Showing papers in "Biologia Plantarum in 1999"
TL;DR: This review is focused upon contemporary information on the changes in leaf structure, water relations and photosynthesis during acclimatization of plantlets to ex vitro conditions and some ways of improving plant survival and for the speeding up of acclimation.
Abstract: The special conditions during in vitro culture result in the formation of plantlets of abnormal morphology, anatomy and physiology. After ex vitro transfer, these plantlets might easily be impaired by sudden changes in environmental conditions, and so need a period of acclimatization to correct the abnormalities. This review is focused upon contemporary information on the changes in leaf structure, water relations and photosynthesis during acclimatization of plantlets to ex vitro conditions. It also describes some ways of improving plant survival and for the speeding up of acclimatization.
414 citations
TL;DR: In this paper, the authors show that salinity decreased the contents of dry mass, chlorophyll, soluble and hydrolysable sugars, soluble proteins and enhanced content of total free amino acids, Na+, Ca2+ and Cl-.
Abstract: Plants of bean (Vicia faba L. cv. Calvor 103) were salt-stressed with NaCl and CaCl2 in concentrations inducing soil osmotic potentials (ψsoil) from 0 to -1.2 MPa and were sprayed with proline (8.7 µM) and glycinebetaine (8.5 µM) solutions. Bean plants respond to increasing soil salinity by decreased leaf relative water content and osmotic potential. Salinity decreased the contents of dry mass, chlorophyll, soluble and hydrolysable sugars, soluble proteins and enhanced content of total free amino acids, Na+, Ca2+ and Cl-. The ratio of K+/Na+ was decreased on salinization. The membranes of leaf discs from salt-stressed plants appeared to be less stable under heat stress (51 °C) than that of unstressed plants. The reverse was true for discs placed under dehydration stress (40 % polyethylene glycol 6000). Proline and glycinebetaine application reduced membrane injury, improved K+ uptake and growth. Also both solutes increased chlorophyll contents.
360 citations
TL;DR: In this article, Salicylic acid (SA) was applied to rice in two cultivars of rice (Oryza sativa L. cvs. Ratna and IR 36) to improve the degradation of membranes caused by lipoxygenase (LOX) activity.
Abstract: Deterioration of membranes caused by lipoxygenase (LOX) activity under 10 µM PbCl2 or 10 µM HgCl2 was partially alleviated by the exogenous application of 100 µM salicylic acid (SA). In two cultivars of rice (Oryza sativa L. cvs. Ratna and IR 36), the presence of SA ameliorated the increased leakage of electrolytes, injury index, and the content of malondialdehyde caused by these heavy metals. Lead decreased H2O2 content whereas Hg increased it in both cultivars. Application of SA increased H2O2 in presence of Pb, while decreased it in presence of Hg. Both Pb and Hg decreased superoxide dismutase activity, while increased peroxidase activity. The activity of catalase was decreased by Hg but increased by Pb and SA reversed their effects. Thus, SA ameliorated the damaging effects of Pb and Hg on membranes.
236 citations
TL;DR: In this article, changes in the starch and sucrose contents, and the sucrose phosphate synthase, acid invertase, and starch phosphorylase activities were studied in the seedlings of salt sensitive and salt tolerant rice cultivars growing under two NaCl concentrations (7 and 14 dS m-1) for 20 d.
Abstract: Changes in the starch and sucrose contents, and the sucrose phosphate synthase, acid invertase, and starch phosphorylase activities were studied in the seedlings of salt sensitive and salt tolerant rice cultivars growing under two NaCl concentrations (7 and 14 dS m-1) for 20 d. Under salinity, the starch content in roots declined more in salt sensitive cvs. Ratna and Jaya than in salt tolerant cvs. CSR-1 and CSR-3 and was unchanged in shoots. The contents of reducing and non-reducing sugars, and the activity of sucrose phosphate synthase was increased more in the sensitive than in the tolerant cultivars. Acid invertase activity decreased in shoots of the salt tolerant cultivars, whereas increased in salt sensitive cultivars. Starch phosphorylase activity decreased in all cultivars.
187 citations
TL;DR: When the medium was supplied with various concentrations of sodium chloride, proline content in regenerants was six times higher than in the control and NaCl also induced formation of new proteins.
Abstract: Shoots of Bacopa monniera exhibited 100 % regeneration on Murashige and Skoog medium with 2 % sucrose, 0.2 mg dm−3 1-naphthaleneacetic acid, 0.5 mg dm−3 6-benzylaminopurine and 50 mg dm−3 glutamine. When the medium was supplied with various concentrations (5 - 15 g dm−3) of sodium chloride, proline content in regenerants was six times higher than in the control. With increasing NaCl concentration photosynthetic rate decreased and fresh mass and root length of regenerants declined. NaCl also induced formation of new proteins.
88 citations
TL;DR: Sunflower (Helianthus annuus L.) seeds were germinated and grown in the presence of 50, 100 and 200 µM CdCl2 and the lower concentration (50 µM) of Cd2 ions produced a slight decrease in reduced glutathione (GSH) content and overall increase (except superoxide dismutase) in antioxidant enzyme activities, and in H2O2 concentration as mentioned in this paper.
Abstract: Sunflower (Helianthus annuus L.) seeds were germinated and grown in the presence of 50, 100 and 200 µM CdCl2. The lower concentration (50 µM) of Cd2 ions produced slight decrease in reduced glutathione (GSH) content and overall increase (except superoxide dismutase) in antioxidant enzyme activities, and in H2O2 concentration. Chlorophyll content, lipid peroxidation and protein oxidation were not affected under 50 µM CdCl2. GSH content was diminished under 100 and 200 µM CdCl2, and except for superoxide dismutase, which activity remained unaltered, overall decreases in the antioxidant enzyme activities (catalase, ascorbate peroxidase, dehydroascorbate peroxidase, glutathione reductase) and in guaiacol peroxidase were observed. These Cd2 concentrations caused a decrease in chlorophyll content as well as an increase in lipid peroxidation, protein oxidation and H2O2 concentration. All the observed effects were more evident with the highest concentration of cadmium chloride used.
84 citations
TL;DR: A transgenic expression system of Chlorella kessleri using the gene for β-glucuronidase (GUS) was developed and stable transformants were able to grow on kanamycin containing medium after repeated passages between selective and nonselective medium and exhibited GUS activity comparable to that of control cells.
Abstract: A transgenic expression system of Chlorella kessleri using the gene for β-glucuronidase (GUS) was developed. Cells of this unicellular green alga were bombarded with the plasmid pBI 121, which bears β-glucuronidase under the control of CaMV 35S promoter and the kanamycin resistant gene. Maximum GUS activity was obtained after 48 h of bombardment using a helium pressure of 900 kPa; GUS activity was then assayed for many generations. The stable transformants were able to grow on kanamycin containing medium after repeated passages between selective and nonselective medium and exhibited GUS activity comparable to that of control cells. Stable transformed cells were confirmed by polymerase chain reaction (PCR) and Southern hybridization of GUS probe with the genomic DNA of C. kessleri.
82 citations
TL;DR: SDS-PAGE analysis has revealed that plants grown under NaCl showed induction or repression in the synthesis of few polypeptides and the esterase patterns of both stems and leaves were less influenced by NaCl in comparison to those of roots.
Abstract: The ability of peanut (Arachis hypogaea L.) to grow at high concentrations of NaCl may be due to the alteration in gene expression. SDS-PAGE analysis has revealed that plants grown under NaCl showed induction (127 and 52 kDa) or repression (260 and 38 kDa) in the synthesis of few polypeptides. In addition, nine different esterase isoenzymes were detected in embryos of seeds germinated in 105 mM NaCl, whereas only five of them were detected in the embryos of untreated seeds. On the other hand, in the cotyledons, the esterase pattern was not affected by NaCl concentration. The esterase patterns of both stems and leaves were less influenced by NaCl in comparison to those of roots. The lipid contents, and fresh and dry masses were increased up to 45 mM NaCl and decreased at higher concentrations.
56 citations
TL;DR: In this paper, the effects of 1 mM cadmium, lead and nickel on dry mass, Cd, Pb, and Ni contents, and changes in leaf structure in young wheat plants were studied.
Abstract: The effects of 1 mM cadmium, lead and nickel on dry mass, Cd, Pb, and Ni contents, and changes in leaf structure in young wheat plants were studied. In leaves, Cd content was highest, followed by Pb and Ni, in roots Cd content was also highest, but followed by Ni and Pb. Roots accumulated considerably larger amounts of the three heavy metals than leaves. Largest reductions of leaf and root mass were obtained with Cd. Pb and Ni effects were almost equal. Ni excess had a strong negative effect on mesophyll thickness, while Cd mostly reduced the number and size of vascular bundles and vessel diameter. High Pb reduced the diameter of vessels causing their different deformations.
51 citations
TL;DR: In this paper, the short-term relationships of monoterpene emission with temperature and relative humidity were studied in Pinus halepensis L. and Quercus ilex L. seedlings grown in an air-conditioned chamber.
Abstract: The short-term relationships of monoterpene emission with temperature and relative humidity were studied in Pinus halepensis L. and Quercus ilex L. seedlings grown in air-conditioned chamber. In P. halepensis terpene emission rate increased with temperature (from 15 to 35 °C) and relative humidity (from 40 - 60 to 65 - 95 %). In Q. ilex, a terpene non-storing species, it increased with temperature only at high relative humidities but not at relative humidities lower than 60 %.
51 citations
TL;DR: The increase in water use efficiency (the ratio of photosynthetic to transpiration rates) is likely to be the commonest positive effect of long-term elevation in CO2 concentration (CE) as mentioned in this paper.
Abstract: The increase in water use efficiency (the ratio of photosynthetic to transpiration rates) is likely to be the commonest positive effect of long-term elevation in CO2 concentration (CE). This may not necessarily lead to decrease in long-term water use owing to increased leaf area. However, some plant species seem to cope better with drought stress under CE, because increased production of photosynthates might enhance osmotic adjustment and decreased stomatal conductance and transpiration rate under CE enable plants to maintain a higher leaf water potential during drought. In addition, at the same stomatal conductance, internal CO2 concentration might be higher under CE which results in higher photosynthetic rate. Therefore plants under CE of the future atmosphere will probably survive eventual higher drought stress and some species may even be able to extend their biotope into less favourable sites.
TL;DR: Stomatal morphology was studied during acclimatization of tobacco plantlets to ex vitro conditions to indicate that the originally circular stomata of in vitro plantlets were changed into elliptical ones in ex vitro acclimatsized plants.
Abstract: Image analysis was used in studying stomatal morphology during acclimatization of tobacco plantlets to ex vitro conditions, 45 d after transfer leaf area was 15 times, and total number of stomata per leaf four times increased. During acclimatization stomatal density was decreased considerably on both leaf sides, and was compensated by an increase in stomatal sizes, e.g., in stomatal length and in stomatal area (both guard cells and pore). Elongation of stomata was increased indicating that the originally circular stomata of in vitro plantlets were changed into elliptical ones in ex vitro acclimatized plants.
TL;DR: In this article, two newly developed salt-tolerant genotypes of spring wheat, S24 and S36, along with a salt-sensitive cv. Potohar were grown in full strength Hoagland's nutrient solution with 0 or 125 mM NaCl.
Abstract: Two newly developed salt-tolerant genotypes of spring wheat, S24 and S36 and their salt-tolerant parents, LU26S (from Pakistan) and Kharchia (from India) along with a salt-sensitive cv. Potohar were grown in full strength Hoagland's nutrient solution with 0 or 125 mM NaCl. At the onset of the booting stage third leaf from top was sampled for protein analysis. Total soluble protein content increased due to salt treatment in all cultivars/lines but this increase was more marked in salt-sensitive cv. Potohar and low in salt-tolerant S24 as compared with the other lines. Patterns of labelled polypeptides in all cultivars/lines were identical; the differences were only quantitative (for instance, 29 kD and 48 kD polypeptides were reduced significantly due to NaCl treatment only in the cv. Potohar).
TL;DR: In this paper, an exposure of Helianthus annuus L. seedlings to Al3+, Cd2+ or Zn2+ resulted in a marked decrease of fresh and dry masses of the shoots and the roots.
Abstract: Exposure of Helianthus annuus L. seedlings to Al3+, Cd2+ or Zn2+ resulted in a marked decrease of fresh and dry masses of the shoots and the roots. The increase of Al3+, Cd2+ or Zn2+ uptake was accompanied by a significant decrease of nitrate, phosphorus and K+ uptake. There was a significant increase of malic and citric acid contents in the shoots and roots of heavy metal-treated seedlings whereas the change in fumaric acid was insignificant. Al3+ and Zn2+ alone stimulated excretion of malic and citric acids to the rhizosphere. Addition of high concentrations of malic or citric acid alleviate to some extent the inhibitory effect of Al3+ and Zn2+ on plant growth.
TL;DR: The magnitude of detrimental effect on these enzymes was reduced during later stage of germination (9 d) largely because of fall in the activities of these enzymes in the control seeds germinated in water.
Abstract: Activities of alcohol dehydrogenase, hexokinase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase were significantly inhibited by cadmium in germinating pea (Pisum sativum L. cv. Bonneville) seeds. The effect was concentration dependent in the range of 0.25 to 1.0 mM CdCl2. The magnitude of detrimental effect on these enzymes was reduced during later stage of germination (9 d) largely because of fall in the activities of these enzymes in the control seeds germinated in water. In vitro, activities of hexokinase, glucose-6-phosphate dehydrogenase, and alcohol dehydrogenase were inhibited at 0.5 mM Cd2+ in the reaction mixture by 62, 67, and 36 %, respectively, however, 6-phosphogluconate dehydrogenase was insensitive to Cd2+.
TL;DR: The benzothiadiazole proved to be an efficient inducer of proteins in sugar beet and was also induced by the other inducers under study regardless of the necrotic or symptomless reaction of plants.
Abstract: The effect of benzothiadiazole (BTH) on protein synthesis was studied in sugar beet plants. Extracellular proteins induced by 0.025 % BTH were examined and their pattern was compared with that induced by sodium salicylate, chitosan, paraquat, AgNO3, and by tobacco necrosis virus. BTH induced synthesis of at least 9 acidic and 6 basic proteins; three of them appeared as acidic chitinase isozymes, three as acidic β-1,3-glucanase isozymes, three as basic chitinase isozymes, and one as a basic β-1,3-glucanase isozyme. One of the basic chitinase isozymes was found also in control plants. The most of the newly formed proteins was also induced by the other inducers under study regardless of the necrotic or symptomless reaction of plants. The benzothiadiazole proved to be an efficient inducer of proteins in sugar beet.
TL;DR: Alterations in essential oil gland number, distribution and fine structure, and the oil content in the leaf of Mentha arvensis L. were examined during its growth and senescence, finding that cuticle remains tightly apposed to the secretory head of oil glands but progressively a sub-cuticular space appears to be created for the oil.
Abstract: Alterations in essential oil gland number, distribution and fine structure, and the oil content in the leaf of Mentha arvensis L. were examined during its growth and senescence. Accumulation of essential oil occurred predominantly during the rapid leaf expansion phase followed by a similar decline. The oil gland (trichome) number increased upto leaf maturation and declined thereafter. Initially, cuticle remains tightly apposed to the secretory head of oil glands but progressively a sub-cuticular space appears to be created for the oil. Considerable enlargement of vacuole with ageing is witnessed, whereas cytoplasm gradually decreases to a thin peripheral layer. Some secretory cells from senescing leaf were found almost empty, having only a few remnant oil droplets.
TL;DR: Evidence is provided for the involvement of osmotin-like proteins in the mechanisms of salt tolerance in potato plants with transformed plants subjected to NaCl for 3 weeks.
Abstract: Potato (Solanum tuberosum L. cv. Bintje) was transformed with a cDNA clone encoding an osmotin-like protein. Transgenic and non-transgenic in vitro plants were subjected to NaCl for 3 weeks. The shoot and root development was slightly affected by salinity indicating that the salt condition used was a mild stress. The endogenous proline content of the osmotin-like transformed clone only raised slightly as compared to the non-transformed genotype, where a marked increase in proline content could be observed as a result to salt stress. These data provide evidence for the involvement of osmotin-like proteins in the mechanisms of salt tolerance in potato plants.
TL;DR: A reliable protocol for plant regeneration from mature embryo derived calli of nine barley cultivars has been developed and the auxins 2,4-dichlorophenoxyacetic acid, picloram and dicamba proved effective in inducing callus from mature embryos of most of the barley cultivARS.
Abstract: A reliable protocol for plant regeneration from mature embryo derived calli of nine barley (Hordeum vulgare) cultivars has been developed. The auxins 2,4-dichlorophenoxyacetic acid, picloram and dicamba proved effective in inducing callus from mature embryos of most of the barley cultivars. The induced primary callus was loose, friable and translucent. It ultimately yielded creamy white and compact callus after 2 - 3 transfers on fresh medium of the same composition. Callus induction and regeneration capacity were highly cultivar dependent. Addition of a high concentration of picloram (4 mg dm-3) promoted regeneration in 3 cultivars (Tallon, Grimmett and Sloop). In cv. Arapiles, abscisic acid and betaine were crucial in generating morphogenic callus from the mature embryos. Plants regenerated from these calli were hardy and developed roots readily when transferred to hormone free medium.
TL;DR: Spirodela polyrhiza L. Schleid plants developed anthocyanin on the abaxial frond surface when grown on Hoagland nutrient solution diluted 1:≥40; AC content was maximum at 1:80 dilution.
Abstract: Spirodela polyrhiza L. Schleid. plants developed anthocyanin (AC) on the abaxial frond surface when grown on Hoagland nutrient solution diluted 1:≥40; AC content was maximum at 1:80 dilution. Till 1:20 dilution there was no or very little AC formation. The formation of AC seems to rely on the availability of excess carbon skeleton in relation to nitrogen in plants. Thus, addition of saccharose to 1:20 diluted medium resulted in a concentration-dependent AC formation. Also fructose, glucose, mannitol, and sorbitol induced AC synthesis. Conversely, urea and ammonium nitrate, when added to the 1:80 diluted medium, suppressed the AC formation. Omission of micronutrients from the growth medium led to the formation of a little amount of AC whereas polyethylene glycol and Cd treatments were ineffective. AC produced under starvation (7 d on distilled water) did not get turned over upon the transfer of plants to nutrient sufficient (1:5 diluted medium) conditions indicating that AC formed does not serve as a reversible C-reserve.
TL;DR: In this paper, the effect of 50 to 200 mM NaCl on two lines (CP with solid stem and CV with hollow stem) of ×Haynaldoticum sardoum was studied.
Abstract: The effect of 50 to 200 mM NaCl on two lines (CP with solid stem and CV with hollow stem) of ×Haynaldoticum sardoum was studied. NaCl significantly reduced root and shoot fresh and dry masses, root length and less markedly shoot length of CP and CV plants. The sodium accumulated in the leaves in relation to the concentration of NaCl and length of the treatment; CP leaves contained twice as much sodium as CV leaves. The leaf chlorophyll a/b ratio was not affected by NaCl. NaCl decreased the leaf water and osmotic potentials. The pressure potential increased due to the increased concentration of dissolved solutes in the leaf, particularly sodium. The proteinase and exopeptidase activities increased during NaCl treatment.
TL;DR: The treatment of seedlings with 50 µM AlCl3 resulted in high accumulation of Al, partial inhibition of root growth, occurrence of surface lesions in peripheral tissues, root thickening caused by expansion of inner cortical cells, and reduced root cap length.
Abstract: Growth and structural responses of primary roots of Zea mays L. to aluminium chloride were studied. The treatment of seedlings with 50 µM AlCl3 resulted in high accumulation of Al, partial inhibition of root growth, occurrence of surface lesions in peripheral tissues, root thickening caused by expansion of inner cortical cells, reduced root cap length, extensive vacuolation, cell distortion, and increased synthesis of callose within 24 h.
TL;DR: It is supposed that main indicator of the pollen damage by ozone in carotenoid-containing microspores are the lipofuscin-like compounds.
Abstract: The changes in the autofluorescence spectra of intact Philadelphus grandiflorus, Epiphyllum hybridum, and Plantago major pollen have been observed with microspectrofluorometric method after 100-h exposure to ozone (3 h per day for 5 d per week in total dose 5.0 cm3 m-3). The fluorescence maximum at 530 - 550 nm disappeared in carotenoid-containing pollen of Philadelphus grandiflorus and Epiphyllum hybridum and new maximum at 475 - 480 nm arose that correlated with lipofuscin-like substances observed in the extracts from the pollen grains. The carotenoid-less pollen of Plantago major showed only the increase of the maximum at 470 nm, and no lipofuscin in the extracts. It is supposed that main indicator of the pollen damage by ozone in carotenoid-containing microspores are the lipofuscin-like compounds.
TL;DR: In this article, the effects of water stress on senescence and enzyme activities of detached rice leaves were compared, and it was shown that the effects were mediated through increased content of endogenous abscisic acid.
Abstract: The effects of abscisic acid (ABA) and water stress on senescence and enzyme activities of oxygen scavenging enzymes of detached rice leaves were compared. Exogenously applied ABA exhibited water stress-like effects by promoting senescence, by decreasing the activities of catalase, peroxidase, ascorbate peroxidase and superoxide dismutase. It seems that the effects of water stress on senescence and enzyme activities are possibly mediated through increased content of endogenous ABA.
TL;DR: Genetic diversity analysis was carried out in chickpea accessions using restriction fragment length polymorphism (RFLP) and random amplified polymorphic DNA (RAPD) techniques and revealed polymorphism only in wild Cicer species (Cicer reticulatum L., JM 2100).
Abstract: Genetic diversity analysis was carried out in chickpea accessions using restriction fragment length polymorphism (RFLP) and random amplified polymorphic DNA (RAPD) techniques. RFLP analysis using 26 Pst I sub-genomic clones on ten chickpea accessions in 130 probe-enzyme combinations detected polymorphism with only two clones. Pst I clones, CG 141 detected polymorphism in ICC 4918 and Pusa 209 while CG 500 detected polymorphism in Pusa 261, ILC 26 and in ILC 13326. These clones detected very few polymorphic markers. Analysis using 10 Eco RI clones on twelve chickpea accessions have shown better hybridisation signal and one clone detected polymorphism in Pusa 256. RFLP analysis of both cultivated and wild Cicer species using heterologous DNA probe Cab3C revealed polymorphism only in wild Cicer species (Cicer reticulatum L., JM 2100). RAPD analysis of 13 chickpea accessions which includes mutants of C 235 and E100Y showed greater degree of polymorphism with 1 - 5 unique DNA bands for all the accessions. Phylogenetic analysis of the RAPD data helped to group the accessions. C 235 and its mutants were found to be closely grouped while E100Y and its mutant E100Ym grouped apart. Desi and kabuli chickpea accessions however, could not be separately grouped.
TL;DR: The histochemical staining of the alkaline phosphatase and NADH-diaphorase activities in the extraradical mycelium of theAMF proved to be more sensitive indication of negative effects of the SAR or SAR+Al stress compared to commonly measured parameters of the AMF such as mycorrhizal colonisation or growth of the ERM.
Abstract: Simulated acid rain (SAR) combined with higher concentration of aluminium (SAR+Al) influenced the ecophysiology of three arbuscular mycorrhizal fungi (AMF) in both the germination and symbiotic phases of their life cycle. Acaulospora tuberculata, an isolate from the soil with low pH, exhibited a higher tolerance to environmental stress as compared to Glomus mosseae and G. fistulosum. This higher tolerance may be related to the edaphic conditions of soil of the isolate origin. The histochemical staining of the alkaline phosphatase and NADH-diaphorase activities in the extraradical mycelium (ERM) of the AMF proved to be more sensitive indication of negative effects of the SAR or SAR+Al stress compared to commonly measured parameters of the AMF such as mycorrhizal colonisation or growth of the ERM.
TL;DR: The effect of agar, MS basal medium strength, sucrose and polyamines on the in vitro rooting of Syzygium alternifolium realized by a two step procedure involving root initiation (RI) and root elongation (RE).
Abstract: This paper describes the effect of agar, MS basal medium strength, sucrose and polyamines on the in vitro rooting of Syzygium alternifolium realized by a two step procedure involving root initiation (RI) and root elongation (RE). RI was carried out on solidified MS medium supplemented with 1.0 mg dm−3 indole-3-butyric acid (IBA) for 3 weeks, and RE following transfer to half-strength MS medium devoid of growth regulators for another 3 weeks. Agar and MS basal medium concentrations played important role on rooting response as well as on health of rooted shoots. Sucrose concentration was positively correlated with the rooting percentage, root number per shoot and root length. The combination of polyamines and 1.0 mg dm−3 IBA increases rooting percentage compared to media containing only 1.0 mg dm−3 IBA. Optimum rooting was attained with half-strength MS medium containing 1.0 mg dm−3 IBA, 2 % sucrose, 10 µM spermine and 0.8 % agar.
TL;DR: The initiation of somatic embryogenesis was favoured in the heartshaped and early cotyledonary stage of the zygotic embryo in all three years and lasted until the acorns reached maximum size in August.
Abstract: To induce somatic embryogenesis in Quercus robur L. immature zygotic embryos at different developmental stages were collected in weekly intervals from June until September in three consecutive years from four open pollinated trees at two Vienna sites. Acorns were surface sterilised and cultured firstly on P24 medium with 5μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.5 μM 6-benzylaminopurine (BAP) or on hormone-free P24 medium and secondly on P24 medium with 0.9 μM BAP. The formation of white-yellow globular structures of somatic embryos started during the fourth week after the induction treatment. High induction frequencies of 30 - 80 % were achieved on 2,4-D/BAP medium, whereas rates on hormone-free medium were below 20 %. The initiation of somatic embryogenesis was favoured in the heartshaped and early cotyledonary stage of the zygotic embryo in all three years and lasted until the acorns reached maximum size in August.
TL;DR: In this article, 3.21d-old seedlings of the soybean (Glycine max) cvs Essex and Forrest were treated with NaCl in a step-wise manner over 9 d (3 d 30 mM, 3 d 70 mM, and 3 d 100 mM) and maintained under 100 mM NaCl for an additional 14 d.
Abstract: 21-d-old seedlings of the soybean (Glycine max) cvs Essex and Forrest were treated with NaCl in a step-wise manner over 9 d (3 d 30 mM, 3 d 70 mM, and 3 d 100 mM) and maintained under 100 mM NaCl for an additional 14 d During salt treatment, osmotic potential decreased more in cv Forrest relative to cv Essex In non-stressed leaf tissue, cv Forrest contained more trigonelline (TRG) relative to cv Essex During salt treatment, TRG amounts increased in cv Forrest but were unchanged in cv Essex Both cvs osmotically adjusted in response to salt stress; the maximal osmotic adjustment was 080 and 018 MPa in cv Forrest and cv Essex, respectively
TL;DR: In this article, the influence of pre-sowing chilling treatments to seeds on seed germination and accumulation of osmotics in Indian mustard under NaCl stress was investigated, and it was shown that the alleviation of NaCL stress was associated with decrease in Na+ and proline accumulation and a slight increase in K+ and Ca2+ contents of seedlings.
Abstract: Influence of pre-sowing chilling treatments to seeds on seed germination and accumulation of osmotics in Indian mustard [Brassica juncea (L.) Czernj & Cosson] under NaCl stress was investigated. Germination was 100 % in water soaked non-chilled (control) seeds upto 100 mM NaCl, whereas it was upto 200 mM NaCl in chilling treated seeds. Pre-sowing chilling treatments to seeds for 5, 10 and 15 d also enhanced the dry mass of 6-d-old seedlings, and concentrations of saccharides and amino acids. The alleviation of NaCl stress by pre-sowing chilling treatments was also associated with decrease in Na+ and proline accumulation and a slight increase in K+ and Ca2+ contents of seedlings.