Knop's Medium Research Articles

Introduction of Salicornia europaea L into in vitro culture

The goal of the research was to develop a technology for introducing Salicornia europaea L.into in vitro culture. Methods of cultivating meristems and callus cultures were studied. To cultivate meristems, the tip of the apical bud were used as an explant. Fragments of stems and leaves were used toobtain callus tissue. To study the influence of various factors on germination, seeds were soaked in sterile tap water and in solutions of gibberellin, cytokinin, auxin and NaCl, and were also subjected to cold stratification (independently and with subsequent placement in Knop’s agarized medium). Salicornia seeds were sterilized with various antiseptics: 70% alcohol, 10% aqueous solution of sodium hypochlorite («Belizna»), amoxicillinand 3% hydrogen peroxide. The ability of the culture to form callus was studied in MS medium. As a result, it was determined that the highest germination of seeds was observed in Knop medium after treating theseeds with a suspension of green algae of the Scenedesmus genus, as well as after preliminary cold stratification, and slightly less after treating the seeds with a solution of NaCl and gibberellic acid. The most effective method of seed sterilization turned out to be treatment with alcohol followed by treatment with sodium hypochlorite. A comparative analysis of seed germination in filter paper in Petri dishes, Knop agar medium, Murashige and Skoog (hormone-free) was carried out. The ability of S. europaea L. to form callusin MS medium with phytohormones was assessed. Conclusion. To improve germination, it is recommended to subject the seeds to cold stratification. To obtain aseptic explants quickly, it is recommended to germinate the seeds in the Knop nutrient medium, having previously sterilized them with alcohol, then with sodiumhypochlorite, followed by washing with distilled water. The most suitable type of microclonal propagationfor S. europaea L. is the production of callus tissue followed by induction of organogenesis or embryogenesis.

Invitro germination and optimization of basal media for protocorm-like bodies proliferation in Dieniaophrydis(J. Koenig) Seidenf

Dienia ophrydis is an endangered terrestrial orchid used for its ornamental and therapeutic purposes. This orchid possesses an anti-malarial alkaloid known as Malaxin. There is ongoing exploitation in the wild due to illegitimate herbal collection and climate change. To control the potential risk of extinction, there are no conservational measures or in vitro protocols established in this genus. The study focuses on addressing a germination protocol and enhancement of protocorm-like bodies (PLB) proliferation by optimizing the basal media and vitamins. It also aims to improve the misinterpretation of tetrazolium viability results in orchid testa along with a permeability test. Further, the seeds were subjected to 1% TTC staining to perform embryo viability test and 0.4% trypan blue (TB) dye for testa permeability. Ten basal media such as Gamborg's medium, Mitra medium, Thomale GD medium, Vacin and Went medium, Knudson C medium, Knop's medium, MS medium and ½ MS medium, ¼ MS medium, and modified MS medium (MMS) were tested for seed germination. The Half-strength MS medium responded with 92% of the highest germination and T-GD medium is not suitable for seed germination. The seed viability and permeability result showed 93% of permeability, 72% viability, and 9% dead seeds. Protocorms were transferred to the modified mMS medium containing half-strength macronutrients, full micronutrients, and 10 ppm of thiamine in vitamin formulation. PLB proliferation was observed and 12 shoots emerged from a single protocorm explant. Subsequently, the seedlings were acclimatized with 8-0-24 ratios of nitrogen, phosphorus, and potassium (NPK) as determined by soil testing. The study contributes in experimenting with seed germination of terrestrial orchid seeds asymbiotically and to establishing a protocol for conservation programs, especially in this genus.

Application of Chlorella vulgaris Beijerinck as a Biostimulant for Growing Cucumber Seedlings in Hydroponics.

Hydroponics is a promising method for growing agricultural plants and is especially relevant in the context of global climate change. Microscopic algae, including Chlorella vulgaris, has great potential for use in hydroponic systems as natural growth stimulators. The effect of the suspension of an authentic strain of Chlorella vulgaris Beijerinck on the length of cucumber shoots and roots, as well as its dry biomass, was studied. During cultivation in a Knop medium with the addition of Chlorella suspension, the length of the shoots was shortened from 11.30 to 8.15 cm, while the length of the roots also decreased from 16.41 to 10.59 cm. At the same time, the biomass of the roots increased from 0.04 to 0.05 g. The data obtained indicate the positive effect of the suspension of the Chlorella vulgaris authentic strain on the dry biomass of cucumber plants in hydroponic conditions and make it possible to recommend this strain for use when growing plants in hydroponic systems.

Activity of photosystem II in spring barley leaves under the action of manganese ions

The influence of manganese ions (30, 60 and 90 mg/l) on the functioning of the photosystem II (PSII) in leaves was assessed on plants of six spring barley cultivars (Belgorodsky 100, st.). The plants were grown on a complete Knop medium without (control) and with the addition of manganese ions (experiment) under natural light conditions. On 14-day-old leaves, parameters of chlorophyll's rapid fluorescence were recorded using a Fluor Pen FP 110/S fluorometer. The sensitivity of the different structural parts of PSII was found to vary depending on the concentration of Mn ions and the genotype used. Thus, absorbed energy flows increased in the cv. Boyarin at 30 and 60 mg/l Mn (by 7.9 and 14.1 %), in cv. Farmer at 60 and 90 mg/l (by 15.8 and 16.1 %), but decreased in cv. Dobryak at 30 and 90 mg/l (by 9.7 and 9.0 %), Farmer at 30 mg/l (by 15.8 %) and Bionic at 60 and 90 mg/l (by 8.0 and 6.8 %). The flow of energy stored in primary photochemical reactions in the cv. Bionic increased at 30 mg/l of manganese (by 6.3 %), but decreased at 60 (by 6.8 %) and 90 mg/l (by 5.3 %); increased in the cv. Boyarin at 30 mg/l of Mn (by 6.4 %), but decreased in the cv. Forward (by 11.7 %). Electronic transport leading to CO2 fixation increased in cv. Farmer at all Mn concentrations (by 8.1...12.6 %), and in cv. Bionic it increased at 30 mg/l (by 7.2 %), but decreased at 90 mg/l (by 7.4 %). The electron flux leading to the oxidation of the finile acceptor of PSI in the studied cultivars did not change under the influence of the stressor. However, the integral parameters of PSII activity (PIABS and PIABS_total indices) under stressful conditions were determined by the plant genotype. This indicates, firstly, the need for targeted selection (to a specific level of the stress factor); secondly, on the possibility of pyramidation of the integral level of resistance to the stressor by selecting parents who differ in the level of change in individual functional reactions of photosynthesis.

Indirect establishment increases the chances of in vitro propagation of mosses occurring in the Cerrado - a new method

Abstract The use of micropropagation techniques is crucial for the conservation of endangered moss species and their reestablishment in nature. This study aimed to establish in vitro cultures of gametophyte fragments of ten species of Cerrado mosses. After disinfestation with alcohol and commercial bleach, moss explants were grown in Petri dishes containing Knop medium. The species Bryum argenteum, B. coronatum, Isopterygium tenerifolium, Leucobryum crispum, Pogonatum pensilvanicum, and Vitalia cuspidifera were successively established with efficiency rate ranging from 1 to 31.2%. However, no aseptic cultures were obtained for the species Barbula indica, Bryum densifolium, Fissidens flaccidus, and Sphagnum platyphylloides. Even though, a few contaminated explants of these species were able to develop and grow. Thus, all ten species were submitted to rescue techniques to establish cultures in aseptic conditions, from partially contaminated explants (indirect establishment). Consequently, the indirect establishment resulted in higher percentages of explant development, which enhanced the establishment of in vitro cultures for most of the species tested. This fact is especially important for conservation purposes, mainly for species whose material is sensitive or scarce. Therefore, indirect establishment as a new in vitro culture methodology was a viable form of propagating the bryophyte species listed in this research. This fact is essential for conservation purpose, especially for species whose material is sensitive or scarcer.

Practical methodology for gametophyte proliferation and sporophyte production in green penny fern (Lemmaphyllum microphyllum C. Presl) using mechanical fragmentation

Propagation of gametophytes and sporophytes using mechanical fragmentation has been considered a suitable method for mass production of ferns. This study aimed to develop a practical propagation method for Lemmaphyllum microphyllum C. Presl, which is a fern of significant ornamental and medicinal value. Gametophytes were obtained through in vitro spore germination and used for propagation experiments. The gametophyte was mechanically fragmented using a scalpel into small fragments, which were then used to investigate gametophyte proliferation. In addition, the gametophyte was fragmented using a blender and then used to study sporophyte formation. Optimal proliferation conditions of the gametophyte were determined using Murashige and Skoog (MS) basal medium (double-, full-, half-, quarter-strength), Knop medium, and medium components (sucrose, nitrogen sources, activated charcoal), at various concentrations. The fresh weight of the gametophyte was 14-fold higher than that of gametophytes (300 mg) used as culture material, when cultured on double-strength MS. Moreover, 1 g of the gametophyte fragmented in 25 mL of distilled water formed more than 430 sporophytes in a soil mixture in an area of 7.5 cm2. The sporophytes were successfully cultivated in the greenhouse after acclimation. A large-scale production method for L. microphyllum that can be easily implemented in a fern production farm is outlined.

Culture condition for gametophyte and sporophyte masspropagation of bamboo fern (Coniogramme japonica) using tissue culture

This study was conducted to investigate the optimal culture method for gametophyte and sporophyte propagation in Coniogramme japonica (Thunb.) Diels, which can be used in various fields. The propagation of prothallus were cultured in 1/4 - 1 Murashige and Skoog medium and Knop medium for 10 weeks. The results indicated that the fresh weight of prothallus was the highest (14.5 g) in 1MS medium. Subsequently, various concentrations of sucrose, activated charcoal and nitrogen source were also added to 1MS medium and cultured for 8 weeks. The results provided that the sucrose concentration was 3% and the fresh weight of prothallus was the highest 10.8 g. According to the concentration in the range of 8.8 ~ 10.8 g, in the case of activated charcoal, the four treatments showed no significant difference. The nitrogen source was added at a concentration of 30, 60 and 120 mM with the ratio of NH4 + : NO3 - being 1 : 2. As a result, the fresh weight of all treatments increased to similar level but there was no significant difference. We investigated sporophyte formation according to soil type and the highest number of sporophytes at 228.0 was formed in soils mixed with horticultural substrate and decomposed granite at 2 : 1 (v : v). On the other hand, sporophyte was not formed in soils containing peatmoss except for the one with peatmoss and decomposed granite at 2 : 1 (v : v).

A methodology for large-scale Athyrium sheareri gametophyte proliferation and sporophyte production using tissue culture

Tissue culture methods using gametophytes are considered the easiest ways to mass-produce fern sporophytes. The aim of this study was to develop a practical propagation method for the ornamental fern, Athyrium sheareri. The gametophytes obtained from in vitro spore germination were used as experimental materials. We used the chopping method to investigate the culturing conditions for proliferating gametophytes and the blending method for evaluating the mass production of sporophytes in mixed soil. Gametophyte proliferation was determined via Knop medium, various concentrations of Murashige and Skoog (MS) basal medium (1, 1/2, 1/4), and media components (sucrose, nitrogen source, and activated charcoal). The fresh weight of the gametophytes increased by more than 24-fold in 1/2 MS medium. In addition, 1 g of gametophyte could produce a maximum of 255.3 sporophytes in a mixed soil of 7.5 cm2 area. Treating gametophytes with exogenous plant growth regulators promoted the formation and growth of sporophytes. The cultivated young sporophytes were acclimated and successfully grown in greenhouses. We developed a mass production protocol for A. sheareri sporophytes suitable for field application, which is expected to have commercial value.

Changes in the chemical composition and the structure of cellulose and lignin in elm wood exposed to various forms of arsenic

The chemical composition of wood depends on many factors, including plant growth conditions. Among the many dangerous elements it was decided in this study to select arsenic in various forms: As(III), As(V) and cacodylic acid (DMAA), as well as various concentrations and mutual combinations. The experiment was conducted on 1-year old elm seedlings planted in pots with an addition of Knop medium and arsenic. Supplementation of the substrate with each arsenic form caused changes in contents of cellulose and lignin as well as extractive substances and those soluble in 1% NaOH. Arsenic also led to changes in the structure of basic wood components. The FTIR analysis showed the greatest changes under the influence of As(V), As(III)/As(V)/DMA. Despite high arsenic concentration in the substrate 1-year old elm seedlings survived the period of the experiment, thus providing valuable results and broadening our knowledge on the response of trees to the environment contaminated with arsenic.Graphical abstract

Arsenate phytoextraction abilities of one-year-old tree species and its effects on the nutritional element content in plant organs

The aim of the study was to evaluate the As phytoextraction potential of four tree species: Acer pseudoplatanus L., Betula pendula Roth., Quercus robur L., and Ulmus laevis Pall. in light of their prospective use in the phytoremediation of arsenate [As(V)] contaminated soils. The content of nutritional elements: B, Ca, K, Mg, Na, Si, P, and S was also analyzed. The trees were grown for 1 month in hydroponic cultures (Knop medium) supplemented with As(V), (1 mM). The results showed that the highest As accumulation efficiency was characterized by B. pendula (BCF = 0.87) and Q. robur (BCF = 0.5). Betula pendula accumulated about 80% of As in its roots (TF = 0.22) whereas Q. robur accumulated more than 60% of As in its shoots (TF = 1.60). The other tree species accumulated significantly lower amounts of As, more than 60% of which collected in their shoots. As(V) phytoextraction led to a significantly lower level of P and S in the roots of all tested tree species. Betula pendula seems promising for phytostabilisation and Q. robur for phytoextraction of As(V) from contaminated soils. The obtained results confirm the accumulation and translocation of As(V), as well as the acquisition of nutritional elements by the selected tree species.

Development of a method for protonema proliferation of peat moss (Sphagnum squarrosum) through regeneration analysis.

The moss Sphagnum (peat moss) is ecologically and economically important. There is a paucity of physiological and developmental studies on Sphagnum because of the lack of an axenic culture system for its whole life cycle. A culture system has been established for the Sphagnum gametophore, but not the protonema (juvenile vegetative stage after spore germination). Therefore, the aim of this study was to develop a protonema culture system for Sphagnum. Sphagnum squarrosum gametophore tissue was disrupted and then cultured in liquid Knop medium. The regeneration of protonemata from the gametophore fragments was analyzed in detail by microscopy. We observed a developmental balance between filamentous and thalloid protonemata, and growth competition between the thalloid protonema and the gametophore. On the basis of these findings, we established a relatively stable peat moss protonema proliferation method. Using this method, all the developmental stages of peat moss vegetative growth could be obtained through differentiation or regeneration. The method can provide abundant homogeneous Sphagnum materials at desired stages for physiological and developmental studies, and will be useful for large-scale Sphagnum vegetative proliferation. The regeneration analysis method will be useful for establishing protonema proliferation systems for other mosses.

Arsenic forms in phytoextraction of this metalloid in organs of 2-year-old Acer platanoides seedlings

The aim of the study was to estimate the significance of the role of arsenite (As(III)), arsenate (As(V)), and dimethylarsinic acid (DMA) presence in modified Knop medium in the efficiency of phytoextraction of arsenic (As) in Acer platanoides root, stem, and leaves. The addition of particular As forms in single, double, and triple experimental systems was associated with a lower increase of seedling biomass compared to control plants (system free of As forms addition). Depending on As forms and their concentration in solution, negative symptoms from slight visible changes (inorganic forms separately or jointly), through smaller and discolored leaves (after DMA addition), and finally to their withering (after high DMA addition) were observed. Changes of color and shape for root systems exposed to particular As forms separately or jointly were also observed, in spite of the fact that there were no significant changes in biomass of seedlings growing in all experimental systems. The highest mean concentrations of As in root, stem, and leaves (590, 70, and 140 mg kg−1 dry weight (DW), respectively) were observed in plants growing under different experimental systems. The highest bioconcentration factor values were 10.8 for plants exposed to 0.06 mM of As(III) and DMA, while the highest translocation factor (1.0) was recorded for plants growing under the same As forms (0.6 and 0.06 mM, respectively). The obtained results indicate that the presence of particular As forms not only determines As phytoextraction and transport of this metalloid form but also has a decisive influence on plant morphology and survivability. As regards the practical aspects of phytoremediation, the kind of As forms present in substrate are more important than their total concentration.

Piriformospora indica, an excellent system for heavy metal sequestration and amelioration of oxidative stress and DNA damage in Cassia angustifolia Vahl under copper stress

Present investigation reveals copper induced phytotoxicity, oxidative stress and DNA damage in Cassia angustifolia Vahl and its amelioration by employing a symbiotic fungus, Piriformospora indica. Seeds were germinated on Knop's medium containing five Cu levels (0, 1, 10, 50, 100 and 200 mg L−1), with and without P. indica. Colonization with P. indica significantly (P < 0.05) ameliorated Cu induced oxidative stress. However, maximum amelioration was observed at 50 mg L−1 Cu with P. indica. Atomic absorption spectroscopy revealed that P. indica colonization significantly inhibited Cu accumulation in shoots. Maximum decline in Cu accumulation in shoots was observed at 50 mg L−1 (27.27%) with P. indica over Cu alone. Besides, P. indica colonized seedlings stored 16.86% higher Cu in roots as compared to Cu alone at 200 mg L−1. Similarly, maximum proline accumulation increased up to 19.32% over Cu alone at 50 mg L−1 Cu with P. indica. Significant elevation in antioxidant enzyme levels of superoxide dismutase, catalase, ascorbate peroxidase, guaiacol peroxidase and glutathione reductase was seen with P. indica. Contrary to increase in antioxidant level, toxic parameters such as lipid peroxidation and hydrogen peroxide decreased significantly with P. indica. Maximum decline in lipid peroxidation (13.76%) and hydrogen peroxide (18.58%) was observed at 50 mg L−1 with P. indica over Cu alone. P. indica significantly reduced DNA damage as well as changed the protein profile in C. angustifolia seedlings. Thus, P. indica proved to be an excellent system to alleviate Cu induced oxidative stress and might be useful as a phytostabilization tool.

A Modified Approach for Axenic Cultivation of Spores of Fern Adiantum capillus-veneris L. with High Germination Rate.

Spores are the primary way of spread and reproduction for ferns, a clade of seed-free vascular plants. However, no detailed protocol for ferns spore cultivation has been reported yet. Here we provide a modified approach for axenic cultivation of fern Adiantum capillus-veneris L., based on Cao's and Li's method (Cao, et al., 2010; Li, et al., 2013). Our approach can be briefly divided into four steps: 1) collect spores; 2) sterilize the spores with 5% sodium hypochlorite solution and wash twice; 3) incubate the spores in liquid Knop's medium in the dark for five days; 4) cultivate the spores on Knop's plate medium. To increase the germination rate, we constrain the sterilization time under 25 min and add dark treatment step after spore sterilization. After these modifications, the germination rate raises from 2% to 25%.

In vitro Propagation of Saprophytic Moss Splachnum sphaericum Hedw.

In vitro propagation of Splachnum sphaericum Hedw. has been carried out to study its growth pattern and morphogenetic attributes. Plants of this species were freshly collected from Se La Pass, Tawang, Arunachal Pradesh. Axenic culture of the species has been established using spores as explants. Half Knop's macronutrients, Half Knop's + Vitamins, Hoagland and Murashige and Skoog media were used for culture. Half Knop's macronutrients medium was found as most suitable for the growth of plants under controlled laboratory condition and after 50 days a well grown dense population of gametophores has been achieved. Observations made on morphogenesis of protonema and gametophyte development in different media are provided.

Determination the Usefulness of AhHMA4p1::AhHMA4 Expression in Biofortification Strategies.

AhHMA4 from Arabidopsis thaliana encodes Zn/Cd export protein that controls Zn/Cd translocation to shoots. The focus of this manuscript is the evaluation of AhHMA4 expression in tomato for mineral biofortification (more Zn and less Cd in shoots and fruits). Hydroponic and soil-based experiments were performed. Transgenic and wild-type plants were grown on two dilution levels of Knop’s medium (1/10, 1/2) with or without Cd, to determine if mineral composition affects the pattern of root/shoot partitioning of both metals due to AhHMA4 expression. Facilitation of Zn translocation to shoots of 19-day-old transgenic tomato was noted only when plants were grown in the more diluted medium. Moreover, the expression pattern of Zn-Cd-Fe cross-homeostasis genes (LeIRT1, LeChln, LeNRAMP1) was changed in transgenics in a medium composition-dependent fashion. In plants grown in soil (with/without Cd) up to maturity, expression of AhHMA4 resulted in more efficient translocation of Zn to shoots and restriction of Cd. These results indicate the usefulness of AhHMA4 expression to improve the growth of tomato on low-Zn soil, also contaminated with Cd.Electronic supplementary materialThe online version of this article (doi:10.1007/s11270-016-2877-0) contains supplementary material, which is available to authorized users.

In vitroStudy on the Reproductive Behavior of the Endemic and Threatened Indian Liverwort:Cryptomitrium himalayenseKashyap (Aytoniaceae)

Axenic cultures of the thalloid liverwort Cryptomitrium himalayense Kashyap were established from spores and propagated in vitro under a variety of culture media and controlled environments to determine the optimum conditions for the onset of sexual phase. Enhanced vegetative growth in form of overlapping rosette-forming thalli occurs on half strength Knop's medium as well as in Hoagland medium under continuous illumination of 2.93 W/m2 at 21°C from the production of innovations from the basal parts of the dorsal surfaces of the thalli. Thalli became shorter and produced tuberous swelling following nutrient depletion and drying out of the medium. Sex organs were produced only on Hoagland medium supplemented with 1% sucrose under a long day regime with colder nights (16 hours light at 21°C and of 8 hours darkness at 15°C). Thalli acclimatized and transferred on soil also produced sex organs under similar conditions of photoperiod and temperature.

English

Artificial seed production is now an outstanding technique for plant propagation and preservation, and has been applied on many plants. This study examines, for the first time the re growth of strawberry capsules under greenhouse conditions. Maximum shoot multiplication response (61.60 shoots) was obtained in Murashige and Skoog (MS) medium having 1.0 mg l-1 of Benzyl Adenine (BA), with an average leaf number of (143.2). However, the highest average shoot length was 6.20 and recorded at 1.5 mg l-1 KN. To protect shoot tips and produce synthetic seeds, gel capsules were standardized using a combination of sodium alginate and calcium nitrate or calcium chloride concentrations. Gel capsules were most effective for the formation of uniform and firm capsules when formed with a combination of 3% (w/v) sodium alginate and 100 mM calcium nitrate for 30 min. The highest percentage of shoot emergence was recorded when encapsulated in 3% Na-alginate dissolved in MS- salt solution containing 0.5mg mg l-1 BA and stored on MS basal medium containing 0.25 mg l-1 BA. The results demonstrated that the sugarcane bagasse could be used effectively as a substitute for agar during capsules storage. The capsules grown on MS media and sugarcane bagasse increase in shoot number, leaf number and shoot length, compared with agar-grown. In vitro storage of capsules was also evaluated by adding sugar alcohols, sorbitol or mannitol, to act as osmotic agents, to the media. Using 0.1M sorbitol or mannitol each to the storage media at 4°C after 12 months increased regrowth when inoculated on growth medium. Root induction was readily achieved within six weeks when shoots were transferred to MS medium supplemented with 0.5 mg l-1 IBA. Significant improvement in the in vitro rooting process, coupled with cost reduction, were obtained by the use of sugarcane bagasse as a substitute for the traditionally used agar-gel medium and Knop medium. Further, rooted plantlets were hardened by placing them in peatmoss + perlite (1:1, v/v) achieving a 75% survival rate in this potting mixture. Finally, the encapsulated shoot-tips coated in 3% Na-alginate, 0.2 or 0.3 g l-1 topsin and 0.5mg l-1 IBA were successfully established in the greenhouse.

Changes in Salix viminalis L. cv. ‘Cannabina’ morphology and physiology in response to nickel ions – Hydroponic investigations

The aim of the study was to assess the ability of ‘basket willow’ to bioaccumulate nickel with simultaneous analysis of biomass parameters and biomarkers of plants physiological reaction to the metal. Cuttings of Salix viminalis L. cv. ‘Cannabina’ were cultivated in Knop's medium containing nickel at 0–3mM stabilized with quartz sand. Higher nickel contents were observed in Salix rods and roots (∼15), and lower for leaves and shoots (∼3mgkg−1DW) after 14days at 3mM Ni. The strongest inhibition was observed for root biomass, weaker for shoot, root and leaf elongation, and the weakest for the photosynthetic area (4, 24, 36, 55 and 70% of control, respectively). Soluble carbohydrates in leaves reached 340% of control at 3.0mM Ni. Phenolics content increased four-fold at 3mM Ni versus control, while salicylic acid content at 2.5mM Ni was nearly 68 times higher than for Ni-untreated plants. The exudation of low molecular weight organic acids increased from ∼40 to 130μMkg−1DW at 3mM. The investigated cultivar exhibits sufficient resistance to nickel and can be cultivated at heavily contaminated sites. Nevertheless, strong inhibition of plant growth was observed resulting probably from Ni-induced disturbances in nutrient uptake accompanied by oxidative stress.

Chlorophyll Fluorescence Analysis of Hermaphrodite and Male Gametophytes from Ceratopteris thalictroides(L.) Brongn. on Different Media

The differences of fluorescence parameters of hermaphrodite gametophyte and male gametophyte from Ceratopteris thalictroides cultured in MS medium and modified knop's medium were investigated.The results showed that the ФPSⅡ and ETRPSⅡ of hermaphrodite gametophyte in MS medium were higher than those of the male gametophyte in MS medium and gametophytes in modified knop's medium,the differences were significant.The values of Fv/Fm had no significant difference in the gametophytes of different groups.The external nutrient had no obvious effect on the qP and qN in the gametophytes of different teams.In conclusion,external sucrose enhanced photosynthetic activity of the gametophytes in MS medium,which was beneficial for hermaphrodite gametophytes to grow and develop rapidly.