Adiantum Reniforme Var Research Articles

Green Globular Body Induction and Plantlet Regeneration of Endangered Fern Adiantum reniforme var. sinense

Background: Adiantum reniforme var. sinense is a pteridophyte with considerable ornamental importance and medicinal value. However, the wild population of A. reniforme var. sinense has gradually become scarce due to sparse distribution and human activities. Green Globular Bodies (GGBs) are specific tissue which use to propagate ferns in vitro. The study uses GGBs induced from sporophytic embryos to preserve and to proliferate this pteridophyte. Methods: The present study was carried out during year 2018-2020 at National Ilan University. The developing sporophyte of Adiantum reniforme var. sinense were used to induce GGBs. The optimal medium for GGBs proliferation and differentiation in terms of basal salts, plant growth regulators, sugar concentrations and gelling agents was examined. The structure of GGBs and the embryos were analyzed by paraffin section as well. Result: The result indicates the 100% GGBs induction rate from sporophytic embryos for the first time could be obtained under BA (0.1 mg L-1) and NAA (0.15 mg L-1). For subsequent proliferation of GGBs required a higher concentration of NAA (10 mg L-1). Cytokinins such BA, KT and TDZ, inhibited GGBs proliferation. In vitro optimal amount of basal salts, plant growth regulators, sugar concentrations and gelling agents for GGB proliferation were obtained as 2 g L-1 Hyponex, 10 mg L-1 NAA, 15 g L-1 sucrose and 4 g L-1 gelrite, respectively. Paraffin sections revealed histological characteristics of the sporophytic embryo and GGB.

Identification and validation of suitable reference genes for quantitative real-time PCR studies in Adiantum reniforme var. sinense

Identification and validation of suitable reference genes for quantitative real-time PCR studies in Adiantum reniforme var. sinense

Morphological and anatomical adaptations to dry, shady environments in Adiantum reniforme var. sinense (Pteridaceae).

The natural distribution of the rare perennial fern Adiantum reniforme var. sinense (Pteridaceae), which is endemic to shady cliff environments, is limited to small areas of Wanzhou County, Chongqing, China. In this study, we used brightfield and epifluorescence microscopy to investigate the anatomical structures and histochemical features that may allow this species to thrive in shady, dry cliff environments. The A. reniforme var. sinense sporophyte had a primary structure and a dictyostele. The plants of this species had an endodermis, sclerenchyma layers and hypodermal sterome, reflecting an adaption to dry cliff environments. Blades had a thin cuticle and isolateral mesophyll, suggesting a tolerance of shady environments. These characteristics are similar to many sciophyte ferns such as Lygodium japonicum and Pteris multifida. Thus, the morphological and anatomical characteristics of A. reniforme var. sinense identified in this study are consistent with adaptations to shady, dry cliff environments.

The chloroplast genome of Adiantum reniforme var. sinense, an endangered fern endemic to China

Adiantum reniforme var. sinense, a rare and endangered fern endemic to Chongqing, China, has been listed as one of the National Key Protected Wild Plants (Class I) in China. Here we assembled its chloroplast genome (cp genome) using Illumina sequencing reads to offer a genetic resource for future conservation genetic studies. The complete cp genome of A. reniforme var. sinense was 150,109 bp in length with an overall GC content of 42.85%. It contains a large single copy (LSC) region of 83,274 bp and a small single copy (SSC) region of 21,459 bp, separated by a pair of inverted repeat regions (IRs) of 22,688 bp each. The cp genome contains 84 protein coding genes, 28 tRNA genes, four rRNA genes, and one pseudogene (ψrps16). Phylogenetic analysis showed that A. reniforme var. sinense clustered together with four other Adiantum species and was sister to A. capillus-veneris.

Comparative transcriptome analysis of two reproductive modes in Adiantum reniforme var. sinense targeted to explore possible mechanism of apogamy

BackgroundApogamy is a unique asexual reproduction in the ferns, in which somatic cells of gametophytes go through dedifferentiation and then differentiate into haploid sporophytes bypassing fertilization. Restricted to the lack of genomic information, molecular mechanisms of apogamy have remained unclear. Comparative transcriptome analysis was conducted at six stages between sexual reproduction and apogamy in the fern Adiantum reniforme var. sinense, in an effort to identify genes and pathways that might initiate the asexual reproduction.ResultsApproximately 928 million high-quality clean reads were assembled into 264,791 unigenes with an average length of 615 bp. A total of 147,865 (55.84%) unigenes were successfully annotated. Differential genes expression analysis indicated that transcriptional regulation was more active in the early stage of apogamy compared to sexual reproduction. Further comparative analysis of the enriched pathways between the early stages of the two reproductive modes demonstrated that starch and sucrose metabolism pathway responsible for cell wall was only significantly enriched in asexual embryonic cell initiation. Furthermore, regulation of plant hormone related genes was more vigorous in apogamy initiation.ConclusionThese findings would be useful for revealing the initiation of apogamy and further understanding of the mechanisms related to asexual reproduction.

A survey on ecological environment of wild Adiantum reniforme var. sinense in Three Gorges Reservoir region

The study aims at investigating the ecological environment Adiantum reniforme var. sinense of in Three Gorges Reservoir region, and providing a reference basis for the protection of resources and artificial cultivation of A. reniforme var. sinense. By using the method of investigation, field survey and experimental analysis, the vegetation, natural geographical environment, climate, soil nutrients of A. reniforme var. sinense were studied and analyzed. The survey found that A. reniforme var. sinense distribution area reduced fast in Three Gorges region, a lot of distribution has diminished and vanished due to excessive digging, currently only in 3 towns of Wanzhou there exist 4 wild distribution areas. The growth of A. reniforme var. sinense needs an environment with low altitude, steep slope and thin soil, northeast slope, canopy height and warm and humid climate characteristics, and the soil in distribution has the characteristics of high organic matter, available nitrogen, available potassium, and low available phosphorus content.

Identification of the relationship between Chinese Adiantum reniforme var. sinense and Canary Adiantum reniforme.

BackgroundThere are different opinions about the relationship of two disjunctively distributed varieties Adiantum reniforme L. var. sinense Y.X.Lin and Adiantum reniforme L. Adiantum reniforme var. sinense is an endangered fern only distributed in a narrowed region of Chongqing city in China, while Adiantum reniforme var. reniforme just distributed in Canary Islands and Madeira off the north-western African coast. To verify the relationship of these two taxa, relative phylogenetic analyses, karyotype analyses, microscopic spore observations and morphological studies were performed in this study. Besides, divergence time between A. reniforme var. sinense and A. reniforme var. reniforme was estimated using GTR model according to a phylogeny tree constructed with the three cpDNA markers atpA, atpB, and rbcL.ResultsPhylogenetic results and divergence time analyses--all individuals of A. reniforme var. sinense from 4 different populations (representing all biogeographic distributions) were clustered into one clade and all individuals of A. reniforme var. reniforme from 7 different populations (all biogeographic distributions are included) were clustered into another clade. The divergence between A. reniforme var. reniforme and A. reniforme var. sinense was estimated to be 4.94 (2.26-8.66) Myr. Based on karyotype analyses, A. reniforme var. reniforme was deduced to be hexaploidy with 2n = 180, X = 30, while A. reniforme var. sinense was known as tetraploidy. Microscopic spore observations suggested that surface ornamentation of A. reniforme var. reniforme is psilate, but that of A. reniforme var. sinense is rugate. Leaf blades of A. reniforme var. sinense are membranous and reniform and with several obvious concentric rings, and leaves of A. reniforme var. reniforme are pachyphyllous and coriaceous and are much rounder and similar to palm.ConclusionAdiantum reniforme var. sinense is an independent species rather than the variety of Adiantum reniforme var. reniforme. As a result, we approve Adiantum nelumboides X. C. Zhang, nom. & stat. nov. as a legal name instead of the former Adiantum reniforme var. sinense. China was determined to be the most probable evolution centre based on the results of phylogenetic analyses, divergence estimation, relative palaeogeography and palaeoclimate materials.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-014-0361-9) contains supplementary material, which is available to authorized users.

Growth characteristics of Adiantum reniforme var. sinensis and A. capillus‐veneris in response to light and soil moisture

Adiantum reniforme var. sinensis (Adiantaceae) is an endangered fern endemic to the Three Gorges region in southwest China. To elucidate possible ecophysiological mechanisms restricting its distribution, effects of the availability of light (28%, 14% and 7% of open field) and soil moisture (60% and 40% of field capacity) on dry matter production and allocation, leaf morphology and water use efficiency (WUE) were examined in A. reniforme var. sinensis and its widespread congener A. capillus‐veneris. Both species had lower root/shoot ratio (R/S) and higher specific leaf area (SLA) when grown at low light. However, A. reniforme var. sinensis showed less plasticity for total leaf area (LA) and leaf area ratio (LAR) than A. capillus‐veneris, and its root mass, total mass and WUE decreased as light availability decreased. Under water stress, all traits of both species except WUE were significantly affected. However, drought stress decreased total mass of A. capillus‐veneris but did not have a significant effect on A. reniforme var. sinensis. Compared with A. capillus‐veneris, A. reniforme var. sinensis had significantly higher R/S but lower values for other analyzed traits. These results suggest that A. reniforme var. sinensis is relatively superior in drought tolerance but inferior at low light, allowing it to persist in habitats with low soil moisture and high light availability but with few coexisting species present.

Effects of light, macronutrients, and sucrose on germination and development of the endangered fern Adiantum reniforme var. sinense (Adiantaceae)

Effects of light, macronutrients strength of Murashige and Skoog (MS) (1962), and sucrose in the culture medium on spore germination and gametophyte development of the endangered fern Adiantum reniforme var. sinense were investigated. The presence of light was found to be essential for both spore germination and gametophyte growth. Moreover, a medium consisting of 1/4 MS with 15 g/l sucrose was optimal for spore germination and early gametophyte development; whereas, MS medium with 30 g/l sucrose was optimal for further gametophyte development. Increasing amounts of sucrose (45–60 g/l) in the medium delayed gametophyte growth and development. Additionally, sporophyte formation and early growth of gametophytes in a medium consisting of clay and peat (v/v = 1:2) was higher than those in a medium consisting of pure river sand. These findings indicated that requirements for nutrients for spore germination and early gametophyte development of A. reniforme var. sinese were relatively low, but these increased with further gametophyte development, formation and growth of sporophytes.

Understanding population structure and historical demography in a conservation context: population genetics of an endangered fern

ABSTRACTThe construction of the world's largest hydroelectric scheme across the Yangtze River, the Three Gorges Dams (TGD), in the centre of a southern‐central Chinese biodiversity hot spot, the Three Gorges Reservoir Area (TGRA), has attracted international concern and conservation action. To examine whether landscape changes to date have impacted regional flora, and to establish long‐term monitoring baselines, we assessed the distribution and dynamics of an endangered and TGRA endemic fern, Adiantum reniforme var. sinense. For eight nuclear microsatellites, high levels of genetic diversity (HE = 0.653–0.781) and slightly elevated inbreeding (FIS = 0.077–0.197) were found across 13 surveyed populations. The population history of this fern is characterized by a balance of gene flow and genetic drift, where historical dispersal, inferred from coalescent (F = 0.129) and genetic differentiation (FST = 0.094 and RST = 0.180) approaches, is moderate, reflecting an isolation by distance relationship. Importantly, most populations exhibited mutation‐drift disequilibrium, suggesting a recent population decline, which is congruent with the known demographic history of the species following dam‐related activities. Based on these results, populations of A. reniforme var. sinense are expected to lose genetic diversity and increase genetic structure as dam‐related activities decrease size and increase genetic isolation of remnants.

Effects of Soil Moisture on Ecophysiological Characteristics of Adiantum reniforme var. sinensis, an Endangered Fern Endemic to the Three Gorges Region in China

ABSTRACT The effects of soil moisture (80%, 60% and 40% water holding capacity) on dry matter production and allocation, leaf morphological and physiological characteristics were examined in Adiantum reniforme var. sinensis, an endangered fern endemic to the Three Gorges region in southwest China. Drought stress decreased leaf growth and photosynthetic capacity, and hence reduced total mass, specific leaf area (SLA) and leaf area ratio (LAR). Dry matter allocation into the root fraction, however, increased with decreasing soil moisture. Leaf relative water content (RWC) decreased as soil water depletion, but the differences were insignificant. Such results might be the result of a physiological balance between the demand for water by the leaves and the water uptake from soil by the roots. The decrease in stomatal conductance (gs) effectively controlled water loss and maintained intrinsic water use efficiency (WUEi) under drought stress. The increase in proline content might contribute to osmotic adjustmen...

Leaf traits of natural populations of Adiantum reniforme var. sinensis, endemic to the Three Gorges region in China

Leaf mass per unit area (LMA), carbon and nitrogen contents, leaf construction cost, and photosynthetic capacity (P max) of Adiantum reniforme var. sinensis, an endangered fern endemic to the Three Gorges region in southwest China, were compared in five populations differing in habitat such as soil moisture and irradiance. The low soil moisture and high irradiance habitat population exhibited significantly higher LMA, area-based leaf construction (CCA), and carbon content (CA), but lower leaf nitrogen content per unit dry mass (NM) than the other habitat populations. The high soil moisture and low irradiance habitat populations had the lowest CCA, but their cost/benefic ratios of CCA/P max were similar to the medium soil moisture and irradiance habitat population due to their lower leaf P max. Hence A. reniforme var. sinensis prefers partially shaded, moist but well-drained, slope habitats. Due to human activities, however, its main habitats now are cliffs or steeply sloped bare rocks with poor and thin soil. The relatively high energy requirements and low photosynthetic capacity in these habitats could limit the capability of the species in extending population or interspecific competition and hence increase its endangerment.

Development and characterization of polymorphic microsatellite loci in endangered fern Adiantum reniforme var. sinense

Fourteen polymorphic microsatellite loci in the endangered fern Adiantum reniforme var. sinense were developed and characterized using the Fast Isolation by AFLP of Sequences Containing repeats (FIASCO) protocol. Polymorphism of each locus was assessed in a bulked sample of 30 individuals from 8 natural populations. The number of alleles per locus varied from 2 to 11, with an average value of 6.2. The ranges of observed and expected heterozygosity were 0.000–0.895 and 0.226–0.868, respectively. These microsatellite markers provide useful tools for the ongoing conservation genetic studies of Adiantum reniforme var. sinense.

Genetic diversity of the natural populations of Adiantum reniforme var. sinense

Adiantum reniforme var. sinense is an economically important plant species endemic to China. It is only found in a few regions of the Chongqing Municipal Region. For decades, its distribution has been shrinking as a result of over-exploitation, which has caused endangerment of this species. To assist in efforts to effectively conserve this species, we investigated the genetic variation of six natural populations using isoelectric focusing in thin-layer polyacrylamide slab gels. Fourteen loci of five enzyme systems were detected, of which seven were polymorphic. The mean number of effective alleles per locus (A_(e))=1.778, the percentage of polymorphic loci (P)=0.441, the mean expected heterozygosity (H_(e))=0.199,and the mean observed heterozygosity (H_(o))=0.235. The results revealed that low levels of genetic diversity existed within the natural populations of A. reniforme var. sinense in comparison with other species of ferns. Only 1.49% of the genetic variation occurred among populations whereas 98.51% existed within populations, suggesting a very low genetic divergence among the populations. The equilibrium state of the populations was measured using HardyWeinberg equilibrium and the Fixation Index (F). The results showed that a mixed mating system was possibly the main heterogamy of this species, and its endangerment was caused by over-exploitation and habitat loss.