scholarly journals Stomatal responses in grapevine become increasingly more tolerant to low water potentials throughout the growing season

2021 ◽  
Author(s):  
Jose Carlos Herrera ◽  
Alberto Calderan ◽  
Gregory A. Gambetta ◽  
Enrico Peterlunger ◽  
Astrid Forneck ◽  
...  
Keyword(s):  
Growing Season ◽  
Stomatal Responses ◽  
Water Potentials

scholarly journals L-band vegetation optical depth as an indicator of plant water potential in a temperate deciduous forest stand

2020 ◽  
Author(s):  
Nataniel Holtzman ◽  
Leander D. L. Anderegg ◽  
Simon Kraatz ◽  
Alex Mavrovic ◽  
Oliver Sonnentag ◽  
...  
Keyword(s):  
Water Potential ◽  
Optical Depth ◽  
Growing Season ◽  
Forest Stand ◽  
Plant Water ◽  
Stem Water Potential ◽  
Water Potentials ◽  
Plant Water Potential ◽  
Stem Water ◽  
L Band

Abstract. Vegetation optical depth (VOD) retrieved from microwave radiometry correlates with the total amount of water in vegetation, based on theoretical and empirical evidence. Because the total amount of water in vegetation varies with relative water content (as well as with biomass), this correlation further suggests a possible relationship between VOD and plant water potential, a quantity that drives plant hydraulic behavior. Previous studies have found evidence for that relationship on the scale of satellite pixels tens of kilometers across, but these comparisons suffer from significant scaling error. Here we used small-scale remote sensing to test the link between remotely sensed VOD and plant water potential. We placed an L-band radiometer on a tower above the canopy looking down at red oak forest stand during the 2019 growing season in central Massachusetts, United States. We measured stem xylem and leaf water potentials of trees within the stand, and retrieved VOD with a single-channel algorithm based on continuous radiometer measurements and measured soil moisture. VOD exhibited a diurnal cycle similar to that of leaf and stem water potential, with a peak at approximately 5 AM. VOD was also positively correlated with both the measured dielectric constant and water potentials of stem xylem over the growing season. The presence of moisture on the leaves did not affect the observed relationship between VOD and stem water potential. We used our observed VOD-water potential relationship to estimate stand-level values for a radiative transfer parameter and a plant hydraulic parameter, which compared well with the published literature. Our findings support the use of VOD for plant hydraulic studies in temperate forests.

Stomatal Responses to Leaf Water Potentials of Drip Irrigated Peach {Prunus persica)

1984 ◽  
Vol 27 (5) ◽  
pp. 1442-1450 ◽  
Author(s):  
J. F. Punthakey ◽  
M. J. McFarland ◽  
J. W. Worthington
Keyword(s):  
Prunus Persica ◽  
Leaf Water ◽  
Stomatal Responses ◽  
Water Potentials

Salinity, Stomatal Responses and Whole-Tree Hydraulic Conductivity of Orchard 'Washington Navel' Orange, Citrus sinensis (L.) Osbeck

1989 ◽  
Vol 16 (2) ◽  
pp. 169 ◽  
Author(s):  
J Lloyd ◽  
H Howie
Keyword(s):  
Vapour Pressure ◽  
Early Morning ◽  
Bulk Water ◽  
Navel Orange ◽  
Diurnal Patterns ◽  
Stomatal Responses ◽  
Water Potentials ◽  
Washington Navel ◽  
Orange Trees ◽  
High Vapour Pressure

Diurnal patterns in stomatal conductance and bulk water potentials were measured over a 6-month period for spring flush leaves on 24-year-old Washington Navel orange trees that had been irrigated with water containing either 5 mol m-3 NaCl or 20 mol m-3 NaCl for 5 years prior to measurements. During summer and autumn, at early morning measurement times, stomatal conductances of leaves on trees irrigated with 20 mol m-3 were significantly below those on trees irrigated with 5 mol m-3 NaCl. Lower values on high salinity trees were not attributable to more negative water potentials or lower turgor pressures but were apparently due to an inability of stomata on leaves from salinised trees to open in response to low vapour pressure deficits (VPDs). There was little effect of salinity on stomatal conductances during afternoon measurements when high vapour pressure deficits prevailed. Laboratory studies confirmed that stomata on salinised trees are less responsive to VPD than those from unsalinised trees. When measurements were made during winter months there was no effect of salinity on diurnal patterns of stomatal conductances but leaf water potentials were less negative for leaves of salinised trees during daylight hours. Hydraulic conductance (G) of trees to liquid water flow was greater for trees irrigated with 5 mol m-3 NaCl in summer, but seasonal reductions in G for trees irrigated with 5 mol m-3 NaCl occurred to a far greater extent than for trees irrigated with 20 mol m-3 NaCl. This may have been a consequence of a reduction in leaf areas of salinised trees during summer and autumn without concomitant decreases in root length.

Water relations and drought resistance of young Pinusbanksiana and P. resinosa plantation trees

1977 ◽  
Vol 7 (1) ◽  
pp. 132-137 ◽  
Author(s):  
J. S. Pereira ◽  
T. T. Kozlowski
Keyword(s):  
Water Potential ◽  
Drought Resistance ◽  
Stomatal Closure ◽  
Growing Season ◽  
Early Morning ◽  
Diffusion Resistance ◽  
Soil Water Depletion ◽  
Water Potentials ◽  
Needle Water Potential ◽  
Better Than

Daytime changes in needle water potential and needle diffusion resistance of young Pinusbanksiana and P. resinosa plantation trees were determined at various times throughout the 1974 growing season in northern Wisconsin. Early in the growing season, early-morning water potential and daytime needle diffusion resistance varied little between the two species. However, midday water potentials generally were higher in P. banksiana than in P. resinosa. As the season progressed, water potentials in the early morning were lower, and they decreased more during the day in P. resinosa than in P. banksiana. In addition, stomata of P. banksiana usually closed earlier in the day. Pinusbanksiana appeared to avoid drought better than P. resinosa because the former maintained a higher needle water potential throughout most of the growing season. This reflected lower transpiration and slower soil water depletion associated with lower leaf area and stomatal closure at higher needle water potential in P. banksiana.

Deep tritiated water uptake and predawn xylem water potentials as indicators of vertical rooting extent in a Quercus–Carya forest

1989 ◽  
Vol 19 (5) ◽  
pp. 627-631 ◽  
Author(s):  
Jeffrey W. Stringer ◽  
Paul J. Kalisz ◽  
John A. Volpe
Keyword(s):  
Water Uptake ◽  
Deep Water ◽  
Tritiated Water ◽  
Water Source ◽  
Growing Season ◽  
Surface Soils ◽  
Water Potentials ◽  
Second Growth ◽  
Highly Correlated ◽  
Fractured Sandstone

Transpiration uptake from a tritiated water source (3H2O) associated with a sandstone bed at 3 m depth was examined in a second-growth Quercus–Carya forest. The effect of utilization of deep water on predawn xylem water potentials (Pstem) was also investigated. The 3H2O saturated the soil contacting the sandstone bed. As surface soils dried during the growing season, 3H2O uptake increased. Although all trees growing over the 3H2O reserve were capable of utilizing some of this water, Q. alba trees from all canopy levels generally exhibited higher foliage tritium (3H) activities than C. glabra (Mill.) Sweet. Higher (less negative) Pstem values were associated with trees having higher foliage 3H activities. The Q. alba tree with the highest foliage 3H activity, 1.2 × 106 Bq•L−1, exhibited the highest Pstem value, −0.875 MPa; the Q. alba tree with the lowest 3H activity also had the lowest Pstem value, 4.5 × 104 Bq•L−1 and −1.75 MPa, respectively. Pstem and the logarithm of 3H activity were highly correlated (r2 = 0.89), suggesting that predawn moisture status was at least partially controlled by the ability of trees to utilize the deep water reserve at or near the fractured sandstone bed.

scholarly journals L-band vegetation optical depth as an indicator of plant water potential in a temperate deciduous forest stand

2021 ◽  
Vol 18 (2) ◽  
pp. 739-753
Author(s):  
Nataniel M. Holtzman ◽  
Leander D. L. Anderegg ◽  
Simon Kraatz ◽  
Alex Mavrovic ◽  
Oliver Sonnentag ◽  
...  
Keyword(s):  
Water Potential ◽  
Optical Depth ◽  
Growing Season ◽  
Forest Stand ◽  
Plant Water ◽  
Stem Water Potential ◽  
Water Potentials ◽  
Plant Water Potential ◽  
Stem Water ◽  
L Band

Abstract. Vegetation optical depth (VOD) retrieved from microwave radiometry correlates with the total amount of water in vegetation, based on theoretical and empirical evidence. Because the total amount of water in vegetation varies with relative water content (as well as with biomass), this correlation further suggests a possible relationship between VOD and plant water potential, a quantity that drives plant hydraulic behavior. Previous studies have found evidence for that relationship on the scale of satellite pixels tens of kilometers across, but these comparisons suffer from significant scaling error. Here we used small-scale remote sensing to test the link between remotely sensed VOD and plant water potential. We placed an L-band radiometer on a tower above the canopy looking down at red oak forest stand during the 2019 growing season in central Massachusetts, United States. We measured stem xylem and leaf water potentials of trees within the stand and retrieved VOD with a single-channel algorithm based on continuous radiometer measurements and measured soil moisture. VOD exhibited a diurnal cycle similar to that of leaf and stem water potential, with a peak at approximately 05:00 eastern daylight time (UTC−4). VOD was also positively correlated with both the measured dielectric constant and water potentials of stem xylem over the growing season. The presence of moisture on the leaves did not affect the observed relationship between VOD and stem water potential. We used our observed VOD–water-potential relationship to estimate stand-level values for a radiative transfer parameter and a plant hydraulic parameter, which compared well with the published literature. Our findings support the use of VOD for plant hydraulic studies in temperate forests.

Techniques for preparing the Lolium perenne coleorhiza for scanning electron microscope evaluation

1992 ◽  
Vol 50 (1) ◽  
pp. 766-767
Author(s):  
Susan B.G. Debaene ◽  
John S. Gardner ◽  
Phil S. Allen
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Lolium Perenne ◽  
Morphological Study ◽  
Root Hairs ◽  
Inner Pressure ◽  
Water Potentials ◽  
Radicle Emergence ◽  
Standard Fixation ◽  
Scanning Electron

The coleorhiza is a nonvascular sheath that encloses the embryonic radicle in Poaceae, and is generally the first tissue to emerge during germination. Delicate hairlike extensions develop from some coleorhiza cells prior to radicle emergence. Similar to root hairs, coleorhiza hairs are extremely sensitive to desiccation and are damaged by exposure to negative water potentials. The coleorhiza of Lolium perenne is somewhat spherical when first visible, after which a knob forms at a right angle to the caryopsis due to inner pressure from the elongating radicle. This knob increases in length until the radicle finally punctures the coleorhiza. Standard fixation procedures cause severe desiccation of coleorhiza cells and hairs, making morphological study of the coleorhiza difficult. This study was conducted to determine a more successful process for coleorhiza preservation.

Growing season

1992 ◽  
Author(s):  
Nicholas Wellington
Keyword(s):  
Growing Season

Irrigation regime and water consumption of potatoes in the Republic of Bashkortostan, depending on the reclamation condition of lands

2020 ◽  
Vol 0 (6) ◽  
pp. 13-19
Author(s):  
Guzel Gumerova ◽  
Georgiy Gulyuk ◽  
Dmitry Kucher ◽  
Anatoly Shuravilin ◽  
Elena Piven
Keyword(s):  
Water Consumption ◽  
Weather Conditions ◽  
Growing Season ◽  
Vegetation Period ◽  
Forest Steppe ◽  
Total Water ◽  
Total Water Consumption ◽  
Republic Of Bashkortostan ◽  
Irrigated Lands ◽  
The Republic

Data of long-term researches (2015–2018) in southern forest-steppe zone of the Republic of Bashkortostan, is justified theoretically and experimentally the mode of irrigation of potatoes on leached chernozems of unsatisfactory, satisfactory and good ameliorative condition of irrigated lands. For the growing periods of potatoes with different heat and moisture supply, the number of watering, the timing of their implementation, irrigation and irrigation norms are established. On lands with unsatisfactory meliorative state the number of irrigation depending on weather conditions of potato vegetation period varied from 0 to 3 (1.5 on average) with average irrigation norm – 990 m3/ha. With satisfactory meliorative state of lands the number of irrigation on average increased from 0 to 4 (2.3 on average) with irrigation norm – 1305 m3/ha. On lands with good meliorative state the number of irrigation was the highest – from 1 to 5 (3 on average) with average irrigation irrigation norm is 1653 m3/ha. It was noted that in the dry periods of potato vegetation the greatest number of watering was carried out (3–5 watering), and in the wet periods (2017) watering was not carried out except for the area with a good reclamation state, where only one irrigation was carried out by the norm of 550 m3/ha. Water consumption of potato was studied in dynamics as a whole during the growing season and the months of the growing season depending on weather conditions of vegetation period and land reclamation condition of irrigated lands, as well as in the control (without irrigation). The lowest total water consumption was in the area without irrigation and averaged 226.8 mm. In irrigated areas, its values increased to 319-353.4 mm. The average daily water consumption varied from 2.12 to 3.3 mm. The highest rates of potato water consumption were observed in June and July, and the lowest – in May and August. In the total water consumption of potatoes on the site without irrigation, the largest share was occupied by atmospheric precipitation and in addition to them the arrival of moisture from the soil. Irrigation water was used in irrigated areas along with precipitation, the share of which was 30.2–46.1 %.

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