Osmotic Adjustment, Induced by Drought, in Seedlings of Three Eucalyptus Species

1986 ◽  
Vol 13 (5) ◽  
pp. 597 ◽  
Author(s):  
BA Myers ◽  
TF Neales
Keyword(s):  
Water Potential ◽  
Osmotic Adjustment ◽  
Osmotic Potential ◽  
Dry Weight ◽  
Eucalyptus Species ◽  
Plant Water ◽  
Mature Trees ◽  
Mean Values ◽  
Turgor Maintenance ◽  
Plant Water Potential

Osmotic adjustment was observed in pot-grown seedlings of Eucalyptus behriana, E. microcarpa and E. polyanthemos that had been subjected to one and two periods of drought. The osmotic potential of sap expressed from rehydrated leaves was significantly lower in seedlings which had wilted twice (-2.02 � 0.05 MPa) compared with those which had wilted once (-1.86 � 0.05 MPa) and those which had been watered daily (-1.66 � 0.05 MPa). After two drought cycles, seedlings began to wilt at lower mean values of plant water potential (- 3.51 � 0.22 MPa) than those which had not wilted previously (-3.14 � 0.22 MPa). Thus drought-induced osmotic adjustment apparently enhanced turgor maintenance. The ratio of turgid weight to dry weight was slightly, but significantly, smaller in the seedlings subjected to two drought cycles (3.83 � 0.04 MPa) compared with those subjected to one drought cycle (4.05 � 0.04). The osmotic adjustment that was induced by two drought cycles in these seedlings was about one third of the observed seasonal osmotic adjustment in mature trees of E. behriana and E. microcarpa in the field.

Water relations of winter wheat. 5. The root system and osmotic adjustment in relation to crop evaporation

1984 ◽  
Vol 102 (2) ◽  
pp. 415-425 ◽  
Author(s):  
M. McGowan ◽  
P. Blanch ◽  
P. J. Gregory ◽  
D. Haycock
Keyword(s):  
Winter Wheat ◽  
Water Potential ◽  
Root System ◽  
Soil Water ◽  
Osmotic Adjustment ◽  
Stomatal Closure ◽  
Soil Water Potential ◽  
Plant Water ◽  
Potential Evaporation ◽  
Plant Water Potential

SummaryShoot and root growth and associated leaf and soil water potential relations were compared in three consecutive crops of winter wheat grown in the same field. Despite a profuse root system the crop grown in the second drought year (1976) failed to dry the soil as throughly as the crops in 1975 and 1977. Measurements of plant water potential showed that the restricted utilization of soil water reserves by this crop was associated with failure to make any significant osmotic adjustment, leading to premature loss of leaf turgor and stomatal closure. The implications of these results for models to estimate actual crop evaporation from values of potential evaporation are discussed.

Osmotic Adjustment in Water Stressed Grapevine Leaves in Relation to Carbon Assimilation

1993 ◽  
Vol 20 (3) ◽  
pp. 309 ◽  
Author(s):  
ML Rodrigues ◽  
MM Chaves ◽  
R Wendler ◽  
MM David ◽  
WP Quick ◽  
...  
Keyword(s):  
Water Potential ◽  
Osmotic Adjustment ◽  
Osmotic Potential ◽  
Soluble Sugars ◽  
Carbon Assimilation ◽  
Dry Weight ◽  
Leaf Water ◽  
Soluble Carbohydrates ◽  
Water Fraction ◽  
The Difference

The response of grapevine plants to severe water deficit (predawn leaf water potential of - 1.13 MPa), imposed at a rate of about 0.16 MPa day-1 was studied in terms of leaf water relations characteristics, stomatal behaviour and gas exchange. Carbohydrate status of leaves was also analysed in order to assess the contribution of soluble sugars as osmotic solutes during drought. Pressure/volume analysis showed an active osmotic adjustment in water-stressed leaves, which decreased osmotic potential at full turgor by 0.45 MPa and the apoplastic water fraction showed a reduction of 19% as compared to the well- watered plants. Cell wall elasticity was not significantly affected by water stress, and turgor loss point in stressed leaves was reached at lower water potential and relative water content values than in the well-watered controls. Photosynthesis was markedly reduced in water-stressed plants. However, well-watered and water-stressed leaves had similar concentrations of glucose and fructose. The concentrations of sucrose and starch decreased in water-stressed leaves. This accounted for a marked decrease in the ratio of leaf dry weight to area in droughted plants. The changes in concentrations of soluble carbohydrates could not account for the difference in osmotic potential between water-stressed and well-watered leaves.

Seasonal trends of several water relation parameters in Cryptomeriajaponica seedlings

1986 ◽  
Vol 16 (1) ◽  
pp. 74-77 ◽  
Author(s):  
Kyoji Doi ◽  
Yasushi Morikawa ◽  
Thomas M. Hinckley
Keyword(s):  
Water Relations ◽  
Osmotic Adjustment ◽  
Osmotic Potential ◽  
Dry Weight ◽  
Water Relation ◽  
Evaporative Demand ◽  
Seasonal Trends ◽  
Air Temperatures ◽  
Turgor Maintenance

The role of osmotic adjustment in turgor maintenance during periods of either cold soil or plant temperatures or of high evaporative demand was described for 2-year-old Cryptomeriajaponica D. Don seedlings. Water relations parameters were measured by the pressure–volume technique for a 1-year period. The osmotic potential at full turgidity and at the point of zero turgor ranged from −1.32 to −2.70 MPa and from −1.70 to −3.52 MPa, respectively. Highest values of osmotic potential were associated with the period of foliage expansion, while lowest values were noted in mid-February during the period of lowest air temperatures. The role of solute changes or changes in symplastic water relative to tissue dry weight in osmotic adjustment is described.

Development of a sensor suite to determine plant water potential

2010 ◽  
Author(s):  
Vasu Udompetaikul ◽  
Shrini K Upadhyaya ◽  
David C Slaughter ◽  
Bruce D Lampinen
Keyword(s):  
Water Potential ◽  
Plant Water ◽  
Plant Water Potential ◽  
Sensor Suite

Internal Water Balance of Brigalow (Acacia harpophylla F. Muell.) Under Natural Conditions

1975 ◽  
Vol 2 (4) ◽  
pp. 489 ◽  
Author(s):  
BR Tunstall ◽  
DJ Connor
Keyword(s):  
Water Potential ◽  
Water Status ◽  
Carbon Uptake ◽  
Diurnal Changes ◽  
Plant Water ◽  
Litter Fall ◽  
Tissue Water ◽  
Diffusive Resistance ◽  
Plant Water Potential ◽  
Water Contents

On one day each month over a period of 2½ years, diurnal measurements of plant water status, leaf diffusive resistance, carbon uptake, irradiance, ambient temperature and humidity were made in a brigalow community. Diurnal changes in leaf diffusive resistance, osmotic potential, plant water potential, and carbon uptake are shown to follow general patterns and the changes in plant water potential were related to the dawn value of plant water potential. The data suggest the development of negative turgor in brigalow and demonstrate the capacity of the plant to maintain high tissue water contents at low water potentials. Measurements of shoot extension and litter fall showed that litter fall occurred principally following shoot extension.

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