Species Of Rhamnaceae Research Articles

Pollen Morphology of some Species of Rhamnaceae from West Bengal

Pollen morphology of 10 species and 2 varieties of Rhamnacequs taxa belonging to all the four tribes have been worked out. Pollen morphology of the family shows a tendency of evolution from basic morphoforms to the derived ones. Pollen grains of all the taxa investigated have been found to possess triangular or sub-triangular amb with three equatorial apertures situated at the angles (angulo aperturate). In Ziziphus xylopyrus the pollen grains are pororate and in rest nine species those are colporate with circular or lalongate endoapertures. Exinc ornamentation shows a gradual tendency from granulose to rugulo-reticulate or reticulate pattern. Palynological features have been evaluated in understanding the taxonomy of the family.

Exploring the chloroplast genomics, comparative analysis, evolution, and phylogenetic relationships of Phylica pubescens (Rhamnaceae) in the Cape Flora

Phylica (Rhamnaceae) plants are mainly distributed in southern Africa and nearby islands. They play a crucial role in studying diversification rates, climate change, and vegetation evolution in the Cape Flora. However, there have been no reports on the complete chloroplast genome of Phylica species, which is essential for investigating evolution and phylogenetic relationships. Herein, we sequenced the complete chloroplast genome of Phylica pubescens and conducted a comparative analysis with 12 Rhamnaceae species. The chloroplast genome size of Phylica pubescens was 161,187 bp, similar to that of other Rhamnaceae species. The absence of infA and psbL genes in certain Rhamnaceae species, compared to Phylica pubescens, has no apparent impact on these species. Positive selection has been observed in the rpl32, psbK, and psbH genes of Rhamnaceae species. Some highly variable regions (trnH-GUG–psbA, trnK-UUU–rps16, rps16–trnQ-UUG, trnS-GCU–trnG-UCC, trnR-UCU–atpA, atpH–atpI, trnC-GCA–petN, trnT-GGU–psbD, psbZ–trnG-GCC, trnT-UGU–trnL-UAA, ndhC–trnV-UAC, accD–psaI, petA–psbJ, ndhF–rpl32, and rpl32–trnL-UAG) were identified, which might be useful for phylogenetic analysis. Based on complete chloroplast genomes for the greatest number of species, the phylogenetic tree of the Rhamnaceae was reconstructed. Phylica pubescens displayed a close phylogenetic relationship with Spyridium species. This study provides valuable information regarding the complete chloroplast genome of Phylica pubescens and its comparative analysis with other Rhamnaceae species. These findings enhance our knowledge of the evolution within the Rhamnaceae family and shed light on the relationships between Phylica pubescens and closely related taxa.

Diversity of Leaf Glands and Their Putative Functions in Rhamnaceae Species

Leaf glands are found in many Rhamnaceae species, the buckthorn family, and are frequently used in taxonomic studies of the group, especially because they are easily visible to the naked eye. Despite the many records and extensive use in the taxonomy of the family, few studies deal with the classification of these glands and their roles for the plant. Thus, this study aimed to unravel the type, functioning, and putative functions of the leaf glands of three Brazilian forest species: Colubrina glandulosa Perkins, Gouania polygama (Jacq.) Urb., and Rhamnidium elaeocarpum Reissek. Leaves were collected and processed for surface, anatomical, histochemical, and ultrastructural analyses. In addition, the presence of visitor animals was registered in the field. The leaf glands of C. glandulosa and G. polygama are defined as extrafloral structured nectaries due to their anatomical structure, interaction with ants, and the presence of reduced sugars and of a set of organelles in the secretory cells. The unusual mechanism of nectar release and exposure in an apical pore stands out in G. polygama. The glands of R. elaeocarpum are ducts or cavities that secrete phenolic oil resin. Their presence is an atypical condition in the family, although they are often confused with mucilage reservoirs, much more common in Rhamnaceae. The extrafloral nectary, secretory cavity, and duct are associated with plant protection against phytophages, either by attracting patrol ants or by making the organs deterrent. Our data, combined with other previously obtained data, attest to the great diversity of gland types found in Rhamnaceae species.

Floral Development of Rhamnaceae and Origin of Its Unique Floral Features.

Rhamnaceae flowers have a peculiar morphology, including keeled sepals, one stamen whorl closely related to the petals, and a broad perigynous hypanthium that supports a voluminous nectary. In the present investigation, we detailed the flower development of five Rhamnaceae species to understand the origin of such specific floral characteristics. Floral buds and flowers were processed for surface and histological analyses. The sepals emerge in sequential order and the other organs in simultaneous order. The development of the perigynous hypanthium renders the floral apex broad and concave. The sepals undergo abaxial thickening early on, forming a keel and strongly influencing the floral merosity. Petals and stamens appear close to each other on the same radius in a very short plastochron. The carpels unite soon after their emergence, forming a syncarpous ovary and free style branches. Differences in intercalary carpel growth promote the formation of inferior (Gouania virgata) and semi-inferior ovaries (Colubrina glandulosa, Hovenia dulcis, and Sarcomphalus joazeiro). Rhamnidium elaeocarpum does not undergo such growth, and the resulting ovary is superior. The keeled sepals promote the isolation of the petal-stamen pair inside the flower bud. The possibility of a common primordium that the originates petal and stamen is refuted. Comparisons with other Rosales families provide insights into the floral origin and diversification of Rhamnaceae.

Effect of Soil Moisture and Calcium Deficiency on Incidence of New Branch Necrosis and Tip-Burn in Jujube (Zizyphus jujuba Mill.)

Jujube (Ziziphus jujuba Mill.) is the most important native species of Rhamnaceae, a large cosmopolitan family, and is one of the oldest cultivated fruit trees in the world. In recent years, consumption of fresh fruit and big fruit jujube has increased. The purpose of this study was to investigate the causes and its alleviation techniques of new branch necrosis and tip-burn, which occur in jujube during the new branch growth period. As a result of analyzing the inorganic component content of leaves, the calcium content was markedly 1.48% of abnormal samples compared to 1.90% of normal samples appeared low. Also, the calcium content in a necrotic new branch was also 0.14%, which was very low compared to 0.76% in the normal sample. In addition, the incidence rate of tip-burn at -30 kPa by soil at starting point of irrigation was 16.53%, higher than 7.22% at -10 kPa. The incidence of tip-burn by calcium foliar application was 0.6%, which was very low compared to control of 4.3%. Therefore, this study suggests that the symptoms of necrosis of new branch and tip-burn that occur during the new branch growth period of Jujube are related to the calcium content in the plant and lack of soil moisture and that calcium foliar application is effective in alleviating the occurrence of these abnormal symptoms.Alleviation effect of leaf tip-burn by Ca foliar application.

The structural diversity of floral nectaries does not mean ontogenic diversity in Rhamnaceae species

Rhamnaceae is a family with small, radially symmetrical flowers, which present nectaries of diverse morphology. Therefore, studies to explain the developmental pathways of this diversity are welcome in understanding the evolutionary biology of this gland. Thus, the objective of the present study was to compare the developing floral nectary of six species of Rhamnaceae belonging to different tribes to check its ontogeny and improve the descriptions of nectary types. Buds and flowers were collected and processed for surface, histological and ultrastructural analyses. The nectaries originate from the hypanthium soon after the gynoecium primordium and are generally positioned above the ovary. All nectaries are structured and vary in terms of surface, shape, and presence of indumentum. Two types of nectary were identified: annular and adpressed. The intensity of intercalary growth in the intrastaminal area has a fundamental role in the hypanthium development and consequently, in the differentiation of nectary types. This phenomenon is also responsible for the different positions of annular and adpressed nectaries in flowers of the Rhamnaceae species studied. We conclude that the origin of nectaries in Rhamnaceae seems to be homologous, despite of their great morphological diversity. Also, this study was successful in testing the value of previous nectary classification, placing the investigated species in the categories already defined for the family.

The historical and current research progress on jujube\u2013a superfruit for the future

Jujube (Ziziphus jujuba Mill.), or Chinese date, is the most important species of Rhamnaceae, a large cosmopolitan family, and is one of the oldest cultivated fruit trees in the world. It originates from the middle and lower reaches of the Yellow River, the ‘mother river’ of the Chinese people. It is distributed in at least 48 countries on all continents except Antarctica and is becoming increasingly important, especially in arid and semiarid marginal lands. Based on a systematic analysis of the unique characteristics of jujube, we suggest that it deserves to be recognized as a superfruit. We summarized historical research achievements from the past 3000 years and reviewed recent research advances since 1949 in seven fields, including genome sequencing and application, germplasm resources and systematic taxonomy, breeding and genetics, cultivation theory and techniques, pest control, postharvest physiology and techniques, and nutrition and processing. Based on the challenges facing the jujube industry, we discuss eight research aspects to be focused on in the future.

Localization, morphology, anatomy and ultrastructure of osmophores in species of Rhamnaceae.

Although the presence of scent was described for several species of Rhamnaceae, localization, morphology and structure of osmophores were unknown. We studied different species of the tribes Rhamneae (Rhamnoids clade), Pomaderreae, Colletieae, Paliureae (Ziziphoids clade) and the species Alphitonia excelsa (unknown tribe, Ziziphoids clade). We expect to have a better comprehension of these structures and provide information on which morphological and anatomical characters may support the phylogeny of the family. We localized the osmophores in the margins and top of the sepals using neutral red. Histochemical tests were made on transverse hand-cut sections of fresh sepals. Observations were made with stereoscopic and bright field microscopes, scanning and transmission electron microscopes. Papillae were observed in the zones with positive reaction to reagents. Different kinds of hairs are present in the sepal epidermis besides papillae. Epidermal cells present a striate cuticle with canals and cavities. Druses are abundant in most species. The ultrastructure of epidermal and subepidermal cells shows high metabolic activity: there are vesicles, mitochondria, endoplasmic reticulum, dictyosomes, plastids with lipids and starch. The vascularization is well developed and reaches the top of the sepal where the principal area of volatile components production is localized. The location and abundance of papillae are the most important traits that allow us recognize and characterize the osmophores in Rhamnaceae. There are no clear anatomical and morphological features exclusive of one clade or tribe. Therefore, in contrast to other sporophytic structures of this family, osmophores do not seem to have any systematic value.

Genome-wide identification of CNGC genes in Chinese jujube (Ziziphus jujuba Mill.) and ZjCNGC2 mediated signalling cascades in response to cold stress

BackgroundsCyclic nucleotide gated channels (CNGCs) play multifaceted roles in plant physiological processes, especially with respect to signalling processes, plant development, and responses to environmental stresses. However, little information is known about the CNGC family in the large cosmopolitan family Rhamnaceae, which has strong tolerance to biotic and abiotic stresses.ResultsIn the current study, a total of 15 ZjCNGCs which located on 7 chromosomes were firstly identified in Chinese jujube (Ziziphus jujuba Mill.), the most important species of Rhamnaceae in terms of economic and ecological values. Phylogenetic analysis showed that these ZjCNGCs could be classified into four groups, ZjCNGC12 belonged to group IVA, and ZjCNGC13, 14, 15 belonged to group IVB. In addition, the paralogous and orthologous homology duplication of ZjCNGC15 occurred during the evolutionary process. The characteristics of ZjCNGCs regarding to exon-intron numbers and post-translational modifications showed diversified structures and functions. Motif composition and protein sequence analysis revealed that the phosphate-binding cassette and hinge regions were conserved among ZjCNGCs. Prediction of the cis-acting regulatory elements and expression profiles by real-time quantitative PCR analysis showed that some of the ZjCNGCs responded to environmental changes, especially ZjCNGC2, which was significantly downregulated in response to cold stress, and ZjCNGC4 was highly induced in response to cold, salt and alkaline stresses. ZjCNGC13 and 14 were highly induced in the phytoplasma-resistant cultivar and downregulated in the susceptible cultivar. Furthermore, ZjCNGC2 could be regulated by cAMP treatment, microtubule changes and interact with ZjMAPKK4, which suggested that cAMP and microtubule might play important roles in ZjCNGC2 mediated ZjMAPKK4 signalling transduction involved in cold stress.ConclusionsThe identification and classification analysis of ZjCNGCs were firstly reported, and some key individual ZjCNGCs might play essential roles in the response to biotic and abiotic stresses, especially ZjCNGC2 mediated ZjMAPKK4 signalling transduction involved in cold stress. This systematic analysis could provide important information for further functional characterization of ZjCNGCs with the aim of breeding stress-resistant cultivars.

Pollen and microsporangium development in Ziziphus jujuba, Z. mucronata, Paliurus spina-christi and Gouania ulmifolia (Rhamnaceae).

The aim of this paper is to investigate the ultrastructural events that occur during pollen grains development, with emphasis in pollen grain wall and tapetum ontogeny in Ziziphus jujuba, Z. mucronata, Paliurus spina-christi (Paliureae) and Gouania ulmifolia (Gouanieae). Anthers at different developmental stages were processed according to classic techniques for transmission electron microscopy. Differences in the number of endothecium layers and in the number of tapetal cell nuclei were found. Tapetal cells present an anastomosing tubular network and large vesicles with fibrillar content in the cytoplasm. Pollen grain development and ontogeny of pollen grain wall are similar in the four species. The number of endothecium layers, the number of nuclei of the tapetal cells and tapetal cells ultrastructure of the four species support the phylogenetic relationships previously published for the Rhamnaceae family. Tapetal vesicles with fibrillar or polysaccharide content seem to be an exclusive characteristic of the tribes Paliureae and Gouanieae. Some ultrastructural characters of the pollen grain wall development are common to other species of Rhamnaceae, such as the primexine matrix present at the microspore mother cell stage, the aperture entirely built up during the tetrad stage, the thick and fibrillar intine, and the granular infractectum.

Karyotype, rDNA localization and meiotic behavior of Hovenia dulcis Thunb. (Rhamnaceae)

AbstractThe species Hovenia dulcis, originally from Asia, was introduced in several Brazilian regions due to its ornamental features, edible fruits and medicinal properties. Despite its importance, few cytogenetic studies have been carried out with this species. Literature data present chromosome counts for H. acerba and H. dulcis (2n = 24) and propose the basic chromosome number x = 12 for Hovenia, with no karyomorphological information. In this way classical and cytomolecular studies were carried out in H. dulcis. This study presents the first meiotic analysis, the karyotype and the first cytomolecular analysis for a Rhamnaceae species. The meiotic analysis showed a regular process and a high rate of viable pollen grains (91.3%). The chromosome numbers were n = 12 and 2n = 24, reinforcing the basic number proposed for the genus. The chromosomes are small (1.5–2.8 μm) and metacentric and the karyotype is symmetric. Two CMA+ bands at secondary constriction of the longest chromosome were identified. One pa...

Pollen development and anther morphology in 14 species of Rhamnaceae

Microsporogenesis, microgametogenesis, and anther structure of 14 species belonging to Rhamneae (Rhamnoids clade), Paliureae, Pomaderreae, Colletieae, and Gouanieae (Ziziphoids clade) of the Rhamnaceae family were analyzed using bright-field, scanning, and transmission electron microscopy. The aim is to look for morphological characters that have systematic value on a suprageneric level within the family. The character states of the number of nuclei in tapetal cells, the endothecial thickening pattern, and the number of endothecial layers are consistent on tribal level. Tribes were previously delineated based on molecular phylogenetic evidence. On the other hand, pollen morphology does not seem to have systematic value at tribal level in Rhamnaceae. The presence or absence of orbicules and their morphology vary within tribes. It seems that for Rhamnaceae, the anatomy of the reproductive sporophytic structures could have more systematic value than the gametophytic structures. However, more studies are needed to confirm this.

Ceanothane and oleanane-type triterpenes from Talguenea quinquenervia have insecticidal activity against Cydia pomonella, Tenebrio molitor and Drosophila melanogaster

Many secondary metabolites from plants are constitutive and/or induced chemical defenses that play a role in protection against phytopathogenic attack. Talguenea quinquenervia (Rhamnaceae) is a notorious weed that possesses several medicinal applications such as American taxa of Rhamnaceae species are toxic to insects, fungi and several bacteria strains. These effects have been associated with the presence of alkaloids, phenolics and terpenes. A methanolic extract from the roots afforded 9 triterpenes belonging to lupane, oleanane, ursane, sterol and ceanothane groups. Our results indicate that these compounds are involved in interference of sclerotization and moulting. They showed selective effects on pre-emergence metabolism of selected insects including lepidoptera and diptera, but not to coleoptera. The results were fully comparable to known natural insect growth inhibitors such as azadirachtin, gedunin and Cedrela extract and have a possible role as natural insecticidal agents. To the best our knowledge, this is the first report of the isolation of ceanothane-type triterpenes from this plant species. The level of activity achieved by the assayed compounds indicated inhibition in a concentration dependent manner with LD50 values between 41 and 17μg/mL.

Do Mediterranean-type ecosystems have a common history?--insights from the Buckthorn family (Rhamnaceae).

Mediterranean-type ecosystems (MTEs) are remarkable in their species richness and endemism, but the processes that have led to this diversity remain enigmatic. Here, we hypothesize that continent-dependent speciation and extinction rates have led to disparity in diversity between the five MTEs of the world: the Cape, California, Mediterranean Basin, Chile, and Western Australia. To test this hypothesis, we built a phylogenetic tree for 280 Rhamnaceae species, estimated divergence times using eight fossil calibrations, and used Bayesian methods and simulations to test for differences in diversification rates. Rhamnaceae lineages in MTEs generally show higher diversification rates than elsewhere, but speciation and extinction dynamics show a pattern of continent-dependence. We detected high speciation and extinction rates in California and significantly lower extinction rates in the Cape and Western Australia. The independent colonization of four of five MTEs may have occurred conterminously in the Oligocene/Early Miocene, but colonization of the Mediterranean Basin happened later, in the Late Miocene. This suggests that the in situ radiations of these clades were initiated before the onset of winter rainfall in these regions. These results indicate independent evolutionary histories of Rhamnaceae in MTEs, possibly related to the intensity of climate oscillations and the geological history of the regions.

Introduction to a Virtual Special Issue on plant ecological strategy axes in leaf and wood traits

Introduction to a <i>Virtual Special Issue</i> on plant ecological strategy axes in leaf and wood traits

Relationships among xylem transport, biomechanics and storage in stems and roots of nine Rhamnaceae species of the California chaparral

Here, hypotheses about stem and root xylem structure and function were assessed by analyzing xylem in nine chaparral Rhamnaceae species. Traits characterizing xylem transport efficiency and safety, mechanical strength and storage were analyzed using linear regression, principal components analysis and phylogenetic independent contrasts (PICs). Stems showed a strong, positive correlation between xylem mechanical strength (xylem density and modulus of rupture) and xylem transport safety (resistance to cavitation and estimated vessel implosion resistance), and this was supported by PICs. Like stems, greater root cavitation resistance was correlated with greater vessel implosion resistance; however, unlike stems, root cavitation resistance was not correlated with xylem density and modulus of rupture. Also different from stems, roots displayed a trade-off between xylem transport safety from cavitation and xylem transport efficiency. Both stems and roots showed a trade-off between xylem transport safety and xylem storage of water and nutrients, respectively. Stems and roots differ in xylem structural and functional relationships, associated with differences in their local environment (air vs soil) and their primary functions.

Floral development and anatomy of Dirachma socotrana, (Dirachmaceae): a controversial member of the Rosales

The floral development and anatomy of Dirachma has been investigated with SEM and LM to discuss the relationship of Dirachmaceae with putative sister taxa (e.g. Rhamnaceae, Malvaceae, Barbeyaceae, Elaeagnaceae) on the basis of morphological synapomorphies. Flowers are initiated in axillary position on terminal branches. An epicalyx consisting of six to eight bracteoles surrounds the valvate calyx. Petal initiation is strongly retarded and primordia arise independently opposite the stamen primordia. The carpels arise independently and become weakly fused at the base; a single ovule develops in an axile position. A hypanthium develops by interprimordial growth between petals and stamens. Nectaries arise in a pouch and are covered with trichomes positioned on a protuberance at the base of the petal. It is suggested that the solitary flowers are derived from compound cymose inflorescences. Comparison between Dirachma and species of Rhamnaceae demonstrates striking similarities in floral structure and anatomy. However, several characters are unique to Dirachma and support a family Dirachmaceae separate from Rhamnaceae.

Population genetic structure of two rare tree species (Colubrina oppositifolia and Alphitonia ponderosa, Rhamnaceae) from Hawaiian dry and mesic forests using random amplified polymorphic DNA markers.

Hawaiian dry and mesic forests contain an increasingly rare assemblage of species due to habitat destruction, invasive alien weeds and exotic pests. Two rare Rhamnaceae species in these ecosystems, Colubrina oppositifolia and Alphitonia ponderosa, were examined using random amplified polymorphic DNA (RAPD) markers to determine the genetic structure of the populations and the amount of variation relative to other native Hawaiian species. Relative variation is lower than with other Hawaiian species, although this is probably not a consequence of genetic bottleneck. Larger populations of both species contain the highest levels of genetic diversity and smaller populations generally the least as determined by number of polymorphic loci, estimated heterozygosity, and Shannon's index of genetic diversity. Populations on separate islands were readily discernible for both species as were two populations of C. oppositifolia on Hawai'i island (North and South Kona populations). Substructure among Kaua'i subpopulations of A. ponderosa that were ecologically separated was also evident. Although population diversity is thought to have remained at predisturbance levels, population size continues to decline as recruitment is either absent or does not keep pace with senescence of mature plants. Recovery efforts must focus on control of alien species if these and other endemic dry and mesic forest species are to persist.

Rhamnaceae with multiple lateral buds: an architectural analysis

TOURN, G. M., TORTOSA, R. D. & MEDAN, D., 1992. Rhamnaceae with multiple lateral buds: an architectural analysis. A study was made of the morphology and architecture of three species of Rhamnaceae (Ziziphusjujuba, Zjziphus mistol and Paliurus spina-Christi) with multiple lateral buds. The developmental potential of individual meristems of bud complexes was studied and different kinds of shoots were recognized: vegetative long shoots (dominant and subordinate), flowering branches, short shoots and thorn-tipped branchlets. According to the different orders of branching and the patterns of growth, the architectural model for every species was determined. The architecture of the three species does not conform to that of known tree models. Ziziphus mistol and Paliurus spina-Christi have an architecture intermediate between Attim's and Roux's models; Ziziphusjujuba results in a combination of Koriba's and Roux's models.

INVESTIGATIONS OF ANGIOSPERMS FROM THE EOCENE OF NORTH AMERICA: RHAMNUS MARGINATUS (RHAMNACEAE) REEXAMINED

Leaf compressions, previously assigned to Rhamnus marginatus Lesquereux, were collected from the Middle Eocene Claiborne Formation of western Kentucky and Tennessee. The leaf architecture and cuticular features of over 40 compressions were carefully examined and compared to those of many extant species of Rhamnaceae and related families as well as fossil specimens previously assigned to this taxon. This leaf type appears to belong to the Rhamnaceae, however, it conforms more closely to species of several genera in the tribe Zizypheae than to those of Rhamnus or other genera in the tribe Rhamneae. Confident assignment to any specific genus within this complex of genera cannot be made on the basis of leaf characteristics alone and would require discovery and analysis of additional vegetative and reproductive organs. Because this fossil leaf form cannot be confidently assigned to any modern genus and earlier classifications appear to be improper, this leaf type has been reassigned to the taxon Berhamniphyllum claibornense gen. et sp. nov. The transfer of this leaf form at the tribe level reaffirms the need for close examination of taxonomic determinations made by early workers.