Water Relations of the Banana. I. Predicting the Water Relations of the Field-Grown Banana Using the Exuding Latex

1990 ◽  
Vol 17 (1) ◽  
pp. 57 ◽  
Author(s):  
JA Milburn ◽  
J Kallarackal ◽  
DA Baker
Keyword(s):  
Water Potential ◽  
Water Relations ◽  
Osmotic Potential ◽  
Quantitative Data ◽  
Narrow Range ◽  
Leaf Angle ◽  
Diurnal Cycles ◽  
Water Influx ◽  
Diurnal Fluctuations ◽  
A New Technique

The free exudation of latex from wounded banana plants renders conventional methods for studying water potential impracticable or suspect. Accordingly, several methods have been devised to provide supportive semi-quantitative data on water relations including measurements of leaf angle, tissue turgor and pseudostem girth throughout many diurnal cycles. Latex exudation itself has been exploited in a new technique for investigating the internal water relations of the banana. The laticifers behave like giant unbranched cells embedded deeply within the tissues of the plant. On wounding, the milky sap escapes at a rate which decreased exponentially. We argue that, as a consequence of pressure-release, the latex is diluted by water influx until equilibrium is reached with the rest of the plant. Hence at equilibrium, the osmotic potential of this diluted latex equals the water potential of the tissues; thus the final osmotic potential can be used to monitor water potential changes of banana tissues. In this study, the water potential of well-watered plants was found to cycle diurnally within the remarkably narrow range of 0 to -0.35 MPa (0 to -3.5 bar). Turgor pressures of intact laticifers were computed from our data, which also exhibit the diurnal fluctuations predictable from our supportive data and reports for other species.

Salinity and drought stress effects on foliar ion concentration, water relations, and photosynthetic characteristics of orchard citrus

1988 ◽  
Vol 39 (4) ◽  
pp. 619 ◽  
Author(s):  
JP Syvertsen ◽  
J Lloyd ◽  
PE Kriedemann
Keyword(s):  
Drought Stress ◽  
Gas Exchange ◽  
Water Potential ◽  
Water Relations ◽  
Osmotic Potential ◽  
High Salinity ◽  
Leaf Water ◽  
Ion Concentration ◽  
Drought Treatment ◽  
Mature Leaves

Effects of salinity and drought stress on foliar ion concentration, water relations and net gas exchange were evaluated in mature Valencia orange trees (Citrus sinensis [L.] Osbeck) on Poncirus trifoliata L. Raf. (Tri) or sweet orange (C. sinensis, Swt) rootstocks at Dareton on the Murray River in New South Wales. Trees had been irrigated with river water which averaged 4 mol m-3 chloride (Cl-) or with river water plus NaCl to produce 10, 14 or 20 mol m-3 Cl- during the previous 3 years. Chloride concentrations in leaves of trees on Tri were significantly higher than those on Swt rootstock. Foliar sodium (Na+) and Cl- concentrations increased and potassium (K+) concentrations decreased as leaves aged, especially under irrigation with 20 mol m-3 Cl-. Leaf osmotic potential was reduced as leaves matured and also by high salinity so that reductions in leaf water potential were offset. Mature leaves had a lower stomatal conductances and higher water use efficiency than young leaves. After 2 months of withholding irrigation water, leaves of low salinity trees on Tri rootstock had higher rates of net gas exchange than those on Swt rootstock, indicating rootstock-affected drought tolerance. Previous treatment with 20 mol m-3 Cl- lowered leaf area index of all trees by more than 50%, and resulted in greater reserves of soil moisture under partially defoliated trees after the drought treatment. This was reflected in more rapid evening recovery of leaf water potential and less severe reductions in net gas exchange after drought treatment in high salinity trees on Swt rootstock. High salinity plus drought stress increased Na+ content of leaves on Swt, but not on Tri rootstocks. Drought stress had no additive effect, with high salinity on osmotic potential of mature leaves. Thus, the salinity-induced reduction in leaf area appeared to be independent of the Cl- exclusion capability of the rootstock and decreased the effects of subsequent drought stress on leaf water relations and net gas exchange.

Effects of sulfur dioxide on water relations of hybrid poplar foliage and bark

1982 ◽  
Vol 12 (3) ◽  
pp. 612-616 ◽  
Author(s):  
Alan R. Biggs ◽  
Donald D. Davis
Keyword(s):  
Sulfur Dioxide ◽  
Water Potential ◽  
Water Relations ◽  
Osmotic Potential ◽  
Hybrid Poplar ◽  
Leaf Conductance ◽  
Unexposed Control ◽  
Poplar Cuttings ◽  
Induced Changes

Hybrid poplar cuttings were exposed to 0.25 ppm SO2 for 72 h/week for 14 consecutive weeks in 1979. In 1980, a second set of cuttings was exposed to 0.12 ppm SO2 for 72 h/week for 6 consecutive weeks. Foliar and bark water potential, osmotic potential, and the pressure component, as well as leaf conductance, were determined during or following exposure and compared with data from unexposed control plants. Leaf conductance was stimulated during 72-h exposures to 0.25 ppm SO2. Six 72 h/week exposures to 0.12 ppm SO2 had no effect on conductance, but induced changes in foliar water potential and osmotic potential.

Comparing plant water relations for wheat with alternative pulse and oilseed crops grown in the semiarid Canadian prairie

2009 ◽  
Vol 89 (5) ◽  
pp. 823-835 ◽  
Author(s):  
H W Cutforth ◽  
S V Angadi ◽  
B G McConkey ◽  
M H Entz ◽  
D Ulrich ◽  
...  
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Water Relations ◽  
Leaf Water Potential ◽  
Osmotic Adjustment ◽  
Osmotic Potential ◽  
Leaf Water ◽  
Oilseed Crops ◽  
Pulse Crops ◽  
The Mean

Understanding the drought physiology of alternate crops is essential to assess the production risks of new cropping systems. We compared the water relations of dry (field) pea (Pisum sativum L.), chickpea (Cicer arietinum L.), canola (Brassica napus L.) and mustard (Brassica juncea L.) with spring wheat (Triticum aestivum L.) under different moisture availabilities in field trials conducted in 1997 and 1998 at Swift Current, SK. Stress experience and stress responses varied with crop type. In general, there were similarities in drought physiology between the two pulse crops and between the two oilseed crops. The mean predawn leaf water potential of pea was frequently lowest, while the mean midday leaf water potential of wheat was at least -0.40 MPa lower than for any other crop. The crops exhibited different strategies to overcome water stress. Wheat had the lowest osmotic potential at full turgor, except under drought when turgor was lowest for chickpea and wheat; the highest values were observed in Brassica spp. Mean midday pressure potentials were lowest in wheat (and mostly negative, indicating loss of turgor) and highest for the pulse crops. Mean midday pressure potential for canola was positive when well-watered, otherwise it was near 0. Despite lowering osmotic potential, wheat could not maintain positive turgor much of the time at midday. Pulse crops, with the contributions from both osmotic adjustment and cell elasticity, maintained positive turgor over a wider range of water potentials compared with the other crops. With regard to both osmotic adjustment and tissue elasticity, we ranked the crops from high to low ability to adjust to moderate to severe water stress as pulses > wheat > Brassica oilseeds. Key words: Leaf water, osmotic, turgor potentials, wheat, pulse, canola, semiarid prairie

Water Relations of Laticifers in Nerium oleander

1981 ◽  
Vol 8 (3) ◽  
pp. 329 ◽  
Author(s):  
WJS Downton
Keyword(s):  
Water Potential ◽  
Water Relations ◽  
Osmotic Potential ◽  
Water Status ◽  
Turgor Pressure ◽  
Death Valley ◽  
Nerium Oleander ◽  
Laboratory Measurements ◽  
Hydrocarbon Sources ◽  
Daily Changes

The water relations of laticifers in N. oleander were examined for plants growing in Death Valley, California, USA. Osmotic potential of laticifers in well watered plants paralleled the daily changes in leaf water potential. The turgor pressure of laticifers was usually less than bulk leaf turgor. Laticifer turgor was maintained in the absence of positive leaf turgor in severely water stressed plants (Ψw ͭ6 -7.0 MPa) and latex exuded when leaves were cut. The recovery in water status of leaves and laticifers following watering of the plants is described. Laboratory measurements confirmed that laticifer turgor differed from bulk leaf turgor and that it was maintained over a range of water potentials. These observations may have relevance for some of the latex-bearing plants currently being considered as future hydrocarbon sources.

Leaf and root osmotic adjustment in drought-stressed Quercusalba, Q. macrocarpa, and Q. stellata seedlings

1988 ◽  
Vol 18 (1) ◽  
pp. 1-5 ◽  
Author(s):  
William C. Parker ◽  
Stephen G. Pallardy
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Water Relations ◽  
Osmotic Adjustment ◽  
Osmotic Potential ◽  
Root Tissue ◽  
Tissue Elasticity ◽  
Tissue Water ◽  
Before And After ◽  
Relative Water

The leaf and root tissue water relations of Quercusalba L., Quercusmacrocarpa Michx., and Quercusstellata Wang. seedlings before and after drought were examined to evaluate the occurrence and comparative extent of osmotic adjustment in seedlings of these species. Drought resulted in active osmotic adjustment in leaves of all three species, with decreases in osmotic potential at full tissue hydration and at the turgor loss point from 0.25 to 0.60 MPa. Active osmotic adjustment in Q. stellata, and increased root tissue elasticity in Q. macrocarpa and Q. alba, resulted in turgor loss of roots occurring at a water potential 0.36 to 0.66 MPa lower in drought-stressed than in well-watered seedlings. Species differed in tissue water relations only before drought, with Q. stellata exhibiting lower osmotic potentials than Q. alba and Q. macrocarpa. Estimates of the osmotic potential at full saturation were generally lower in leaves than in roots, but the osmotic potential at turgor loss was similar. Roots exhibited turgor loss at lower values of relative water content and experienced a more gradual decrease in water potential per unit water content during dehydration than did leaves. This response indicates greater relative tissue capacitance in roots than in leaves in these species.

scholarly journals Water Relations of Fruit End Cracking in French Prune (Prunus domestica L. cv. French)

1992 ◽  
Vol 117 (5) ◽  
pp. 824-828 ◽  
Author(s):  
Rémy E. Milad ◽  
Kenneth A. Shackel
Keyword(s):  
Mechanical Properties ◽  
Water Stress ◽  
Water Potential ◽  
Water Relations ◽  
Osmotic Potential ◽  
Vertical Axis ◽  
Field Conditions ◽  
Prunus Domestica ◽  
Irrigation Regimes

Irrigation of previously water-stressed French prune trees is known to induce fruit end cracking. The relationships between end cracking, water relations, and mechanical properties of the skin of French prune were studied as a function of irrigation regimes under field conditions. Water stress resulted in the accumulation of solutes in the fruit of nonirrigated trees. A gradient in osmotic potential (ΨS) existed along the vertical axis of fruit from all treatments; ΨS was always lower at the stylar than stem end. Irrigation of previously water-stressed trees (irrigated-dry treatment) resulted in ΨS gradients exceeding those of all other treatments. Moreover, estimated turgor (ΨP) at the stylar end of the fruit increased 2-fold within 24 hours after irrigation. These changes were accompanied by the onset of fruit end cracking, and neither the well-watered controls nor the continuously droughted fruit exhibited such changes. During the 24 hours following irrigation, the overall ΨS of irrigated-dry treatment fruit was diluted by the same amount as the calculated increase in fruit volume. However, during the same period, ΨS at the stem end of the fruit showed more dilution than expected, and ΨS at the stylar end of the fruit concentrated, indicating a redistribution of solutes. There were no differences in skin mechanical properties along the fruit vertical axis and, hence, this could not have accounted for the observed changes in ΨS and ΨP. Thus, when previously stressed French prune trees were irrigated, the overall recovery in water potential (Ψ) and the subsequent movement of solutes to the stylar end of the fruit resulted in apparently excessive turgors in this region and hence the observed pattern of end cracking.

scholarly journals Effect of Irrigation on Crabapple Growth and Water Relations During Field Production with In-Ground Fabric Containers

1994 ◽  
Vol 12 (2) ◽  
pp. 108-111
Author(s):  
R. Kjelgren ◽  
C. Spihlman ◽  
B.R. Cleveland
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Leaf Area ◽  
Water Relations ◽  
Osmotic Potential ◽  
Management Practices ◽  
Summer Drought ◽  
Irrigation Frequency ◽  
Trunk Diameter

Abstract Growth and water relations of irrigated and non-irrigated Malus sieboldii var. zumi produced with and without in-ground fabric containers in a field-nursery setting were investigated. Predawn and midday leaf water potential and midday stomatal conductance were measured periodically through the season, and trunk increment, leaf area, root growth, and osmotic potential were measured in late season. Water potential became more negative and stomatal conductance decreased in non-irrigated treatments during an extended mid-summer drought that resulted in less trunk diameter growth and leaf area. Trees grown in fabric-containers, both irrigated and non-irrigated, exhibited no detectable differences in water relations over the season. These trees did have fewer roots and less leaf area than the trees grown without fabric containers, indicating that in-ground fabric containers can limit growth even when irrigated. Non-irrigated trees in fabric containers were nonetheless affected by water stress as they had the least trunk growth and most negative osmotic potential of all treatments. Careful management practices would suggest increased irrigation frequency during production with in-ground fabric containers to avoid water stress.

Some Aspects of the Water Relations of the Lichen Parmotrema Tinctorum Measured Using Thermocouple Psychrometry

1996 ◽  
Vol 28 (3) ◽  
pp. 257-266 ◽  
Author(s):  
R. P. Beckett
Keyword(s):  
Bulk Modulus ◽  
Water Potential ◽  
Water Content ◽  
Water Relations ◽  
Osmotic Potential ◽  
Relative Water Content ◽  
Thermocouple Psychrometer ◽  
Relative Water ◽  
Parmotrema Tinctorum

AbstractThe thermocouple psychrometer was used to determine water potential, Ψ and its components in the lichen Parmotrema tinctorum. Data suggested that using conventional pressure-volume curves to study the water relations of lichens may give anomalous results, possibly because lichens may contain appreciable amounts of intercellular water. A way of correcting pressure-volume curves to remove the effect of intercellular water is discussed. Parmotrema tinctorum had a very low osmotic potential at full turgor (c. −2.5 MPa), and a low bulk modulus of elasticit (c. 2.1 MPa). As a result, P. tinctorum lost turgor only when the relative water content dropped below 0.47. Likely benefits of this for the lichen are discussed.

Seasonal Changes in the Water Relations of Eucalyptus behriana F. Muell. And E. microcarpa (Maiden) Maiden in the Field

1984 ◽  
Vol 32 (5) ◽  
pp. 495 ◽  
Author(s):  
BA Myers ◽  
TF Neales
Keyword(s):  
Water Potential ◽  
Water Relations ◽  
Rainfall Intensity ◽  
Field Measurements ◽  
Canopy Conductance ◽  
Laboratory Studies ◽  
Short Term ◽  
The Mean ◽  
Type Response ◽  
Vapour Pressure Difference

Field observations of some parameters of the water relations of the two eucalypt species E. behriana and E. microcarpa in dry sclerophyll, mallee and woodland vegetation were made at three sites from 1980 to 1983. The mean ( n = 519) water potential measured at dawn (Ψdawn) was -3.07± 0.01 MPa and fluctuated seasonally with rainfall intensity over the range -2.0 ± 0, 1 to -4.4 ± 0.1 MPa ( n = 30). Both species behaved similarly and some osmotic adjustment took place. Mean leaf conductance (gs) varied between 0.151 ± 0.006 and 0.003 ± 0.001 mol m-2 s-1 . Maximum daily values of gs were linearly related to Ψdawn as it fluctuated seasonally. The slope of this linear regression was not significantly different from that relating these values of gs and Ψ, when both were measured concurrently. There were thus no indications of a distinction between the responses of gs to long- and short-term fluctuations of Ψ or of a threshold-type response of gs to Ψ. Field measurements indicated that gs was decreased at high values of vapour pressure difference (Δe). In laboratory studies with seedlings of the two species gs decreased from 0.5 to 0.1 mol m-2 s-I as Δe increased from 0.5 to 3.0 kPa. Leaf and canopy conductance were the predominant plant determinants of transpiration rate (Er) in this type of vegetation which has the capacity to restrict Et via the effect of water potential (Ψ) on gs and also by the response of gs to Δe. Some of the water relations parameters of E. behriana indicated that this species was better able to withstand drought than was E microcarpa.

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