• Title/Summary/Keyword: Osmotic stress

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Comparative Water Relations of Two Vitis vinifera Cultivars, Riesling and Chardonnay

  • Park, Yong-Mok
    • The Korean Journal of Ecology
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    • v.24 no.4
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    • pp.223-226
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    • 2001
  • The leaf water relations and photosynthetic rate during acute soil drying were compared in potgrown grapevine cultivars, Vitis vinifera cv. Chardonnay and V. vinifera cv. Riesling. Leaf water potential in Riesling decreased significantly from day 2 after water had been withheld, while in Chardonnay leaf water potential for the water-stressed plants was almost identical with that in well watered plants during the first 4 days. Higher stomatal conductance and photosynthetic rate in Chardonnay than Riesling were observed until day 3 after withholding water. Photosynthetic rate in water-stressed Chardonnay was not different from that in control plants until day 3 after withholding water, while that in water-stressed Riesling was reduced markedly from day 2. In Riesling, osmotic potential at turgor loss point was not changed irrespective of watering conditions. However, in Chardonnay osmotic potential at turgor loss point decreased more in the water stressed conditions than in well watered conditions. The osmotic adjustment in Chardonnay under water stress conditions must contribute to the maintenance of higher stomatal conductance and photosynthetic rate than those in Riesling for a significant period of the drying process. Though difference in stomatal conductance between the two cultivars was shown in the process of soil drying, stomatal conductance of both cultivars responded to vapor pressure difference between leaf and ambient air, rather than soil water status and leaf water potential.

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Effects of Osmoprotectants on the Growth and Nitrogenase Activity of Rhizobium and Azospirillum under Osmotic Stress (질소고정균의 성장과 질소고정력에 대한 osmoprotectant의 영향)

  • Gal, Sang-Wan;Choi, Young-Ju
    • Applied Biological Chemistry
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    • v.41 no.1
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    • pp.53-59
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    • 1998
  • The Rhizobium and Azospirillum spp. were isolated from the root nodules of several leguminous plants and rhizosphere of various paddy rice varieties. The growth of the nitrogen-fixing strains isolated was largely inhibited in yeast extract-mannitol medium (AMA) containing 0.6 M NaCl. In response to osmotic stress, the nitrogen-fixing strains accumulate intracellular free glutamate. The growth and nitrogenase activity of Rhizobium and Azospirillum were increased by addition of osmoprotectants such as proline, glycine betaine, and glutamate during salt stress. Glycine betaine was the most effective among exogenous osmoprotectants tested. In the absence of sodium chloride, nitrogenase activity seem to be slightly decreased by the presence of the proline or glycine betaine. These results revealed that nitrogenase activity was repressed by fixed nitrogens such as proline or glycine betaine.

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Hypoosmotic shock adaptation by prolactin involves upregulation of arginine vasotocin and osmotic stress transcription factor 1 mRNA in the cinnamon clownfish Amphiprion melanopus

  • Park, Mi Seon;Kim, Na Na;Shin, Hyun Suk;Min, Byung Hwa;Kil, Gyung-Suk;Cho, Sung Hwoan;Choi, Cheol Young
    • Animal cells and systems
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    • v.16 no.5
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    • pp.391-399
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    • 2012
  • We cloned cDNA-encoding arginine vasotocin (AVT) from the brain of the cinnamon clownfish Amphiprion melanopus, and that was predicted to encode a protein of 153 amino acids. We examined changes in the expression of AVT mRNA in the brain and arginine vasotocin receptor (AVTR) mRNA and osmotic stress transcription factor 1 (OSTF1) mRNA in the gills of the cinnamon clownfish using quantitative real-time PCR in an osmotically changing environment (seawater (35 psu) ${\rightarrow}$ brackish water (BW, 17.5 psu) and BW with prolactin [PRL]). The expression of AVT, AVTR, and OSTF1 mRNA in the brain and gills increased after transfer to BW, and the expression was repressed by PRL treatment. AVT-immunoreactive cells were almost consistently observed in the telencephalon. The plasma $Na^+$ and $Cl^-$ levels decreased in BW, but the level of this parameter increased in BW with PRL treatme during salinity change. These results suggest that AVT, AVTR, and OSTF1 play important roles in hormonal regulation in osmoregulation organs, and that PRL improves the hyperosmoregulatory ability of cinnamon clownfish in BW environment.

Efficient Selection Method for Drought Tolerant Plants Using Osmotic Agents

  • Park, Dong-Jin;Im, Hyeon-Jeong;Jeong, Mi-Jin;Song, Hyeon-Jin;Kim, Hak-Gon;Suh, Gang-Uk;Ghimire, Balkrishna;Choi, Myung-Suk
    • Journal of Forest and Environmental Science
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    • v.34 no.3
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    • pp.224-234
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    • 2018
  • An efficient method to select drought tolerant Korean native plants using in vitro culture system was established in this study. While the plant growths and root inductions of each plant were proportionately affected by concentrations of mannitol on in vitro culturing seven plant species to test tolerance to osmotic stress, growth index (GI) and number of root induction of Chrysanthemi zawadskii var. latilobum and Dianthus chinensis var. semperflorens plantlets were higher than the others in 125mM mannitol. In test with polyethylene glycol (PEG), plantlets of C. zawadskii var. latilobum and D. chinensis var. semperflorens showed higher GI and number of root induction than the others in 33.3mM. On testing whether the well grown plants under osmotic stress are tolerant to virtual drought stress, there were significant differences in the withering rates of C. zawadskii var. latilobum and D. chinensis and those of were Aster yomena and Centaurea cyanus after 12 days without watering. It was found that significantly lower stomata numbers were shown in both drought tolerant plants than the sensitive plants. Averages of the stomata circumferences and the stomata area in the plantlets of the tolerant species were larger than those of the sensitive plants D. chinensis var. semperflorens showed the lowest transpiration level per unit area. The highest stomatal area per unit area was found in C. zawadskii, followed by D. chinensis var. semperflorens, Aster yomena and C. cyanus. In conclusion, C. zawadskii var. latilobum and D. chinensis var. semperflorens were more tolerant to drought than other two species. Furthermore in vitro selection was successfully used to screen drought tolerance species of native plant species.

Effects of Water Stress on Germination in Winter Barley (수분부족이 보리의 발아에 미치는 영향)

  • 백형진;최원열
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.39 no.2
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    • pp.139-145
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    • 1994
  • This study was intended to obtain the basic information on the germination status, changes of $\beta$-amylase activity and reducing sugar contents during seed germination of barley after an imposition of water stress by adding Polyethylene glycol solution. The effects of water deficit on germination were to be decreased in germination rate and velocity. Respiratory Quotient was increased as the osmotic potential in culture solution was decreased. But $\beta$-amylase activity and reducing sugar contents were decreased and the ratio of dry to fresh weight of germinated seeds was increased as the osmotic potential of the culture solution was decreased.

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Ectopic expression of soybean KS-type dehydrin, SLTI66 and SLTI629 conferred tolerance against osmotic and metal stresses of Escherichia coli and Arabidopsis

  • Chung, Eun-Sook;Cho, Chang-Woo;Kim, Kyoung-Mi;Lee, Jai-Heon
    • Journal of Plant Biotechnology
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    • v.36 no.1
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    • pp.38-44
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    • 2009
  • Two low temperature induced genes designated as SLTI66 and SLTI629 encoding KS-type dehydrin were heterologously expressed in E coli and A. thaliana. E coli cells expressing SLTI66 and SLTI629 protein grew better with iron stress compared to the control cells. Ectopic expression of SLTI629 conferred tolerance to iron stress in Arabidopsis but SLTI66 did not. Arabidopsis plants expressing SLTI66 showed enhanced tolerance to freezing and drought stress compared to those of wild type and SLTI629 lines. We propose that SLTI66 and SLTI629 play a different role as a protector against osmotic and metal stresses.

The Shaker Type Potassium Channel, GORK, Regulates Abscisic Acid Signaling in Arabidopsis

  • Lim, Chae Woo;Kim, Sang Hee;Choi, Hyong Woo;Luan, Sheng;Lee, Sung Chul
    • The Plant Pathology Journal
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    • v.35 no.6
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    • pp.684-691
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    • 2019
  • Evolution of adaptive mechanisms to abiotic stress is essential for plant growth and development. Plants adapt to stress conditions by activating the abscisic acid (ABA) signaling pathway. It has been suggested that the ABA receptor, clade A protein phosphatase, SnRK2 type kinase, and SLAC1 anion channel are important components of the ABA signaling pathway. In this study, we report that the shaker type potassium (K+) channel, GORK, modulates plant responses to ABA and abiotic stresses. Our results indicate that the full length of PP2CA is needed to interact with the GORK C-terminal region. We identified a loss of function allele in gork that displayed ABA-hyposensitive phenotype. gork and pp2ca mutants showed opposite responses to ABA in seed germination and seedling growth. Additionally, gork mutant was tolerant to the NaCl and mannitol treatments, whereas pp2ca mutant was sensitive to the NaCl and mannitol treatments. Thus, our results indicate that GORK enhances the sensitivity to ABA and negatively regulates the mechanisms involved in high salinity and osmotic stresses via PP2CA-mediated signals.

Influence of Culture Conditions on Production of NGPs by Aspergillus tubingensis

  • Lilia, Lopez De Leon;Isaura, Caceres;Julie, Bornot;Elodie, Choque;Jose, Raynal;Patricia, Taillandier;Florence, Mathieu
    • Journal of Microbiology and Biotechnology
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    • v.29 no.9
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    • pp.1412-1423
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    • 2019
  • The filamentous fungus Aspergillus tubingensis that belongs to the black Aspergillus section has the capacity to produce high-value metabolites, for instance, naphtho-gamma-pyrones (NGPs). For these fungal secondary metabolites, numerous biological properties of industrial interest have been demonstrated, such as antimicrobial, antioxidant and anti-cancer capacities. It has been observed that production of these secondary metabolites is linked with fungal sporulation. The aim of this research was to apply osmotic and oxidative environmental stresses to trigger the production of NGPs in liquid cultures with CYB (Czapek Dox Broth). In addition, numerous parameters were tested during the experiments, such as pH value, incubation time, container geometry, and static and agitation conditions. Results demonstrate that the produced amount of NGPs can be enhanced by decreasing the water activity ($a_w$) or by adding an oxidative stress factor. In conclusion, this study can contribute to our knowledge regarding A. tubingensis to present an effective method to increase NGP production, which may support the development of current industrial processes.

EPS Production, PHB Accumulation and Abiotic Stress Endurance of Plant Growth Promoting Methylobacterium Strains Grown in a High Carbon Concentration

  • Woo, Sung-Man;Subramanian, Parthiban;Ramasamy, Krishnamoorthy;Joe, M. Melvin;Sa, Tong-Min
    • Korean Journal of Soil Science and Fertilizer
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    • v.45 no.4
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    • pp.572-581
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    • 2012
  • In this study, we compared growth pattern, floc yield, Exo-polysaccharides (EPS) production, Poly-${\beta}$-hydroxybutyrate (PHB) accumulation, resistance to osmotic and acid stress in Methylobacterium strains CBMB20, CBMB27, CBMB35, and CBMB110. Modified high C:N ratio medium denoted as HCN-AMS medium was used with a C:N ratio of 30:1. The HCN-AMS medium favored increased growth in all the studied strains. All Methylobacterium strains tested positive for EPS production and showed positive fluorescence with calcoflour stain. Elevated levels of EPS production from 4.2 to 75.0% was observed in HCN-AMS medium. Accumulation of PHB in HCN-AMS medium increased by 3.8, 36.7, and 12.0% in strains CBMB27, CBMB35, and CBMB110 respectively. Among the abiotic stresses, osmotic stress-induced growth inhibition of Methylobacterium strains was found to be lowered when grown in HCN-AMS medium. Likewise, growth inhibition due to acid stress at pH 5.0 was lower for strains grown in HCN-AMS medium compared to growth in AMS medium. Enhanced survivability under stress conditions may be attributed to the high EPS and PHB production at increased carbon concentration in the growth medium.