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In Berberidaceae, the phylogenetic position and systematic affinities of the monotypic genus Nandina have long been debated and remain unclear. In addition, previous comparative studies have provided conflicting reports on the origin and development of its petals. Using scanning electron microscopy and microtome sections, we studied the structure and development of the flower and perianth in Nandina domestica to re-evaluate its affinities and homology of its petals. Our results confirm that N. domestica essentially shares the same Bauplan (organization) with other Berberidaceae and its petals are neither delayed in development nor much differentiated from sepals. However, we sometimes also observed the initiation of additional primordia that become confluent with the base of stamens of the outer whorl, but do not develop further and are no longer visible in later stages of development. Our study thus not only reconciles previous conflicting interpretations on the origin and development of petals in Nandina , but also confirms that it has a unique suite of vegetative and reproductive features supporting its position as a distinct member of the family. In addition, it suggests that the most recent common ancestors of both Berberidaceae and Ranunculales probably had two types of petaloid organs with distinct origin and development but still sharing a deep common genetic identity. [ABSTRACT FROM AUTHOR]

The Ranunculales are a hyperdiverse lineage in many aspects of their phenotype, including growth habit, floral and leaf morphology, reproductive mode, and specialized metabolism. Many Ranunculales species, such as opium poppy and goldenseal, have a high medicinal value. In addition, the order includes a large number of commercially important ornamental plants, such as columbines and larkspurs. The phylogenetic position of the order with respect to monocots and core eudicots and the diversity within this lineage make the Ranunculales an excellent group for studying evolutionary processes by comparative studies. Lately, the phylogeny of Ranunculales was revised, and genetic and genomic resources were developed for many species, allowing comparative analyses at the molecular scale. Here, we review the literature on the resources for genetic manipulation and genome sequencing, the recent phylogeny reconstruction of this order, and its fossil record. Further, we explain their habitat range and delve into the diversity in their floral morphology, focusing on perianth organ identity, floral symmetry, occurrences of spurs and nectaries, sexual and pollination systems, and fruit and dehiscence types. The Ranunculales order offers a wealth of opportunities for scientific exploration across various disciplines and scales, to gain novel insights into plant biology for researchers and plant enthusiasts alike. [ABSTRACT FROM AUTHOR]

The Berberidaceae and the six other families of Ranunculales form a sister clade to all other eudicots, and are crucial to reconstructing the common ancestor of flowering plants. Previous studies have suggested that the petals of most Berberidaceae are derived from stamens, and some are thought to develop petals from common petal/stamen primordia. However, the flower ontogeny is still poorly known in the family and the presence of common primordia needs to be re-evaluated from a comparative developmental perspective. Here, we used scanning electron microscopy to study the floral development of the endemic Chinese species Dysosma versipellis (Hance) M. Cheng ex Ying, which was originally placed in Podophyllum. Our results show that the floral organs are all free and the sepals, petals, and stamens are initiated centripetally in successive and alternate trimerous pairs of whorls around a single carpel. The nectarless petals are initiated separately and do not develop from common primordia with the stamens. Floral and developmental features of D. versipellis are similar to those of most members of Berberidaceae. The regular development of multiple flowers and absence of a secondary increase in the number of stamens in Dysosma support its exclusion from Podophyllum, and this is also inferred by the DNA sequence data. Keywords: Berberidaceae, Dysosma, floral development, floral phyllotaxis, Podophyllum. Les Berberidacees et les six autres familles de Renonculales forment un clade jumeau de toutes les autres dicotyledones vraies et elles sont cruciales pour reconstituer l'ancetre commun des angiospermes. Des etudes anterieures ont suggere que les petales de la plupart des Berberidacees derivent des etamines et que pour certaines, les petales se developpent a partir d'une ebauche commune petale/etamine. Cependant, l'ontogenie florale chez cette famille est encore mal comprise et la presence d'une ebauche commune doit etre reevaluee selon une perspective developpementale comparative. Les auteurs ont utilise ici la microscopie electronique ti balayage afin d'etudier le developpement floral d'une espece endemique en Chine, Dysosma versipellis (Hance) M. Cheng ex Ying, placee a l'origine chez Podophyllum. Leurs resultats montrent que les organes floraux sont tous libres et que les sepales, les petales et les etamines sont inities de facon centripete par paires successives et alternees de verticilles trimeres, autour d'un carpelle unique. Des petales sans nectar sont inities de maniere separee et ne se developpent pas a partir d'une ebauche commune avec les etamines. Les caracteristiques florales et developpementales de D. versipellis sont similaires a celles de la plupart des membres des Berberidacees. Le developpement regulier des multiples fleurs et l'absence d'un accroissement secondaire du nombre d'etamine chez Dysosma justifient son exclusion de Podophyllum, exclusion aussi deduite par les donnees de sequences d'ADN. [Traduit par la Redaction] Mots-cles: Berberidacees, Dysosma, developpement floral, phyllotaxie florale, Podophyllum., Introduction As sister to the largest clade of flowering plants (eudicots), the barberry family (Berberidaceae) and other members of the Ranunculales are crucial for reconstructing the evolutionary history of flowers [...]

Ever since Erasmus and Charles Darwin laid down the foundations of the concept, sexual selection has largely been regarded as a matter of male competition and female selection. While their role in plant evolution and the elusive origin of flowering plants has largely been neglected in contrast to the situation with animals, there is a growing body of evidence accumulated over the past 50 years supporting the hypothesis that, together with the flower and the carpel, increased pollination has led to an intensification of the competition between the fittest (and faster) pollen tubes and their selection by the surrounding maternal tissue. In contrast, the potential role of female competition was historically seldom considered but started to re-emerge a decade ago in both animal and plant evolution. Here, I review a large body of the vast embryological literature to re-evaluate unusual developmental traits in the plant female germline, traditionally considered as teratological occurrences of mere systematic interest, in the light of the current phylogenetic framework for flowering plants. After a summary of the basic tenets of sexual selection and the role of male competition and maternal selection in shaping plant evolution and diversity, I show how recent insights into the deepest nodes of flowering plant phylogeny and confirmation of their systematic relationships over the past 30 years have led to major shifts in our understanding of the reproductive biology of their most recent common ancestor. I also show that a re-evaluation of these unusual developmental traits in the female germline, especially in early-diverging lineages of flowering plants, may potentially be correlated with some floral structural traits. On the basis of these results, I argue that there is circumstantial evidence for mechanisms of female intrasexual competition and selection in individual ovules of flowering plants that are similar to those between pollen tubes competing inside the carpel. I also argue that although they may have evolved independently multiple times in unrelated lineages, they could also be the 'burning embers' of plesiomorphic traits that would have been largely selected against after the evolution of their most recent common ancestor. [ABSTRACT FROM AUTHOR]

Strigolactones were originally identified as stimulators of the germination of root-parasitic weeds (1) that pose a serious threat to resource-limited agriculture (2). They are mostly exuded from roots and function as signalling compounds in the initiation of arbuscular mycorrhizae (3), which are plant-fungus symbionts with a global effect on carbon and phosphate cycling (4). Recently, strigolactones were established to be phytohormones that regulate plant shoot architecture by inhibiting the outgrowth of axillary buds (5,6). Despite their importance, it is not known how strigolactones are transported. ATP-binding cassette (ABC) transporters, however, are known to have functions in phytohormone translocation (7-9). Here we show that the Petunia hybrida ABC transporter PDR1 has a key role in regulating the development of arbuscular mycorrhizae and axillary branches, by functioning as a cellular strigolactone exporter. P. hybrida pdrl mutants are defective in strigolactone exudation from their roots, resulting in reduced symbiotic interactions. Above ground, pdrl mutants have an enhanced branching phenotype, which is indicative of impaired strigolactone allocation. Overexpression of Petunia axillaris PDR1 in Arabidopsis thaliana results in increased tolerance to high concentrations of a synthetic strigolactone, consistent with increased export of strigolactones from the roots. PDRl is the first known component in strigolactone transport, providing new opportunities for investigating and manipulating strigolactone-dependent processes., Strigolactones are a new class of carotenoid-derived (10) phytohormone in land plants. In addition to their role in shoot branching, strigolactones are exuded into the rhizosphere under phosphorus-limiting conditions (5) [...]

Although most living organisms reproduce sexually, some have developed a uniparental reproduction where the embryo usually derives from the female parent. A unique case of paternal apomixis in plants has been recently reported in Cupressus dupreziana, an endangered Mediterranean conifer. This species produces unreduced pollen that develop into all-paternal embryos within the seed tissues. We analyzed seedlings produced by open-pollinated C. dupreziana seed trees using morphological descriptors, ploidy levels assessed through flow cytometry, and AFLP genetic diversity. In situ C. dupreziana seed trees (from Algeria) produced only diploid C. dupreziana progeny. In contrast, only one-third of the progeny produced by ex situ C. dupreziana seed trees planted in French collections were similar to C. dupreziana seedlings; the other progeny were haploid or diploid C. sempervirens seedlings. These results demonstrate that C. dupreziana ovules allow for the development of all-paternal embryos from pollen produced by another species, C. sempervirens. Thus, the in planta androgenesis is achieved through the combination of the embryogenic behavior of pollen grains and the ability of seed tree ovules to act as a surrogate mother. This phenomenon offers a unique opportunity to produce, by natural means, highly valuable material for genetic studies and selection of sterile cultivars.