Gladys Flávia Melo-de-Pinna

Comparative leaf anatomy and morphology of some neotropical Rutaceae: Pilocarpus Vahl and related genera

Previous anatomical studies have been restricted to the foliar aspects of Pilocarpus. However, no anatomical studies analyzing the foliar aspects of Pilocarpus in relation to related genera have been carried out. Therefore, the aim of this study was to identify characters for future taxonomic and phylogenetic studies in Rutaceae, particularly in Pilocarpus, and to discuss the characteristics associated with the simple or compound leaf condition for the group. The petiole and the leaf blade of 14 neotropical Rutaceae species were analyzed, and the following characteristics were observed in all leaves studied: stomata on both surfaces; secretory cavities, including mesophyll type; camptodromous–brochidodromous venation pattern; and free vascular cylinder in the basal region of the petiole. Additional promising characters were identified for future taxonomic and phylogenetic studies in the Rutaceae family, especially for the Pilocarpus genera.

Anatomia foliar de Richterago Kuntze (Mutisieae, Asteraceae)

Leaf anatomy of Richterago species revealed rather variability concerning mesophyll organization and stomata arrangement. As a character of taxonomic value, only non-glandular thricomes were used to compare R. arenaria and R. lanata,R. conduplicata and R. radiata, whose leaves are morphologically similar. Anatomical xeromorphic characters, e.g. the bundles sheath extensions and terminal tracheids were observed in all species. The waterside species (R. polymorpha e R. riparia) showed hydathodes in the leaves, which represent the first record in Mutisieae.

Morpho-anatomical variations during stem development in some epiphytic Cactaceae

Abstract In this study, the morpho-anatomical features of Hatiora salicornioides (Harworth) Britton & Rose, Rhipsalis floccosa Salm-Dyck Pfeiffer, Rhipsalis elliptica G. Lindb. ex K. Schum. and Epiphyllum phyllanthus (L.) Haworth. were studied during different phases of stem development. Primary (more developed) and terminal (less developed) segments showed variations of anatomical features as exhibited by the epidermal cells in surface view and transverse section. Features of the vascular system, e.g., the occurrence of non-lignified parenchyma in bands (H. salicornioides) or in small groups (R. floccosa and R. elliptica), as well as pericycle fibers and lignified cells in the medullar region, were only observed on the primary segments. Nevertheless, based on our anatomical analysis of stem segments in different developmental phases, we conclude that some characters described and used in systematic interpretations should be revised, mainly in the vascular (secondary xylem; non-xylematic vascular fibers) and dermal systems (epidermis in surface view and transverse section).

Elementos traqueais de cinco táxons de Cactaceae da caatinga pernambucana, Brasil

ABSTRACT – (Traqueary elements of five taxons of Cactaceae of the caatinga from Pernambuco State, Brazil). This work brings amorphological characterization of traqueary elements (vessels and tracheids) in root and cladode of five taxons of Cactaceae ( Harrisiaadscendens (Gurke) Britton & Rose, Melocactus × horridus Wedermann Notizbl., M . zehntneri (Britton & Rose) Luetzelb., Tacingainamoena (Schumann) N.P. Taylor & Stuppy and T . palmadora (Britton & Rose) N.P. Taylor & Stuppy) occurent in the caatinga ofPernambuco State, Brazil. The vessels elements observed in the roots and cladodes seem almost same among the studied taxons, we reobserved alternate, opposite and scalariform pitting, and simple perforation plate transversal or oblique. The tracheids (WBT) wereexclusively noted in the cladodes of four studied taxons, except Harrisia adscendens . The WBTs with annular and helical thickening arepresent in all taxons and the mix thickening is present only in Melocactus

Expression patterns of Passiflora edulis APETALA1/FRUITFULL homologues shed light onto tendril and corona identities

BackgroundPassiflora (passionflowers) makes an excellent model for studying plant evolutionary development. They are mostly perennial climbers that display axillary tendrils, which are believed to be modifications of the inflorescence. Passionflowers are also recognized by their unique flower features, such as the extra whorls of floral organs composed of corona filaments and membranes enclosing the nectary. Although some work on Passiflora organ ontogeny has been done, the developmental identity of both Passiflora tendrils and the corona is still controversial. Here, we combined ultrastructural analysis and expression patterns of the flower meristem and floral organ identity genes of the MADS-box AP1/FUL clade to reveal a possible role for these genes in the generation of evolutionary novelties in Passiflora.ResultsWe followed the development of structures arising from the axillary meristem from juvenile to adult phase in P. edulis. We further assessed the expression pattern of P. edulis AP1/FUL homologues (PeAP1 and PeFUL), by RT-qPCR and in situ hybridization in several tissues, correlating it with the developmental stages of P. edulis. PeAP1 is expressed only in the reproductive stage, and it is highly expressed in tendrils and in flower meristems from the onset of their development. PeAP1 is also expressed in sepals, petals and in corona filaments, suggesting a novel role for PeAP1 in floral organ diversification. PeFUL presented a broad expression pattern in both vegetative and reproductive tissues, and it is also expressed in fruits.ConclusionsOur results provide new molecular insights into the morphological diversity in the genus Passiflora. Here, we bring new evidence that tendrils are part of the Passiflora inflorescence. This points to the convergence of similar developmental processes involving the recruitment of genes related to flower identity in the origin of tendrils in different plant families. The data obtained also support the hypothesis that the corona filaments are likely sui generis floral organs. Additionally, we provide an indication that PeFUL acts as a coordinator of passionfruit development.

Wide-band tracheids (WBTs) of photosynthetic and non-photosynthetic stems in species of Cactaceae1

Abstract The absence of WBTs and wood polymorphisms in some species of the Caryophyllales may be related to the particular area of plant analyzed. The present research has the objective of studying the photosynthetic and non-photosynthetic stems of different species and stages of differentiation to register wood polymorphisms and to understand the distribution and occurrence of WBTs. Wood polymorphism was observed in the non-photosynthetic stem of young and adult plants of Opuntioideae and Cactoideae and is also found in the photosynthetic stem of young plants of some species of Cactoideae. Cactoideae present WBT/fibrous dimorphic wood that can be related to cambial variation associated with growth habits and plant development. As expected, in the photosynthetic stem of the adult columnar cacti the wood is monomorphic fibrous in which WBTs were not found. This wood contains a great amount of fibers due to necessity of the mechanical support. In contrast, the globular species do not possess fibers in this area of the stem in either adult or young plants. Opuntia monacantha Haw. had non-fibrous wood in which WBTs were observed in the axial system and in the inner parts of the rays. Fiber clusters were present in the axial system. This wood represents a variation in the wood types described for Opuntioideae. Also, in O. monacantha, cells similar to the WBTs were observed in the pith, which can be interpreted as variation in the morphogenic processes during the ontogeny of the plant, probably a case of homeosis. Monomorphic fibrous wood without WBTs was found along the entire stem of Pereskia bahiensis Gürke. This feature has been observed in other pereskias, and in addition to the others, indicates its proximity to the ancestral cacti.

Wide-band tracheids in Brazilian cacti

Summary: Wide-band tracheids (WBTs) were present in species with dimorphic and monomorphic wood. In all types of dimorphic wood in which WBTs were present, the phase that contains the WBTs is produced first. In seedlings of Cipocereus minensis the first phase consists of vessels and parenchyma in a matrix of wide-band tracheids and the second phase consists of a fibrous matrix with vessels and parenchyma (wide-band tracheid wood followed by fibrous wood). Adult plants of Discocactus placentiformis and Melocactus ernestii have monomorphic WBT wood which consists of parenchyma distributed in the form of small clusters between the vessels and wide-band tracheids. In all species examined a band-like secondary wall is present in the form of annular rings or a helix. We observed annularhelical thickening in D. placentiformis and M. ernestii or a double-helix in D. placentiformis.

Different Ways to Build Succulent Leaves in Portulacineae (Caryophyllales)

Species of the suborder Portulacineae (Caryophyllales) often possess succulent leaves with wide morphological diversity, including flat and terete leaves. Terete leaves are described as not developing a marginal meristem during their growth, but in Portulacineae little is known about anatomical development in this particular leaf type. To better understand the mechanisms underlying the development of different leaf morphologies within this group, we examined leaf histogenesis in species of four families with succulent leaves—Basellaceae, Didiereaceae, Portulacaceae, and Talinaceae—through optical microscopy. We observed two morphological patterns (terete and flat leaves) and three developmental patterns regarding blastozone positioning. While species with flat leaves always show the expected pattern of marginal blastozone activity, terete leaves of Didiereaceae present marginal blastozones for only a very brief period. On the other hand, terete leaves of Portulacaceae show a persistent peripheral blastozone enveloping the entire leaf during its development. We also demonstrate anatomical evidence suggesting that the terete leaves of Portulacaceae are adaxialized, i.e., their entire surface is homologous to the adaxial side, while terete leaves of Didiereaceae seem to result from a less severe modification.

Growth Patterns and Different Arrangements of Vascular Tissues in Succulent Leaves

By their wide morphological diversity, succulent leaves have aroused the interest of many researchers. Nonetheless, comparative anatomical studies of unifacial, bifacial, and subunifacial leaves are scarce. To address this gap, our study examines the growth and differentiation of vascular tissues in succulent leaves of 12 families of angiosperms. Altogether, we identified six arrangements arising as variations of three basic vascularization patterns. In addition, cases of convergent evolution were identified in (1) terete leaves showing both endoscopic peripheral bundles and a central bundle in some Crassulaceae (Saxifragales, eudicots) and Aizoaceae (Caryophyllales, eudicots) and (2) terete leaves showing exclusively endoscopic peripheral bundles in some Asteraceae (eudicots) and Orchidaceae (monocots). Both endoscopic and exoscopic bundles originate from a peripheral region, and in all species with endoscopic peripheral bundles, the differentiation of the vascular bundles begins from abaxial domains, whereas in leaf blades with exoscopic bundles, differentiation begins from adaxial domains. These observations suggest that the molecular mechanism(s) involved in the abaxialization/adaxialization process of the leaf blade could be related to activity of the peripheral region. Therefore, further investigation is being carried out to elucidate peripheral meristematic activity responsible for the differentiation of vascular bundles and the fundamental system.

Anatomia floral de Aechmea distichantha Lem. e Canistropsis billbergioides (Schult. & Schult.f) Leme (Bromeliaceae)

Aechmea Ruiz & Pav. and Canistropsis (Mez) Leme belong to the subfamily Bromelioideae, which has the largest morphological diversity in Bromeliaceae. The flower buds of Aechmea distichantha Lem. and Canistropsis billbergioides (Schult. & Schult. f.) Leme were collected, fixed, and processed according to usual techniques in plant anatomy. The species share characteristics such as the presence of spherical crystals of silica in the epidermal cells of perianth; idioblasts with raphids; endothecium with annular thickening; and inferior ovary with axillary placentation. Nonvascular petal appendages were observed only in A. distichantha, arranged in pairs on each petal. Both species present a septal nectary, which nectar is rich in of proteins and carbohydrates. A placental obturator occurs in both species and histochemical tests revealed that the secretion produced by the obturator contains carbohydrates and proteins, probably related to the pollen tube guidance.