CLONAL VARIATIONS IN THE WATER RELATIONS OF RED OSIER DOGWOOD DURING COLD ACCLIMATION

1981 ◽  
Vol 61 (2) ◽  
pp. 351-363 ◽  
Author(s):  
ELIZABETH A. BRAY ◽  
LAWRENCE R. PARSONS
Keyword(s):  
North Dakota ◽  
Water Content ◽  
Cold Acclimation ◽  
Water Relations ◽  
Dry Weight ◽  
Stomatal Resistance ◽  
Pressure Potential ◽  
Xylem Pressure Potential ◽  
Chamber Studies ◽  
Growth Chamber Studies

The water relations of six climatic races of red osier dogwood (Cornus sericea L.) were followed during cold acclimation in St. Paul, Minnesota in the fall of 1977. The following year, a similar study was completed on three of the climatic races. The clones originated from Alaska, Washington, Oregon, Montana, Idaho and North Dakota. By November, differences in rates of acclimation could be distinguished. Races could be divided into two groups: Oregon, Idaho and Montana became hardy to between − 25 and − 30 °C and Alaska, North Dakota and Washington became hardy to between − 37 and − 42 °C. After the initial frost, daytime stomatal resistance increased first in Alaska and then in Washington, Montana and North Dakota, but not in Idaho and Oregon. Differences among the races could be distinguished by this trait. The remaining water relations parameters measured did not show differences among the races. Stem water content of all clones decreased into mid-October when they reached a similar water content of approximately 1 g H2O/g dry weight. Midday leaf xylem pressure potential of all clones increased during acclimation. Relative water content of the stems decreased during acclimation but later increased. The water relations parameters of the outdoor acclimation process were very similar to those reported for growth chamber studies.

Comparative Studies in Selected Species of Eucalyptus Used in Rehabilitation of the Northern Jarrah Forest, Western Australia. II. Wood and Leaf Anatomy

1984 ◽  
Vol 32 (4) ◽  
pp. 375 ◽  
Author(s):  
RW Ridge ◽  
WA Loneragan ◽  
DT Bell ◽  
IJ Colquhoun ◽  
J Kuo
Keyword(s):  
Water Relations ◽  
Leaf Anatomy ◽  
Structural Features ◽  
Stomatal Resistance ◽  
Indigenous Species ◽  
Pressure Potential ◽  
Distinctive Character ◽  
Jarrah Forest ◽  
Eucalyptus Marginata ◽  
Xylem Pressure Potential

Previous studies have established differences in water relations between the major dominant of the northern jarrah forest, Eucalyptus marginata, which transpires freely except under conditions of extreme drought, and potential replacement species which exhibit some measure of stomatal control. The anatomy of the water-conducting system of three indigenous species (Eucalyptus marginata, E. calophylla and E. wandoo) and four eastern Australian species (E. globulus, E. maculata, E. resinifera and E. saligna) is described with reference to their patterns of stomatal resistance and xylem pressure potential. Vessel and parenchyma distribution generally correlated with taxonomic affinities of the species. Groups based on wood anatomy had little in common with groupings based on eco-physiological behaviour but did tend to confirm the distinctive character of E. marginata. By using leaf anatomy, a third grouping of species was possible. E. globulus, E. maculata and E. wandoo are amphistomatous whereas E. calophylla, E. resinifera, E. saligna and E. marginata are hypostomatous. However, the major structural features associated with previously observed patterns of water relations appear related to differences in vessel size (particularly in E. wandoo) and the presence and size of the stomatal antechambers. The anatomical structures described here confirm the special way in which E. rnarginata responds to environmental factors, and thus emphasize the challenge of finding a substitute species that exhibits similar anatomical and physiological adaptations.

Adaptation to Water Stress of the Leaf Water Relations of Four Tropical Forage Species

1980 ◽  
Vol 7 (2) ◽  
pp. 207 ◽  
Author(s):  
JR Wilson ◽  
MM Ludlow ◽  
MJ Fisher ◽  
E Schulze
Keyword(s):  
Water Stress ◽  
Water Content ◽  
Water Relations ◽  
Bound Water ◽  
Leaf Tissue ◽  
Dry Weight ◽  
Panicum Maximum ◽  
Soil Drying ◽  
Buffel Grass ◽  
Heteropogon Contortus

Three tropical grasses, green panic (Panicum maximum var, trichoglume), spear grass (Heteropogon contortus) and buffel grass (Cenchrus ciliaris) and the tropical legume siratro (Macroptilium atropurpureum), were grown in plots in a semi-arid field environment. The water relations characteristics of leaves from plants subjected to a soil drying cycle were compared with those of unstressed leaves from plants in irrigated plots. Minimum water potentials attained in the stressed leaves were c. -44, - 38, - 33 and - 13 bar for the four species, respectively. The grass leaves adjusted osmotically to water stress, apparently through accumulation of solutes, so that there was a decrease in osmotic potential at full turgor (Ψπ100) of 5.5, 3.9 and 7.1 bar, and in water potential at zero turgor (Ψ0) of 8.6, 6.5 and 8.6 bar for green panic, spear grass and buffel respectively. Water stress appeared to increase slightly the proportion of bound water (B) and the bulk modulus of elasticity (ε) of the grass leaves, but it did not alter the relative water content at zero turgor (RWC0) or the ratio of turgid water content to dry weight of the tissue. The Ψπ100 and Ψ0 of stressed siratro leaves decreased by 2.5-4 bar and 3-5 bar respectively when subjected to soil drying cycles. These changes could be explained by the marked decrease in the ratio of turgid water content to dry weight of the leaf tissue rather than by accumulation of solutes. The values of RWC0 and ε for siratro leaves were not altered by stress but, in contrast to the grasses, B was apparently decreased although the data exhibited high variability. Adjustments in Ψπ100 and Ψ0 of stressed leaves of buffel grass and siratro were largely lost within 10 days of rewatering.

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.

Foliar and Root Absorption of Atrazine Applied Postemergence to Giant Foxtail

Weed Science ◽  
1969 ◽  
Vol 17 (2) ◽  
pp. 251-256 ◽  
Author(s):  
Lafayette Thompson ◽  
F. W. Slife
Keyword(s):  
Field Experiments ◽  
Soil Surface ◽  
Dry Weight ◽  
Field Studies ◽  
Simulated Rainfall ◽  
Root Absorption ◽  
Giant Foxtail ◽  
Setaria Faberii ◽  
Chamber Studies ◽  
Growth Chamber Studies

In growth chamber studies, high relative humidity and rewetting crystalline spray deposits of 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) increased absorption by and phytotoxicity to giant foxtail (Setaria faberii Herrm.), but phytotoxicity was restricted to expanded (unrolled) leaves unless some atrazine was absorbed by the roots. Though phytotoxicity was increased by simulated rainfall when root absorption was prevented, an appreciable number of the plants were killed only when atrazine residues were washed into the soil. In field studies, atrazine applied to a wet soil surface was as effective as the same rate of atrazine foliarly applied. In other field experiments, atrazine applied to giant foxtail on a wet soil and followed by simulated rainfall reduced stand and dry weight, but on a dry soil and not followed by simulated rainfall, atrazine reduced dry weight less and did not reduce stand. These results are due to root absorption of atrazine from wet soil. Spray additives increased phytotoxicity.

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.

Response of soybean leaf water relations to tropospheric ozone

1995 ◽  
Vol 73 (4) ◽  
pp. 517-526 ◽  
Author(s):  
Edwin L. Fiscus ◽  
Joseph E. Miller ◽  
Fitzgerald L. Booker ◽  
Chantal D. Reid
Keyword(s):  
Water Relations ◽  
Leaf Water ◽  
Growth And Yield ◽  
Wall Structure ◽  
Tissue Elasticity ◽  
Leaf Water Relations ◽  
Pressure Potential ◽  
Volume Analysis ◽  
Xylem Pressure ◽  
Xylem Pressure Potential

Tropospheric O3 and water stress cause significant reductions in crop growth and yield. The effects of chronic O3 exposures on leaf water relations have been less thoroughly studied. Soybeans were grown in two years in open-top field chambers equipped to control O3. The seasonal mean O3 concentrations for the charcoal-filtered controls and supplemental O3 treatments were 24 and 83 nL∙L−1 for the first year (1990) and 20 and 99 nL∙L−1 for the second year (1992). In 1990 leaves were sampled during four intervals of the 106-d growing season and subjected to potential–volume analysis. In 1992, leaves were sampled over a 3-week period, centered on 49 days after planting for potential–volume analysis as well as for midday xylem pressure potentials and leaf conductance. Ontogenetic changes in most of the parameters were large compared with treatment effects. O3 treatment consistently caused decreased symplastic volume, specific leaf mass, and tissue elasticity. In 1992, these effects were accompanied by decreased leaf conductances with no discernable change in xylem pressure potential, although midday turgor increased by 32% and stomatal competency was maintained. Tissue elasticity decreases may be related to O3-induced changes in cell wall structure during leaf expansion and may result in decreased symplastic volume. Key words: Glycine max, ozone, leaf water relations, pressure–volume analysis, elasticity, elastic modulus.

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.

Growth and ecophysiological responses of black spruce seedlings to elevated CO2 under varied water and nutrient additions

1993 ◽  
Vol 23 (6) ◽  
pp. 1033-1042 ◽  
Author(s):  
Kurt H. Johnsen
Keyword(s):  
Gas Exchange ◽  
Black Spruce ◽  
Seedling Emergence ◽  
Net Photosynthesis ◽  
Dry Weight ◽  
Pressure Potential ◽  
Foliar N ◽  
Nutrient Additions ◽  
Xylem Pressure Potential ◽  
Ecophysiological Responses

Two controlled-environment studies examined growth and ecophysiological responses of black spruce (Piceamariana (Mill.) B.S.P.) seedlings to elevated CO2 under varied water and nutrient additions. Growth analyses were conducted followed by measurements of gas exchange, xylem pressure potential and foliar N concentrations. Growth under elevated CO2 (700 ppm) increased final seedling dry weights by 20–48% compared with seedling growth under ambient CO2 (350 ppm). Percent increases in seedling dry weight were greater under drought versus well-watered conditions and higher versus lower nutrient additions. Seedlings grown under elevated CO2 displayed higher water use efficiency than seedlings grown under ambient CO2. This was apparent based upon instantaneous gas exchange as well as xylem potential pressure measurements. Elevated CO2-induced stimulation of relative growth rate was greatest shortly after seedling emergence and decreased with increased seedling size. Acclimation of net photosynthesis was observed and was reversible. Analyses using allometric principles indicate net photosynthetic acclimation resulted from: (i) growth-induced nutrient dilution; (ii) a decrease in foliar N levels not owing to dilution; and (iii) a decrease in net photosynthetic activity.

Growth and Development of False Cleavers (Galium spurium L.)

Weed Science ◽  
1987 ◽  
Vol 35 (4) ◽  
pp. 490-495 ◽  
Author(s):  
Najib Malik ◽  
William H. Vanden Born
Keyword(s):  
Plant Density ◽  
Vegetative State ◽  
Dry Weight ◽  
Sowing Date ◽  
Shoot Dry Weight ◽  
Early Fall ◽  
Chamber Studies ◽  
Growth Chamber Studies ◽  
Galium Spurium ◽  
Number Of Branches

Seeds of false cleavers (Galium spurium L.) grown in mid-May germinated 12 to 14 days after planting in central Alberta. The plants flowered from early July to late August and developed fruits from mid-July to early September. Plants from the late-June sowing date developed fruits until early October unless early fall frost killed the plants. Plants from seeds sown after mid-July remained in a vegetative state until late September and did not flower. Seedlings that emerged in August and September survived a mild prairie winter and resumed growth the following spring. Under greenhouse conditions, plant height ranged from 77 to 113 cm and the number of branches at first node ranged from 6 to 14, as plant density decreased from 16 to 1 plant/pot. Shoot dry weight decreased by 50% as plant population doubled, 46 days after emergence. The number of seeds produced/plant decreased from 3500 to 175 as plant density increased from 1 to 16 plants/pot. In growth chamber studies, plant growth was greatest at 20 compared to 16 or 24C.

Sign in / Sign up

Export Citation Format

Share Document