Groups Of Dicotyledons Research Articles

Floristic Composition and Vegetation Diversity Status of Khagrachari Sadar, Chattogram, Bangladesh

Floristic diversity of Khagrachari Sadar of Khagrachari district, within Chittagong Hill Tracts of Bangladesh, has been investigated. A territory's vegetation type and diversity provide insight into the overall resources, their usage structures, and conservation status that are crucial to developing conservation plans and regulations. This analysis helps to portray the overall scenario of a region's plant biomass/vegetation diversity exquisitely. This study has revealed the occurrence of 369 vascular plant species belonging to 144 genera under 97 families from the study area. Out of these 32 are pteridophytes, 2 are gymnosperms and the rest of 335 are angiosperms. Based on habit distribution, herbs are represented by 150 species followed by shrubs (48), trees (108), climbers (47) and epiphytes by 16 species. Dicotyledonous (Magnoliopsida) group was dominant and represented by 254 species belonging to 73 genera under 62 families, followed by monocotyledonous (Liliopsida) with 81 species under 52 genera and 17 families. Among the dicotyledonous plants, Rubiaceae was found to be the largest family with 24 species, whereas with 17 species Orchidaceae is the largest family in monocotyledonous. It appears that Forested areas are dominated by Melocanna baccifera, with an IVI of 8.00 and have the scanty appearance of two herbs (Spathoglottis plicata, Adiantum flabellaletum) and one tree species (Cycas pectinata). For effective conservation management and sustainable usage of the taxa, the status of occurrence has been determined where 304 species (82.23 percent) are considered as ‘Common’, 61 (16.53 percent) are considered ‘Least Concern’, 2 (0.54%) are considered ‘Vulnerable’ and 2 (0.54%), are considered ‘Critically Endangered’. Several diversity indices, such as Margelef’s richness, Shannon-Winer Index, Pielou’s Evenness, and Simpson’s Index values showed the substantial diversity status of the vascular plant in selected 4 sites. A considerable seasonal fluctuation was evident in the diversity indices at four different research locations where data reflected that the rainy season is more diverse than others.

Functional analysis of a PISTILLATA-like gene CcMADS20 involved in floral organs specification in citrus

PISTILLATA (PI), as a member of MADS-box transcription factor, plays an important role in petal and stamen specification in Arabidopsis. However, little is known about PI-like genes in citrus. To understand the molecular mechanism of PI during the developmental process of citrus flower, a PI-like gene CcMADS20 was isolated from Citrus Clemantina. Sequence alignment and phylogenetic analysis revealed that CcMADS20 had relatively high similarity with PI-like homolog and was classified in the core dicotyledonous group. The temporal and spatial expression analyses showed that CcMADS20 was specifically expressed in petal and stamen of citrus flower, which was consistent with PI expression pattern in Arabidopsis. Protein interaction revealed that CcMADS20 could form heterodimer with AP3-like proteins. Furthermore, ectopic overexpression of CcMADS20 in Arabidopsis resulted in transformation of sepals into petal-like structure, as observed in other plants overexpressing a functional PI-like homolog. Additionally, promoter fragments of CcMADS20 were also cloned in the representative 21 citrus varieties. Interestingly, four types of promoters were discovered in these citrus varieties, resulting from two stable insert/deletion fragments (Locus1 and Locus2). The homo/hetero-zygosity of promoter alleles in each variety was strongly related to the evolutionary origin of citrus. Four promoters activity analysis indicated that Locus1 presence inhibited CcMADS20 transcriptional activity and Locus2 presence promoted its transcriptional activity. These findings suggested that CcMADS20 determines petal and stamen development during the evolutionary process of citrus and four promoters discovered, as effective genetic markers, are valuable for citrus breeding practices.

Биоразнообразие флористических комплексов на территории хребета Кетпен-Темирлик

The article provides an analysis of the biodiversity of the floristic complexes of the Ketpen-Temerlik range within Kazakhstan and China. According to the results of perennial floristic studies in the territory of the Ketpen-Temerlik range within Kazakhstan and China, there are 1,890 species of vascular plants belonging to 593 genera and 120 families. In terms of species composition, the Magnoliophyta section dominates in the study area of the Ketpen-Temerlik range, which accounts for 98.4% and 1.6% for Pinophyta, Polypodiophyta, Lycopodiophyta, and Equisetophyta. The ratio of monocotyledonous and dicotyledonous groups in the flora of the ridge is approximately 1: 5.4, where Magnoliopsida prevails over Liliopsida by species and genus composition more than 5 times. The total number of dicotyledonous plants is 1,510 species, which is 80%, monocotyledonous plants are only 350 species. We have identified 13 floristic complexes for the Ketpen-Temerlik range: desert, desert-steppe, meadow, meadow-forest, deciduous-forest, coniferous-forest, cryophilic-meadow, steppe, tree-shrub, petrophilic, wetland and coastal-water and synanthropic. Their isolation as floristic complexes is quite natural, since they are zonal for the studied territory, the vegetation cover of which is distinguished by complexity and mosaic. Dominant on the Ketpen-Temerlik range are meadow-forest, steppe, co- ISSN 1563-0218; eISSN 2617-7498 Experimental Biology. №1 (78). 2019 47 Садырова Г.А. nifer-forest, cryophilic-meadow, petrophilic, woody shrub, gypsum-gammad and variegated floristic (landscape-geographical) complexes. Key words: biodiversity, flora, Ketpen range, Temerlik, floristic complexes

Floristic composition and phytodiversity status of Sitakunda Ecopark, Chittagong, Bangladesh

The present study dealt with the exploration and documentation of the floristic composition and phyto-diversity of Sitakunda Eco-park, Chittagong, Bangladesh. A total of 412 vascular plant species under 315 genera belonging to 94 plant families have been recorded from the study area during February, 2013 to April, 2015. Out of these recorded taxa, 330 were dicotyledons, 62 were monocotyledons, 5 were gymnosperms and 15 were pteridophytes. Among those, the maximum 144 species belonged to herbs followed by 138, 75 and 55 species as trees, shrubs and climbers, respectively. The species composition among the plant families varied in plant groups. In dicotyledonous group, Euphorbiaceae appeared to be the largest family with 35 species, whereas Poaceae showed the largest family containing 30 species among monocotyledonous group. The highest values of both Shannon-Weiner and Simpson diversity indices have been observed as 3.82 and 0.98, respectively to site D during monsoon season, whereas the lowest values 3.19 and 0.95, respectively of these indices were recorded in site A during summer season.Jahangirnagar University J. Biol. Sci. 5(1): 29-45, 2016 (June)

Spatial Pattern of Weeds Based on Multispecies Infestation Maps Created by Imagery

Weeds are often spatially aggregated in maize fields, and the level of aggregation varies across and within fields. Several annual weed species are present in maize fields before postemergence herbicide application, and herbicides applied will control several species at a time. The goal of this study was to assess the spatial distribution of multispecies weed infestation in maize fields. Ground-based imagery was used to map weed infestations in rain-fed maize fields. Image segmentation was used to extract weed cover information from geocoded images, and an expert-based threshold of 0.102% weed cover was used to generate maps of weed presence/absence. From 19 site-years, 13 (68%) demonstrated a random spatial distribution, whereas six site-years demonstrated an aggregated spatial pattern of either monocotyledons, dicotyledons, or both groups. The results of this study indicated that monocotyledonous and dicotyledonous weed groups were not spatially segregated, but discriminating these weed groups slightly increased the chances of detecting an aggregated pattern. It was concluded that weeds were not always spatially aggregated in maize fields. These findings emphasize the need for techniques allowing the assessment of weed aggregation prior to conducting site-specific weed management.

ABA‐stimulated SoDOG1 expression is after‐ripening inhibited during early imbibition of germinating Sisymbrium officinale seeds

DELAY OF GERMINATION 1 (AtDOG1) was the first gene identified as dormancy-associated, but its physiological role in germination is far from being understood. Here, an orthologue of AtDOG1 in Sisymbrium officinale (SoDOG1; KM009050) is being reported. Phylogenetically, the SoDOG1 gene is included into the dicotyledonous group together with DOG1 from Arabidopsis thaliana (EF028470), Brassica rapa (AC189537), Lepidium papillosum (JX512183, JX512185) and Lepidium sativum (GQ411192). The SoDOG1 expression peaked at the onset of the silique maturation stage and there was presence of SoDOG1-mRNA in the freshly collected viable dry seed (i.e. AR0). The SoDOG1 transcripts were also found in other organs, such as open and closed flowers and to a lesser degree in roots and stems. We have previously reported in S. officinale seeds in which sensu stricto germination is positively affected by nitrate and both testa and micropylar endosperm ruptures are temporally separated. In dry viable seeds, the SoDOG1-mRNA level in three different after-ripening (AR) status was AR0 ≈ AR7 (optimal AR) < AR27 (optimal AR was almost lost). The presence of nitrate in the AR0 seed imbibition medium markedly decreased the SoDOG1 expression during sensu stricto germination. However, the nitrate stimulated the SoDOG1 expression during imbibition of AR7 compared to AR0. At the early AR0 seed imbibition (3-6 h), exogenous ABA provoked a very strong stimulation of the SoDOG1 expression. AR inhibits ABA-induced SoDOG1 expression during early germination and gibberellins (GA) can partially mimic this AR effect. A view on the integration of all found results in the sensu stricto germination of S. officinale was conducted.

Identification and characterization of granule bound starch synthase (GBSS-I) from common buckwheat (Fagopyrum esculentum Moench)

Starch grains present in the endosperm of grains of common buckwheat (Fagopyrum esculentum Moench) show a monomodal distribution with size ranging from 4 to 10 μm. SDS-PAGE analysis of starch granule bound proteins revealed the presence of a single band corresponding to molecular mass of 59.7 kDa. The protein is localized within the central core of the starch grains. Antisera raised against the 59.7 kDa protein cross reacted with the 61 kDa GBSS-I from endosperm starches of maize and the 60 kDa GBSS-I from endosperm starches of rice and wheat, thereby indicating serological homology between the 59.7 kDa buckwheat starch granule bound protein and GBSS-I of wheat, maize and rice. 2D-PAGE of starch granule bound proteins of common buckwheat resolved the fraction into 7 spots with pI ranging from 5.2 to 5.6. N-terminal amino acid sequence for 25 residues of two immunoreactive proteins separated by 2D PAGE showed 94 % homology with N-terminal amino acid sequence of GBSS-I from Hordeum vulgare, Triticum spp. and Phaseolus vulgaris. Even though analysis of the sequence alignment revealed a clear diversification into monocotyledonous and dicotyledonous groups, the protein from buckwheat showed similarities with GBSS-I from both dicots as well as monocots. As is the case with dicots, the sequence of GBSS-I from buckwheat has valine as the 11th residue. GBSS-I from majority of monocots has methionine at this position. The sequence also showed similarities with monocots with valine at P’5 from the N-terminus. GBSS-I from majority of dicots has isoleucine at this position. The significance of these substitution remains to be ascertained.

Characterization of the first specific jasmonate biosynthetic pathway gene allene oxide synthase from Artemisia annua

Allene oxide synthase (AOS) is the first committed step in the biosynthetic pathway of Jasmonate. In this study, a full-length cDNA of AOS gene (named as AaAOS) was cloned from Artemisia annua. The gene was 1891 bp in size containing an open reading frame (1581 bp) encoding 526 amino acids. Comparative and bioinformatic analysis revealed that the deduced protein of AaAOS was highly homologous to AOSs from other plant species. Phylogenetic analysis indicated that the protein of AaAOS belonged to the dicotyledonous group, which was consistent with the category of A. annua. Southern blot analysis revealed that it was a low-copy gene. Quantitative Real-time PCR (qRT-PCR) analysis showed that AaAOS mRNA accumulated most abundantly in leaves and flowers. The qRT-PCR analysis revealed that MeJA, ABA and ethylene treatments significantly enhanced AaAOS transcript expression.

The chloroplast genome of Nymphaea alba: whole-genome analyses and the problem of identifying the most basal angiosperm.

Angiosperms (flowering plants) dominate contemporary terrestrial flora with roughly 250,000 species, but their origin and early evolution are still poorly understood. In recent years, molecular evidence has accumulated suggesting a dicotyledonous origin of monocots. Phylogenetic reconstructions have suggested that several dicotyledonous groups that include taxa such as Amborella, Austrobaileya, and Nymphaea branch off as the most basal among angiosperms. This has led to the concept of monocots, "eudicots," "basal dicots," and "ANITA" groupings. Here, we present the sequence and phylogenetic analyses of the chloroplast DNA of Nymphaea alba. Phylogenetic analyses of our 14-species data set, consisting of 29,991 aligned nucleotide positions per chloroplast genome, revealed consistent support for Nymphaea being a divergent member of a monophyletic dicot assemblage. Three distinct angiosperm lineages were supported in the majority of our phylogenetic analyses-eudicots, Magnoliopsida, and monocots. However, the monocot lineage leading to the grasses was the deepest branching. Although analyses of only one individual gene alignment (out of 61) is consistent with some recently proposed hypotheses for the paraphyly of dicots, we also report observations that nine genes do not support paraphyly of dicots. Instead, they support the basal monocot-dicot split. Consistent with this finding, we also report observations suggesting that the monocot lineage leading to the grasses has the strongest phylogenetic affinity to gymnosperms. Our findings have general implications for studies of substitution model specification and analyses of concatenated genome data.

Wood and Stem Anatomy of Stegnosperma (Caryophyllales); Phylogenetic Relationships; Nature of Lateral Meristems and Successive Cambial Activity

Wood and bark histology data on stems of two species of Stegnospenna (Stegnospermataceae, or Phytolaccaceae s.l.) is presented, complementing previous accounts . Wood of Stegnosperma is relatively primitive within Caryophyllales because of presence of tracheids , diffuse parenchyma, and both multiseriate and uniseriate rays . The solitary nature of vessels is held to be correlated with tracheid presence , as in other groups of dicotyledons with vessels solitary or nearly so. Bark anatomy is newly reported for the genus . The method of section used permits analysis of divisions in cells with primary walls. Radial rows of parenchyma ('secondary cortex') develop in the inner cortex and are perpetuated by tangential divisions collectively termed a diffuse lateral meristem here. Successive cambia form within the radial rows of parenchyma. Despite diverse terminology and interpretations in literature on plants with successive cambia, the successive cambia and their origin in Stegnosperma are believed to represent the same anatomical phenomena as in other Phytolaccaceae s.l.

Transport of nutrients into developing seeds: a review of physiological mechanisms

AbstractAfter synthesis in the vegetative parts of the plant, assimilates are translocated to fruits through xylem and phloem. Research on factors controlling nutrient transport into developing seeds via the phloem has been stimulated by the development of the empty seed coat technique.There is a consensus that as assimilates are transported from maternal tissues to filial tissues they are delivered to the extracellular space (the apoplast) separating the two generations, prior to uptake from the apoplast into the tissues of the embryo or endosperm. The empty seed coat technique has been used for the study of several aspects of nutrient transport into seeds, e.g. metabolic control and turgorsensitive transport. The osmotic environment of seed tissues has a strong effect on assimilate transport into empty seeds. Several lines of evidence suggest that one of the main ‘secrets’ of the high sink strength of developing seeds, at least in many taxonomic groups of dicotyledons, is that the sink end of the phloem pathway is ‘bathed’ in an apoplast solution with a high concentration of osmotically active solutes. Data on maize do not fit this pattern. A turgor homeostat mechanism may help to maintain high solute concentrations in the seed apoplast. The apoplast environment of seed tissues may also stimulate synthesis of storage proteins and be involved in the prevention of precocious germination. In addition to the osmotic environment, other factors influencing sink strength are discussed. Some aspects of solute transformation during transport through seed tissues are described.

On pollen shape in some groups of dicotyledons

Abstract Shape change of pollen grains under different conditions are discussed for some families of dicotyledons. Reversibility of pollen form in relation to age and humidity are described. A technique for stabilizing shape is discussed.

Variation in amino acid composition of cytochrome c of species in the fungal genusUstilago

Cytochrome c was extracted and purified from nine species of the genusUstilago, representing five pathogen for monocotyledonous and four for dicotyledonous host species. The amino acid compositions of acid hydrolysates of cytochrome c from these species were compared and divergence values were calculated for all pairs of species. Aspartic acid, serine, glutamic acid, proline, glycine, alanine, valine, leucine, phenylalanine, lysine, and arginine were the most variable amino acids for both dicot and monocot pathogens. Differences in lysine, glutamic acid, alanine, and histidine distinguished most monocot and dicot pathogens. The dicotyledonous pathogens had fewer glutamic acid and additional alanine and histidine residues. Divergence values for cytochrome c were generally highest between species of dicotyledonous and monocotyledonous hosts and lowest for species within the monocotyledonous group. Pairs of species in the dicotyledonous group gave values only slightly lower than those for pairs with species from different groups.

Developmental Changes in the Wood of Bocconia Vulcanica Donn. Smith

Developmental changes in the xylem were studied in a stem of Bocconia vulcanica Donn. Smith with a xylem radius of 3.0–4.5 cm. Growth rings are absent. The vascular cambium is nonstoried with fusiform initials averaging 282 µm long. The specialised vessel members are short, with oblique to transverse end walls, simple perforations, and alternate intervascular pitting. Vessels are relatively uniform in diameter and arrangement throughout the wood. Fibres have moderately thin walls and do not increase in length from the primary xylem to the cambium. Axial parenchyma is paratracheal, scanty to vasicentric. Rays are exclusively multiseriate, tall, and heterocellular with a predominance of erect and square cells. Sheath cells occur along the sides. There are no fibres in the secondary phloem and a periderm is not present. The xylem and bark are similar in many respects to that formed in some groups of dicotyledons that are basically herbaceous with evolution toward woodiness.

Wood Anatomy of Calyceraceae and Valerianaceae, with Comments on Aberrant Perforation Plates in Predominantly Herbaceous Groups of Dicotyledons

Wood Anatomy of Calyceraceae and Valerianaceae, with Comments on Aberrant Perforation Plates in Predominantly Herbaceous Groups of Dicotyledons

Wood Anatomy of Buxaceae: Correlations with Ecology and Phylogeny

Summary The family Buxaceae consists of four genera, with the desert shrub Simmondsia dubiously included in the family as a fifth genus. Styloceras (Andean rain forest) has the most mesomorphic and primitive wood features, followed by Sarcococca and then by Buxus, which can be grouped closely with Notobuxus in terms of wood anatomy. Pachysandra was excluded from this study because of its essentially herbaceous habit. For a small family, Buxaceae have a wide span in expression of wood features. Characters in Buxaceae s.s. which show a range within the family probably explainable in terms of ecology include vessel element length, number of vessels per mm2, vessel diameter, number of bars per perforation plate, presence or absence of helical thickenings in vessels and tracheids, and presence or absence of growth rings. The woods in the family can be ranked as highly mesic (Styloceras, Sarcococca) to moderately mesic (Buxus, Notobuxus), with a few species in the latter pair of genera notably more mesomorphic in wood construction. Retention of scalariform perforation plates throughout Buxaceae s.s. may be due to compensatory low transpiration capabilities of the foliage, which may have very thick cuticles and tend toward microphylly. Features which are susceptible to evolutionary interpreation but which do not bear as direct a relationship to ecology include ratio of tracheid length to vessel element length, presence of tracheids with fully bordered pits, degree of aggregation of axial parenchyma cells (diffuse, diffuse-in-aggregates, abaxial) and degree of cellular heterogeneity in ray histology. The ray types of Sarcococca reflects a type of juvenilism, and scarcity of axial parenchyma in the genus also seems related to innovation of numerous shoots, each with limited duration. Simmondsia differs from Buxaceae s.s. in its desert habitat, its successive cambia, and its anemophily. Distinctive features of wood anatomy (lack of acial parenchyma, juvenilism in ray histology, and presence of very short vessel elements with helical thickenings) can be attributed to the first two factors. No features of wood anatomy clearly rule out relationship to Buxaceae. Presence of tracheids in wood of Simmondsia may be related to the high selective value for tracheids in a desert environment; this feature (and the encyclocytic stomata) suggest affinity to Buxaceae, even if the genus is segregated in Simmondsiaceae. Buxaceae have been claimed to be related to four major groups of dicotyledons: Celastrales, Euphorbiales, Hamamelidales, and Pittosporales. Of these, Euphorbiales shows the least degree of resemblance to Buxaceae in terms of wood anatomy. The placement of the isolated Madagascan genus Didymeles may be related to the problem of placement of Buxaceae, and is discussed in this context.

Angiosperm phylogeny, floral morphology and pollination ecology

The different aspects of floral evolution—Angiosperm descent, floral morphology and pollination ecology—are discussed on the basis of the anthocorm theory of the angiospermous flower. Opposed ideas are critically compared and rejected mainly on account of several inconsistencies and flaws in old floral concepts. Floral evolution passed from a very early phase of dicliny, anemophily and aphananthy of the anthocorm to a phase of incipient entomophily soon associated with a partial sex reversal within the anthocorm. This second phase culminated in the monoclinous and primarily zoophilous flower types, whereas other floral types, more particularly the primarily anemophilous, diclinous flowers, are the direct descendants of the anthocorms of the initial phase. The second phase (to be differentiated in phase II and phase IIA) gave rise to at least two morphologically different flower types and two separate semophyletic lines of floral evolution (phase III and III A), in each of which the primary zoophily is almost always associated with the development of intrafloral semaphylls (petals) usually (at least in dicotyledonous groups) of androecial derivation. Early flower types were aphananthous and clearly anthocormoid (a condition still approximately represented by the so-called inflorescences of theSaururaceae) and assumed the morphology and other characteristics of a true flower by contractions, condensations, readjustments, oligomerisations, reductions and modifications (semaphylls!) leading to the great variety of adaptive floral patterns.

FACTS AND FICTION IN FLORAL MORPHOLOGY WITH SPECIAL REFERENCE TO THE POLYCARPICAE 3. CONSEQUENCES AND VARIOUS ADDITIONAL ASPECTS OF THE ANTHOCORM THEORY

In this third, and final, part the various implications of the Anthocorm Theory with regard to the floral morphology, the taxonomy (classification) and the phylogenetic relationships of a number of major angiospermous groups are discussed, including the organogeny, the phyllo-and stachyotaxis, the homotopy, and the homologies in the floral region, and the so-called ‘cortical’ vascular system in the flower of the Magnoliaceae. In the final discussion, the divergent semophyletic evolution of the floral region from a primitive anthocormoid reproductive structure is shown to have culminated in an early phylogenetic divergence of the major dicotyledonous groups from ancestral forms whose floral organs (anthocorms) must have been rather similar to those of the recent Saururaceae. The functional reproductive units of some of these taxa (notably of the Piperales) have not advanced to an appreciable extent beyond the anthocormoid archetype and have not attained the semophyletic level of a (true) flower.

Orcein staining and the study of the effect of chemicals on chromosomes.

Plant materials of both dicotyledonous and monocotyledonous groups were subjected to treatment with alloxan followed by coumarin, phenols, oxyquinoline etc. for 3 to 4 hours. Root tips were then heated in an orcein-acid mixture for 10 to 40 seconds and studied after mounting in 1% orcein. Clear metaphase plates were obtained after 10 seconds of heating, whereas after 20 and 30 seconds considerable erosion and fragmentation respectively were recorded. Complete loss of stainability resulted after heating for 40 seconds. Fragmentation is caused only by orcein under heat conditions. This is demonstrated by control series checking all variables. Pretreatment with the chemicals stated is of absolute necessity for fragmentation. It is suggested that this pretreatment causes depolymerisation of DNA and lability of nucleoprotein linkage at certain segments from which the DNA becomes detached during subsequent heating. Of all the chemicals tested for pretreatment effects, marked positive results were obtained with alloxan (1 hour) followed by coumarin (2 hours at 16–20 ° C.). Phenols also gave positive results. The other chemicals tried need slightly longer time of treatment for fragment induction.

On the Primary Groups of Dicotyledons

On the Primary Groups of Dicotyledons