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a Croton urucurana: lateral view of the dendriticporrect trichomes on the rib; b Croton caldensis trichomes: simple (1), 2-radiate (2), 3-radiate (3), 4-radiate (4), and stellate-porrect, in frontal view, on the adaxial surface of the leaf blade; c Croton sp.2: frontal view of the dendritic-porrect trichomes on the abaxial surface of the leaf blade; d Croton echinocarpus: frontal view of the rosulate trichome on the adaxial surface of the leaf blade; e Croton macrobothrys: frontal view of the stellate-lepidote trichome on the adaxial surface of the leaf blade; f Croton vulnerarius: frontal view of the epidermis of the abaxial surface of the leaf blade bearing idioblasts with lipophilic content (arrows); g Croton caldensis: frontal view of the idioblast with lipophilic content associated with the stipite of a trichome. Scale bars a, d = 10 lm; b, c = 30 lm; e-g = 5 lm
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Euphorbiaceae s.s. is one of the largest angiosperm families, comprising nine major lineages. Molecular analysis indicated a polyphyletic condition
in the subfamily Crotonoideae s.l., with four lineages identified, including one termed inaperturate crotonoids, which encompasses the tribe Crotoneae. Anatomical data were obtained from 15 species of C...
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Context 1
... sect. Cyclostigma species Leaves of the Croton sect. Cyclostigma species analysed have a smooth cuticle, one-cell-layered epidermis, with straight or sinuous anticlinal walls. Non-glandular tric- homes with a complex and varied morphology are present on both sides of the blade (Fig. 1a-e). Idioblasts with lipophilic content are always present, especially on the abaxial surface (Fig. 1f, ...
Context 2
... sect. Cyclostigma species Leaves of the Croton sect. Cyclostigma species analysed have a smooth cuticle, one-cell-layered epidermis, with straight or sinuous anticlinal walls. Non-glandular tric- homes with a complex and varied morphology are present on both sides of the blade (Fig. 1a-e). Idioblasts with lipophilic content are always present, especially on the abaxial surface (Fig. 1f, ...
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Citations
... 4C, H), and two or three of annular collenchyma in C. glandulosus and C. piriquetifolius (Figs. 4M, R) The anatomical characteristics of the species studied repeat those found in other species of Croton and or other genera of Euphorbiaceae (Solereder 1908, Metcalfe & Chalk 1983, Freitas et al. 2001, Sá-Haiad et al. 2009, Soares 2013, Riina et al. 2015, Vitarelli et al. 2016, Sodré et al. 2019a, Sodré & Silva 2020, Pinto-Silva et al. 2023, with some of them (e.g., presence of tiny substomatal chambers, emergencies, fibers associated with the phloem, hypostomatic leaves, densely hairy leaves, presence of phenolic compounds) related to xeromorphic environments (Fahn & Cutler 1992, Sandquist & Ehleringer 1997, Bieras & Sajo 2009, Vitarelli et al. 2016. ...
Taxonomic studies on the genus Croton in the Midwest region of Brazil enabled the analysis of about 700 collections from all over the country. Three of these collections were identified as a new species, Croton piriquetifolius, which is described and illustrated here. We also give a preliminary evaluation of its conservation status, provide data on flowering and fruiting seasons, geographic distribution environmental preferences, as well as its systematic position. The new species is compared macro-and micromorphologically with C. adamantinus, C. glandulosus and C. eremophilus, with which it resembles or has been confused in herbaria. Morphological (e.g., presence, shape, and location of the acropetiolar nectaries, presence, and distribution of glands on stipules, presence, and size of pedicel on pistillate flower, integrity of styles, type, and location of trichomes) and anatomical (e.g., disposition of the stomata, contour of petiole and midrib, organization of vascular bundles, type of mesophyll, and types of trichomes) characters serve to differentiate the species studied.
... Given the diversity of features and the lack of easily visualized diagnostic characters in external morphology, plant anatomy can reveal structural convergence or divergences among taxa. The diagnostic capacity of plant anatomy has already been recognized in different groups, including families of Malpighiales such as Euphorbiaceae (Sá-Haiad et al., 2009;Cunha Neto et al., 2014, 2017Vitarelli et al., 2015;Feio et al., 2018;Cardiel et al., 2020), Malpighiaceae (Almeida et al., 2017;Araújo et al., 2010Araújo et al., , 2020, and Salicaceae (Thadeo et al., 2014;Fernandes et al., 2018). In Violaceae, anatomical studies in Viola L. (Yousefi et al., 2012;Mehrvarz et al., 2013;Shahrestani et al., 2014), Fusispermum Cuatrec. ...
... Common problems on the use of the trichome types proposed by Webster et al. (1996) include the distinction between stellate and lepidote types, and among the fasciculate, rosulate and multiradiate types (e.g. Lucena & Sales, 2006;Sá-Haiad et al., 2009;Senakun & Chantaranothai, 2010;Caruzo et al., 2011). Webster et al. (1996) also introduced a subdivision in the lepidote trichome type based on the degree (%) of webbing among rays. ...
... We defined a set of diagnostic parameters for the classification of Croton trichomes based on relevant literature on plant anatomy Chalk, 1957, 1979;Evert, 2006) and the examination of studies including trichome micromorphology of Croton spp. (Webster et al., 1996;Gordillo and Matías, 2005;Sá-Haiad et al., 2009;Secco, 2012;Barros and Soares, 2013;Caruzo and Cordeiro, 2013;Liu et al., 2013;Sodré and Silva, 2015;Vitarelli et al., 2015Vitarelli et al., , 2016Vitarelli et al., , 2021Feio et al., 2018a). Types and subtypes of non-glandular trichomes were proposed based on those parameters. ...
... The high diversity of trichomes present in Croton revealed by our comprehensive survey confirms and expands the findings of previous accounts (Froembling, 1896;Webster et al., 1996;Lucena and Sales, 2006;Sá-Haiad et al., 2009;Senakun and Chantaranothai, 2010;Liu et al., 2013;Feio et al., 2018a;Rosa et al., 2021). In addition, we clarify conflicting denominations and provide precise parameters to facilitate the interpretation of trichome typologies in the genus. ...
Trichomes are key functional traits that protect plants against abiotic stresses, herbivores and pathogens. In addition to their ecological roles, trichomes show high morphological variability in many lineages, providing useful characters for species characterization and taxon delimitation. Here, we focus on trichomes in Croton, a megadiverse genus (c. 1200 spp.) of Euphorbiaceae, in which these structures are ubiquitous and exhibit significant variation in form, location on the plant body, density and function. Owing to their functional and taxonomic relevance and the current need for further standardization of their terminology and classification, we revised previous trichome classifications used in the genus. We also provide new trichome data by expanding taxon sampling and using different methodological approaches in plant anatomy to improve understanding of the structural patterns of the trichome types present in the genus. On the basis of our results and literature review, we propose a new classification for trichomes in Croton based on well-defined parameters; this clarifies existing redundancies, is consistent with anatomical evidence and can be easily updated as new types are revealed in future surveys. This contribution will improve communication among taxonomists and promote more meaningful morphological comparability across systematics studies, including those focusing on morphological evolution and functional traits.
... Paracytic stomata are considered primitive, whilst anomocytic, diacytic, anisocytic, and parallelocytic are more advanced [46]. A study by de Sá-Haiad et al. [47] revealed that paracytic stomata are predominant in Croton species. ...
Croton gratissimus (Lavender croton) possesses three distinct secretory structures. These include lepidote and glandular trichomes and non-articulated unbranched laticifers. The lepidote trichomes form a dense indumentum on the abaxial surface of the leaves and canopy the glandular trichomes. Although assumed to be non-glandular, transmission electron microscopy (TEM) indicated high metabolic activity within the stalk and radial cells. Glandular trichomes are embedded in the epidermal layer and consist of a single cell which forms a prominent stalk and dilated head. Laticifers occur on the mid-vein of leaves and are predominantly associated with vascular tissue. In the stems, laticifers are associated with the phloem and pith. Both trichome types and laticifers stained positive for alkaloids, phenolic compounds, and lipids. Positive staining for these compounds in lepidote trichomes suggests their involvement in the production and accumulation of secondary metabolites. These metabolites could provide chemical defense for the plant and potentially be useful for traditional medicine.
... Various types of NGTs are frequently mentioned and recognized as relevant taxonomic characters for Croton constituting important elements in the recognition of the genus and the characterization of the taxa [69]. In the plants analyzed here, we found that the different morphologies of nonsecreting trichomes could be applied in their recognition, corroborating the proposals of other authors who also point out the use of these appendages in the delimitation of clades or phylogenetic approaches [70,71]. A previous study about the comparative anatomy of Croton [69] or Crotoneae [12] demonstrated that types of trichomes are useful for taxonomy mostly at a species level. ...
Euphorbiaceae and Phyllantaceae are two of the most taxonomically complex and diverse families among angiosperm. Therefore, this study aims to identify the common, variation, and diagnostic traits of foliar anatomy and micromorphology of selected Euphorbiaceae and Phyllanthaceae taxa collected from Hainan Island. A total of 42 individuals of 38 species belonging to these two families were examined under light microscopy (LM) and scanning electron microscopy (SEM). A multivariate detrended correspondence analysis (DCA), principal component analysis (PCA), and chord diagram analysis were performed to visualize the variations and relationships between the species. The nonglandular trichomes were further classified into long falcate and short conical with pa-pillae on their surface, and stellate and lepidote subentire, while the glandular trichomes were divided into capitate, subsessile capitate, sessile capitates, and peltate. The paracytic-type stomata were found in most of the species. The prominent continuous or discontinuous cuticular striations radiating from the guard cells in parallel, horizontal, or reticulate patterns were analyzed in most of the taxa. Variation was also found in epidermal cells and anticlinal wall patterns. Together, these traits are useful for identification, discrimination, and to define species boundaries at various levels. Our study will provide a basis for future studies to strengthen the systematic of Euphorbiaceae taxa.
... A noncancerous human lung fibroblast cell line (MRC-5) was used as a customary control cell line for comparison. The assay relies on the flexibleness of mitochondrial dehydrogenase enzyme present in viable cells to cleave the tetrazolium rings of the yellowness MTT dye and from dark purple formazan crystals which are largely impermeable to cell membranes, finally lands up in its accumulation within the cells which provides a quantitative determination of viable cells (de Sá-Haiad et al., 2009). Cancer cells were plated onto 96 well plates at a cell density of 2×105 cells/ml per well in 100 μl of Roswell Park Memorial Institute medium (RPMI 1640) and allowed to grow in an exceedingly CO2 incubator for twenty-four h (37 ˚C, 5 % CO 2 ). ...
... Microscopic examination of aerial parts powder of C. socatranus demonstrated the presence of xylem vessels, sclerenchymatous cells, slender-shaped fibers, vessel elements with scalariform thickenings, palisade cells, paracytic stomata, and stellate trichomes ( Figure 1). Paracytic stomata are one of the characteristics of the Croton genus (de Sá-Haiad et al., 2009). This type of stomata was abundant in C. socatranus powder. ...
Croton socatranusis a shrub or small tree endemic to Socotra Island and is widespread on the island. It has some interesting ethnomedicinal uses. The dry powder was subjected to extraction till exhaustion using methanol. The methanol extract was evaluated phytochemically, chromatographically, and for its antimicrobial and antioxidant activity. Toxicological and cytotoxic effectswere also investigated. Microscopic examination of C.socatranusaerial parts confirmed the presence of xylem vessels, sclerenchymatous cells, slender-shaped fibers, vessel elements with scalariform thickenings, palisade cells, paracytic stomata, and stellate trichomes. Phytochemical investigationshowed that the methanol extract possessed alkaloids, high levelsof phenolic compounds, tannins, flavonoids, triterpenes, diterpenes, phytosterol, and saponin.Notably, the methanol extract of C.socatranusdid not cause any mortality or behavioral changes in the rats even at the highest tested dose(5000mg/kg of methanol extract). It showed inhibition zone against Streptococcus pneumonia and Escherichiacoli and MIC values were between 156.25-655 μg/ml for gram-positive strains while 625-2500 μg/ml forgram-negative bacteria. Antifungal activity was recordedagainst ten tested fungal species. Furthermore, a dose-dependent antioxidant activitywas observed. C. socatranusextractdisplayed moderate cytotoxic activity against eight cancerous cell lines. Theextract was highly effective on MCF-7, HepG-2, and RD cell lines when compared with other celllines and the IC50 was less than 30 μg/ml which suggeststhe presence of selective cytotoxic compounds.Further investigations are required to understand the possible mechanism(s) of action of this extract on various cancer cells and the isolation of active phytochemicals.
... Taxonomic classification of this species-rich family includes ca. 37 tribes, 334 genera and 8000 species (Sá-Haiad & al. 2009). Like Apocynaceae and some Monocotyledons and Dicotyledons, Euphorbiaceae are characterized by a milky latex (Rudall 1987;Feio & al. 2016), which is innocuous in Crotonoideae but poisonous in Euphorbioideae (Ramos & al. 2019). ...
... The authors have further observed presence of a pair of long stipitate glands at the leaf base in C. hirtus and extrafloral nectaries at the leaf base of C. zambesicus, which were not spotted in C. lobatus. These observation have further confirmed the results of Hutchinson & Dalziel (1958) and Sá-Haiad & al. (2009), which mentioned presence and position of the stipitate glands and extrafloral nectaries on the margin, base and leaf blade of some Croton species. ...
... Four major stomata types were observed (anisocytic, anomocytic, paracytic and tetracytic), with paracytic stomata as the most dominant. Dominance of paracytic stomata among these species was in conjunction with the findings of Sá-Haiad & al. (2009) of some closely related species in the tribe Crotoneae. Therefore, this implies that the Croton species could be characterized by the dominance of paracytic stomata at epidermal layer. ...
Three Croton species, namely C. hirtus, C. lobatus. and C. zambesicus have been examined with a view of using the morphological, anatomical and histological characters in the systematics of the Croton species. Croton hirtus and C. lobatus are herbs with simple and lobed leaves, respectively, while C. zambesicus is a shrubby plant, with simple leaves. Variations in the trichome morphology and stomata orientation clearly distinguished the species. Localization, abundance and morphology of tannins and calcium oxalates have differed across the species. The three lines of study have proved useful in highlighting the basic diagnostic characters of the species.
... macrosepalus Sodré & M.J.Silva) of section Geiseleria, but they did not provide any insights into the ecological implications of that finding. Although not indicated with the term emergence, the presence of sclereids connected with leaf trichome-like structures has already been reported in representatives of other five different sections of Croton (Metcalfe and Chalk, 1950;Sá-Haiad, 1987;Starling, 1993;Louro et al., 2003;Appezzato-da-Glória and Carmello--Guerreiro, 2006;Sá-Haiad et al., 2009;Sodré et al. 2019b). ...
... Secretory idioblasts have been reported in the literature in different lineages of Croton (Sá-Haiad et al., 2009;Soares, 2013;Vitarelli et al., 2015;Feio et al., 2016Feio et al., , 2018. They are common in Croton sect. ...
Identifying traits contributing to the success of organisms growing in harsh environments has always been of great interest in evolutionary ecology. Here we focused on morphological features that could be advantageous for the survival of Croton mollis, a slender shrub occurring in the extreme white-sand habitats of the Amazonian igapos (black/clear-water rivers). We examined macro-morphological characters, as well as leaf micro-morphology using light microscopy and scanning electron microscopy. We also estimated areas of habitat suitability for C. mollis based on climatic, soil, and elevation variables using species distribution modeling (SDM) and available herbarium collections. Our results show that C. mollis presents morphological attributes similar to those of rheophytes, which may allow the species to overcome drastic seasonal changes in water level. We report the presence of five secretory structures (extrafloral nectaries, colleters, idioblasts, glandular trichomes, and laticifers) in the leaves. The size and position of the secretory idioblasts support the hypothesis of the existence of a transitional storage for secondary metabolites from idioblasts to secretory trichomes. Besides glandular trichomes, we also found stellate trichomes and trichome-like emergences in leaves. We hypothesize that these emergences could have an important role in the species’ survival due to their capacity of absorbing atmospheric moisture. Finally, the SDM supported the known habitat preferences of C. mollis and estimated a relatively wider geographic range than the currently known distribution based on herbarium records, suggesting that collecting efforts in the Amazonian region need to be increased in the future.
... Detailed studies on the nectar secretion and the concomitant structural and anatomical traits of the EFNs can help us to better understand the ecological and evolutionary processes between these glands and their associated insects. In Crotoneae (Euphorbiaceae), five types of secretory glands have been identified: laticifers, secretory trichomes, secretory idioblasts, colleters and extrafloral nectaries; the latter two possess similar morphological and anatomical characteristics (Vitarelli et al., 2015), making difficult to differentiate between these glands (Sá-Haiad et al., 2009;Riina et al., 2014). Despite the histochemical similarity between these two types of glands, they can be distinguished by examining their several factors such as their structure, function, and activity (Feio et al., 2016;Vitarelli et al., 2015). ...
In the Brazilian Cerrado, Coelocephalapion weevils induce galls on the leaves of Croton antisyphiliticus (Euphorbiaceae). Gall induction results in dozens of extrafloral nectaries (EFNs) being produced on the gall surface. This plant has a low number of EFNs at the margin of its healthy leaves. The interaction weevil-plant induces the overproduction of EFNs on the galls. The presence of glands on leaves and galls in the same plant is a rare condition in nature. We examined the EFNs on young and old leaves and on the surface of young and old galls, and described the trichomes and stomata on leaves and galls on C. antisyphiliticus. To measure the differences in structures we used digital photographs and standard scanning electron microscopy. Two-way ANOVA and post hoc Tuckey tests were used to compare their number and size of EFNs. We found more EFNs on galls than on leaves. No stomata or trichomes were found on the EFNs surface. The size and shape of the secretory EFNs heads on leaves and galls were different. Trichome density was higher on young and mature galls than on leaves. Trichome secretory heads on leaves are concave, while those on galls are convex. The nuclei of the EFNs epidermal cells of the leaf blade margin occupy smaller areas than those of the petiole and young galls. This study highlights the potential of gall traits that might increase plant defense against galling insects through the overproduction of these glands.
... In M. fistulifera, leaf-margin glands were defined as colleters by Paiva (2012), which reinforces the need for a correct identification of these glandular structures. Since leaves of Euphorbiaceae species may have colleters, nectaries and glandular trichomes (Sá-Haiad et al., 2009;Coutinho et al., 2010;Vitarelli et al., 2015;Feio et al., 2016) and as these glands may frequently share structural similarities, anatomical studies on foliar glands of Mabea species are greatly needed. These colleters occur on apex of marginal teeth, which are typical of Mabea and several other Euphorbiaceae (Webster, 1994(Webster, , 2014. ...
