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Ericales is an ancient eudicot order encompassing numerous species of economic and ornamental values. Despite several phylogenomic studies, the evolutionary relationship among certain families of this group remains un¬certain. The present study assessed a multilocus species tree of Ericales based on 107 chloroplast genomes. The plastome derived microsatellite motifs were also simultaneously explored to check their dynamicity in cor¬robo¬ration of species phylogeny and systematics. In addition to resolving the usual hierarchy, the present phylogenetic analysis enabled to resolve the persisting lineage disparity with valid statistical support. Accordingly, divergence incongruences of Primulaceae, Ebenaceae, and Sapotaceae from earlier reports were reinstated in presently inferred phylogeny, which further supported the latest transcriptome-based relationship of the corresponding group. Various SSR motif characteristics emerged following the recognition of the evolutionary pathway. Nu¬merical variation in tetranucleotide repeats showed even intraspecific or varietal differences in Camellia sinensis. Validation of plastome microsatellite-based polymorphism among the related taxa might pave the way for future phylogenetic and population studies of this economically important group.

Traces of genetic introgression from wild donors that occurred during the origin trajectory of a crop would be concealed in the existing gene pool of its cultivated varieties. Dissection of signature motifs from wild relatives and diverse genotypes of a crop, not only can elucidate the probable ancestry but also offer a potential tool to authenticate varieties with a particular phenotype. We selected twenty-two distinct genotypes representing diverse commercial tea germplasms of both assamica and sinensis lineage to trace genetic signatures of their wild ancestors. A total of 176 sequences were generated from eight coding and non-coding loci belonging to both plastid and nuclear genome of the commercial tea accessions and compared with corresponding homologous loci from various wild Camellia species. The concatenated multi-locus tree of the selected cultivars and the allied species was constructed to examine phylogenetic relatedness among and within the species. Present study uncovered several signature motifs that carry evidence of multiple hybridization events during the origin trajectory of the cultivated tea plant. Identified genotype-specific indels of chloroplast and nuclear non-coding regions might imitate their varietal origin.

In recent years, low copy nuclear genes became a promising choice in plant phylogeny and systematic studies for being bi-parentally inherited and highly variable, thus possessing more phylogenetically informative sites in contrast to widely used organellar genes. Here, a set of nuclear genes has been fished out from the plant genome database targeting their single copy presence in whole genomes of most of the taxa. Low copy genes, that are yet to be included in molecular phylogenetic studies of plants, were selected. All group of green plants from algae to angiosperm has been considered for validating these markers towards determining both species level and deep lineage hierarchy. The reconstructed phylogeny with selected genes, in present work, exhibited good resolution up to family level with high statistical support. Moreover, NAD, PS54, P4H, CDIPT, and GTF could also serve well up to higher rank clustering. Concatenated species tree through best predicted substitution model with and without third codon position corroborated the prospects of nuclear gene-based phylogeny with some incongruences in the hierarchy. The study acclaimed fourteen low copy nuclear genes concerning the determination of their efficacy toward inferring the taxonomic relationship of green plants which might be used in further molecular systematics and population genetic studies.

PREMISE Unique among vascular plants, some species of Selaginella have single giant chloroplasts in their epidermal or upper mesophyll cells (monoplastidy, M), varying in structure between species. Structural variants include several forms of bizonoplast with unique dimorphic ultrastructure. Better understanding of these structural variants, their prevalence, environmental correlates and phylogenetic association, has the potential to shed new light on chloroplast biology unavailable from any other plant group. METHODS The chloroplast ultrastructure of 76 Selaginella species was studied with various microscopic techniques. Environmental data for selected species and subgeneric relationships were compared against chloroplast traits. RESULTS We delineated five chloroplast categories: ME (monoplastidy in a dorsal epidermal cell), MM (monoplastidy in a mesophyll cell), OL (oligoplastidy), Mu (multiplastidy, present in the most basal species), and RC (reduced or vestigial chloroplasts). Of 44 ME species, 11 have bizonoplasts, cup-shaped (concave upper zone) or bilobed (basal hinge, a new discovery), with upper zones of parallel thylakoid membranes varying subtly between species. Monoplastidy, found in 49 species, is strongly shade associated. Bizonoplasts are only known in deep-shade species (

Shelf life studies play a significant role in determination of time duration for the retention of product quality after packaging. Assessment of tea shelf life in terms of antioxidant quality, a prime health benefit trait of tea would substantiate its marketing and consumption preference to the trade and end users. In shelf life analysis of tea with respect to its antioxidant potentialities, both antioxidant activity and incidences of secondary metabolites are responsible. A temporal analysis with regular intervals since 1 year of said characteristics has been carried out in four types of processed teas. To be precise, the overall initial antioxidant concentrations and activities were almost maintained up to 90–120 days and thereafter declination appeared. Beyond 180 days, rapid declination occurs and beyond 330 days, depletion recorded up to 60–75% of the initial activity. Black tea showed maximum ferrous ion chelating activity initially and white tea commenced with slight lower value but it maintained a similar trend up to 150 days while a rapid declination occurred in such activity of black and green tea after 30 days only. It is observed that total tannins or proanthocyanidins amount highest in white tea among all other three types. The preservation of metal chelating activity of white tea was observed as comparable to its stability in tannin composition (r(2) = 0.869, P ≤ 0.01) during the storage period. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13197-020-04300-0) contains supplementary material, which is available to authorized users.

Arsenic contamination in agricultural soil now imposing a major threat to crop productivity and causing several hazardous health effects through percolation in food chain. Bioremediation, an effici...

Antioxidant and free radical scavenging ability of tea polyphenols are considered as health benefit traits that mainly contributed by tea catechins. Therefore understanding of genetic and molecular basis of this secondary metabolite production is of prime interest to facilitate the crop improvement program in tea plant efficiently. Some QTLs for these quality traits have already been available. In present study, 10 QTL linked SSRs and 14 newly developed microRNA based SSRs have been characterized in two Darjeeling tea cultivars having contrast characters and their progeny clone TS569 for validating possible association with catechin contents and antioxidant activities. Individual catechins and radical scavenging activity have been estimated by high performance liquid chromatography and UV-Vis spectrophotometry. Some of the polymorphic loci are indicated to be co-varied with such biochemical physiognomies. Characterization of microRNA based SSRs polymorphism are being the first time report in tea and discussed as ideal choice for further genotypic studies in tea.

The myo-inositol biosynthesis pathway triggering protein MIPS is best known for its necessity, ubiquitous nature and occurrence throughout all living kingdom. However, the functional disparity of MIPS genes in green plant is still viable. The present work considered a comprehensive genome-wide analysis from sequenced plants to identify MIPS homologs in respective organisms and their genomic architecture. Variation of MIPS gene expression in twelve different species in diverse conditions has also been analysed. All MIPS genes share a conserved sequence property in most of its coding region, but its regulatory elements, gene structure and expression network vary significantly. Phylogenetic inference confirms the evolution of MIPS from a single common algal ancestor to seed plants and acquiring functional variation through genomic control. This paper represents MIPS as a model for studying gene duplication, functional divergence and diversification events in plant lineages.

Vivipary is an extremely evolved type of epigeal germination in seed plants and very common in tropical estuarine plant communities (mangroves), ensuring a greater number of viable settings of offspring. In addition to this, there are some other non‐mangrove angiosperm taxa that have a successful existence, and because of their invasive nature, vivipary has been reported as an attribute of their uncongenial abiotic stress. The present observation confirms the incidence of true vivipary in Bidens pilosa L. (a member of the family Asteraceae) from the eastern Himalayan region.

Owing to the diverse growing habitats, ecophysiology might have a regulatory impact on characteristic chemical components of tea plant. This study aimed to explore natural variations in the ecophysiological traits within seasons and the corresponding multifaceted biochemical responses given by the gene pool of 22 tea cultivars. Leaf temperature and intercellular carbon concentration (Ci), which varies as a function of transpiration and net photosynthesis respectively, have significant impact on the biochemical traits of the leaf. Occurrence of H2O2, in leaves, was associated to Ci that in turn influenced the lipid peroxidation. With the increment of Ci, total phenolics, epicatechin gallate (ECG), reducing power, and radical scavenging activity is lowered but total catechin and non-gallylated catechin derivatives (e.g. epicatechin or EC, epigallocatechin or EGC) are elevated. Leaf temperature is concomitantly associated (p ≤ 0.01) with phenolics, flavonoids, proanthocyanidin, tannin content, reducing power, iron chelation and free radical scavenging activities. Increased phenolic concentration in leaf cells, conceivably inhibit photosynthesis and moreover, gallic acid, thereafter conjugated to catechin derivatives. This study shed light on the fundamental information regarding ecophysiological impact on the quality determining biochemical characteristics of tea, which on further validation, might ascertain the genotype selection paradigm toward climate smart cultivation.

Genotyping by sequencing and identification of functionally relevant nucleotide variations in crop accessions are the key steps to unravel genetic control of desirable traits. Elite cultivars of Darjeeling tea were undergone SNP genotyping by double-digest restriction-site associated DNA sequencing method. This study reports a set of 54,206 high-quality SNP markers discovered from ~10.4 GB sequence data, encompassing 15 chromosomes of the reference tea genome. Genetic relatedness among the accessions conforms to the analyses of Bayesian clustering, UPGMA, and PCoA methods. Genomic positions of the discovered SNPs and their putative effect on annotated genes designated a thoughtful understanding of their functional aspects in tea system biology. A group of 95 genes was identified to be affected by high impact variants. Genome-wide association analyses of 21 agronomic and biochemical phenotypes resulted in trait-linked polymorphic loci with strong confidence (p 0.05 and 0.001).

Genotyping by sequencing and identification of functionally relevant nucleotide variations in crop accessions are the key steps to unravel genetic control of desirable traits. In the scope of present work, elite cultivars of Darjeeling tea were undergone SNP genotyping by double-digest restriction site associated DNA sequencing method. This study reports a set of 54,206 high-quality SNP markers discovered from ∼10.4 GB sequence data, encompassing 15 chromosomes of reference tea genome. Genetic relatedness among the accessions conforms to the analyses of Bayesian clustering, UPGMA, and PCoA methods. High percent of heterozygous loci in the majority of the cultivars reflect their ‘hybrid’ ancestry as reported earlier. Genomic positions of the discovered SNPs and their putative effect on annotated genes designated a thoughtful understanding of their functional aspects in tea system biology. A group of 95 genes was identified to be affected by high impact variants, most of them are involved in signal transduction, biosynthesis of secondary metabolite, transcriptional and translational regulation. Genome-wide association analyses of 21 agronomic and biochemical phenotypes resulted in trait-linked polymorphic loci with strong confidence (p < 0.05 and 0.001). The selection of significant marker-trait associations with the Bonferroni correction threshold retained a set of 57 SNPs distributed across 14 chromosomes to be linked with eight phenotypic traits. High impact and trait-associated nucleotide polymorphisms perceived in this study can be exploited in worldwide germplasm of contrasting origin to depict their heritability and to unlock their potentiality in marker-assisted breeding.

Arsenic contamination in agricultural soil now imposing a major threat to crop productivity and causing several hazardous health effects through percolation in food chain. Bioremediation, an efficient way of soil health restoration toward sustainability offered by some soil-borne microorganisms, has been reported. The present work deals with application of two potent arsenic-tolerant bacterial strains (

Tea, Camellia sinensis (L.) O. Kuntze, an agro-based industry, is considered as one of the prime sector of exporting resources and thus considered as “cash-crop”. Earlier report shows that tea is n...

Tea, an evergreen shrub, is commercially cultivated in dense population as bushes in tea gardens. Periodical pruning of tea bushes makes tea plants distinct from other tree plants. Tea bushes have almost constant height throughout their life-time and have more compact canopy as compared to any forest trees. Hence, established methods of elucidating carbon dioxide (CO2) absorption in forest trees could not be employed for measuring CO2 assimilation in tea bushes. In this study, CO2 assimilation potentials of a high-yielding tea cultivar and a better quality producing tea cultivar had been periodically measured by closed-chamber method under field condition. Such type of experiment was not conducted before. This study revealed that tea bushes had potential to assimilate 1243.8–2526.7 kg CO2 ha−1 year−1 and the high yielding tea cultivar absorbed significantly higher amount of CO2 as compared to better quality producing tea cultivar. Several physiological parameters namely number of branches, plucking point density, leaf area and stomatal index were positively correlated to the annual CO2 assimilation by tea bushes. Higher CO2 assimilation in high yielding tea cultivars can be attributed to their larger and dense canopy structure due to more branching, higher plucking point density and higher leaf area. An algorithm has been derived for computing CO2 assimilation in tea bushes by considering the above-mentioned variable as indicators. This will enable to determine CO2 assimilation by tea plantation over a large area by measuring the physiological indicators without exercising in-situ experiments.

The new arena of crop improvement program requires next generation genomic technology in combination with a high throughput precised phenotyping. The aim and efforts of the research through unified molecular-morphological approach will be fulfilled only if they can be effectively employed in the cultivation process which ultimately would be positive to the beneficiaries. Development of competent and time saving tools for assessing the varying expression of agronomic traits of a crop and understanding its genetic background is a prerequisite. Recently, the commercially important beverage crop, tea (Camellia sinensis (L.) O. Kuntze), is of prime importance for its worthwhile health-benefit attributes. Although due to some inherited bottleneckness, several advanced genomics and phenomics technologies have already been utilized in tea for crop improvement program. Attempts have been made for its yield and quality trait associated marker development and next generation phenotyping considered to be the unique point of scientific interest. Moreover, definite selection of tea varieties with specific traits is being carried out for ensuring the premium tea products and brand by barcoding technology. This review summarises the concurrent advances of scientific research in tea improvement program as well as its prospects towards the production of superior cultivars and authenticity. Keywords: Crop improvement, Marker assisted selection, Next generation phenotyping, Tea, Varietal authentication

Mangroves are defined as woody, evergreen group of plant community; grow on the swampy substrate at tropical and sub-tropical habitatsadjusted to high salinity, periodical tidal influence, strong winds, high temperatures, high precipitation and anaerobic soils. They possessunique morphological and physiological adaptive features to cope with these extreme conditions. Mangrove vegetation is the cradle of several marine fauna and provides first line of defense against devastating sea surges, typhoon, tsunami, etc. However, since industrial era, many of the mangrove members were affected by several environmental constrains and anthropogenic activities that raised the sea level, lowered sweet water influx from the adjacent rivers and encroachment for the new settlement formation, increasing salinity. Hence, mangrove restoration program is the front line topic of interest to the plant biologists across the tropical and subtropical world since it has a productive and protective role for the inhabitants. Sound knowledge of molecular characteristic of the individual taxa will be provide an advantage for this initiative.Recent advancement in molecular markers based on the PCR technique techniqueswill enhance the knowledge about genetic background of each individual taxon, ultimately leading to valid guided references towards the understanding the inherent nature of the plant itself and beneficial to proper restoration program.

Mangrove, a specialized group of plant communities, provide immense ecological and protective benefits to the coastal areas of the tropical and subtropical world where they thrive. Demographic obligation and climatic hostilities have massively altered their vegetation pattern and, even ruined some key species to large extent. The present study aims to consider Reactive Oxygen Species (ROS) scavenging skills in some degrading mangrove taxa of Indian Sundarbans (Xylocarpus granatum and Heritiera fomes) compared with some opulently growing ones (Excoecaria agallocha, Bruguiera gymnorrhiza and Phoenix paludosa) in increasing salinity gradient, in relation to their sustainability. Non-enzymatic antioxidants (secondary metabolites) Proanthocyanidin and Tannin were estimated and Free radical scavenging ability was evaluated by Singlet Oxygen Scavenging Activity Assay, Reducing power assay, effects on Peroxynitrite, Nitric Oxide Radical Scavenging, Hydrogen Peroxide Scavenging Activity Assay, Reaction with Hypochlorous Acid, Superoxide Radical Scavenging Activity Assay and Hydroxyl Radical Scavenging Activity. Relatively higher occurrence of secondary metabolites and improved antioxidant ability were recorded in E. agallocha, B. gymnorrhiza and P. paludosa; than the other two plants X. granatum and H. fomes; where the trend showed a decline in the ROS scavenging after a certain increase in salinity. Strong positive correlation of both secondary metabolites and radical scavenging ability with salinity pose the three stable taxa more viable in the higher salty environment of the Indian Sundarbans. But relatively less ROS scavenging ability in more saline zones, may be the potential reason for the unfavorable existence of the two red listed plants, which would ultimately lead to gradual natural extinction of them from the Indian Sundarbans.

A comparative deliberation has been considered among three Indian processed teas (black, green and white) in respect to their prevalence of some secondary metabolites, antioxidant ability (ABTS and DPPH assay), nutritional properties, inorganic elemental profile and bactericidal efficiency. Green and white tea, incidence of total phenol, total flavonoids, proanthocyanidins and tannin are higher than the black. ABTS and DPPH study reveals lower IC50 occurred in Green tea. Green tea is enriched in Na, Fe, Mg, and Mn content; black is rich in K, Ca and white has highest Zn. Total sugar and free amino acid are highest in white tea; total protein content is almost same in all three types. Green tea is enriched with vitamin C. Antimicrobial asset is experienced against Bacillus subtilis, Staphylococcus aureus (gram + ve) and Escherichia coli and Pseudomonas aeruginosa (gram - ve) bacteria. Study revealed that green tea has higher antimicrobial activity than the other two, though higher inhibitory effect of black tea might be attributed to the presence of substantial amount of tannin. Statistical evaluation reflects that in all organic and aqueous extracts, secondary metabolites correlate linearly with DPPH and ABTS assays but are not consistent with bactericidal efficiency in all cases.

Not only for the age-old customs but also the recent advancement in researches has pointed towards the fact that the several beneficial components present in tea help to achieve its popularity as a second best drink after water across the world. According to World Tea News, in 2015–2016, the total world tea production reached up to 4,481,860 tonnes, in which Indian share was 28.8% (1,29,190 tonnes) and this is almost twice the amount to that of 10 years back. Similarly, world tea economy has also appeared to its healthy business figure since the last decades (28.2 billion US$ in 2016). The global market is broadly controlled by black and green teas, although there are more types of teas that are being consumed according to local consumer’s perception (oolong, white, yellow, and pu-erh). Commercially, tea leaves are harvested at different stages of growth and undergo a series of processing techniques (withering, disrupting, oxidising, fixing, sweltering, rolling, and drying) before being packaged and marketed. Subject to the implementation of the all steps of processing or omitting some steps and duration, different types of teas are prepared. During processing, the phytochemicals present in green tea leaves are being greatly modified, and each variety of tea appears with specific colour, aroma, taste, and briskness after infusion. A typical agroclimatic condition is required for quality production of tea. Acidic soil, 5–10° of slopes, temperature ranging from 10 to 30 °C, minimum average rainfall 100–120 cm/year, more than 2000 mt. above sea level of elevation, and well drainage system are the ideal agroclimatic situation for tea cultivation. Different polyphenols and their derivative (catechin, epicatechin, epigallocatechin gallate, epigallocatechin, theaflavins, thearubigins, etc.) and several free radical scavenging elements in infused tea have proven their health assistance feature in recent researches. Conventional breeding technique is not competently applicable for this utility crop because of their self-incompatibility. Hence, several techniques of molecular breeding occupy the frontline research on tea. In this regard, molecular marker-assisted research for better facility to locate the essential gene location in whole genome sequence for the desirable agronomic traits is in lime light.

MicroRNAs are the short, noncoding, regulatory molecules, effective variation on which may lead to anomalous gene manifestation on its target downstream pathway. Variants related to miRNA genes can affect the miRNA transcription, maturation, or target specificity, consequently hindering their functionality in the development or stress responses of plants. Both sequence and length variations in mature miRNA and its precursor can be responsible for conferring the functional alteration. miRNA based SSR is the newly incorporated type of functional marker and is being applied to plant breeding in recent years. Changes in the number of repeat motifs within the miRNA precursors are supposed to play important role in miRNA biogenesis by persuading alternative splicing and thereby linked to phenotypic diversity. Collectively, miRNA sequence polymorphisms may serve as the potential, reproducible biomarkers associated with important agronomic traits thus would assist in future breeding programs. In this context, the present review epitomizes the miRNA variant based markers and their significance in crop science from a functional standpoint.

Comparative adaptability against salinity was assessed between the two wellknown mangroves (Avicennia marina and Heritiera fomes) from Indian Sundarbans in vitro. Occurrence of H. fomes is intermittent in and around of this mangrove swamp. A harmony has to maintain between ROS production and efficient scavenging of ROS by the plant itself for sustainability. In the present work, extent of salt tolerance was evaluated by mainly two ways: i) accumulation of free amino acids in the cytoplasm for proficient osmotic adjustment and ii) promoting elevated amount of antioxidants (both enzymes and secondary metabolites) with respect to substrate salinity. Occurrence of free amino acids (Alanine, Leucine and Proline) in A. marinaare well correlated (p ≤ 0.01) with the increasing salinity and H. fomes (Alanine and Phenyl Alanine) correlation value showed p ≤ 0.05. ROS scavenging reflected through ABTS, DPPH and Fe2+ chelating activity and results indicating that A. marina have some advantage over the other investigated taxa. Amount of phenols and flavonoids also designated the same. Additional number of isoforms of two antioxidant enzymes (peroxidase and super oxide dismutase) occurred in A. marina as the salinity enhanced, but in case of H. fomes, which was lacking. The experimental results might be designated towards the comfortable adaptability to A. marina, rather to H. fomes.

Tea (Camellia sinensis, (L.) Kuntze) is considered as most popular drink across the world and it is widely consumed beverage for its several health-benefit characteristics. These positive traits primarily rely on its regulatory networks of different metabolic pathways. Development of microsatellite markers from the conserved genomic regions are being worthwhile for reviewing the genetic diversity of closely related species or self-pollinated species. Although several SSR markers have been reported, in tea, the trait-specific Simple Sequence Repeat (SSR) markers, leading to be useful in marker assisted breeding technique, are yet to be identified. Micro RNAs are short, non-coding RNA molecules, involved in post transcriptional mode of gene regulation and thus effects on related phenotype. Present study deals with identification of the microsatellite motifs within the reported and predicted miRNA precursors that are effectively followed by designing of primers from SSR flanking regions in order to PCR validation. In addition to the earlier reports, two new miRNAs are predicting here from tea expressed tag sequence database. Furthermore, 18 SSR motifs are found to be in 13 of all 33 predicted miRNAs. Trinucleotide motifs are most abundant among all followed by dinucleotides. Since, miRNA based SSR markers are evidenced to have significant role on genetic fingerprinting study, these outcomes would pave the way in developing novel markers for tagging tea specific agronomic traits as well as substantiating non-conventional breeding program.

Comparative adaptability in five halophytes (Bruguiera gymnorrhiza, Excoecaria agallocha, Heritiera fomes, Phoenix paludosa and Xylocarpus granatum, of which, H. fomes and X. granatum presently are stressed in Sundarbans area) were evaluated with respect to occurrence of total phenol, flavonoids, and radical scavenging ability following ABTS [2, 2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid)], DPPH (1, 1-diphenyl-2-picrylhydrazyl) assay and Fe2+ chelating ability. Amount of total phenol (TP) and flavonoids (TF) were much higher in all taxa grown in Sundarbans than those of mesophytic one. TP and TF were significantly augmented as the substrate salinity increased in B. gymnorrhiza, E. agallocha and P. paludosa but disordered in H. fomes and X. granatum, where increment occurred only up to a certain salinity level. Percent of free radical scavenging of extractants by DPPH and ABTS radical perceived significant correlation with salinity in former three but differ in H. fomes and X. granatum. Ferrous ion chelating ability also showed the similar trend. Owing to polyphenols occurrence and ROS scavengers, the present work clearly indicates the better adaptability of B. gymnorrhiza, E. agallocha and P. paludosa in elevated substrate salinity than those of the other two. Lower ROS scavenging ability of H. fomes and X. granatum also points to their perilous occurrence in elevated saline zones.

Palynological evidence is recognized as a logical deduction of paleoclimatic extrapolation, as coastal vegetation is so specialized that any minor deviations in hydrological or tidal influences cause radical variations in the vegetational succession. Sedimentological and biological characteristics in terms of pollen/spore analysis of the peat along with dating of subsurface deposits are highly instructive in reconstructing the vegetational history, ecological status, and palaeoenvironment of the Quaternary. A comparative study of fossil pollen morphology was carried out with an objective towards the assessment of past vegetation and its similarity, if any, with the modern habitat. The present study involved investigation, accompanied by 14C dating of undisturbed bore-hole peat samples collected from Garia, a suburb of Calcutta (Lower Bengal Basin), near the world's largest mangrove forest, the Sundarbans. Pollen data indicates the existence of typical mangrove vegetation in and around Calcutta, presently confined to the Sundarbans forest, south of the studied area. The lowermost peat layer (ca. 7000–6500 BP) reveals that the vegetation sequence was comparatively uniform and mainly comprised of typical mangrove families such as Heritiera, Rhizophora, Sonneratia, Excoecaria, Phoenix and grasses, implying insignificant fluctuations in climatic conditions. The middle layer indicates a mixed vegetation of fern spores, mangroves and some terrestrial plants (e.g. Acanthus, Cynometra, Suaeda, and grass). The lower part of the middle peat layer (ca. 6450–6100 BP) consisted of marshy habitat as indicated by fern spores, whereas their absence in the upper part implies relatively dry environmental conditions. The upper peat layer (ca. 2600 BP) is dominated by grass, pollen of terrestrial habitats (Typha, Cassia, Eucalyptus, Desmodium, Salicornia, members of Fabaceae, Asteraceae and Rhamnaceae) and some typical mangroves (Heritiera and Excoecaria). Low amounts of fern spores indicate that the Lower Bengal changed towards terrestrial habitats. The pollen/spore assemblages in the three successive peat layers indicate the presence of typical mangrove vegetation, presently observed in the Sundarbans region. Frequent sea water inundation mixed with fresh water flow from the northern upstream at the low lying topography of Basin seems to have led to the formation of peat by deposition rather than by drifting.

Ten Darjeeling tea clones (BT15/263, RR17/144, B777, T253, B157, Sundaram, HV39, AV2, K1/1 and TTV1) were collected from the experimental garden of Darjeeling Tea Research and Development Centre, Kurseong. Total phenol, flavonoids and two antioxidating enzymes (peroxidase and superoxide dismutase) were estimated. The total phenol ranged between 241 and 28 GAE mg g(-1) of leaf dry weight. The highest amount obtained in four clones, B15/263 (241.47), RR17/144 (221.2), B777 (154.54) and B157 (140.23 mg g(-1)). Flavonoids were estimated as Catechin equivalent (CE) and ranged between 56.88 and 20.81 CE mg g(-1) leaf dry weight. Higher amounts occurred in BT15/263 (56.88 mg g(-1)), B777 (56.69) and RR17/144 (48.63). Antioxidant activities were measured following DPPH and ABTS free radicle scavenging procedures and the results were well according to total polyphenol content among the clones (in total phenols, ranges of correlation in DPPH assay were r (2) = 0.990-0.989, p ≤ 0.05; in flavonoids r (2) = 0.954, p ≤ 0.01-0.987, p ≤ 0.05). Similarly, ABTS percent scavenging results were quiet significant. The IC50 values were determined for both DPPH and ABTS assay. PAGE expressions of isoforms in two antioxidative enzymes and quantification of them also varied much among the investigated clones. The incidence of total phenols, flavonoids, PRX and SOD and ROS scavenging assay in in-situ condition, might be used as biochemical markers towards the superior adaptability against abiotic stress. In the present work, four clones (B15/263, B777, RR17/144 and B157) would be designated as comparatively better suited to the predicted abiotic stress.

Myoporum bontioides A. Gray (Myoporaceae), a red list plant in Japan, is restricted to only a few East Asian countries like China, Japan and Taiwan, associated to some true mangroves. The leaf is isolateral and has a thick cuticle; stomata are anomocytic, sunken and have a beak-shaped cuticular outgrowth at the inner and outer side of the stomatal pore (ledges); profuse glandular hairs are scattered on both leaf surfaces of young leaves. The mesophyll is compact with palisade and spongy parenchyma cells in the young stage, but at maturity profuse intercellular spaces can be observed. Secretory ducts occur in young leaves. Pear-shaped glandular hairs protrude from the epidermal layer. Hair primordia are well distinct by their larger size and undergo divisions to produce two laterally placed basal cells, two stalk cells and four radiating terminal cells. The cuticle layers of the terminal cells are often separated from the cell wall to form a space, in which ions accumulate for excretion. Inner walls of the basal cells are connected with the mesophyll. Though ontogeny and structure of glandular hairs have resemblance to typical mangroves, considering leaf micromorphology, this plant is better termed as “mangrove associate” instead of “true man

Cellular ion homeostasis through osmotic adjustment and efficient free radical scavenging ability are considered as fundamental salt tolerance determinants of plants. Increased salinity (~30 ppt) in Indian Sundarbans has incurred detrimental impact on vegetation pattern, and leading to the precarious existence of some taxa. A comparative account on some physiological and biochemical determinants towards salt stress were assayed in order to focus on the extent of adaptability among the three true mangroves. An in vitro experiment was carried out with mangrove seedlings of Avicennia marina, Bruguiera gymnorrhiza and Heritiera fomes in differential NaCl treatments. Among the five sets of treatment (0, 100, 200, 300 and 400 mM), leaf osmotic potential (ψ) shows consistent hike in A. marina and B. gymnorrhiza along the salinity gradient, at least up to 300 mM (77 and 58 % respectively over control) and comparatively poor in 400 mM. On the other hand, H. fomes reaches its maximum OP value in 200 mM NaCl treatment (64 % increment from control). Thin layer Chromatography was employed for assessing seven free amino acids and spectrophotometric quantification of them from leaf tissues grown in different salinity gradients were performed. The two antioxidative enzymes (Peroxidase and Superoxide dismutase) were estimated qualitatively and quantitatively in three taxa at different salinity level. As compared to other two taxa, H. fomes depicted fewer numbers of isoforms of two enzymes in PAGE analysis, and less enzyme activity across the salinity gradients. Considering the studied parameters, H. fomes might be endorsed towards the feeble adaptability in the present day’s elevated salinity of Indian Sundarbans.

Ceriops (Rhizophoraceae) is a genus comprised of five species of mangroves distributed in tropical and subtropical coastal regions. In this study, sequences from nuclear ribosomal ITS and the plastid trnL intron are used to construct molecular phylogenies of this genus revealing two species complexes, the C. tagal complex (C. tagal and C. australis), and the C. decandra complex (C. decandra, C. pseudodecandra and C. zippeliana), each forming a distinct clade. All five species, including the newly designated species C. pseudodecandra, are well supported. However, natural hybridization and historical introgression between Ceriops species are also demonstrated. The ITS sequences of Ceriops species, in contrast to their plastid trnL intron sequences, show a great amount of homoplasy during evolution. Historical introgression originating from natural hybridization was demonstrated based on the additivity of ITS sequences from putative parents. Of the five Ceriops species, C. pseu- dodecandra is a relatively isolated species. C. decandra and C. zippeliana show mutual introgression in most populations. According to both the nuclear ITS sequences and the plastid trnL intron, an intermediate form from Darwin is likelya natural hybrid, with C. tagal and C. australis respectively the maternal and paternal parents.

Elevated substrate salinity and anthropogenic impulse are the major threat to the mangrove ecosystem. In the Indian subcontinent, Sundarbans have the richest mangrove species diversity. Due to geomorphic characteristics and unplanned management, the elevated salinity prevails in the western part and that has direct impact on vegetation. Seven mangrove taxa were examined, of which four (Aegialitis rotundifolia, Heritiera fomes, Xylocarpus granatum, and X. mekongensis) were considered as degrading and three (Bruguiera gymnorrhiza, Excoecaria agallocha, and Phoenix paludosa) were considered as natural control. The targeted taxa were collected from five different islands and were selected on the basis of increasing salinity gradient. As salinity increased from site I to V (11.76–15.2 ppt), the amount of total leaf proteins decreased in all the targeted species and ranged between 5.67 and 25.23%. The percentage of protein depletion was less in Aegialitis, Heritiera, and Xylocarpus than the other three taxa in higher salinity that pointed out their less adaptability, as degradation of protein may be essential for efficient stress management. Two antioxidative (peroxidase and superoxide dismutase) and two hydrolyzing (acid phosphatase and esterase) enzymes showed a positive correlation with salinity. In four degrading taxa, the percentage of enzyme increment was less than those of their natural control taxa. Salinity imposed increment of antioxidant enzymes facilitate ROS scavenging, which is an inevitable elevated byproduct during photo-inhibition. Lower amount and number of isoforms in higher salinity indicated towards less suitability of Aegialitis rotundifolia, Heritiera fomes, Xylocarpus granatum, and X. mekongensis in increased salinity level of western Sundarbans.

Five typical mangroves were taken (Bruguiera gymnorrhiza, Excoecaria agallocha, Heritiera fomes, Phoenix paludosa and Xylocarpus granatum) both from Sundarbans (in situ) and grown in a mesophytic environment (ex situ, in the Institute’s premises) for 12–15 years. A comparative account of PAR utilization for maximum photosynthesis, stomatal conductance and production of two antioxidant enzymes (peroxidase and Superoxide dismutase) were done between the in situ and ex situ habitats. The present work revealed that the average net photosynthesis was slightly higher in mangroves from non-saline habitats than that of the native ones. At the same time, stomatal conductances were remarkably reduced under salinity-stressed habitats when compared with those of the mesophytic counterparts, by 25–52%. Salinity imposed increase of antioxidant enzymes was observed. Both the investigated antioxidant enzymes showed considerable increase in saline-grown individuals and proved their efficient scavenging ability to evolve reactive oxygen species (ROS), but these increases were relatively lower in Heritiera and Xylocarpus even though the net photosynthesis was higher. This might be related to their lower adaptability under increased salinity stress than those of the other three species investigated.

A comparative account of the polymorphic expression of two antioxidative enzymes (Peroxidase and Superoxide dismutase), two hydrolyzing enzymes (Esterase and Acid phosphatase) and total proteins was estimated both qualitatively and quantitatively from the leaves of five mangroves (Bruguiera gymnorrhiza, Excoecaria agallocha, Heritiera fomes, Phoenix paludosa and Xylocarpus granatum) from two different habitats (in situ habitat of Sundarbans and their replicas from ex situ habitat in fresh water condition) and discussed. The higher amount of total protein occurred in fresh water plants compared to their Sundarbans counterparts. The increment of total protein ranged among 156% to 5.7%. Gel electrophoresis experiments revealed that in most of the cases there were extra numbers of protein bands expressed with relatively low molecular weight in saline habitat. In all salinity imposed plants, there were sharp increases in band intensity and the number of isoforms of investigated enzyme. Peroxidase incr...

Palynological analysis was conducted in view of past ecological reconstruction trends of Calcutta, the Lower Bengal Basin (West Bengal), India. Floristic compositions were derived from peat samples collected from Garia, located at the southern extremity of the city. Garia, being one of the oldest settlements in this region, is situated by the ‘Tolly Nullah’ connecting Calcutta to the Vidhyadhari River at the east. Bore hole samples were radiocarbon dated and three successive peat layers of 7000 (+170) y. B.P. to 2650 (+150) y. B.P. were analyzed for their pollen composition. Pollen data indicates the existance of typical swampy vegetation of mangrove plant community in and around Calcutta, which are presently confined to the Sundarbans forest, the further south of the studied area. The lower most peat layer (ca. 7000–6500 y. B.P.) reveals that the vegetational sequence was comparatively uniform and mainly comprised of Heritiera, Rhizophora, Sonneratia, Excoecaria, Phoenix paludosa and grasses, implying insignificant fluctuations in climatic conditions. The middle layer indicates a mixed vegetational type of fern spores, mangroves and some terrestrial plants (e.g. Acanthus, Cynometra, Suaeda, and grasses). The lower part of the middle peat layer (ca. 6450–6100 y. B.P.) consisted of marshy habitat as evidenced by fern spores, whereas their absence in the upper part implies relatively dry environmental conditions. The upper peat layer (ca. 2600 y. B.P.) is dominated by grass, pollen grains terrestrial habitats (Typha, Cassia, Eucalyptus, Desmodium, Salicornia, and Rhamnaceae) and some of typical mangroves (Heritiera and Excoecaria). Low amounts of fern spores indicating Lower Bengal change towards the terrestrial habitats. The pollen/spore assemblages in the three successive peat layers indicate the presence of typical mangrove vegetation, of the type currently observed in the Sundarbans region. Frequent sea water inundation mixed with fresh water flow from the northern upstream at the low lying topography of Basin seems to have led to the formation of peat by deposition rather than by drifting. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Mangroves are physiologically interesting as potential models for stress tolerance and as sources of alternative ideas about physiological strategies relevant at the ecosystem level. Variation in habitat has great impact on the physiological behavior and biochemical expression level of a particular plant species. Five species of mangroves, growing in saline and fresh water conditions were assessed for their ecological fitness in two different habitats. Assessments were based on some physiological and biochemical parameters measured from the fully exposed mature leaves under saline (15–27 PPT) and non-saline (1.2–2 PPT) conditions. Among the five species considered for investigation Bruguiera gymnorrhiza, Excoecaria agallocha and Phoenix paludosa grow luxuriously in the Sundarbans forest, while the rest two (Heritiera fomes, Xylocarpus granatum) are scanty. A comparative account of photosynthetic efficiency, chlorophyll content, mesophyll and stomatal conductance, specific leaf area, photosynthetic nitrogen use efficiency, total foliar free amino acids and differential expression of some antioxidant isoenzymes in leaf were estimated between the saline and non-saline plants. Elevated assimilation rate coupled with increased chlorophyll content, increased conductance and higher specific leaf area in non-saline condition indicates ability of these mangroves to grow even under minimal substrate salinity. The optimum PAR acquisition for photosynthesis in B. gymnorrhiza, E. agallocha and P. paludosa was higher under salt stress, while the maximum assimilation rate was lower in control plants. The opposite trend occurred in H. fomes and X. granatum, where the peak photosynthesis was lower under non-saline conditions even at a higher irradiance than in the saline forest. The isoform patterns of peroxidase, acid phosphatase and esterase indicated considerable difference in regulation of these enzymes due to salt stress and /or reverse adaptation.

A study on pollen morphology of four common Indian mangroves from Sundarbans mangrove swamps, three species from the family Rhizophoraceae (Bruguiera sexangula Laur., Ceriops tagal Perr.and Rhizophora mucronata Lamk.) and one species from the family Avicenniaceae (Avicennia marina Forsk.) was carried out. Shape of the pollen grains were prolate, prolate spheroidal and subprolate with tricolporate apertures. Surface ornamentation of the studied taxa was reticulate, finely reticulate or scabrate. Pollen grain viability of the said taxa was determined by stain test (1% aceto-orcein) under in situ condition and percentage of viable pollen production was recorded. The result revealed that all the studied taxa produce a fairly good amount of viable pollen grains in natural condition, an indication that they are good propagule producer in the long run. Pollen grain germination and measurements of pollen tube length using different sucrose concentrations (0.2, 0.6, 1.0, 1.2, 1.6 and 2.0%). Maximum pollen fertility and pollen tube length occurred in 2% sucrose solution in case of A. marina and B. sexangula, whereas 1.6% in C. tagal and 1.0% in R. mucronata. A strong positive correlation exist between pollen germination and pollen tube length, but there was a hardly relation between sucrose concentration and pollen tube length.