Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    The site of action of abscisic acid at the guard cell plasmalemma of Valerianella locusta (1983)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 6 (1983), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract. Abscisic acid (ABA) is taken up by guard cells of isolated epidermata of Valerianella locusta only at low external pH values. At pH 8.0, when nearly all ABA molecules are present as the union of ABA (ABA−), no uptake can be observed. ABA-dependent movement of stomata was tested at external pH values between 5.0 and 8.0. Independent of the external pH, ABA induced stomatal closure at all tested ABA concentrations. It is concluded that ABA need not be taken up into the cytosol of the guard cells in order to induce slomatal closure. The primary site of ABA action at the guard cell plasmalemma must be located either at the outer surface of the plasmalemma or at least be easily accessible from outside. ABA− is as effective as undissociated ABA (ABAH).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3040.1983.tb01276.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Compartmentation and transport of 1-aminocyclopropane-1-carboxylic acid and N-malonyl-1-aminocyclopropane-1-carboxylic acid in barley and wheat mesophyll cells and protoplasts (1989)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 75 (1989), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Intracellular compartmentation of 1-aminocyclopropane-1-carboxylic acid (ACC) and N-malonyl-1-aminocyclopropane-1-carboxylic acid (MACC) in wheat (Triticum aestivum L. cv. Kanzler) and barley (Hordeum vulgare L. cv. Gerbel) leaves was studied using different methods: first, the isolation of intact vacuoles from protoplasts and, second, a non-aqueous fractionation procedure. The two methods gave similar results. ACC concentrations were similar in the extravacuolar space and in the vacuole, whereas MACC was accumulated in the vacuolar space. Transport studies revealed that no specific carrier for ACC exists at the tonoplast. MACC transfer across the tonoplast was enhanced by 120% in the presence of ATP. MACC competitively inhibited malate transport into the vacuole indicating that the same transfer system catalyzes the transfer of the two dicarboxylates.It is concluded that malonylation of ACC is not a prerequisite for the transport of ACC through the tonoplast.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1989.tb04635.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Abscisic add levels of individual leaf cells (1990)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 80 (1990), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abscisic acid (ABA) concentrations of guard cells, subsidiary cells and epidermis cells of Comrnelina communis L. and Tradescantia virginiana L. were determined in cell sap samples extracted by means of micro glass capillaries. Concentrations up to 6.7 mM were indicated by commercial immunoassay test kits. A gradient of ABA concentration was found between guard cells (2,49 ± 1.81 mM, n = 25), subsidiary cells (1.25 ± 1.46 mM, n = 21) and epidermis cells (0.86 ± 0.76 mM, n = 20; mean values ± SD).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1990.tb04373.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Diurnal variations in abscisic acid content and stomatal response to applied abscisic acid in leaves of irrigated and non-irrigated Arbutus unedo plants under naturally fluctuating environmental conditions (1983)
    Springer
    Oecologia 58 (1983), S. 128-131 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Endogenous abscisic acid content (ABA) of Arbutus unedo leaves growing under natural conditions in a macchia near Sobreda, Portugal, was very high (0.25 to 2.3 μg g1 fresh weight). Highest concentrations were found during the very early morning hours and at midday. During the late morning hours and in the late afternoon ABA concentrations decreased to between one-third and one-fourth of peak values. The samples for ABA content were obtained from both irrigated (Ψ between-10 and-25 bar) and non-irrigated plants experiencing natural water stress during the dry season (Ψ of-50 bar). During the course of the measurement day, stomatal conductance was relatively constant and conductance of watered plants was 50 to 100% greater than that of unwatered plants. No clear correlations between ABA content and stomatal conductance and/or xylem water potential were observed. Despite large differences in water potential and differences in degree of stomatal opening, absolute concentrations of ABA were not found to differ. Small quantities (8–14 pmoles cm2 leaf area) of ABA were applied to leaves of irrigated and non-irrigated Arbutus unedo plants by injection into the petiole. These extremely small ABA doses resulted in transient reductions in stomatal conductance. The effectiveness with which injected ABA closed stomata was highest during the morning and decreased substantially at midday. Increased sensitivity to injected ABA may again occur in the late afternoon but recent measurements suggest that this may depend on long-term drought experience of the plants. The characteristics of the response to injected ABA were similar in irrigated and non-irrigated plants although irrigated plants responded in general more strongly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00384552
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Uptake of amino acids by the aquatic resurrection plant Chamaegigas intrepidus and its implication for N nutrition (1998)
    Springer
    Oecologia 117 (1998), S. 63-69 
    Details
    ISSN: 1432-1939
    Keywords: Key words Amino acids ; Chamaegigas intrepidus ; Glycine uptake ; Nitrogen sources ; Resurrection plant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chamaegigas intrepidus is a poikilohydric aquatic plant that lives in rock pools on granitic outcrops in Central Namibia. The pools are filled intermittently during the summer rains, and the plants may pass through up 20 rehydration/dehydration cycles during a single wet season. Rehydrated plants also have to cope with substantial diurnal fluctuations in the pH and extreme nutrient deficiency. Ammonium concentrations are normally around 30 μM. Additional nitrogen sources are amino acids. Total free amino acids are up to 15 μM with glycine and serine as the predominant amino acids. Experiments on uptake of radiolabelled amino acids into roots of C. intrepidus showed high␣affinity (K M= 16 μM) and low-affinity (K M= 159 μM) uptake systems. The K M of the high-affinity system is well in accordance with the free amino acid concentration found in the water of the pools. We conclude that amino acids, predominantly glycine and serine, can be utilised by C. intrepidus in its natural habitat. Since glycine uptake showed a strong reduction at pH 10, nitrogen uptake from glycine or serine should occur mainly in the morning when the pH of the pool water is slightly acid. Further experiments with 15N-labelled ammonium in combination with non-labelled glycine demonstrated high 15N values in plant tissues. Under experimental conditions C. intrepidus preferred ammonium as a nitrogen source. The implication of amino acids for nitrogen nutrition of C. intrepidus may depend on the relation of inorganic and organic nitrogen available in the pool water and the preferential utilisation of one or the other nitrogen source may change during the day corresponding with pH changes in the water.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004420050632
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Effect of water stress on transport of [2-14C]abscisic acid in intact plants ofPhaseolus coccineus L. (1976)
    Springer
    Oecologia 26 (1976), S. 177-183 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Eight- to 10-day-old plants ofPhaseolus coccineus, which grow on vermiculite with a water content of 12–17% of the water-holding capacity, stop growing completely, whereas water potential and relative water content are almost unaffected. [2-14C]Abscisic acid, which is applied to the midrib of a primary leaf, is transported especially to the roots and the apical bud, but not to the second primary leaf and the cotyledons. Water-stressed plants, however, export only negligible amounts of ABA from the donor leaf to the plant. Thus an accumulation of ABA occurs in the donor leaf. Consequently water stress can increase ABA concentration in leaves not only by stimulating ABA synthesis but also by inhibiting ABA transport. Recovery of growth and ABA transport after reirrigation is very weak. Water stress has no effect on ABA metabolism in bean plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00582895
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    The permeability of the epidermal cell plasma membrane of barley leaves to abscisic acid (1993)
    Springer
    Planta 191 (1993), S. 41-47 
    Details
    ISSN: 1432-2048
    Keywords: Abscisic acid (carrier) ; Epidermal cell protoplast ; Hordeum ; Permeability coefficient ; Plasma membrane (permeability)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Uptake of 3H-labelled (±)-abscisic acid (ABA) into isolated barley (Hordeum vulgare L.) epidermal cell protoplasts (ECP) was followed over a range of pH values and ABA concentrations. The present results show that ABA uptake is not always linearly correlated with the external concentration of undissociated ABA (ABAH). At pH 7.25, ABA uptake exhibited saturation kinetics with an apparent K m value of 75 mmol·m−3 to tal ABA. This saturable transport component was inhibited by pretreating the protoplasts with 1 mol·m−3 p-chloromercuribenzenesulfonic acid at pH 8.0, conditions that minimized the uptake of this acid sulfhydryl reagent. Moreover, the rate of (±)-[3]HABA uptake was reduced by addition of 0.1 mol·m−3 (±)-ABA to 41%, whereas the same concentration of (±)-ABA was approximately half as effective (46% of the inhibitory effect). Thus, it was concluded that only (±)-ABA competes for an ABA carrier that is located in the epidermal cell plasma membrane. The permeability of the epidermal cell plasma membrane was studied by performing a Collander analysis. At pH 6 the overall plasma-membrane permeability of epidermal cells was similar to that of guard cells but was about two times higher than that of mesophyll cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00240894
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Abscisic acid causes changes in gene expression involved in the induction of the landform of the liverwort Riccia fluitans L. (1996)
    Springer
    Planta 199 (1996), S. 169-169 
    Details
    ISSN: 1432-2048
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00196894
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Cadmium leads to stimulated expression of the lipid transfer protein genes in barley: implications for the involvement of lipid transfer proteins in wax assembly (1997)
    Springer
    Planta 203 (1997), S. 9-19 
    Details
    ISSN: 1432-2048
    Keywords: Key words: Abscisic acid ; Cuticle ; Epidermis ; Heavy metal ; Hordeum ; Wax ; Lipid transfer protein (expression)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. In order to investigate the nature of genes expressed in leaf epidermal cells of higher plants, we have identified the nucleotide sequence of a cDNA designated ltp 7a2b encoding a novel nonspecific lipid transfer protein of barley (Hordeum vulgare L. cv. Gerbel). The cDNA of 755 basepairs contains an open reading frame of 366 nucleotides coding for a 12.3-kDa polypeptide. The first 29 amino acids constitute the putative signal peptide, characteristic for targeting to the secretory pathway. Analysis of mRNA levels by Northern blotting indicated that ltp 7a2b is preferentially expressed in the leaf epidermis. Levels of mRNA decreased during ageing of leaf tissue. Expression of ltp 7a2b was stimulated by a factor of 2–3 when the seedlings were grown in the presence of cadmium (10–1600 μM). Concomitantly, the primary leaves of Cd-exposed seedlings contained elevated levels of abscisic acid and a thicker wax layer of the cuticle. At 100 μM Cd in the hydroponic medium, the wax cover was increased by 50%. The increase in abscisic acid content, ltp 7a2b mRNA and wax coverage was either not seen, or seen much less, in Ni- and Zn-stressed seedlings. The data add circumstantial evidence to the recently proposed hypothesis that nonspecific lipid transfer proteins function in transfer of cutin and/or wax monomers from the site of synthesis in the cell to the cuticle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004250050159
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Apoplastic transport of abscisic acid through roots of maize: effect of the exodermis (2000)
    Springer
    Planta 210 (2000), S. 222-231 
    Details
    ISSN: 1432-2048
    Keywords: Key words: Abscisic acid – Exodermis – Hydraulic conductivity – Root (ABA transport) – Water transport –Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. The exodermal layers that are formed in maize roots during aeroponic culture were investigated with respect to the radial transport of cis-abscisic acid (ABA). The decrease in root hydraulic conductivity (Lpr) of aeroponically grown roots was stimulated 1.5-fold by ABA (500 nM), reaching Lpr values of roots lacking an exodermis. Similar to water, the radial flow of ABA through roots (JABA) and ABA uptake into root tissue were reduced by a factor of about three as a result of the existence of an exodermis. Thus, due to the cooperation between water and solute transport the development of the ABA signal in the xylem was not affected. This resulted in unchanged reflection coeffcients for roots grown hydroponically and aeroponically. Despite the well-accepted barrier properties of exodermal layers, it is concluded that the endodermis was the more effective filter for ABA. Owing to concentration polarisation effects, ABA may accumulate in front of the endodermal layer, a process which, for both roots possessing and lacking an exodermis, would tend to increase solvent drag and hence ABA movement into the xylem sap at increased water flow (JVr). This may account for the higher ABA concentrations found in the xylem at greater pressure difference.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00008129
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...