Stomatal Behaviour of Kenaf and Sorghum in a Semiarid Tropical Environment. II. During the Day

1980 ◽  
Vol 7 (5) ◽  
pp. 621 ◽  
Author(s):  
RC Muchow ◽  
MJ Fisher ◽  
MM Ludlow ◽  
RJK Myers
Keyword(s):  
Water Stress ◽  
Feedback Control ◽  
Water Potential ◽  
Soil Water ◽  
Leaf Water Potential ◽  
Water Status ◽  
Stomatal Closure ◽  
Controlled Environment ◽  
Saturation Deficit ◽  
Stomatal Behaviour

The influence of leaf water potential (Ψl), saturation deficit (δe), and temperature on stornatal conductance (gs) of kenaf and sorghum was determined at non-limiting quantum fluxes both at high and low soil water status in the field, and under controlled environment conditions. Sorghum stomata closed in response to Ψl in a manner consistent with the classical feedback control, while kenaf stomata responded directly to δe, independently of Ψl. The rate of decrease of gs of kenaf with increasing δe was greater at higher temperatures. Also the stomata of stressed kenaf were less sensitive to δe than those of the well-watered crop due to the limitation in degree of stomatal opening imposed by water stress. The degree of stomatal adjustment in kenaf was also assessed. In the stressed kenaf, the Ψl at half the maximum gs was c. 0.17 MPa lower and gs was more sensitive to decreases in Ψl, than in the well watered control. However, there was little difference in the Ψl at 95% stomatal closure.

Photosynthesis in Coffea arabica. II. Effects of Water Stress

1980 ◽  
Vol 16 (1) ◽  
pp. 21-27 ◽  
Author(s):  
D. Kumar ◽  
Larry L. Tieszen
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Coffea Arabica ◽  
Water Status ◽  
Stomatal Closure ◽  
Leaf Water ◽  
Plant Water

SUMMARYExperiments were carried out to relate soil moisture to leaf water potential (Ψ1), and to determine the effects of varying Ψ1, on leaf conductances and photosynthesis in coffee. Stomatal conductance was maximum at 0900 h, but plants growing in drier soil showed marked mid-day stomatal closure. After 1500 h, stomata began closing although plant water status improved. Photosynthesis in relation to changing Ψ1 appeared to exhibit roughly three different rates. At the fixed experimental temperature (25°C) low Ψ1 reduced photosynthesis throughits influence on stomata, but under field conditions low Ψ1 and an accompanying rise in temperature could lower the rate by lowering both mesophyll and stomatal conductances.

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.

scholarly journals Geospatial variation of grapevine water status, soil water availability, grape composition and sensory characteristics in a spatially heterogeneous premium wine grape vineyard

2014 ◽  
Vol 1 (1) ◽  
pp. 1013-1072
Author(s):  
D. R. Smart ◽  
S. Cosby Hess ◽  
R. Plant ◽  
O. Feihn ◽  
H. Heymann ◽  
...  
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Leaf Water Potential ◽  
Water Availability ◽  
Water Status ◽  
Leaf Water ◽  
Sensory Characteristics ◽  
Soil Water Availability ◽  
Wine Grape ◽  
Available Water

Abstract. The geoscience component of terroir in wine grape production continues to be criticized for its quasi-mystical nature, and lack of testable hypotheses. Nonetheless, recent relational investigations are emerging and most involve water availability as captured by available water capacity (AWC, texture) or plant available water (PAW) in the root zone of soil as being a key factor. The second finding emerging may be that the degree of microscale variability in PAW and other soil factors at the vineyard scale renders larger regional characterizations questionable. Cimatic variables like temperature are well mixed, and its influence on wine characteristic is fairly well established. The influence of mesogeology on mesoclimate factors has also been characterized to some extent. To test the hypothesis that vine water status mirrors soil water availability, and controls fruit sensory and chemical properties at the vineyard scale we examined such variables in a iconic, selectively harvested premium winegrape vineyard in the Napa Valley of California during 2007 and 2008 growing seasons. Geo-referenced data vines remained as individual study units throughout data gathering and analysis. Cartographic exercises using geographic information systems (GIS) were used to vizualize geospatial variation in soil and vine properties. Highly significant correlations (P < 0.01) emerged for pre-dawn leaf water potential (ΨPD), mid-day leaf water potential (ΨL) and PAW, with berry size, berry weight, pruning weights (canopy size) and soluble solids content (°Brix). Areas yielding grapes with perceived higher quality had vines with (1) lower leaf water potential (LWP) both pre-dawn and mid-day, (2) smaller berry diameter and weight, (3) lower pruning weights, and (4) higher °Brix. A trained sensory panel found grapes from the more water-stressed vines had significantly sweeter and softer pulp, absence of vegetal character, and browner and crunchier seeds. Metabolomic analysis of the grape skins showed significant differences in accumulation of amino acids and organic acids. Data vines were categorized as non-stressed (ΨPD ≥ −7.9 bars and ΨL ≥ −14.9 bars) and stressed (ΨPD ≤ −8.0 bars and ΨL ≤ −15.0 bars) and subjected to analysis of variance. Significant separation emerged for vines categorized as non-stressed versus stressed at véraison, which correlated to the areas described as producing higher and lower quality fruit. This report does not advocate the use of stress levels herein reported. The vineyard was planted to a vigorous, deep rooted rootstock (V. rupestris cv. St. George), and from years of management is known to be able to withstand stress levels of the magnitude we observed. Nonetheless, the results may suggest there is not a linear relationship between physiological water stress and grape sensory characteristics, but rather the presence of an inflection point controlling grape composition as well as physiological development.

Carbon dioxide enrichment and water stress interaction on growth of two tomato cultivars

1984 ◽  
Vol 102 (3) ◽  
pp. 687-693 ◽  
Author(s):  
Alejandra Paez ◽  
H. Hellmers ◽  
B. R. Strain
Keyword(s):  
Carbon Dioxide ◽  
Water Stress ◽  
Plant Growth ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Osmotic Potential ◽  
Water Status ◽  
Carbon Dioxide Concentration ◽  
Leaf Water ◽  
Total Leaf

SummaryIf atmospheric carbon dioxide concentration continues to increase, plant growth and crop yield could be affected. New Yorker and Better Boy cultivars of tomato (Lycopersicon esculentum) were used to investigate possible intraspecific variation in the response of crop species to increased CO2. Because precipitation and temperature are predicted to change with the increasing atmospheric CO2 concentration, the response of the two cultivars to the interaction between CO2 and water stress was also examined. Seeds of the two cultivars were germinated and grown under controlled environmental conditions, in either 350 or 675 μ1 CO2/1.The plant water status of the two cultivars was inherently different but was little affected by the CO2 concentration when the plants were well watered. When water was withheld for 5 days the total leaf water potential and osmotic potential decreased in both CO2 treatments but less rapidly in high CO2 than in low. Under low CO2 total leaf water potential decreased to a lower value than osmotic potential. The differences were due, at least in part, to the reduced stomatal conductance and transpiration rate under high CO2.Increased CO2 ameliorated the detrimental effects of drought stress on plant growth. The results indicate that increased CO2 could differentially affect the relative drought resistance of species cultivars.

Adaptation of Species of Centrosema to Water Stress

1983 ◽  
Vol 10 (2) ◽  
pp. 119 ◽  
Author(s):  
MM Ludlow ◽  
ACP Chu ◽  
RJ Clements ◽  
RG Kerslake
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Stomatal Closure ◽  
Leaf Water ◽  
Water Stress Tolerance ◽  
Strong Positive Relationship ◽  
Eastern Australia ◽  
North Eastern ◽  
Macroptilium Atropurpureum

The responses to water stress of five accessions representing four species of the legume Centrosema from contrasting moisture environments were compared under controlled conditions with those of Macroptilium atropurpureum cv. Siratro, a species which avoids dehydration. Species of Centrosema were able to tolerate leaf water potentials as low as -8 to -12 MPa, and all showed osmotic and stomatal adjustment. However, they differed in the tolerance of their leaves to water stress and in the leaf water potential at which stomata were effectively closed. There was a strong positive relationship between water stress tolerance of leaves and the leaf water potential for effective stomatal closure, among the Centrosema accessions and Siratro. The results are consistent with the natural ecological distribution of the species and their behaviour in different moisture environments in northern and north-eastern Australia.

Relationship Between Root/Soil Hydraulic Properties and Stomatal Behaviour in Sugarcane

1989 ◽  
Vol 16 (3) ◽  
pp. 241 ◽  
Author(s):  
NZ Saliendra ◽  
FC Meinzer
Keyword(s):  
Stomatal Conductance ◽  
Water Potential ◽  
Soil Water ◽  
Leaf Water Potential ◽  
Water Status ◽  
Hydraulic Conductance ◽  
Leaf Water ◽  
Soil Drying ◽  
Root Hydraulic Conductance ◽  
High Soil Moisture

Stomatal conductance, leaf and soil water status, transpiration, and apparent root hydraulic conductance were measured during soil drying cycles for three sugarcane cultivars growing in containers in a greenhouse. At high soil moisture, transpiration and apparent root hydraulic conductance differed considerably among cultivars and were positively correlated, whereas leaf water potential was similar among cultivars. In drying soil, stomatal and apparent root hydraulic conductance approached zero over a narrow (0.1 MPa) range of soil water suction. Leaf water potential remained nearly constant during soil drying because the vapor phase conductance of the leaves and the apparent liquid phase conductance of the root system declined in parallel. The decline in apparent root hydraulic conductance with soil drying was manifested as a large increase in the hydrostatic pressure gradient between the soil and the root xylem. These results suggested that control of stomatal conductance in sugarcane plants exposed to drying soil was exerted primarily at the root rather than at the leaf level.

NET CO2 EXCHANGE RATE AS A SENSITIVE INDICATOR OF PLANT WATER STATUS IN CORN (Zea mays L.)

1988 ◽  
Vol 68 (3) ◽  
pp. 597-606 ◽  
Author(s):  
R. CEULEMANS ◽  
I. IMPENS ◽  
M. C. LAKER ◽  
F. M. G. VAN ASSCHE ◽  
R. MOTTRAM
Keyword(s):  
Zea Mays ◽  
Exchange Rate ◽  
Water Stress ◽  
Water Potential ◽  
Soil Water ◽  
Leaf Water Potential ◽  
Zea Mays L ◽  
Leaf Water ◽  
Water Capacity ◽  
Available Water Capacity

With the objective to evaluate and compare different physiological plant parameters as indicators of water stress, net CO2 exchange rate (NCER), leaf temperature, predawn and daytime leaf water potential were monitored diurnally on last fully expanded leaves of corn (Zea mays L.) plants under two different soil water treatments (stressed and nonstressed) during a 10-d period at anthesis in a semi-arid region in South Africa. Profile available water capacity (PAWC) was used to express the soil water contents during the experiments. A significant decrease in NCER was noticed as soon as 30% of PAWC was extracted, i.e. 2 or 3 d after irrigation. Although the results were limited to a short, well-defined measuring period, NCER, and especially NCER at noon, seemed to be a more sensitive and more reliable indicator of corn water stress than, for example, predawn or daytime leaf water potential, at least under the conditions studied here. This reduction in NCER might have a significant impact on total biomass, rooting density, flower and ear formation.Key words: Corn, irrigation scheduling, photosynthesis, leaf water potential, profile available water capacity, soil water content

Effect of Water Stress on Stomatal Conductance and Leaf Water Relations of Leaves Along Current-Year Branches of Peach

1989 ◽  
Vol 16 (6) ◽  
pp. 549 ◽  
Author(s):  
SL Steinberg ◽  
MJ Mcfarland ◽  
JC Miller
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Water Status ◽  
Stomatal Closure ◽  
Water Flux ◽  
Leaf Water ◽  
Leaf Water Status ◽  
Mature Leaves ◽  
Water Potentials

A gradation, that reflects the maturity of the leaves, exists in the leaf water, osmotic and turgor potential and stomatal conductance of leaves along current and 1-year-old branches of peach. Predawn leaf water potentials of immature folded leaves were approximately 0.24 MPa lower than mature leaves under both well-watered and dry conditions. During the daytime the leaf water potential of immature leaves reflected the water potential produced by water flux for transpiration. In well- watered trees, mature and immature unfolded leaves had a solute potential at least 0.5 MPa lower than immature folded leaves, resulting in a turgor potential that was approximately 0.8 MPa higher. The turgor requirement for growth appeared to be much less than that maintained in mature leaves. As water stress developed and leaf water potentials decreased, the osmotic potential of immature folded leaves declined to the level found in mature leaves, thus maintaining turgor. In contrast, mature leaves showed little evidence of turgor maintenance. Stomatal conductance was lower in immature leaves than in fully mature leaves. With the onset of water stress, conductance of mature leaves declined to a level near that of immature leaves. Loss of turgor in mature leaves may be a major factor in early stomatal closure. It was concluded that osmotic adjustment played a role in maintenance of a leaf water status favorable for some growth in water-stressed immature peach leaves.

Divergence in plant water-use strategies in semiarid woody species

2017 ◽  
Vol 44 (11) ◽  
pp. 1134 ◽  
Author(s):  
Rachael H. Nolan ◽  
Kendal A. Fairweather ◽  
Tonantzin Tarin ◽  
Nadia S. Santini ◽  
James Cleverly ◽  
...  
Keyword(s):  
Water Potential ◽  
Leaf Area ◽  
Leaf Water Potential ◽  
Specific Leaf Area ◽  
Osmotic Potential ◽  
Water Status ◽  
Stomatal Closure ◽  
Woody Species ◽  
Leaf Water ◽  
Leaf Water Status

Partitioning of water resources amongst plant species within a single climate envelope is possible if the species differ in key hydraulic traits. We examined 11 bivariate trait relationships across nine woody species found in the Ti-Tree basin of central Australia. We found that species with limited access to soil moisture, evidenced by low pre-dawn leaf water potential, displayed anisohydric behaviour (e.g. large seasonal fluctuations in minimum leaf water potential), had greater sapwood density and lower osmotic potential at full turgor. Osmotic potential at full turgor was positively correlated with the leaf water potential at turgor loss, which was, in turn, positively correlated with the water potential at incipient stomatal closure. We also observed divergent behaviour in two species of Mulga, a complex of closely related Acacia species which range from tall shrubs to low trees and dominate large areas of arid and semiarid Australia. These Mulga species had much lower minimum leaf water potentials and lower specific leaf area compared with the other seven species. Finally, one species, Hakea macrocarpa A.Cunn ex.R.Br., had traits that may allow it to tolerate seasonal dryness (through possession of small specific leaf area and cavitation resistant xylem) despite exhibiting cellular water relations that were similar to groundwater-dependent species. We conclude that traits related to water transport and leaf water status differ across species that experience differences in soil water availability and that this enables a diversity of species to exist in this low rainfall environment.

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