scholarly journals Leaf Conductance and Xylem Water Potential of Ecotypes and Cultivars of Acer saccharum and A. nigrum

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 649a-649
Author(s):  
Steve C. Yuza ◽  
Art L. Youngman ◽  
John C. Pair
Keyword(s):  
Stomatal Conductance ◽  
Water Potential ◽  
Acer Saccharum ◽  
Sugar Maple ◽  
Soil Water Potential ◽  
Leaf Conductance ◽  
Physical Factors ◽  
Green Mountain ◽  
Xylem Water Potential ◽  
Old Trees

This study examined physical factors and physiological responses of five different ecotypes and cultivars of Acer saccharum and A. nigrum. The objective was to determine variations in leaf conductance and xylem water potential and correlations associated with their natural geographic distribution. Compared were two ecotypes of sugar maple, Caddo and Wichita Mountains, native to Oklahoma with cultivars Green Mountain and Legacy, plus black maple seedlings from Iowa. Measurements taken included leaf conductance, xylem water potential and soil water potential in a replicated block of 15-year-old trees. The two ecotypes had consistently higher photosynthetic rates, stomatal conductance and transpiration rates than other selections. Xylem water potentials were significantly higher for Caddo maples than Green Mountain, Legacy and Acer nigrum in both predawn and midday samples. This difference in water availability can be associated with a tendency for Caddo to vary its stomatal conductance. The other tree types maintained stable stomatal conductances.

scholarly journals 571 EVALUATION AND PROPAGATION OF SUPERIOR CADDO MAPLES

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 513e-513 ◽  
Author(s):  
John C. Pair
Keyword(s):  
Drought Stress ◽  
Acer Saccharum ◽  
Sugar Maple ◽  
Green Mountain ◽  
Xylem Water Potential ◽  
Leaf Quality ◽  
Leaf Emergence ◽  
South Central ◽  
Sugar Maples ◽  
Early Fall

In 1983, a trial was initiated to compare numerous selections of sugar maple (Acer saccharum) for adaptability to stressful conditions in south central Kansas (zone 6). Included were seedlings of Caddo maple, a southern ecotype, collected from a population native to central Oklahoma. Selected trees have shown superior resistance to scorch and leaf tatter compared to cultivars in the trade. Pre-dawn measurements indicated higher xylem water potential than `Green Mountain' and `Fairview' under drought stress. Leaf emergence of Caddo maples has been earlier in the spring, and fall color develops later than other sugar maples. Propagation of potential cultivars with early fall color has been principally by T-budding on Caddo understock in July and August, although side-veneer grafting in winter has been successful. In addition to superior summer leaf quality, growth in caliper and total height has been greater than other A. saccharum cultivars.

scholarly journals Response of Acer saccharum seedlings to elevated O3 and CO2 concentrations

2005 ◽  
Vol 86 (1) ◽  
pp. 7-17
Author(s):  
Catherine Gaucher ◽  
Pierre Dizengremel ◽  
Yves Mauffette ◽  
Normand Chevrier
Keyword(s):  
Stomatal Conductance ◽  
Acer Saccharum ◽  
Sugar Maple ◽  
Growing Season ◽  
Growth Conditions ◽  
High Light ◽  
Assimilation Rate ◽  
Competitive Growth ◽  
Elevated O3 ◽  
Fertilizing Effect

The effects of three times ambient [O3] (3x) and high [CO2] (650 µL L-1 CO2) alone and in combination were studied on 2-yr-old sugar maple (Acer saccharum) seedlings for 86 days in open top chambers. Sugar maple net CO2 assimilation rate and growth were not decreased by the O3 treatment after one growing season, and the epicuticular wax was not damaged compared with the control. The absence of response to the O3 treatment is attributable to the low stomatal conductance of this species resulting in a low O3 uptake, together with the succession of periods of high and low [O3], which allowed the seedlings to alleviate the oxidative stress. At the end of August, under high [CO2], the growth of the seedlings and net CO2 assimilation to stomatal conductance to CO2 ratio in the second flush of leaves had doubled. Under the environmental growth conditions of the chambers (high light, nutrients and water availabilities), the seedlings may benefit from the availability of CO2. Sugar maple seedlings may have a competitive growth advantage under elevated CO2 conditions and three times ambient [O3] did not decreased the fertilizing effect of CO2.

Leaf Gas Exchange and Water Relations of Lupins and Wheat. II. Root and Shoot Water Relations of Lupin During Drought-Induced Stomatal Closure

1989 ◽  
Vol 16 (5) ◽  
pp. 415 ◽  
Author(s):  
CR Jensen ◽  
IE Henson ◽  
NC Turner
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Water Transport ◽  
Water Uptake ◽  
Water Relations ◽  
Leaf Gas Exchange ◽  
Stomatal Closure ◽  
Soil Water Potential ◽  
Root Water Uptake ◽  
Leaf Conductance

Plants of Lupinus cosentinii Guss. cv. Eregulla were grown in a sandy soil in large containers in a glasshouse and exposed to drought by withholding water. Under these conditions stomatal closure had previously been shown to be initiated before a significant reduction in leaf water potential was detected. In the experiments reported here, no significant changes were found in water potential or turgor pressure of roots or leaves when a small reduction in soil water potential was induced which led to a 60% reduction in leaf conductance. The decrease in leaf conductance and root water uptake closely paralleled the fraction of roots in wet soil. By applying observed data of soil water and root characteristics, and root water uptake for whole pots in a single-root model, the average water potential at the root surface was calculated. Potential differences for water transport in the soil-plant system, and the resistances to water flow were estimated using the 'Ohm's Law' analogy for water transport. Soil resistance was negligible or minor, whereas the root resistance accounted for 61-72% and the shoot resistance accounted for about 30% of the total resistance. The validity of the measurements and calculations is discussed and the possible role of root- to-shoot communication raised.

Water relations of loblolly pine trees in southeastern Oklahoma following precommercial thinning

1990 ◽  
Vol 20 (9) ◽  
pp. 1508-1513 ◽  
Author(s):  
Bert M. Cregg ◽  
Thomas C. Hennessey ◽  
Philip M. Dougherty
Keyword(s):  
Water Potential ◽  
Water Relations ◽  
Loblolly Pine ◽  
Soil Water Potential ◽  
Basal Area ◽  
Leaf Conductance ◽  
Pressure Potential ◽  
Precommercial Thinning ◽  
Xylem Pressure ◽  
Xylem Pressure Potential

Xylem pressure potential, leaf conductance, transpiration, and soil moisture were measured during three summers following precommercial thinning of a 10-year-old stand of loblolly pine (Pinustaeda L.) in southeastern Oklahoma. The stand was thinned to three target basal-area levels: 5.8, 11.5, and 23 m2•ha−1 (control). Soil water potential increased significantly in response to thinning during the summer of each year studied. However, plant water relations were relatively unaffected by the treatments. Significant thinning effects on diurnal xylem pressure potential were observed on only 7 of 55 measurement periods. Treatment differences in conductance and transpiration observed during the first year of the study appeared to be related to differences in light interception and crown exposure. Regression analysis indicated response of leaf conductance and transpiration to predawn xylem pressure potential and vapor pressure deficit was not affected by the thinning treatments. Overall, the results of this study are consistent with a hypothesis in which transpiration, leaf area, and water potential interact to form a homeostatic relationship.

scholarly journals Environmental and physiological control of water flux through Pinuscontorta

1980 ◽  
Vol 10 (1) ◽  
pp. 82-91 ◽  
Author(s):  
Steven W. Running
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Potential Temperature ◽  
Water Flux ◽  
Soil Water Potential ◽  
Leaf Conductance ◽  
Leaf Water ◽  
Physiological Control ◽  
Indirect Measure ◽  
Predawn Leaf Water Potential

This study reports measurements of leaf conductance, leaf water potential, temperature, humidity, and radiation collected on a stand of Pinuscontorta Dougl. ex Loud, lodgepole pine throughout a growing season at the Fraser Experimental Forest in central Colorado, U.S.A. The daily range of leaf conductances decreased 10-fold from June through August. A high correlation (R2 = 0.75) was found between predawn leaf water potential and morning maximum leaf conductance. Low atmospheric humidity significantly decreased midday leaf conductance. A comparison with humidity responses published for other conifers showed good agreement with this study. Seasonal change in total soil–plant resistance to water flux was nonlinearly correlated (R2 = 0.99) with change in predawn leaf water potential, an indirect measure of soil water potential.

scholarly journals Water Relations of Acer rubrum in Response to Summer Digging

HortScience ◽  
1997 ◽  
Vol 32 (4) ◽  
pp. 595C-595
Author(s):  
P.R. Knight ◽  
J.R. Harris ◽  
J.K. Fanelli ◽  
M.P. Kelting
Keyword(s):  
Stomatal Conductance ◽  
Water Potential ◽  
Water Relations ◽  
Leaf Water Potential ◽  
Sap Flow ◽  
Acer Rubrum ◽  
Leaf Water ◽  
Xylem Embolism ◽  
Ball Diameter ◽  
Old Trees

Two experiments were conducted on Acer rubrum L. to determine the influence of root severance on sap flow, stomatal conductance, leaf water potential (ψ), and stem xylem embolism. Experiment 1 utilized 3-year-old trees, and experiment 2 utilized 2-year-old trees. Sixteenmm sap flow gauges were installed on both groups. Trees for experiment 1 were harvested on 31 May 1996 with a root ball diameter of 30.5 cm. Sap flow was reduced within one day after plants were harvested and was still lower 1 week after harvest. On 7 June 1996, harvested trees had lower stomatal conductance measurements, compared to not-harvested trees, but ψ were similar. A second experiment was initiated on 20 Aug. 1996, using the same protocol as in experiment 1. Sap flow was reduced within 2 h after harvest for harvested trees compared to not-harvested trees. Leaf stomatal conductances were reduced within 4 h of harvest. Leaf water potentials were not influenced on the day that the trees were harvested. Embolism levels were increased by harvest within 24 h. These results indicate that transplant stress begins shortly after harvest and not at the actual time of transplant.

scholarly journals EFFECT OF ROOT PRUNING ON WATER RELATIONS AND SHOOT GROWTH OF `BELLAIRE' PEACH.

HortScience ◽  
1991 ◽  
Vol 26 (6) ◽  
pp. 748A-748
Author(s):  
Roberto Santos ◽  
Bradley H. Taylor ◽  
Roger Kjelgren
Keyword(s):  
Stomatal Conductance ◽  
Water Potential ◽  
Water Relations ◽  
Shoot Growth ◽  
Stomatal Closure ◽  
Shoot Elongation ◽  
Root Pruning ◽  
Diurnal Pattern ◽  
June July ◽  
Old Trees

The effect of root pruning on shoot length and water relations of `Bellaire' peach was investigated as a means of controlling vegetative growth. On 27 April, 25 May, and 23 June, 1990, five-year-old trees were root pruned to a 0.35 m depth at either 0.4 or 0.8 m from the tree trunks along both sides of the row. Shoot growth was measured biweekly through the growing season, and the diurnal pattern of stomatal conductance and water potential was followed in late June, July, and August. Stomatal conductance of the root-pruned treatments was less than the control, while there were no differences in water potential among treatments. Reduced shoot elongation was evident within a month of root pruning at 0.4 m for all timing treatments, but at 0.8 m it varied with the date of pruning. The first root pruning at 0.4 m reduced cumulative shoot elongation 39% compared to the un-pruned control trees, while the remaining treatments reduced it 14%. While root pruning limited cumulative shoot elongation in all treatments, the earliest 0.4 m treatment was most effective, possibly due to pruning of a larger percent of the root system prior to rapid shoot elongation. Stomatal closure in root-pruned trees appeared to moderate diurnal water deficits at levels similar to the control.

scholarly journals The effect of irrigation frequency on growth, flowering and stomatal conductance of osteospermum 'Denebola' and New Guinea impatiens 'Timor' grown on ebb·and-flow benches

2013 ◽  
Vol 54 (2) ◽  
pp. 59-68
Author(s):  
Jadwiga Treder ◽  
Joanna Nowak
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Growth Parameters ◽  
Soil Water Potential ◽  
New Guinea ◽  
Growth Stages ◽  
Irrigation Frequency ◽  
Growing Period ◽  
New Guinea Impatiens

The response of osteospermum 'Denebola' and New Guinea impatiens 'Timor' grown on ebb-and-flow benches to different water potential of growing medium applied during whole growing period was investigated by measuring plant growth parameters and stomatal conductance (g<sub>S</sub>). After cutting establishment, four different irrigation treatments based on soil water potential were applied to osteospermum: at -0,5 , -3,0 , -10,0 , -20 kPa. In the case of impatiens the last water treatment was omitted. Plants were evaluated when they reach one ofthe three growth stages: lateral shoots development, visible flower buds (osteospermum) or beginning of flowering (impatiens) and at flowering. All plants produced with a moderate water deficit (irrigation at -3 and -10 kPa) were more compact than plants irrigated at -0,5 kPa but their flowering were not affected. Strong decrease in pIant growth and flowering was observed when plants were irrigated at the lowest water potential (-20 kPa). However, for impatiens the highest irrigation frequency was also not favorable. As a result of water stress the decrease in stomatal conductance (g~) in both plants was observed. Osteospermum was more resistant to water stress than impatiens.

A modelling framework to predict transpiration reductions during drought based on soil hydraulics 

2021 ◽  
Author(s):  
Andrea Carminati ◽  
Mathieu Javaux
Keyword(s):  
Hydraulic Conductivity ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Soil Water ◽  
Stomatal Closure ◽  
Soil Water Potential ◽  
Soil Drying ◽  
Soil Hydraulic Conductivity ◽  
Plant Hydraulics ◽  
Soil Hydraulic

&lt;p&gt;There is increasing need for mechanistic and predictive models of transpiration and stomatal response to drought. Global measurements of transpiration showed that the decrease in soil moisture is a primary constrain on transpiration. Additionally, a recent meta-analysis indicated that stomatal closure is explained by the loss in soil hydraulic conductivity, more than that of the xylem. Despite these evidences on the role of soil drying as a key driver of transpiration reduction, the mechanisms by which soil drying impacts transpiration, including the effect of different soil hydraulic properties, are not fully understood.&lt;/p&gt;&lt;p&gt;Here, we propose that stomata regulate transpiration in such a way that the relation between transpiration and the difference in water potential between soil and leaves remains linear during soil drying and increasing vapor pressure deficit (VPD). The onset of hydraulic nonlinearity sets the maximum stomatal conductance at a given soil water potential and VPD. The resulting trajectory of the stomatal conductance for varying soil water potentials and VPD depends on soil and plant hydraulics, with the soil hydraulic conductivity and root length being the most sensitive parameters.&lt;/p&gt;&lt;p&gt;From this hydraulic framework it follows that stomatal closure is not simply a function of soil moisture, soil water potential or leaf water potential. Instead, it depends on transpiration demand and soil-plant hydraulics in a predictable way. The proposed concept allows to predict transpiration reductions during drought with a limited number of parameters: transpiration demand, plant hydraulic conductivity, soil hydraulic conductivity and active root length. In conclusion, this framework highlights the role of the soil hydraulic conductivity as primary constrain on transpiration, and thus on stomatal conductance and photosynthesis.&lt;/p&gt;

Glasshouse and field studies on the effects of groundcovers on banana and macadamia growth and water relations

2003 ◽  
Vol 43 (10) ◽  
pp. 1245 ◽  
Author(s):  
D. J. Firth ◽  
G. G. Johns ◽  
R. D. B. Whalley
Keyword(s):  
Adverse Effect ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Water Status ◽  
Field Studies ◽  
Bare Soil ◽  
Soil Bulk Density ◽  
Early Morning ◽  
Xylem Water Potential ◽  
Penetrometer Resistance

Groundcovers can be useful for controlling erosion in macadamia orchards but they can have adverse effects on tree growth and crop yield. The effects of groundcovers versus bare soil on banana and macadamia were compared in a glasshouse study and on macadamia in the field. A glasshouse trial compared the effect of 3 water regimes with unmown or mown Arachis pintoi cv. Amarillo groundcover versus bare soil, on stomatal conductance and growth of banana and macadamia. Mean stomatal conductance was higher overall for macadamia (178 mmol/m2.s) compared with banana (90 mmol/m2.s) when data were pooled across groundcover and water treatments. Medium and dry substrate moisture treatments significantly reduced the growth and vigour of banana compared with the wet treatments, as indicated by reduced total dry matter, leaf area, number of live leaves at harvest, and total root length, but had no significant effect on macadamia. Groundcover had a more adverse effect on the growth of banana than macadamia compared with bare soil and, likewise, unmown cover had a greater effect on growth of banana than mown cover, while there was no mowing effect on macadamia.In an unirrigated field trial, mown and unmown groundcover and bare soil treatments were compared for their effect on early morning leaf xylem water potential of young and older macadamia trees at 3 sites where groundcover was established at different tree ages. Water potential was generally <0.2 MPa more negative in the groundcover treatment than bare soil in spring and summer under dry seasonal conditions over 2 years, although there was no apparent effect on tree health. The difference in water potential between groundcover and bare soil was highest in young trees planted in established groundcover. The more adverse effect of groundcover on water status of young trees in established cover correlates with a greater reduction in growth compared with older trees reported separately (Firth et al. 2003 Aust. J. Exp. Agric. 43, 419–423).Soil bulk density under groundcover was slightly reduced (0.028 g/cm3) at 0–10 cm depth, and penetrometer resistance also slightly reduced (<0.3 MPa) at 0–12 cm depth, compared with bare soil. Higher penetrometer readings in the traffic zone (often >4 MPa at 30–40 cm in the initial survey) compared with the tree line indicate the potential long-term benefits to be derived from groundcovers.

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