Inhibition of Flowering in Lolium temulentum L. By Water Stress: a Role for Abscisic Acid

1977 ◽  
Vol 4 (2) ◽  
pp. 225 ◽  
Author(s):  
RW King ◽  
LT Evans
Keyword(s):  
Abscisic Acid ◽  
Water Stress ◽  
Long Day ◽  
Relative Water ◽  
The One ◽  
Floral Evocation ◽  
Leaf Photosynthetic Rate ◽  
Response To Water ◽  
Aba Content ◽  
High Intensity Light

A brief, 8-h water stress during the induction of flowering in L. temulentum reduces the flowering response, the more so the greater the stress. Water stress also affected leaf photosynthetic rate, relative water content of leaves and leaf elongation. Water stress was most inhibitory to flowering when applied during the period of high-intensity light at the beginning of the one long day. The abscisic acid (ABA) content of leaves increased up to 30-fold during the imposition of water stress and fell rapidly after stress was relieved, regardless of when the stress was imposed. The greater the stress, the higher was the level of ABA in leaves and the greater was the inhibition of flowering. The ABA content of apices also rose in response to water stress, in some cases during the stress treatment but usually 8-22 h later. Flowering was inhibited when apical ABA contents were high at the end of the long day. Although water stress may influence the flowering of plants in several ways, these experiments suggest that water stress during the long day induction of L. temulentum inhibits flowering by raising the content of ABA at the shoot apex during floral evocation.

Influence of Chilling and Drought on Water Relations and Abscisic Acid Accumulation in Bean

1991 ◽  
Vol 18 (1) ◽  
pp. 25 ◽  
Author(s):  
P Vernieri ◽  
A Pardossi ◽  
F Tognoni
Keyword(s):  
Abscisic Acid ◽  
Water Stress ◽  
Water Relations ◽  
Cold Treatment ◽  
Relative Water ◽  
Different Temperatures ◽  
Saturated Atmosphere ◽  
Water Saturated ◽  
Aba Content ◽  
Chilling Treatment

Intact bean seedlings were subjected to either chilling (4°C) or drought stress. Leaf water relations and abscisic acid (ABA) content were monitored throughout a stress-recovery cycle. Chilling at low relative humidity (RH) and drought caused similar water deficits, as indicated by the decline in relative water content and water potentials, but they had different effects on ABA accumulation. There was a rapid increase in ABA levels in the leaves of water-deprived plants while only slight ABA accumulation was observed after 48 h of chilling (4°C). After 24 h cold treatment there were large changes in turgor but no change in ABA content. Plants chilled for 24 h accumulated ABA only when transferred to recovery conditions (20°C, 90-95% RH, in the dark) to an extent that was related to the rate of leaf rehydration. When the chilling treatment was performed in a water-saturated atmosphere, plants did not suffer any water stress and ABA levels did not increase over a period of 48 h. However, when the chilling treatment lasted for a longer period (72 h), a significant increase in ABA levels was found also in the absence of water deficit. Experiments performed with leaf discs incubated in a mannitol solution (osmotic potential - 1.6 MPa) at different temperatures indicated that low temperature markedly inhibits ABA synthesis and that water stress induces increases in ABA content only at non-limiting warm temperatures.

Primary Root Elongation Rate and Abscisic Acid Levels of Maize in Response to Water Stress

Crop Science ◽  
2011 ◽  
Vol 51 (1) ◽  
pp. 157-172 ◽  
Author(s):  
Kristen A. Leach ◽  
Lindsey G. Hejlek ◽  
Leonard B. Hearne ◽  
Henry T. Nguyen ◽  
Robert E. Sharp ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Water Stress ◽  
Root Elongation ◽  
Primary Root ◽  
Elongation Rate ◽  
Root Elongation Rate ◽  
Response To Water

Proline Analogues in Melaleuca Species: Response of Melaleuca lanceolata and M. uncinata to Water Stress and Salinity

1987 ◽  
Vol 14 (6) ◽  
pp. 669 ◽  
Author(s):  
BP Naidu ◽  
GP Jones ◽  
LG Paleg ◽  
A Poljakoff-Mayber
Keyword(s):  
Water Stress ◽  
Osmotic Adjustment ◽  
Osmotic Potential ◽  
Compatible Solutes ◽  
Species Response ◽  
Laboratory Conditions ◽  
Relative Water ◽  
Response To Water ◽  
First Time

Fifteen species of Melaleuca and two species of Callistemon from the field were examined to determine whether they accumulated nitrogen-containing compatible solutes and, if so, which. In addition to L-proline, N-methyl-L-proline (MP) (isolated for the first time from plants), trans-4-hydroxy-N-methyl- L-proline (MHP), and N, N'-dimethyl-trans-4-hydroxy-L-proline (DHP) were found in various combinations in the 15 Melaleuca species. M. lanceolata seedlings were subjected to water or salinity stress and M. uncinata to water stress under laboratory conditions. In both species significant reductions in leaf water potential (Ψw), osmotic potential (Ψs), turgor potential (Ψp), and relative water content (RWC) were observed in response to water stress. Salinised M. lanceolata plants showed considerable osmotic adjustment and maintained Ψp comparable to that of control plants; salinity, however, decreased RWC. In response to the imposed stresses under laboratory conditions, proline and MHP levels in M. lanceolata, and MHP and DHP levels in M. uncinata, increased. In addition to possible protective or osmotic roles in vivo, these proline analogues may be useful in chemotaxonomic investigations of Melaleuca species.

The rôle of abscisic acid and farnesol in the alleviation of water stress

1978 ◽  
Vol 284 (1002) ◽  
pp. 471-482 ◽  
Keyword(s):  
Abscisic Acid ◽  
Water Stress ◽  
Carbon Dioxide Concentration ◽  
Vapour Pressure Deficit ◽  
Guard Cells ◽  
Chloroplast Envelope ◽  
Water Vapour Pressure ◽  
Second Line ◽  
Short Supply ◽  
Response To Water

The complex responses of stomata which provide protection for land plants against excessive water loss are best understood if we consider them as occupying two lines of defence. The first line of defence consists of immediate responses to factors of the aerial environment, especially carbon dioxide concentration and water vapour pressure deficit, which ensure that the rate of transpiration is regulated to a level which can be supported by water uptake through the roots in moist soil. When the soil becomes dry, further controls become necessary, and the second line of defence comes into operation. A ceiling is imposed on the extent to which stomata can open, and an increase in the efficiency of water use is achieved, though at the expense of some reduction in the rate of photosynthesis. A sesquiterpenoid, abscisic acid (ABA) plays a major part in the second line of defence. It is contained in the mesophyll chloroplasts in leaves of well watered plants and is released when the water potential falls; the synthesis of new ABA is also induced by water stress. Movement of ABA from the mesophyll to the guard cells is assumed to take place, because the chloroplasts of guard cells appear to be unable to form ABA in response to water stress. We suggest that farnesol, another sesquiterpenoid hitherto considered to have a separate role as a regulator of transpiration, is the agent responsible for altering the permeability of chloroplast envelope membranes, allowing the release of ABA into the cytoplasm. The closure of stomata induced by ABA appears to be part of a series of integrated responses throughout the plant which helps to maintain turgor and growth when water is in short supply.

scholarly journals The Combination of Abscisic Acid (ABA) and Water Stress Regulates the Epicuticular Wax Metabolism and Cuticle Properties of Detached Citrus Fruit

2021 ◽  
Vol 22 (19) ◽  
pp. 10242
Author(s):  
Paco Romero ◽  
María Teresa Lafuente
Keyword(s):  
Abscisic Acid ◽  
Water Stress ◽  
Expression Patterns ◽  
Citrus Fruit ◽  
Epicuticular Wax ◽  
Storage Duration ◽  
Metabolism Regulation ◽  
Response To Water ◽  
Layer Composition ◽  
Wax Load

The phytohormone abscisic acid (ABA) is a major regulator of fruit response to water stress, and may influence cuticle properties and wax layer composition during fruit ripening. This study investigates the effects of ABA on epicuticular wax metabolism regulation in a citrus fruit cultivar with low ABA levels, called Pinalate (Citrus sinensis L. Osbeck), and how this relationship is influenced by water stress after detachment. Harvested ABA-treated fruit were exposed to water stress by storing them at low (30–35%) relative humidity. The total epicuticular wax load rose after fruit detachment, which ABA application decreased earlier and more markedly during fruit-dehydrating storage. ABA treatment changed the abundance of the separated wax fractions and the contents of most individual components, which reveals dependence on the exposure to postharvest water stress and different trends depending on storage duration. A correlation analysis supported these responses, which mostly fitted the expression patterns of the key genes involved in wax biosynthesis and transport. A cluster analysis indicated that storage duration is an important factor for the exogenous ABA influence and the postharvest environment on epicuticular wax composition, cuticle properties and fruit physiology. Dynamic ABA-mediated reconfiguration of wax metabolism is influenced by fruit exposure to water stress conditions.

scholarly journals   Role of abscisic acid and drought stress on the activities of antioxidant enzymes in wheat

2012 ◽  
Vol 58 (No. 4) ◽  
pp. 181-185 ◽  
Author(s):  
A. Bano ◽  
F. Ullah ◽  
A. Nosheen
Keyword(s):  
Abscisic Acid ◽  
Drought Stress ◽  
Seed Treatment ◽  
Oxygen Species ◽  
Wheat Cultivars ◽  
Drought Tolerant ◽  
Relative Water ◽  
Aba Content ◽  
Endogenous Aba

The effect of drought stress and abscisic acid (ABA) applied at tillering stage (55 days after sowing) was compared in 2 wheat cultivars differing in drought tolerance. The activities of superoxide dismutase (SOD) and peroxidase (POD) and contents of endogenous ABA in plants were measured at 3 days of drought stress in cv. Chakwal-97 (drought tolerant) and cv. Punjab-96 (drought susceptible). ABA was applied at 10<sup>&ndash;6</sup> mol/L as presowing seed treatment for 18 h. Drought tolerant cultivar has a more efficient mechanism to scavenge reactive oxygen species as shown by a significant increase in the activity of antioxidant enzyme SOD. Under drought stress, ABA significantly increased the activities of SOD and POD, showing a significant decline on rewatering. The relative water content was significantly increased by ABA priming under drought stress in both wheat cultivars. The sensitive cultivar exhibiting lower endogenous ABA content was more responsive to ABA priming. On rewatering, the magnitude of recovery from drought stress was greater in tolerant cultivar. ABA was highly effective in improving grain weight of tolerant cultivar under drought stress. &nbsp;

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