Abscisic Acid and Cytokinin Contents of Leaves in Relation to Salinity and Relative Humidity

Mizrahi, Yosef; Blumenfeld, A.; Bittner, Shmuel; Richmond, Amos

doi:10.1104/pp.48.6.752

Cited by 94 publications

(45 citation statements)

References 11 publications

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“…Water and osmotic stresses alter the content of endogenous cytokinin and ABA: cytokinin activity in the root exudate declines drastically after 48 hr of salinity stress (!tai, Richmond, and Vaadia 1968), and ABA content in leaves of such plants increases considerably (Wright and Hiron 1969;Mizrahi et al 1971) the increase starting within 40 min of commencement of salinity stress (Mizrahi and Richmond, unpublished data). This study describes the effects of ABA and kinetin on plant response to various conditions which impair plant water balance.…”

Section: Introductionmentioning

confidence: 99%

Hormonal Modification of Plant Response to Water Stress

Mizrahi¹,

Richmond²

1972

Aust. Jnl. Of Bio. Sci.

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Addition of either kinetin or abscisic acid (ABA) to the root medium of tobacco plants grown in culture solution greatly modified their response to different types of root stresses that were applied 48 hr after the addition of the hormones.All the stresses employed impaired the water balance of the plants as evidenced by a decline of shoot turgor. The stresses consisted of cessation in root aeration, reduction of root temperature, and decrease in the osmotic potential of the root media by addition of either N aCl or mannitol.Response of plants to a stress was estimated by measuring the water saturation deficit (W.S.D.) in the leaves 3 hr after the stress started. Pretreatment with kinetin resulted in an increased W.S.D. in the leaves whereas pretreatment with ABA, with the exception of the 3-hr saline stress, effected decreased W.S.D. in comparison with the appropriate controls.A possible explanation of this phenomenon and its practical applications are discussed.

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Section: Introductionmentioning

confidence: 99%

Hormonal Modification of Plant Response to Water Stress

Mizrahi¹,

Richmond²

1972

Aust. Jnl. Of Bio. Sci.

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“…It has been implicated in a variety of physiological processes (1,11,13,15) and is found in elevated levels under several stressful conditions (3,4,7,8,16,18,23 Samples for ABA determination were harvested at 0, 12, 24, 48, and 72 h. Zero sampling time (09:00 h) was 3 h after the lights came on; therefore, all samples, except those at 12 h, were harvested 3 h after the lights came on. The 12-h samples were taken 1 h before the end of the light period (2 1:00 h).…”

Section: Introductionmentioning

confidence: 99%

“…It has been implicated in a variety of physiological processes (1,11,13,15) and is found in elevated levels under several stressful conditions (3,4,7,8,16,18,23).…”

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confidence: 99%

Response of Tomato Plants to Stressful Temperatures

Daie¹,

Campbell²

1981

Plant Physiol.

164

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To investigate the abscisic acid (ABA) production of tomato (Mill.) plants in response to diurnal stressful temperatures, five-week old seedlings were exposed to day/night temperatures of 10/5, 15/10, 25/15, 35/25, or 45/35 C. The daylength was 16 hours with a light intensity of approximately 400 microeinsteins per meter per second. Plant tops were sampled at 12, 24, 48, and 72 hours. Free, alkaline-hydrolyzable (conjugated), and total ABA quantities were measured using standard gas chromatographic techniques. AU temperature regimes significantly increased both free and conjugated ABA levels over concentrations in control plants (25/15 C). The highest ABA levels were observed in plants exposed to the coolest temperature of 10/5 C. Since normal water potentials were obtained in plants of al treatments, the observed ABA response was not due to temperature-induced water stress. Therefore, temperature stress, like several other environmental stresses, induces the plant to produce high levels of ABA. Because of the similar involvement of ABA in temperature-induced and other environmental stresses, ABA may be a common mediator for all plant stresses.ABA is a naturally occurring compound of major importance in regulating plant growth and development. It has been implicated in a variety of physiological processes (1,11,13,15) and is found in elevated levels under several stressful conditions (3,4,7,8,16,18,23 Samples for ABA determination were harvested at 0, 12, 24, 48, and 72 h. Zero sampling time (09:00 h) was 3 h after the lights came on; therefore, all samples, except those at 12 h, were harvested 3 h after the lights came on. The 12-h samples were taken 1 h before the end of the light period (2 1:00 h). At each harvest, three single plant replicates (exclusive of the root system) were immediately frozen on dry ice and stored in a freezer at -18 C until analyzed. A representative sample (1-3 g) of each frozen and crushed plant was weighed, homogenized in ice-cold 90% methanol (10 ml/g fresh tissue), and filtered. ABA was analyzed according to the method described by Seeley and Powell (21). The alkaline-hydrolyzable ABA (conjugated ABA) was determined by adjusting the pH of the remaining aqueous phase to 11.0 with KOH, heating it at 60 C for 45 min, and re-extracting with methylene chloride. Acidic fractions were derivatized by ethereal diazomethane. ABA was quantified with a Tracor 222 Gas Chromatograph equipped with a Ni3 electron capture detector. Column packing was 3% OV-25 on Gas Chrom Q (100 to 200 mesh support). Purified N2 at a flow rate of 80 ml/min was used as the carrier gas.

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“…Gas chromatography on a Packard model 873 gas chromatograph equipped with a model 873 electron capture detector was carried out as detailed by Mizrachi et al (1971). Peaks indicating endogenous ABA were interpolated from identical retention times of marker ABA.…”

Section: Gibberellin Extraction and Bioassaymentioning

confidence: 99%

“…The extraction procedure was that of Mizrachi et al (1971) and the final extract was chromatographed as described above. Commercial ABA (Sigma-mixed isomers) was used as a marker on the chromatograms.…”

Section: Gibberellin Extraction and Bioassaymentioning

confidence: 99%

ON HORMONES AND WEEPING: ASYMMETRIC HORMONE DISTRIBUTION AND THE PENDULOUS GROWTH HABIT OF THE WEEPING MULBERRY, MORUS ALBA VAR. PENDULA

1974

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SUMMARYThe possibility that asymmetric hormone distribution causes downward bending of weeping mulberry {Morus alba var. pendula) twigs was investigated. By extraction, bioassay and gas chromatography it was shown that while upper and lower twig sections had no differences in auxin activity, the two sides differed considerably in content of GA and ABA. The lower side contained high levels of endogenous GA while the upper side had higher concentrations of ABA. The significance of these results and their possible role in the weeping habit of tree growth are discussed. It is suggested that the high GA levels coupled to low ABA content induce greater lignification on the lower side of the twig and that this tissue is less sensitive to auxin and has a lower growth response than the upper side of the twig thus causing a downward inclination of growth.

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Abscisic Acid and Cytokinin Contents of Leaves in Relation to Salinity and Relative Humidity

Cited by 94 publications

References 11 publications

Hormonal Modification of Plant Response to Water Stress

Hormonal Modification of Plant Response to Water Stress

Response of Tomato Plants to Stressful Temperatures

ON HORMONES AND WEEPING: ASYMMETRIC HORMONE DISTRIBUTION AND THE PENDULOUS GROWTH HABIT OF THE WEEPING MULBERRY, MORUS ALBA VAR. PENDULA

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