Effects of growth temperature on the response of lupin stomata to drought and abscisic acid

1999 ◽  
Vol 26 (6) ◽  
pp. 549 ◽  
Author(s):  
M. Leonor Osório ◽  
M. Lucília Rodrigues ◽  
M. Manuela Chaves ◽  
Maria João Correia

To assess how growth temperature affects stomatal responses to xylem-transported abscisic acid (ABA), leaf conductance (g), the concentrations of ABA and calcium ions, and the pH of the xylem sap were measured in well-watered and water-stressed Lupinus albus L. plants grown under two thermal regimes: 10/15°C and 20/25°C, night/day temperature. Moderate water deficit was imposed, at the same thermal time, and induced a significant reduction in g regardless of temperature. In the morning, g was higher in plants grown at 20/25°C than in cooler conditions, and these differences could not be explained by dissimilarities in shoot water status or xylem ABA concentration. At midday, the apparent stomatal sensitivity to xylem-carried ABA was increased and the effect of temperature on the relationship between g and xylem ABA was no longer observed. A positive effect of higher temperature on stomatal aperture was also evident when artificial sap containing ABA was fed to leaves of well-watered plants. In response to exogenous ABA, stomata closed to the same extent as observed in the morning in water-stressed plants. However, exogenous ABA feeding could not mimic the relationship between g and xylem ABA determined at midday in intact plants. The pH and the concentration of calcium in xylem were not affected by temperature. At midday, however, the calcium concentrations were higher in water-stressed than in well-watered plants. These changes in the concentrations of calcium or other xylem components, such as ABA conjugates, together with possible changes in the ability of the leaves to degrade and/or to compartmentalise ABA, may partly explain the midday increase in the apparent stomatal sensitivity to xylem ABA.

1991 ◽  
Vol 18 (1) ◽  
pp. 17 ◽  
Author(s):  
Z Kefu ◽  
R Munns ◽  
RW King

Exposing barley and cotton plants to 75 mol m-3 NaCl reduced transpiration and increased abscisic acid (ABA) levels in leaves, roots and xylem sap. Exposing saltbush (Atriplex spongiosa) plants to 75 mol m-3 NaCI, at which concentration they grow best, did not affect transpiration or ABA levels but when the NaCl was increased to 150 mol m-3 transpiration fell and ABA levels rose. ABA levels in leaves were high in salt-treated barley and saltbush even when the leaf water status was raised by pressurising the roots. These responses indicate that an increased leaf ABA level was not triggered by leaf water deficit, but by the root's response to the salinity. The flux of ABA in the xylem sap of the three species was more than enough to account for the amount of ABA in leaves, in the presence and absence of salinity. This suggests that the roots may be the source of at least part of the ABA found in leaves.


1986 ◽  
Vol 64 (10) ◽  
pp. 2295-2298 ◽  
Author(s):  
Tsai-Yun Lin ◽  
Edward Sucoff ◽  
Mark Brenner

The relationship between abscisic acid (ABA) and leaf water status was studied during the air drying of detached leaves of eastern cottonwood (Populus deltoides Marsh.). The ABA content increased exponentially as leaf water potential and leaf turgor potential decreased. No clearly defined thresholds were observed between ABA content and these variables. ABA content was linearly related to the relative fresh weight and was not related to the osmotic potential.


Horticulturae ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 12
Author(s):  
Massimiliano Cocco ◽  
Luca Mercenaro ◽  
Mauro Lo Cascio ◽  
Giovanni Nieddu

Beyond climatic conditions, qualitative performance is led by the intrinsic characteristics of the genotype. The aim of this study was to investigate the relationship between vine water status and exogenous abscisic acid (ABA) application on berry composition of the cultivars Cannonau, Merlot and Sangiovese. The experiment, carried out in 2016 and 2017, consisted of comparing two levels of irrigation treatments, full irrigation versus a non-irrigation treatment. Within each treatment, two sub-treatments were set up: (i) 4 mL L−1 of exogenous ABA applied at veraison to clusters only and subsequently repeated after six days; (ii) a control (untreated vines). The application of different irrigation regimes confirmed that the response to water stress is highly cultivar-dependent. Berry composition was influenced differently among cultivars by water stress. In terms of metabolites, positive influences were observed with Cannonau. No significant effects were observed by spraying exogenous ABA directly on grapes. Moreover, no significant interactions were found between the application of water stress and ABA. Exogenous ABA application did not appear to be a viticultural practice capable of influencing must composition in environments characterized by severe environmental conditions such as heat and drought.


HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 838A-838
Author(s):  
Robert C. Ebel ◽  
Xiangrong Duan ◽  
Robert M. Augé

Mycorrhizal colonization can alter stomatal behavior of host leaves before or during soil drying, but the mechanism of influence is not always clear. We examined the possibility that mycorrhizal symbiosis might result in either altered stomatal sensitivity to abscisic acid (ABA) moving from roots to shoots in xylem sap, or altered movement of ABA in xylem as a function of soil water content (θ). Mycorrhizal colonization of Vigna unguiculata did not change the relationship between stomatal conductance (gs) and xylem [ABA] during drying of whole root systems. Stomatal conductance was higher in mycorrhizal than in similarly sized and similarly nourished nonmycorrhizal plants when soil moisture was relatively high, perhaps related to lower xylem [ABA] in mycorrhizal plants at high soil θ. Neither gs nor xylem [ABA] was affected by mycorrhizae at low soil θ. Higher gs in mycorrhizal plants was evidently not related to a mycorrhizal effect on leaf water status, as neither gs/shoot Ψ nor shoot Ψ/soil θ relationships were altered by the symbiosis. Stomatal conductance was much more closely correlated with xylem [ABA] than with soil θ or shoot Ψ. Decreased xylem [ABA] may explain why mycorrhizal colonization sometimes increases gs of unstressed mycorrhizal plants in the absence of mycorrhizae-induced changes in host nutrition. This work was supported by USDA NRICGP grant 91-37100-6723 (R.M.A).


1985 ◽  
Vol 12 (5) ◽  
pp. 463 ◽  
Author(s):  
A Benzioni ◽  
RL Dunstone

Jojoba flower buds break dormancy in response to low temperatures in the presence of adequate water. The possibility that abscisic acid (ABA) is involved in the regulation of dormancy was examined by following endogenous ABA levels in flower buds and leaves and by applying synthetic (�)-ABA. Under controlled conditions endogenous levels of ABA were high in dormant flower buds and decreased under conditions of low temperatue that led to flowering. Similar results were obtained in the field. Levels in the leaves were low and changes in response to environmental treatments were small. Daily spraying of the plants with water containing 0.01% Tween enhanced flowering while water stress inhibited it. The application of (�)-ABA delayed flowering and reduced the percentage of flowers open at the end of the experiment. An experiment aimed at distinguishing between the effects of temperature and of water status was inconclusive and part of the effect of temperature on ABA may be related to the effect of temperature on the water status of plant.


1949 ◽  
Vol 40 (2) ◽  
pp. 239-265 ◽  
Author(s):  
S. Pradhan

1. A series of exploratory experiments on the relationship between temperature and toxicity of DDT films to adults of Tribolium castaneum, and larvae of Plutella maculipennis, are described. The main conclusions with T. castaneum are:—(a) When the insects are continuously kept on the film at different temperatures there is a higher kill at higher temperatures.(b) When the insects are exposed to the film for about 24 hours at the same temperature and then kept away from it at different temperatures there is a higher kill at the lower temperature.(c) When the insects are kept on the film at different temperatures for about 24 hours and then kept away from the film for reaction at the same temperature, there is a higher kill in those kept on the film at the higher temperature.(a) and (b) above apply equally to larvae of P. maculipennis but (c) is reversed. The probable cause of this reversal appears to be the observed fact that at higher temperatures these larvae cover the film with much more silk thread and thus avoid contact to a greater extent than at lower temperatures.2. A review of literature, in the light of the conclusions arrived at, indicate that many of the observations made upon the temperature-toxicity relationship can be accounted for by the following generalisations:—(a) Insect resistance to poisons changes with temperature as do its other vital activities, increasing up to a critical degree and afterwards declining.(b) The amount of poison reaching the site of action in unit time also varies with the temperature, generally but not always, increasing with its rise. Insect activity, especially locomotor and respiratory, may play an important part in these effects.(c) The apparent effects of temperature on insecticidal action is the combination of these two factors, namely, resistance and pick-up.


2021 ◽  
Vol 12 ◽  
Author(s):  
Shenglan Li ◽  
Fulai Liu

Plants have evolved multiple strategies to survive and adapt when confronting the changing climate, including elevated CO2 concentration (e[CO2]) and intensified drought stress. To explore the role of abscisic acid (ABA) in modulating the response of plant water relation characteristics to progressive drought under ambient (a[CO2], 400 ppm) and e[CO2] (800 ppm) growth environments, two tomato (Solanum lycopersicum) genotypes, Ailsa Craig (AC) and its ABA-deficient mutant (flacca), were grown in pots, treated with or without exogenous ABA, and exposed to progressive soil drying until all plant available water in the pot was depleted. The results showed that exogenous ABA application improved leaf water potential, osmotic potential, and leaf turgor and increased leaf ABA concentrations ([ABA]leaf) in AC and flacca. In both genotypes, exogenous ABA application decreased stomatal pore aperture and stomatal conductance (gs), though these effects were less pronounced in e[CO2]-grown AC and gs of ABA-treated flacca was gradually increased until a soil water threshold after which gs started to decline. In addition, ABA-treated flacca showed a partly restored stomatal drought response even when the accumulation of [ABA]leaf was vanished, implying [ABA]leaf might be not directly responsible for the decreased gs. During soil drying, [ABA]leaf remained higher in e[CO2]-grown plants compared with those under a[CO2], and a high xylem sap ABA concentration was also noticed in the ABA-treated flacca especially under e[CO2], suggesting that e[CO2] might exert an effect on ABA degradation and/or redistribution. Collectively, a fine-tune ABA homeostasis under combined e[CO2] and drought stress allowed plants to optimize leaf gas exchange and plant water relations, yet more detailed research regarding ABA metabolism is still needed to fully explore the role of ABA in mediating plant physiological response to future drier and CO2-enriched climate.


Sign in / Sign up

Export Citation Format

Share Document