Base Of Leaflets Research Articles

Intentional Laceration of the Anterior Mitral Valve Leaflet to Prevent Left Ventricular Outflow Tract Obstruction During Transcatheter MitralValve Replacement: Pre-Clinical Findings.

The authors propose a novel transcatheter transection of the anterior mitral leaflet to prevent iatrogenic left ventricular outflow tract (LVOT) obstruction during transcatheter mitral valve replacement (TMVR). LVOT obstruction is a life-threatening complication of TMVR caused by septal displacement of the anterior mitral leaflet. Invivo procedures in swine were guided by biplane x-ray fluoroscopy and intracardiac echocardiography. Retrograde transaortic 6-F guiding catheters straddled the anterior mitral leaflet. A stiff 0.014-inch guidewire with polymer jacket insulation was electrified and advanced from the LVOT, through the A2 leaflet base, into the left atrium. The wire was snared and externalized, forming a loop that was energized and withdrawn to lacerate the anterior mitralleaflet. The anterior mitral leaflet was successfully lacerated in 7 live and 1 post-mortem swine under heparinization. Lacerations extended to 89 ± 19% of leaflet length and were located within 0.5 ± 0.4 mm of leaflet centerline. The chordae were preserved and retracted the leaflet halves away from the LVOT. LVOT narrowing after benchtop TMVR was significantly reduced with intentional laceration of the anterior mitral leaflet to prevent LVOT obstruction than without (65 ± 10% vs. 31 ± 18% of pre-implantation diameter, p< 0.01). The technique caused mean blood pressure to fall (from54 ± 6 mm Hg to 30 ± 4mmHg, p< 0.01), but blood pressure remained steady until planned euthanasia. No collateral tissue injury was identified on necropsy. Using simple catheter techniques, the anterior mitral valve leaflet was transected. Cautiously applied inpatients, this strategy can prevent anterior mitral leaflet displacement and LVOT obstruction caused by TMVR.

New species Dalembia jiayinensis (Magnoliopsida) from the Upper Cretaceous Yong'ancun Formation, Heilongjiang, northern China

Leaves of Dalembia jiayinensis sp. nov. are reported from the Santonian Yong'ancun Formation exposed along the Heilongjiang (Amur) River in Jiayin County, Northeast China. The leaves are compound, odd-pinnate, consisting of five leaflets. Leaflets are pinnately-lobed, trilobate or unlobed, elliptic, oblong, elliptic-rhomboid or ovate in outline, with blunt or rounded apex and the leaflet base is variable being cuneate, slightly decurrent, truncate or slightly cordate and sometimes asymmetric. Margin is entire or lobed. Lobes are short, simple, decreasing upwards, with wide and rounded sinuses. Apices of the lobes are usually rounded, sometimes notched. Venation is pinnate or palmately-pinnate, craspedodromous or semi-craspedodromous. The new species D. jiayinensis extends both the geographical and stratigraphic ranges of the genus Dalembia. This is the first occurrence of Dalembia in China and the most southern and youngest (Santonian) occurrence of this genus.

The First Comprehensive Phylogeny of Coptis (Ranunculaceae) and Its Implications for Character Evolution and Classification.

Coptis (Ranunculaceae) contains 15 species and is one of the pharmaceutically most important plant genera in eastern Asia. Understanding of the evolution of morphological characters and phylogenetic relationships within the genus is very limited. Here, we present the first comprehensive phylogenetic analysis of the genus based on two plastid and one nuclear markers. The phylogeny was reconstructed using Bayesian inference, as well as maximum parsimony and maximum likelihood methods. The Swofford-Olsen-Waddell-Hillis and Bayesian tests were used to assess the strength of the conflicts between traditional taxonomic units and those suggested by the phylogenetic inferences. Evolution of morphological characters was inferred using Bayesian method to identify synapomorphies for the infrageneric lineages. Our data recognize two strongly supported clades within Coptis. The first clade contains subgenus Coptis and section Japonocoptis of subgenus Metacoptis, supported by morphological characters, such as traits of the central leaflet base, petal color, and petal shape. The second clade consists of section Japonocoptis of subgenus Metacoptis. Coptis morii is not united with C. quinquefolia, in contrast with the view that C. morii is a synonym of C. quinquefolia. Two varieties of C. chinensis do not cluster together. Coptis groenlandica and C. lutescens are reduced to C. trifolia and C. japonica, respectively. Central leaflet base, sepal shape, and petal blade carry a strong phylogenetic signal in Coptis, while leaf type, sepal and petal color, and petal shape exhibit relatively higher levels of evolutionary flexibility.

Fibrotic Aortic Valve Stenosis in Hypercholesterolemic/Hypertensive Mice.

Hypercholesterolemia and hypertension are associated with aortic valve stenosis (AVS) in humans. We have examined aortic valve function, structure, and gene expression in hypercholesterolemic/hypertensive mice. Control, hypertensive, hypercholesterolemic (Apoe(-/-)), and hypercholesterolemic/hypertensive mice were studied. Severe aortic stenosis (echocardiography) occurred only in hypercholesterolemic/hypertensive mice. There was minimal calcification of the aortic valve. Several structural changes were identified at the base of the valve. The intercusp raphe (or seam between leaflets) was longer in hypercholesterolemic/hypertensive mice than in other mice, and collagen fibers at the base of the leaflets were reoriented to form a mesh. In hypercholesterolemic/hypertensive mice, the cusps were asymmetrical, which may contribute to changes that produce AVS. RNA sequencing was used to identify molecular targets during the developmental phase of stenosis. Genes related to the structure of the valve were identified, which differentially expressed before fibrotic AVS developed. Both RNA and protein of a profibrotic molecule, plasminogen activator inhibitor 1, were increased greatly in hypercholesterolemic/hypertensive mice. Hypercholesterolemic/hypertensive mice are the first model of fibrotic AVS. Hypercholesterolemic/hypertensive mice develop severe AVS in the absence of significant calcification, a feature that resembles AVS in children and some adults. Structural changes at the base of the valve leaflets include lengthening of the raphe, remodeling of collagen, and asymmetry of the leaflets. Genes were identified that may contribute to the development of fibrotic AVS.

Abstract 18485: Runx2 Haploinsufficiency Attenuates Angiotensin II-mediated Fibrosis and Proliferation in Mouse Mitral Valves

We recently reported activation of TGF-β superfamily pathways and activation of Wnt/β-catenin signaling in the pathogenesis of myxomatous mitral valve disease (MMVD), which may converge upon increased Runx2 expression. We also demonstrated that chronic in vivo administration of angiotensin II (AngII) recaptures various molecular aberrations characteristic of human disease -including increased TGF-β signaling and activation of Runx2- in mouse mitral valves. Here, we sought to determine whether Runx2 haploinsufficiency can attenuate molecular and/or phenotypic effects of AngII infusion in mouse mitral valves. We implanted littermate matched Runx2+/+ and Runx2+/- mice with osmotic minipumps delivering AngII (1000ng/kg/min) or saline for 2 weeks. We measured changes in mRNA (qRT-PCR) and protein (immunohistochemistry) levels in mitral valves, and assessed mitral valve function by echocardiography. In Runx2+/+ mice, AngII elicited increased mRNA levels of TGF-β3 and the TGF-β target COL3A1, and increased staining for canonical (p-SMAD2/3) and non-canonical (p-AKT) TGF-β signaling proteins. Runx2 haploinsufficiency attenuated AngII-induced changes in COL3A1 expression and p-AKT staining, without impacting AngII-mediated alterations in TGF-β3 and p-SMAD2/3. Evaluating collagen thickness by picrosirius red staining and visualization under circularly polarized light, AngII infusion in Runx2+/+ mice was associated with increased collagen density at the base of posterior mitral valve leaflets, a change that was abrogated by Runx2 haploinsufficiency. Similarly, Runx2-haploinsufficiency was again protective when examining mRNA and protein levels of the proliferation marker KI67 in response to AngII. Echocardiography identified a trend towards increased mitral valve regurgitation following AngII infusion that was unaltered by Runx2 haploinsuffiency. Collectively, these data suggest that increases in Runx2 expression in the mitral valve may serve to orchestrate tissue fibrosis and cellular proliferation that are hallmarks of MMVD, and that future pharmacological strategies aimed at reducing activity of Runx2 in the mitral valve may yield viable non-surgical alternatives for the management of this condition.

Three-dimensional macro-scale assessment of regional and temporal wall shear stress characteristics on aortic valve leaflets

The aortic valve (AV) achieves unidirectional blood flow between the left ventricle and the aorta. Although hemodynamic stresses have been shown to regulate valvular biology, the native wall shear stress (WSS) experienced by AV leaflets remains largely unknown. The objective of this study was to quantify computationally the macro-scale leaflet WSS environment using fluid–structure interaction modeling. An arbitrary Lagrangian–Eulerian approach was implemented to predict valvular flow and leaflet dynamics in a three-dimensional AV geometry subjected to physiologic transvalvular pressure. Local WSS characteristics were quantified in terms of temporal shear magnitude (TSM), oscillatory shear index (OSI) and temporal shear gradient (TSG). The dominant radial WSS predicted on the leaflets exhibited high amplitude and unidirectionality on the ventricularis (TSM>7.50 dyn/cm2, OSI < 0.17, TSG>325.54 dyn/cm2 s) but low amplitude and bidirectionality on the fibrosa (TSM < 2.73 dyn/cm2, OSI>0.38, TSG < 191.17 dyn/cm2 s). The radial WSS component computed in the leaflet base, belly and tip demonstrated strong regional variability (ventricularis TSM: 7.50–22.32 dyn/cm2, fibrosa TSM: 1.26–2.73 dyn/cm2). While the circumferential WSS exhibited similar spatially dependent magnitude (ventricularis TSM: 1.41–3.40 dyn/cm2, fibrosa TSM: 0.42–0.76 dyn/cm2) and side-specific amplitude (ventricularis TSG: 101.73–184.43 dyn/cm2 s, fibrosa TSG: 41.92–54.10 dyn/cm2 s), its temporal variations were consistently bidirectional (OSI>0.25). This study provides new insights into the role played by leaflet–blood flow interactions in valvular function and critical hemodynamic stress data for the assessment of the hemodynamic theory of AV disease.

Lateral suppressor and Goblet act in hierarchical order to regulate ectopic meristem formation at the base of tomato leaflets.

In seed plants, new axes of growth are established by the formation of meristems, groups of pluripotent cells that maintain themselves and initiate the formation of lateral organs. After embryonic development, secondary shoot meristems form in the boundary zones between the shoot apical meristem and leaf primordia, the leaf axils. In addition, many plant species develop ectopic meristems at different positions of the plant body. In the compound tomato leaf, ectopic meristems can initiate at the base of leaflets, which are delimited by two distinct boundary zones, referred to as the proximal (PLB) and distal (DLB) leaflet boundaries. We demonstrate that the two leaflet boundaries differ from each other and that ectopic meristem formation is strictly limited to the DLB. Our data suggest that the DLB harbours a group of pluripotent cells that seems to be the launching pad for meristem formation. Initiation of these meristems is dependent on the activities of the transcriptional regulators Goblet (Gob) and Lateral suppressor (Ls), specifically expressed in the DLB. Gob and Ls act in hierarchical order, because Ls transcript accumulation is dependent on Gob activity, but not vice versa. Ectopic meristem formation at the DLB is also observed in other seed plants, like Cardamine pratensis, indicating that it is part of a widespread developmental program. Ectopic meristem formation leads to an increase in the number of buds, enhances the capacity for survival and opens the route to vegetative propagation.

Coronary Flow Impacts Aortic Leaflet Mechanics and Aortic Sinus Hemodynamics.

Mechanical stresses on aortic valve leaflets are well-known mediators for initiating processes leading to calcific aortic valve disease. Given that non-coronary leaflets calcify first, it may be hypothesized that coronary flow originating from the ostia significantly influences aortic leaflet mechanics and sinus hemodynamics. High resolution time-resolved particle image velocimetry (PIV) measurements were conducted to map the spatiotemporal characteristics of aortic sinus blood flow and leaflet motion with and without physiological coronary flow in a well-controlled in vitro setup. The in vitro setup consists of a porcine aortic valve mounted in a physiological aorta sinus chamber with dynamically controlled coronary resistance to emulate physiological coronary flow. Results were analyzed using qualitative streak plots illustrating the spatiotemporal complexity of blood flow patterns, and quantitative velocity vector and shear stress contour plots to show differences in the mechanical environments between the coronary and non-coronary sinuses. It is shown that the presence of coronary flow pulls the classical sinus vorticity deeper into the sinus and increases flow velocity near the leaflet base. This creates a beneficial increase in shear stress and washout near the leaflet that is not seen in the non-coronary sinus. Further, leaflet opens approximately 10% farther into the sinus with coronary flow case indicating superior valve opening area. The presence of coronary flow significantly improves leaflet mechanics and sinus hemodynamics in a manner that would reduce low wall shear stress conditions while improving washout at the base of the leaflet.

Heterogeneity of Mitral Leaflet Matrix Composition and Turnover Correlates with Regional Leaflet Strain.

To determine how extracellular matrix and contractile valvular cells contribute to the heterogeneous motion and strain across the mitral valve (MV) during the cardiac cycle, regional MV material properties, matrix composition, matrix turnover, and cell phenotype were related to regional leaflet strain. Radiopaque markers were implanted into 14 sheep to delineate the septal (SEPT), lateral (LAT), and anterior and posterior commissural leaflets (ANT-C, POST-C). Videofluoroscopy imaging was used to calculate radial and circumferential strains. Mechanical properties were assessed using uniaxial tensile testing and micropipette aspiration. Matrix composition and cell phenotypes were immunohistochemically evaluated within each leaflet region [basal leaflet (BL), mid-leaflet (ML), and free edge]. SEPT-BL segments were stiffer and stronger than other valve tissues, while LAT segments demonstrated more extensibility and strain. Collagens I and III in SEPT were greater than in LAT, although LAT showed greater collagen turnover [matrix metalloprotease (MMP)-13, lysyl oxidase] and cell activation [smooth muscle alpha-actin (SMaA), and non-muscle myosin (NMM)]. MMP13, NMM, and SMaA were strongly correlated with each other, as well as with radial and circumferential strains in both SEPT and LAT. SMaA and MMP13 in POST-C ML was greater than ANT-C, corresponding to greater radial strains in POST-C. This work directly relates leaflet strain, material properties, and matrix turnover, and suggests a role for myofibroblasts in the heterogeneity of leaflet composition and strain. New approaches to MV repair techniques and ring design should preserve this normal coupling between leaflet composition and motion.

Intraoperative three-dimensional transesophageal echocardiography for evaluating an unusual structure in the left ventricular outflow tract: a case report.

Intraoperative three-dimensional (3D) transesophageal echocardiography (TEE) facilitates an understanding of the complex cardiac pathology that is not fully delineated in a two-dimensional (2D) echocardiographic evaluation, and it suggests earlier and more precise surgical planning and intraoperative decision making. In the present case, the intraoperative 2D-TEE midesophageal long-axis view indicated a significant narrowing of the left ventricular outflow tract (LVOT) area by a band-like structure that vertically traversed the middle of the LVOT and connected to the anterior mitral leaflet base and the interventricular septum. However, additional 3D-TEE images of the LVOT and their cropped and rendered 2D images showed that web-like tissue, which presumably had grown around the patch closure from a previous atrioventricular septal defect, was obstructing the LVOT partially.

Diastolic function assessed by cardiac MRI using longitudinal left ventricular fractional shortening

IntroductionDiastolic dysfunction contributes significantly to diastolic heart failure. We examined the use of cardiac magnetic resonance imaging (CMR) using midwall longitudinal fractional shortening (MLFS) in the evaluation of transthoracic echocardiogram (TTE)-evidenced diastolic dysfunction. MethodsA total of 80 patients with CMR within 6months of TTE and normal ejection fraction were identified. MLFS was calculated as percentage change in distance from the anterior mitral leaflet base to the apical endocardium in systole and diastole. ResultsMLFS of grade II/III [0.14 (0.12–0.16)] was significantly lower than that of grade 0/I [0.20 (0.19–0.21)], P=.001. MLFS detected age-related changes with grade 0 [0.22 (0.21–0.23)] significantly lower than grade I [0.18 (0.16–0.20)], P=.001. ConclusionTTE-evidenced diastolic dysfunction can be reliably identified by CMR using MLFS.

Cycas fushunensis sp. nov. (Cycadaceae) from the Eocene of northeast China

A new cycad species, Cycas fushunensis sp. nov., is described from the Lutetian Jijuntun Formation at Fushun Coalmine, Liaoning Province, northeast China, based on a well-preserved partial frond containing about 15 leaflets. The fossil is characterized by a single strong vein per leaflet, decurrent leaflet base and haplocheilic stomata, suggesting that the fossil is attributed to the genus Cycas of Cycadaceae. Epidermal anatomical comparisons between the fossil and 17 selected modern Cycas species further indicate that C. fushunensis sp. nov. closely resembles Cycas panzhihuaensis Zhou et Yang, an endemic cycad to southwest China, due to characters shared, such as the straight anticlinal walls of both adaxial and abaxial epidermal cells and granular to striate cuticular characters on the internal surface of guard cell periclinal walls. The occurrence of close-to-modern Cycas from the early Cenozoic largely casts doubt on a hypothesis of the late Miocene differentiation of modern cycads, suggested by a recent molecular phylogenetic study.

Development of Rapid Propagation Methods and a Miniature Plant for Export-oriented Foliage, Zamioculcas zamiifolia

Zamioculcas zamiifolia is an ornamental potted foliage plant and a relatively new introduction to the world of interior plants. However, its low growth rate in conventional solid media is a constraint in mass propagation. The present study aimed at developing improved culture techniques that would enhance the growth and rapid propagation of the plant. Three experiments were conducted to find out the best type of vegetative cuttings, the effect of light on plant growth in a liquid (distilled water) medium, and to develop a new solid medium with nutrients to increase the growth rate. Basal leaflets without rachis were found to be the best cutting type for rapid propagation. Solid substrate was better than liquid medium for rapid rooting. Compost + sand + 0.75 g l-1 fertilizer nutrients can be recommended for rapid propagation of the plant. Plant growth was high in the light-exposed liquid medium compared to dark treatment. Interestingly, the liquid medium led to development of a miniature plant which could be introduced as a novel table-top ornament. The results of the present study would contribute immensely to the export industry of Z. zamiifolia.DOI: http://dx.doi.org/10.4038/cjsbs.v42i1.5899 Ceylon Journal of Science (Bio. Sci.) 42 (1): 55-62, 2013

ITS phylogeny of Middle Asian geophilic Umbelliferae-Apioideae genera with comments on their morphology and utility of psbA-trnH sequences

Generic delimitation and relationships within the taxonomically controversial group of geophilic Umbelliferae from Middle Asia are problematic. Geophilic plants in arid regions have a short period of development during spring and early summer and survive unfavorable seasons due to the presence of tuber-like underground storage organs. To investigate the circumscription of recently recognized Middle Asian geophilic genera and their relationships, we conducted phylogenetic analyses using DNA sequence data from rapidly evolving nuclear (nrITS) and chloroplast (psbA-trnH intergenic spacer) regions as well as multivariate analyses of the morphological and ITS data. Our results show that Galagania and Mogoltavia are monophyletic, whereas Bunium, Hyalolaena and Oedibasis are polyphyletic. Elaeosticta, one of the larger genera of geophilic Middle Asian umbellifers, is rendered paraphyletic by the inclusion of the enigmatic Hyalolaena melanorrhiza. The genus Scaligeria, in which most species of Elaeosticta were initially described, is not grouped with these genera and has other affinities. Our analyses also show that the morphological characters used for the delimitation of genera within this group of Umbelliferae (such as life form, cotyledon number, presence/absence of petiolules of basal leaflets, shape of mericarp ribs, width of mericarp commissure, number of secretory ducts in mericarp furrows) are rather homoplastic. The psbA-trnH sequences were not informative enough to reveal relationships among the genera studied, although some interesting features in the spacer evolution were revealed (maximum reduction in length among Umbelliferae, homoplasious directed substitutions to restore secondary structure).

719 Proteoglycan-Rich Leaflet Thickening in Diet-Induced Early Aortic Valve Disease in Mice

719 Proteoglycan-Rich Leaflet Thickening in Diet-Induced Early Aortic Valve Disease in Mice

First Report of Tomato torrado virus Infecting Tomato in Colombia.

Tomato (Solanum lycopersicum L.) plants grown in plastic greenhouses near Villa de Leyva, northeast of Bogota, Colombia showed necrotic spots on the leaves in September 2008. Initial symptoms were necrosis beginning at the base of leaflets that were surrounded by yellow areas. These symptoms resembled those described for Tomato torrado virus (ToTV; family Secoviridae, genus Torradovirus), which was first found in Spain (2). Other (tentative) members of the genus Torradovirus, Tomato marchitez virus (ToMarV), Tomato chocolate spot virus (ToChSV), and Tomato chocolàte virus (ToChV) (3) induce similar symptoms on tomato plants. One sample, coded T418, was stored in the freezer and brought to our lab in 2011. Serological tests (double-antibody sandwich-ELISA) using polyclonal antibodies (Prime Diagnostics, Wageningen, The Netherlands) on leaf extracts showed the absence of Pepino mosaic virus (PepMV), Tobacco mosaic virus (TMV), Tomato spotted wilt virus (TSWV), Cucumber mosaic virus (CMV), Potato virus X (PVX), and Potato virus Y (PVY). Leaf extracts were mechanically inoculated onto the indicator plants Physalis floridana, Nicotiana hesperis '67A', and N. occidentalis 'P1' (six plants in total) and were kept in a greenhouse at 20°C with 16 h of light. Necrotic symptoms appeared 4 to 5 days postinoculation and resembled those described for ToTV (2). Two dip preparations of systemically infected P. floridana and N. occidentalis leaves were examined by electron microscopy, which revealed the presence of spherical virus particles of approximately 30 nm. To confirm the presence of ToTV, total RNA was extracted from the original leaf material and an inoculated P. floridana and N. occidentalis plant using the Qiagen Plant Mini Kit (Qiagen, Hilden, Germany) following manufacturer's instructions. ToTV-specific primer sets ToTV-Dp33F/ToTV-Dp20R (5'-TGCTCAATGTTGGAAACCCC-3'/5'-AGCCCTTCATAGGCTAGCC-3', amplifying a fragment of the RNA1 polyprotein with an expected size of 751 bp) and ToTV-Dp1F/ToTV-Dp2R (5'-ACAAGAGGAGCTTGACGAGG-3'/5'-AAAGGTAGTGTAATGGTCGG-3', amplifying a fragment on the RNA2 movement protein region with an expected size of 568 bp) were used to amplify the indicated regions in a reverse transcription (RT)-PCR using the One-Step Access RT-PCR system (Promega, Madison, WI). Amplicons of the predicted size were obtained in all tested materials. The PCR products were purified with the Qiaquick PCR Purification Kit (Qiagen) and sequenced directly. BLAST analyses of the obtained sequences (GenBank Accession Nos. JQ314230 and JQ314229) confirmed the identity of isolate T418 as ToTV, with 99% identity to isolate PRI-ToTV0301 in both fragments (GenBank Accession Nos. DQ388879 and DQ388880 for RNA1 and RNA 2, respectively). To our knowledge, this is the first report of ToTV in Colombia, and interestingly, since ToTV has been found only in Europe and Australia (1) so far, this is the first report of ToTV on the American continent.

Uptake and Distribution of Boron in Coconut and Paurotis Palms

Natural distribution patterns of boron (B) among leaves within a canopy, among leaflets within a leaf, and within single leaflets were determined for coconut palm (Cocos nucifera L.) and within leaves for paurotis palm [Acoelorrhaphe wrightii (Griseb. &amp; H. Wendl.) Becc.]. Leaf B concentrations did not vary significantly among leaves within the canopy or among leaflets within a single leaf for coconut palm, but basal leaflets of paurotis palm had higher B concentrations than central leaflets. Boron concentrations were significantly higher toward the tips of individual leaflets in both species. Application of Solubor to the soil significantly increased leaf B concentrations in all leaves of coconut palm after 2 months as well as in new leaves produced up to 6 months later. Application of Solubor as a leaf axil drench was much less effective in increasing foliar B concentrations than soil treatment.

Genetic divergence among accessions of Arachis repens based on vegetative morphological traits

The objective of this study was to verify the existence of genetic variability among accessions of Arachis repens based on vegetative morphological characters, identifying those which contribute least for distinction of those accessions. Nineteen accessions were evaluated in a completely randomized design with ten replicates, established in 4-m2 plots. The traits evaluated were: basal leaflet length, basal leaflet width, apical leaflet length, apical leaflet width, petiole length, internode average length and internode diameter. The data obtained were submitted to univariate statistical analysis and accessions were grouped by the Scott-Knott test, at 1% of probability. The analysis of canonical variables and Tocher method were used to study the genetic divergence among accessions. Six heterogeneous groups were formed by Tocher method and eight groups were formed by technique of canonical variables, in which a consistency among grouping set by the different techniques used was observed. There is genetic divergence among accessions of A. repens on the basis of vegetative morphology traits, but there is the need to extend variability in Banco Ativo de Germoplasma de Amendoim Forrageiro (Active Germplasm Bank of Forage Peanut). Apical leaflet length is the trait that contributes least to the accessions' distinctions, but it is important to maintain the standard cluster, and it should not be discarded

Circadian rhythm leaf movement of Phaseolus vulgaris and the role of calcium ions

Legume plants, due to their distinctive botanical characteristics, such as leaf movements, physiological characteristics, such as nitrogen fixation, and their abilities to endure environmental stresses, have important roles in sustainable pastures development. Leaf movement of legume plants is turgor regulated, and osmotically active fluxes of ions between extensor and flexor of pulvinus cause this movement. To determine the role of calcium ions in circadian leaf movements of Phaseolus vulgaris L., a radiotracer technique experiment using 45Ca ions were employed. Measurements were taken during circadian leaf movements, and samples were taken from different parts of the leaflet. The 45Ca beta-particle activity reduced from leaflet base pulvinus to leaf tip. The pulvinus had the highest activity, while the leaf tip had the lowest. By increase of the ratio of 45Ca beta-particle activity within flexor to extensor (Fl/Ex) the midrib-petiole angle, as an indicator of leaf movement, increased linearly during circadian leaf movement (r = 0.86). The 45Ca beta-particle activity of Flex/Ext ratio reduced linearly (r = - 0.88) toward midnight. In conclusion, it was found that calcium ions accumulation is opposite to the fluxes of somatically active ions and water movement. Calcium ions accumulate at less negative water potential side of the pulivnus.

Important Morphological Characters in Several Species of Cassiinae (Leguminosae) in South-Western Nigeria

Macromorphological characters of some species of Cassia L. emend. Gaertner, Senna Miller and Chamaecrista Moench occurring in South Western Nigeria were studied. The aim was to search for stable, distinctive and diagnostic characters for the identification of these genera and their species. Qualitative characters were noted and recorded while quantitative observations were done by the use of a metric ruler and the measurements were taken to the nearest centimeters. The habit ranges from all shrubs in Senna, shrubs and herbs in Chamaecrista while the Cassia species studied are all trees. The shape of the leaflet apex varies in both Senna and Cassia species, while it is distinctly mucronate in Chamaecrista genus. Occurrence of foliaceous stipule in the genus Chamaecrista clearly separates it from Senna and Cassia, which are completely exstipulate. In general, other characters such as number of leaflet pairs, length and width of leaflets, leaflet base, and number of leaflets lateral nerves revealed generic distinctions. Others include the degree of hairiness in sepals, petals shape, types of inflorescence, fruit shape and fruit length. The attributes that delimits the species are mainly quantitative. The results of this investigation suggest macromorphological characters that clearly enhance the taxonomy of these genera and their species and they can be subsequently employed in their delimitation.