Placentation refers to the mode of ovule attachment on the wall of the ovary. In multiovulate ovaries, placentation influences interactions among developing seeds with varying degrees of kinships. Placentation is a taxonomically informative character in flowering plants, yet little has been written about the origin and evolutionary trends of various placentation types in flowering plants since Puri’s and Stebbins’ work, over six decades and almost four decades ago, respectively. More recently, some authors have written about the evolution of placentation in certain groups, but an overall perspective for angiosperms is lacking. For 421 families of angiosperms, we collected data on placentation types and ovule number, and analyzed the data in the phylogenetic context using recent comprehensive phylogeny of angiosperms to test the hypotheses on the evolution of various placentation types and their association with ovule number. The distribution of placentation types across flowering plants suggests that axile placentation, followed by parietal and basal placentation, occurs more frequently than laminar and free central placentation that are very rare. Our results are more consistent with evolutionary trends proposed by Puri than by Stebbins and suggest that marginal placentation is the ancestral and most primitive placentation type, while axile is the most advanced. Placentation types show strong association with ovule number. Finally, our results on ovule number and placentation types indicate that most angiosperms may fall into two categories: one with one or few ovule(s) and basal placentation, and another with many ovules and parietal and axile placentation. Kin selection within ovaries may play a role in explaining the observed patterns. Overall, our results provide new insights into the evolution of placentation, particularly into the drivers underlying the diversification of various placentation types.

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Inferences on gynoecium evolution inXyris(Xyridaceae, Poales) based on floral anatomy and development

Cited by 4 publications

References 30 publications

Patterns of Carpel Structure, Development, and Evolution in Monocots

Patterns of Carpel Structure, Development, and Evolution in Monocots

Flower and Spikelet Construction in Rapateaceae (Poales)

The Evolution of Placentation in Flowering Plants: A Possible Role for Kin Selection

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