Abscisic acid, phaseic acid and gibberellin contents associated with dormancy and germination in barley

2002 ◽  
Vol 115 (3) ◽  
pp. 428-441 ◽  
Author(s):  
John V. Jacobsen ◽  
David W. Pearce ◽  
Andrew T. Poole ◽  
Richard P. Pharis ◽  
Lewis N. Mander
Keyword(s):  
1981 ◽  
Vol 8 (5) ◽  
pp. 443 ◽  
Author(s):  
WJS Downton ◽  
BR Loveys

Changes in abscisic acid, phaseic acid, stomatal resistance, water potential, osmotic potential, turgor potential, proline, reducing sugars and ion content (Na+, K+, Cl-) in leaves from grapevines (Vitis vinifera L.) subjected to 0, 25, 50 or 100 mM NaCl (osmotic potentials of 0, - 0.1, - 0.2 and - 0.4 MPa, respectively) were monitored over a 3-week period. Abscisic acid concentration increased within 6 h for the 50 and 100 mM NaCl-treated vines. Proline did not accumulate until the next day for the 100 mM NaCl-treated plants and continued to accumulate for the duration of the experiment. Phaseic acid showed kinetics consistent with its being derived from abscisic acid. Stomatal resistance to water vapour exchange increased in the salt-treated plants over the course of the experiment despite a decline in abscisic acid concentration after the initial upsurge. Reducing sugar concentration showed an early upsurge, its contribution to osmotic readjustment being at least equal to that of accumulated Na+, K+ and Cl- the day after stress began. Potassium was preferentially accumulated over sodium into leaves during the first 8 days of the experiment and the sum of these two cations generally balanced accumulating chloride. Except for an initial loss of turgor in vines given 100 mM NaCl, turgor potential was maintained within 0.1 MPa of control plants for all of the treatments throughout the experiment.


Author(s):  
Nicolás E Figueroa ◽  
Thomas Hoffmann ◽  
Klaus Olbricht ◽  
Suzanne R Abrams ◽  
Wilfried Schwab

Abstract Abscisic acid (ABA) is a key hormone in non-climacteric Fragaria spp, regulating multiple physiological processes throughout fruit ripening. Its level increases during ripening, and it promotes fruit (receptacle) development. However, its metabolism in the fruit is largely unknown. We analyzed the levels of ABA and its catabolites at different developmental stages of strawberry ripening in diploid and octoploid genotypes and identified two functional ABA-glucosyltransferases (FvUGT71A49 and FvUGT73AC3) and two regiospecific ABA-8’-hydroxylases (FaCYP707A4a and FaCYP707A1/3). ABA-glucose-ester content increased during ripening in diploid F. vesca varieties but decreased in octoploid F. xananassa. Dihydrophaseic acid content increased throughout ripening in all analyzed receptacles, while 7’-hydroxy-ABA and neo-phaseic acid did not show significant changes during ripening. In the studied F. vesca varieties, the receptacle seems to be the main tissue for ABA metabolism, as the content of ABA and its metabolites in the receptacle was generally 100 times higher than in achenes, respectively. The accumulation patterns of ABA catabolites and transcriptomic data from the literature show that all strawberry fruits produce and metabolize considerable amounts of the plant hormone ABA during ripening, which is therefore a conserved process, but also illustrate the diversity of this metabolic pathway which is species, variety and tissue dependent.


1992 ◽  
Vol 70 (8) ◽  
pp. 1550-1555 ◽  
Author(s):  
L. V. Gusta ◽  
B. Ewan ◽  
M. J. T. Reaney ◽  
S. R. Abrams

Optical isomers of abscisic acid (ABA) and racemic mixtures of both abscisic acid and abscisic acid metabolites were studied to determine their effects on the emergence of root primordia and cotyledons from cress seed. The relative emergence sensitivity of cress seed to the racemic compounds was (±)-ABA aldehyde ≥ (±)-ABA alcohol > (±)-ABA > (±)7′-hydroxy ABA > (±)-phaseic acid. Thus ABA and ABA precursors were effective inhibitors whereas the ABA catabolites, phaseic acid, and 7′-hydroxy ABA had little or no effect on germination. The naturally occurring optically pure enantiomer (+)ABA was a more potent germination inhibitor than synthetic (−)-ABA. An ABA analog, 2′,3′-cis dihydro ABA (DHABA), that is not metabolized to phaseic acid was also studied for inhibitory activity. Although optically pure DHABA has the same configuration at C-1 as (+)-ABA, it was less inhibitory than (+)-ABA and its (−) enantiomer was inactive. The pattern of activity observed in treatments with the enantiomers of DHABA indicates that the configuration at C-1′ is important for maximum inhibition of cress seed germination. It also suggests that in contrast to monocot seeds, the formation of phaseic acid is not required for the inhibition of cress seed germination. Key words: abscisic acid, phaseic acid, ABA alcohol, ABA aldehyde, 7′OHABA, germination, ABA analogs.


1991 ◽  
Vol 30 (5) ◽  
pp. 1483-1485 ◽  
Author(s):  
R.D. Willows ◽  
A.G. Netting ◽  
B.V. Milborrow

1983 ◽  
Vol 63 (1) ◽  
pp. 131-145 ◽  
Author(s):  
R. C. DURLEY ◽  
T. KANNANGARA ◽  
G. M. SIMPSON ◽  
N. SEETHARAMA

Concentrations of free and conjugated abscisic acid (AbA), phaseic acid (PA) and indole-3-acetic acid (IAA) were measured in leaves of sorghum (Sorghum bicolor (L.) Moench) genotypes grown in the field. Hormone levels were compared and related to grain yield stability under drought, expressed as the percentage reduction in grain yield (percent RGY) of drought-stressed compared to irrigated plants. Although hormone concentrations were similar in irrigated plants, there was considerable genotypic variation in drought-stressed plants. In a four genotype comparison during the panicle initiation stage, mean leaf AbA concentrations in drought-stressed plants were positively related to percent RGY. Furthermore, the slopes of regression lines of AbA on leaf water potential in stressed genotypes were also positively related to percent RGY. In contrast, PA and total AbA metabolite concentrations were negatively related to percent RGY, implying a higher efficiency of conversion of AbA to its metabolites in drought resistant than in drought-susceptible genotypes. There was genotypic variation in free and conjugated IAA concentration in leaves of stressed plants, but these concentrations were not directly related to percent RGY. Nevertheless, high levels of free and conjugated IAA were found at some periods in leaves of drought-susceptible genotypes. The positive relationship between free AbA concentration and percent RGY was confirmed in a nine genotype comparison. Mean leaf AbA concentrations during flowering and early grain filling in drought-stressed plants were found to be a significantly correlated (r = 0.86**) with percent RGY. It is concluded that it is possible to evaluate genotype drought resistance to a given stress treatment in sorghum by examination of AbA, PA and IAA concentations in leaves. The potential of the method as a tool for plant breeders is discussed.Key words: Sorghum bicolor, drought stress, abscisic acid, phaseic acid, indole-3-acetic acid, yield


2002 ◽  
Vol 127 (5) ◽  
pp. 737-741 ◽  
Author(s):  
Satoru Kondo ◽  
Wanvisa Ponrod ◽  
Sirichai Kanlayanarat ◽  
Nobuhiro Hirai

Endogenous abscisic acid (ABA), its 2-trans isomer (trans-ABA), phaseic acid (PA), and dihydrophaseic acid (DPA) concentrations were quantified in the peel, aril, and seed of mangosteen (Garcinia mangostana L.). Changes in carbon dioxide (CO2) and ethylene (C2H4) production and 1-aminocyclopropane-1-carboxylic acid (ACC) concentration in the peel and aril were also examined. ACC concentration and CO2 and C2H4 production were high at the beginning of fruit development and gradually decreased toward harvest, which confirms that mangosteen is a nonclimacteric fruit. In the peel and aril, the increase in ABA concentration preceded the decrease in peel firmness and coloring of the peel. This suggests that ABA may induce the maturation of mangosteens. The state of ABA metabolism varied with the part of fruit. In the peel, PA and DPA were not considered to be predominant metabolites of ABA because their concentrations were low compared to ABA throughout fruit development. In contrast, in the aril and seed, it is possible that the PA-DPA pathway may be a main pathway of ABA metabolism because the concentrations of DPA in the aril and of PA in the seed directly coincided with the concentrations of ABA. The differences in the ABA metabolites between aril and seed may be caused by the rate of ABA metabolism. The concentrations of ABA and its metabolite in the seed decreased toward harvest.


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