Embryogenesis, endospermogenesis and fruit development in Lophophytum (Balanophoraceae): Focus on endosperm and embryo initiation

Sato, Héctor Arnaldo; González, Ana María

doi:10.1016/j.flora.2017.05.001

Cited by 5 publications

(6 citation statements)

References 16 publications

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“…Furthermore, it is not possible yet to cultivate this species and the tiny flower size does not allow bagging of female flowers or excising of anthers in male flowers. Nevertheless, a similar pattern in embryo and endosperm formation was also described in Balanophora [77,78] and Lophophytum [16,39], the only other two Balanophoraceae s.str. genera studied ontogenetically.…”

Section: Discussionsupporting

confidence: 71%

“…is definitely one of the most unusual eudicot families. Indeed, its genera are characterised by aberrant vegetative bodies [4,13,27], highly reduced flowers [2,12,28], inversion and aggressiveness of the ES [15], irregular embryogenesis and small and reduced embryos [2,16,28,29]. This study focused on H. cayennensis , a monoecious species with endogenously developed inflorescences.…”

Section: Discussionmentioning

confidence: 99%

“…The present study focuses on H. cayennensis , as part of a broader project lead by the first author on the embryology of traditionally circumscribed Balanophoraceae (hereafter referred to as Balanophoraceae s.l.) [12,13,14,15,16]. The species was found in 2006 ([17] fontana), growing in a single spot of about 15 m 2 in a mesophyll forest of Argentina, where the only evidence of its presence was the appearance of numerous inflorescences at various developmental stages, from barely visible buds hidden in the forest mulch to open mature inflorescences.…”

Section: Introductionmentioning

confidence: 99%

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Embryology in Helosis cayennensis (Balanophoraceae): Structure of Female Flowers, Fruit, Endosperm and Embryo

González

Sato

Marazzi³

2019

Plants

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Helosis cayennensis (Balanophoraceae s.str.) is a holoparasite characterised by aberrant vegetative bodies and tiny, reduced unisexual flowers. Here, we analysed the development of female flowers to elucidate their morpho-anatomy and the historical controversy on embryo sac formation. We also studied the developmental origin of inflorescences and the ontogeny of fruits, embryo and endosperm and discussed in a phylogenetic framework. Inflorescences were analysed by optical, fluorescence and scanning electron microscopy. Inflorescences of H. cayennensis arise endogenously. Female flowers lack perianth organs, thus only consist of the ovary, two styles and stigmata. Ovules are undifferentiated; two megaspore mother cells develop inside a nucellar complex. The female gametophyte, named Helosis-type, is a bisporic four-celled embryo sac, provided with a typical egg apparatus and a uni-nucleated central cell. Fertilization was not observed, yet a few-celled embryo and cellular endosperm developed. In sum, results confirm that, among Santalales holoparasites, Helosis is intermediate in the reduction series of its floral organs. Although perianth absence best supports the Balanophoraceae s.str. clade, our literature survey on female flower developmental data across Balanophoraceae s.l. highlights the many gaps that need to be filled to really understand these features in the light of new phylogenetic relationships.

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Section: Discussionsupporting

confidence: 71%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Embryology in Helosis cayennensis (Balanophoraceae): Structure of Female Flowers, Fruit, Endosperm and Embryo

González

Sato

Marazzi³

2019

Plants

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“…The species is at least partially selfing, and seeds germinate while still inside fruit after the inflorescence falls into the leaf litter (Alves et al, 2021). There is extreme reduction in the ovule integuments (i.e., completely ategmic ovules lacking a micropyle), which has not been observed in other orchids (Alves et al, 2019) and is otherwise very rare in angiosperms (Bouman, 1984; Brown et al, 2010; Sato and Gonzales, 2017). This structural reduction does not appear to compromise its ability to produce seeds, as the synergids continue to secrete substances for pollen‐tube attraction, penetration, and subsequent fertilization (Alves et al, 2019).…”

mentioning

confidence: 97%

Phylogenomics and plastome evolution of a Brazilian mycoheterotrophic orchid, Pogoniopsis schenckii

Klimpert

Mayer

Sarzi

et al. 2022

American J of Botany

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Premise Pogoniopsis likely represents an independent photosynthesis loss in orchids. We use phylogenomic data to better identify the phylogenetic placement of this fully mycoheterotrophic taxon, and investigate its molecular evolution. Methods We performed likelihood analysis of plastid and mitochondrial phylogenomic data to localize the position of Pogoniopsis schenckii in orchid phylogeny, and investigated the evolution of its plastid genome. Results All analyses place Pogoniopsis in subfamily Epidendroideae, with strongest support from mitochondrial data, which also place it near tribe Sobralieae with moderately strong support. Extreme rate elevation in Pogoniopsis plastid genes broadly depresses branch support; in contrast, mitochondrial genes are only mildly rate elevated and display very modest and localized reductions in bootstrap support. Despite considerable genome reduction, including loss of photosynthesis genes and multiple translation apparatus genes, gene order in Pogoniopsis plastomes is identical to related autotrophs, apart from moderately shifted inverted repeat (IR) boundaries. All cis‐spliced introns have been lost in retained genes. Two plastid genes (accD, rpl2) show significant strengthening of purifying selection. A retained plastid tRNA gene (trnE‐UUC) of Pogoniopsis lacks an anticodon; we predict that it no longer functions in translation but retains a secondary role in heme biosynthesis. Conclusions Slowly evolving mitochondrial genes clarify the placement of Pogoniopsis in orchid phylogeny, a strong contrast with analysis of rate‐elevated plastome data. We documented the effects of the novel loss of photosynthesis: for example, despite massive gene loss, its plastome is fully colinear with other orchids, and it displays only moderate shifts in selective pressure in retained genes.

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“…Safranin O and fast green FCF staining combination, easier to apply than hematoxylin, is also considered one of the most valuable stains both for nuclear as well as anatomical and embryological studies and it has even replaced hematoxylin stain for routine work in some cases [40]. This staining combination has been applied in embryological studies of several plant species [9,41,42] and, in grapevine, as far as we know, for carpel morphogenesis, flower formation, fruit set and early stages of fruit development studies [37,38,43].…”

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confidence: 99%

An optimized histological proceeding to study the female gametophyte development in grapevine

et al. 2020

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Background: Reproductive success in seed plants depends on a healthy fruit and seed set. Normal seed development in the angiosperms requires the production of functional female gametophytes. This is particularly evident in seedless cultivars where defects during megagametophyte's developmental processes have been observed through cytohistological analysis. Several protocols for embryo sac histological analyses in grapevine are reported in literature, mainly based on resin-or paraffin-embedding approaches. However their description is not always fully exhaustive and sometimes they consist of long and laborious steps. The use of different stains is also documented, some of them, such as hematoxylin, requiring long oxidation periods of the dye-solution before using it (from 2 to 6 months) and/or with a differentiation step not easy to handle. Paraffin-embedding associated to examination with light microscope is the simplest methodology, and with less requirements in terms of expertise and costs, achieving a satisfactory resolution for basic histological observations. Safranin O and fast green FCF is an easy staining combination that has been applied in embryological studies of several plant species. Results: Here we describe in detail a paraffin-embedding method for the examination of grapevine ovules at different phenological stages. The histological sample preparation process takes 1 day and a half. Sections of 5 µm thickness can be obtained and good contrast is achieved with the safranin O and fast green FCF staining combination. The method allows the observation of megasporogenesis and megagametogenesis events in the different phenological stages examined. Conclusions: The histological sample preparation process proposed here can be used as a routine procedure to obtain embedded ovaries or microscope slides that would require further steps for examination. We suggest the tested staining combination as a simple and viable technique for basic screenings about the presence in grapevine of a normally and fully developed ovule with embryo sac cells, which is therefore potentially functional.

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Embryogenesis, endospermogenesis and fruit development in Lophophytum (Balanophoraceae): Focus on endosperm and embryo initiation

Cited by 5 publications

References 16 publications

Embryology in Helosis cayennensis (Balanophoraceae): Structure of Female Flowers, Fruit, Endosperm and Embryo

Embryology in Helosis cayennensis (Balanophoraceae): Structure of Female Flowers, Fruit, Endosperm and Embryo

Phylogenomics and plastome evolution of a Brazilian mycoheterotrophic orchid, Pogoniopsis schenckii

An optimized histological proceeding to study the female gametophyte development in grapevine

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