Drought-induced leaf abscission and whole-plant drought tolerance of seedlings of seven black walnut families

1985 ◽  
Vol 15 (5) ◽  
pp. 818-821 ◽  
Author(s):  
William C. Parker ◽  
Stephen G. Pallardy
Keyword(s):  
Drought Tolerance ◽  
Water Status ◽  
Black Walnut ◽  
Leaf Abscission ◽  
Pressure Potential ◽  
Xylem Pressure ◽  
Whole Plant ◽  
Geographic Origins ◽  
Xylem Pressure Potential ◽  
Different Levels

Whole-plant drought tolerance and leaf abscission in response to drought of 5-month-old, half-sib black walnut (Juglansnigra L.) seedlings representing seven geographic origins were examined. Seedlings were subjected to six different levels of drought stress and then reirrigated. Mortality, leaf abscission, and refoliation responses were measured. Only one of 404 seedlings actually died. Survival of stem cambial tissues at predawn leaf xylem pressure potential values as low as −4.0 MPa was associated with the capacity for drought-induced leaf abscission. The percentage of seedlings exhibiting at least 80% leaf abscission increased linearly as predawn leaf xylem pressure potential decreased from −1.5 to −3.5 MPa. Although substantial differences in leaf abscission among families were observed, these differences were not statistically significant (P ≤ 0.05). Eighteen percent of all seedlings exhibited some degree of refoliation upon recovery of plant water status. However, the cumulative area of regrowth foliage was insignificant in terms of its adaptive value for resumption of photosynthetic activity following stress relief.

Pressure Chamber and Air Flow Porometer for Rapid Field Indication of Water Status and Stomatal Condition in Wheat

1977 ◽  
Vol 13 (4) ◽  
pp. 341-351 ◽  
Author(s):  
R. A. Fischer ◽  
M. Sanchez ◽  
J.R. Syme
Keyword(s):  
Field Experiments ◽  
Water Status ◽  
Air Flow ◽  
Pressure Chamber ◽  
Plant Responses ◽  
Pressure Potential ◽  
Xylem Pressure ◽  
Xylem Pressure Potential ◽  
Plant Water Potential ◽  
Key Features

SUMMARYPlant water potential and leaf diffusive conductance, key features of plant responses to water stress in field experiments, can be estimated, respectively, by xylem pressure potential measured with the pressure chamber apparatus, and leaf permeability measured with the air flow porometer. This paper describes modifications to these two techniques in order to increase the rapidity of measurements in wheat to 60/h with the pressure chamber, and 200/h with the porometer. Rapid measurements are needed because of the large within-and between-plot errors encountered with daytime measurements in typical field experiments, examples of which are presented.

The water status of six woody species coexisting in the Sahel (Ferlo, Senegal)

1996 ◽  
Vol 12 (5) ◽  
pp. 607-627 ◽  
Author(s):  
A. Berger ◽  
M. Grouzis ◽  
C. Fournier
Keyword(s):  
Anthropogenic Disturbance ◽  
Water Status ◽  
Woody Species ◽  
Dry Season ◽  
Pressure Potential ◽  
Balanites Aegyptiaca ◽  
Xylem Pressure ◽  
Xylem Pressure Potential ◽  
Boscia Senegalensis ◽  
Coexisting Species

ABSTRACTIn the Sahel during recent decades, anthropogenic disturbance and periods of drought have caused changes in woody species frequency. The internal water status of six coexisting species was analysed to estimate the importance of water constraints in this process. Predawn and midday xylem pressure potential and stomatal conductance were monitored monthly for two years. The relations between xylem pressure potential and transpiration made it possible to determine the hydraulic conductivity of the soil—plant system. Two types of results were obtained. First, there was considerable diversity in water status of the different species. Minimum predawn xylem pressure potentials (dry season) ranged from – 1.5 MPa to – 5 MPa depending on species, with interseasonal variation from 0.08 MPa to 2 MPa. Response to rainfall was very rapid (a few days) or very slow (several months). The three functioning types defined using these results were compared with the phytogeographical status of the species. Second, more specific phenomena were observed, (a) Some species (Balanites aegyptiaca and Boscia senegalensis) showed an imbalance between the predawn xylem pressure potential and the soil water status during the rainy season; (b) a sharp increase in xylem pressure potential was observed in deciduous species in the middle of the dry season; probably related to bud break; and (c) the water status was always favourable for Combrelum glutinosum. The few remaining individuals seem to benefit from very favourable subsoil water supply conditions.

Effect of Biostimulants on Drought Tolerance of Ornamental Annuals

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 539d-539
Author(s):  
S.A. Geer ◽  
T.J. Smalley ◽  
M.W. Rieger
Keyword(s):  
Drought Tolerance ◽  
Relative Water Content ◽  
Dry Weight ◽  
New Haven ◽  
Pressure Potential ◽  
Xylem Pressure ◽  
Shoot Dry Weight ◽  
Salvia Splendens ◽  
Xylem Pressure Potential ◽  
Relative Water

This study determined the effect of the granular humate Earthgreen (Menefee Mining Corp., Dallas) and the biostimulant ROOTS2™ (LISA Products Corp., New Haven, Conn.) on drought tolerance of the ornamental annuals Impatiens wallerana `Accent White' and Salvia splendens `Red Hot Sally'. Earthgreen was incorporated into the soil and ROOTS2™ applied as a root drench at transplanting and 30 days after transplanting, Transplants were established in greenhouse beds under irrigated conditions for 8 weeks, then subjected to a five week drought. Data indicates rates of 43.9 and 87.9 g·m–2 of Earthgreen or 300 ml of 1% or 2% ROOTS2™ per plant had no significant effect on Salvia shoot dry weight or chlorophyll content of Salvia or Impatiens at the end of the 8-week establishment period. However, Salvia flower dry weight was significantly increased with the higher rate of Earthgreen. During the 5-week drought, Earthgreen or ROOTS2™ did not significantly affect xylem pressure potential of Salvia or relative water content of Impatiens. After the 5-week drought no significant effect of either product on shoot dry weight of Salvia or Impatiens or flower dry weight of Salvia was observed.

Stomatal and photosynthetic response of sweet gum (Liquidambarstyraciflua) to flooding

1985 ◽  
Vol 15 (2) ◽  
pp. 371-375 ◽  
Author(s):  
S. R. Pezeshki ◽  
J. L. Chambers
Keyword(s):  
Stomatal Conductance ◽  
Water Status ◽  
Stomatal Closure ◽  
Net Photosynthesis ◽  
Controlled Environment ◽  
Photosynthetic Response ◽  
Short Term ◽  
Pressure Potential ◽  
Xylem Pressure ◽  
Xylem Pressure Potential

Effects of short-term flooding on stomatal conductance, net photosynthesis, and water status of sweet gum (Liquidambarstyraciflua L.) seedlings were studied under controlled environment conditions. Flooding for 9 days induced partial stomatal closure, resulting in significant declines in transpiration and net photosynthesis. The response to flooding was rapid with an average daily stomatal conductance declining from a preflood level of 0.43 cm•s−1 to 0.26 cm•s−1 by 24 h after flooding began (40% reduction). The average preflooding daily net photosynthesis was reduced from 13.7 to 10.2 mg CO2•dm−2•h−1 (25% reduction) during the same period and the average daily stomatal conductance and net photosynthesis for the 9th day of flooding were reduced by 70 and 77%, respectively, compared with preflood levels. The leaf xylem pressure potential measurements, however, indicated that water deficits did not develop as a result of flooding. Partial stomatal reopening 3 days after termination of flooding was noted with an average daily stomatal conductance approaching 63% of the preflood levels and an average daily net photosynthesis reaching 46% of its preflood levels. Maintenance of positive net photosynthesis throughout flooding, and partial stomatal and photosynthetic recovery following drainage may account for the tolerance of sweet gum seedlings to short-term flooding.

scholarly journals Postharvest Characteristics of Canaan Fir and Fraser Fir Christmas Trees

HortScience ◽  
2004 ◽  
Vol 39 (7) ◽  
pp. 1674-1676 ◽  
Author(s):  
Ricky M. Bates ◽  
James C. Sellmer ◽  
David A. Despot
Keyword(s):  
Water Status ◽  
Abies Balsamea ◽  
Pressure Potential ◽  
Fraser Fir ◽  
Xylem Pressure ◽  
Needle Retention ◽  
Seed Sources ◽  
Christmas Trees ◽  
Xylem Pressure Potential

Needle retention, xylem pressure potential and overall quality of canaan fir (Abies balsamea var. phanerolepis (L.) Mill.) and fraser fir (Abies fraseri (Pursh) Poir.) Christmas trees were evaluated over a 40-day display period. Cut trees were stored outdoors for 24, 48, or 96 hours, and half the trees had a 2.5-cm section trimmed from the basal portion of the stem, before placement in water at an indoor display room. Controls were placed in water immediately after harvest. Xylem pressure potentials and overall quality were similar for both species except for trees stored 96 hours. Untrimmed canaan fir dried to -2.4 MPa and was rated below average by the end of the display period compared to -1.3 MPa and a good quality rating for fraser fir. Needle retention and color characteristics were excellent across all treatments for fraser fir during the entire display period. Needle loss for canaan fir began relatively soon during display, generally increased across all treatments, and was highly variable. In addition, quality of some canaan fir trees decreased as needles turned brown, but did not shed during the display period. Tree water status alone did not completely account for loss of needles and quality in canaan fir; the need exists to identify seed sources with better postharvest characteristics.

scholarly journals Water Relations of Container-grown Woody and Herbaceous Plants Following Antitranspirant Sprays

HortScience ◽  
1990 ◽  
Vol 25 (7) ◽  
pp. 772-775 ◽  
Author(s):  
Rita L. Hummel
Keyword(s):  
Species Differences ◽  
Water Status ◽  
Pressure Potential ◽  
Visual Evaluation ◽  
Xylem Pressure ◽  
Unit Leaf ◽  
Film Forming ◽  
Xylem Pressure Potential ◽  
Vapor Gard ◽  
Chinese Elm

Four film-forming antitranspirants, Vapor Gard, Envy, Wilt-Pruf, and Folicote, and a new metabolic antitranspirant UC86177 were applied to container-grown Ulmus parvifolia Jacq. (Chinese elm), Malus sargentii Rehd. (Sargent's crabapple), Viburnum plicatum tomentosum Thunb. (doubleflle viburnum), Lycopersicon esculentum Mill. `Early Giant' (tomato), Petunia × hybrids Hort. Vilm-Andr. `Royal Pearls' (petunia), and Impatiens wallerana Hook. f. `Blitz Orange' (impatiens) plants. Water status was assessed by the following methods: transpiration as water loss per unit leaf area, wilt by visual evaluation, and xylem pressure potential (XPP) determined with a pressure chamber. Antitranspirant treatment had no beneficial effect on water status of doublefile viburnum. In comparison to control plants, results of wilt ratings, XPP, and transpiration measurements for the elm, crabapple, tomato, petunia, and impatiens plants can be summarized as follows: UC86177-treated plants showed significantly less stress in 11 measures and were not different once; Wilt-Pruf was beneficial 10 times and not different twice; Folicote was beneficial nine times and not different three times; Vapor Gard produced eight beneficial results and four similar results; and Envy was beneficial three times and no different nine times. Species differences in response to antitranspirants as well as differences in product efficacy were demonstrated. UC86177 antitranspirant was shown to be as or more effective in controlling water status than the film-forming antitranspirants and may have potential for protecting various plant species against water stress.

Critical Period of Weed Interference in Transplanted Tomatoes (Lycopersicon esculentum): Growth Analysis

Weed Science ◽  
1983 ◽  
Vol 31 (4) ◽  
pp. 476-481 ◽  
Author(s):  
Susan E. Weaver ◽  
Chin S. Tan
Keyword(s):  
Lycopersicon Esculentum ◽  
Critical Period ◽  
Growth Analysis ◽  
Canopy Temperature ◽  
Dry Weight ◽  
Pressure Potential ◽  
Xylem Pressure ◽  
Fruit Number ◽  
Weed Interference ◽  
Xylem Pressure Potential

The critical period of weed interference in transplanted tomatoes (Lycopersicon esculentumMill. 'Springset’) was from 28 to 35 days after transplanting. A single weeding during this period was sufficient to prevent yield reductions. A growth analysis revealed that significant differences in plant dry weight and fruit number between tomatoes from weed-free and weed-infested plots were not apparent until 56 to 70 days after transplanting. The shorter the initial weed-free period, or the longer weeds were allowed to remain in the plots before removal, the earlier reductions in tomato dry weight and fruit number appeared. Weed interference was due primarily to shading rather than water stress. Tomatoes from weed-infested plots had significantly lower stomatal conductances than those from weed-free plots, but did not differ in xylem-pressure potential or in canopy temperature. If tomatoes were kept weed-free for more than 28 days, or when weeds were present for less than 28 days after transplanting, stomatal conductances were not significantly reduced.

Comparative Studies in Selected Species of Eucalyptus Used in Rehabilitation of the Northern Jarrah Forest, Western Australia. I. Patterns of Xylem Pressure Potential and Diffusive Resistance of Leaves

1984 ◽  
Vol 32 (4) ◽  
pp. 367 ◽  
Author(s):  
IJ Colquhoun ◽  
RW Ridge ◽  
DT Bell ◽  
WA Loneragan ◽  
J Kuo
Keyword(s):  
Western Australia ◽  
Water Loss ◽  
Seasonal Patterns ◽  
Pressure Potential ◽  
Jarrah Forest ◽  
Eucalyptus Marginata ◽  
Xylem Pressure ◽  
Diffusive Resistance ◽  
Xylem Pressure Potential ◽  
The Impact

Land use which reduces tree canopy density and the impact of Phytophthora cinnamomi are believed to be altering the hydrological balance of parts of the northern jarrah forest, Western Australia. In the drier eastern zones of the forest, replacement plant communities must maintain the soil-salt-water balance to prevent significant increases in salinization of streams in water supply catchments. Daily and seasonal patterns of the diffusive resistance of leaves and xylem pressure potential were determined for the major natural dominant of the region, Eucalyptus marginata, and five other species of Eucalyptus used in rehabilitation. Three types of daily and seasonal patterns were observed. E. marginata and E. calophylla exhibited little stomatal control of water loss, and leaf resistances remained low throughout the study period (type 1). E. maculata, E. resinifera and E. saligna exhibited marked stomatal regulation during summer days when xylem pressure potentials fell below -2.O MPa (type 2). E. wandoo (type 3) also controlled water loss but developed xylem pressure potentials far lower than all other species tested (<-3.0 MPa). Although none of the species tested replicated the summer stomatal resistance and xylem pressure potential patterns of E. marginata, it is suggested that total annual water use should be examined before selecting the most appropriate species to rehabilitate disturbed sites in the eastern zones of the northern jarrah forest region.

Stomatal control and the development of water deficit in Engelmann spruce seedlings during drought

1979 ◽  
Vol 9 (3) ◽  
pp. 297-304 ◽  
Author(s):  
Merrill R. Kaufmann
Keyword(s):  
Flux Density ◽  
Stomatal Closure ◽  
Absolute Humidity ◽  
Pressure Potential ◽  
Evaporative Demand ◽  
Xylem Pressure ◽  
Full Sunlight ◽  
Engelmann Spruce ◽  
Xylem Pressure Potential ◽  
The Relationship

The effects of soil drying on water relations of Engelmann spruce (Piceaengelmannii Engelm.) were studied by withholding water from 4-year-old potted seedlings in full sunlight and under a shade screen transmitting 55–60% light. During a period of 2 months, xylem pressure potential, water vapor conductance, and transpirational flux density gradually declined compared with well watered controls, with drying being more rapid in full sunlight. As drying progressed, xylem pressure potential at 0 transpiration (predawn potential) decreased and the slope of the relationship between xylem pressure potential and transpirational flux density became more negative. Hysteresis in the relationship occurred when predawn xylem pressure potential was −6 bars (1 bar = 105 Pa) or lower. Needle conductance during daylight hours decreased as the absolute humidity difference from leaf to air increased but conductances were lower in September than in August for given humidity differences. Xylem pressure potentials between −15 and −19 bars had no clear effect on conductance in August but apparently caused significant stomatal closure in September. Because of humidity-induced stomatal closure, evaporative demand had little effect on transpirational flux density over a broad range of humidity gradient. Thus increased leaf-to-air vapor gradients for transpiration are not always accompanied by increased transpiration.

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