A comparison of water relations, visual symptoms, and changes in stem girth for evaluating impact of Phytophthoracinnamomi dieback on Eucalyptusmarginata

1990 ◽  
Vol 20 (2) ◽  
pp. 233-240 ◽  
Author(s):  
D. Stuart Crombie ◽  
J. T. Tippett
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Water Relations ◽  
Subjective Assessment ◽  
Forest Trees ◽  
Short Term ◽  
Visual Symptoms ◽  
Severe Water Stress ◽  
Crown Form

Water relations, stem girth, and crown vigour were measured in jarrah (Eucalyptusmarginata Donn ex Sm.) trees in adjoining areas of healthy and dieback-affected forest. The soil-borne fungus Phytophthoracinnamomi Rands was recovered from soils in the dieback areas, but not from neighbouring healthy forest. Trees on dieback sites were found to be more water stressed (with lower dawn water potentials and daytime stomatal conductances) than healthy trees on nearby areas free of P. cinnamomi. Severe water stress usually preceded crown deaths by several weeks to months. Dawn water potential and midday stomatal conductance were the most useful nondestructive indicators of dieback severity in declining trees. Subjective assessment of crown form was slightly less reliable than water relations as a separator of dieback and healthy trees. Changes in trunk girth were the least sensitive indicators of dieback severity. Midday stomatal conductance is recommended as a useful tool for monitoring short-term changes in vigour of dieback-affected trees.

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.

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.

scholarly journals Interactions between leaf water potential, stomatal conductance and abscisic acid content of orange trees submitted to drought stress

2004 ◽  
Vol 16 (3) ◽  
pp. 155-161 ◽  
Author(s):  
Mara de Menezes de Assis Gomes ◽  
Ana Maria Magalhães Andrade Lagôa ◽  
Camilo Lázaro Medina ◽  
Eduardo Caruso Machado ◽  
Marcos Antônio Machado
Keyword(s):  
Abscisic Acid ◽  
Water Stress ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Acid Content ◽  
Stomatal Closure ◽  
Leaf Water ◽  
Orange Trees ◽  
Abscisic Acid Content

Thirty-month-old 'Pêra' orange trees grafted on 'Rangpur' lemon trees grown in 100 L pots were submitted to water stress by the suspension of irrigation. CO2 assimilation (A), transpiration (E) and stomatal conductance (g s) values declined from the seventh day of stress, although the leaf water potential at 6:00 a.m. (psipd) and at 2:00 p.m. (psi2) began to decline from the fifth day of water deficiency. The CO2 intercellular concentration (Ci) of water-stressed plants increased from the seventh day, reaching a maximum concentration on the day of most severe stress. The carboxylation efficiency, as revealed by the ratio A/Ci was low on this day and did not show the same values of non-stressed plants even after ten days of rewatering. After five days of rewatering only psi pd and psi2 were similar to control plants while A, E and g s were still different. When psi2 decreases, there was a trend for increasing abscisic acid (ABA) concentration in the leaves. Similarly, stomatal conductance was found to decrease as a function of decreasing psi2. ABA accumulation and stomatal closure occurred when psi2 was lower than -1.0 MPa. Water stress in 'Pera´ orange trees increased abscisic acid content with consequent stomatal closure and decreased psi2 values.

Stomatal conductance and growth of five Alnusglutinosa clones in response to controlled water stress

1988 ◽  
Vol 18 (4) ◽  
pp. 421-426 ◽  
Author(s):  
T. C. Hennessey ◽  
E. M. Lorenzi ◽  
R. W. McNew
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Drought Tolerance ◽  
Leaf Area ◽  
Water Status ◽  
Height Growth ◽  
Plant Water ◽  
Black Alder ◽  
Severe Water Stress ◽  
Progressive Water Stress

An experiment to quantify the response of unnodulated, fertilized European black alder (Alnusglutinosa (L.) Gaertn.) seedlings to progressive water stress showed contrasting drought tolerance among five clones, using stomatal conductance, leaf area, and height as indices of drought sensitivity. In particular, one rapidly growing clone (AG 8022-14) showed the ability to moderate changes in water stress more efficiently than the more slowly growing clones. After 30 days of moderate levels of water stress, clones that had higher stomatal conductance also had greater leaf area and height growth. Leaf area and height were both sensitive to plant water status, although no threshold of stress associated with a cessation of leaf area or height expansion was found even though stomatal conductance decreased to 0.05 cm s−1 under severe water stress.

scholarly journals Stem Water Potential and Apple Size

1995 ◽  
Vol 120 (4) ◽  
pp. 577-582 ◽  
Author(s):  
Amos Naor ◽  
Isaac Klein ◽  
Israel Doron
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Fruit Size ◽  
Plant Water ◽  
Stem Water Potential ◽  
Plant Water Stress ◽  
Stem Water ◽  
Irrigation Treatments ◽  
Highly Correlated

The sensitivity of leaf (ψleaf) and stem (ψstem) water potential and stomatal conductance (gs) to soil moisture availability in apple (Malus domestics Borkh.) trees and their correlation with yield components were studied in a field experiment. Two drip irrigation treatments, 440 mm (H) and 210 mm (L), were applied to a `Golden Delicious' apple orchard during cell enlargement stage (55-173 days after full bloom). Data collected included ψstem, y leaf, gs, and soil water potential at 25 (ψsoil-25) and 50 cm (ψsoil-50). No differences in midday ψleaf's were found between irrigation treatments. Stem water potential was higher in the H treatment than in the L treatment in diurnal measurements, and at midday throughout the season. Stomatal conductance of the H treatment was higher than the L treatment throughout the day. Stomatal conductance between 0930 and 1530 hr were highly correlated with ψstem. The H treatment increased the percentage of fruit >65 mm, and increased the proportion of earlier harvested fruit reaching marketable size compared to the L treatment. Fruit size in the first harvest and the total yield were highly correlated with ψstem. The degree of correlation between plant water stress indicators and yield component decreased in the following order: ψstem>ψsoil-25,>ψsoil-50>ψleaf. The data suggest that midday ψstem may serve as a preferable plant water stress indicator with respect to fruit size.

Change in photosynthesis and water relations with age and season in Abiesamabilis

1984 ◽  
Vol 14 (1) ◽  
pp. 77-84 ◽  
Author(s):  
R. O. Teskey ◽  
C. C. Grier ◽  
T. M. Hinckley
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Water Relations ◽  
Net Photosynthesis ◽  
Carbon Gain ◽  
Xylem Water Potential ◽  
Needle Age ◽  
Stressful Environment ◽  
Competitive Success ◽  
One Year

Seasonal changes in water relations and net photosynthesis were measured over a year in current and 1-year-old foliage of Abiesamabilis (Dougl.) Forbes, a subalpine conifer. Responses were compared with maximum rates achieved in older foliage. Current-year foliage developed slowly during the growing season. Although growth began on 22 June, highest rates of stomatal conductance and net photosynthesis did not occur until September and October. One-year-old foliage had the highest rates of net photosynthesis (12.9 mg CO2•dm−2•h−1) and stomatal conductance (3.1 mm•s−1) during the summer. Net photosynthesis decreased with needle age, but foliage as old as 7 years had rates of net photosynthesis as high as 5.0 mg CO2•dm−2•h−1. There was no evidence of photosynthetic adjustment to seasonal change in temperature. The optimum temperature for photosynthesis remained at 15 ± 1.5 °C throughout the year. No water stress was observed during the summer. Xylem water potential never decreased below −1.65 MPa and was always well above the turgor loss point. The lack of any apparent water stress, combined with photosynthetic characteristics, indicated that summer was the most important season for carbon gain. These results also suggested that a strategy for competitive success by Abiesamabilis in this cold, stressful environment is minimum dependence on the carbon gain of any individual age-class of foliage. Instead trees rely on the combined photosynthetic capacity of many years of foliage.

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