Water stress and phenology in wheat

1977 ◽  
Vol 28 (2) ◽  
pp. 177 ◽  
Author(s):  
JF Angus ◽  
MW Moncur
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Soil Water ◽  
Leaf Water Potential ◽  
Leaf Water ◽  
Mild Stress ◽  
Floral Initiation ◽  
Severe Stress ◽  
Development Models ◽  
Crop Development

Single wheat plants (cv. Gabo) were sown in tall pots and top-watered so that growth proceeded without stress until the time of floral initiation. Having reached this stage, plants encountered increasing stress as soil water was depleted. At intervals after the dawn leaf water potential, ψ1, had reached values of –5, –10, –15 bars etc., the stress was relieved with water sufficient for unstressed development until anthesis. The anthesis dates of plants which had encountered mild stress (ψ1 down to about ndash;15 bars) were ahead of the well-watered control, while those which had encountered more severe stress (ψ1 from about ndash;25 to ndash;40 bars) flowered after the controls. The results are discussed in relation to the possibilities of including the effects of stress in crop development models.

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

scholarly journals COMPARATIVE DROUGHT RESISTANCE AMONG SIX BIRCH (BETULA) SPECIES

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1143f-1143
Author(s):  
Thomas G. Ranney ◽  
R.E. Bir ◽  
W.A. Skroch
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Water Relations ◽  
Leaf Water Potential ◽  
Leaf Gas Exchange ◽  
Leaf Water ◽  
Mild Stress ◽  
Turgor Loss Point ◽  
Leaf Osmotic Potential ◽  
Response To Water

In order to evaluate and compare adaptability to dry sites, plant water relations and leaf gas exchange were compared in response to water stress among six birch species: monarch birch (Betula maximowicziana), river birch (B. nigra), paper birch (B. papyrifera), European birch (B. pendula), `Whitespire' Japanese birch (B. platyphylla var. japonica `Whitespire'), and gray birch (B. pendula). After 28 days without irrigation, Japanese birch maintained significantly higher stomatal conductance (gs) and net photosynthesis (Pn) than did any of the other species, despite having one of the lowest mid-day water potentials. Evaluation of tissue water relations, using pressure-volume methodology, showed no evidence of osmotic adjustment for any of these species in response to water stress. However, there was substantial variation among species in the water potential at the turgor loss point; varying from a high of -1.34 MPa for river birch to a low of -1.78 MPa for Japanese birch. Rates of Pn and gs under mild stress (mean predawn leaf water potential of -0.61 MPa) were negatively correlated with leaf osmotic potential at full turgor and the leaf water potential at the turgor loss point.

Effects of severity and repetition of water stress on seed production of Macroptilium atropurpureum cv. Siratro

1987 ◽  
Vol 38 (3) ◽  
pp. 529 ◽  
Author(s):  
L Kowithayakorn ◽  
LR Humphreys
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Seed Production ◽  
Leaf Water Potential ◽  
Leaf Water ◽  
Severe Stress ◽  
Constant Height ◽  
Young Leaves ◽  
Macroptilium Atropurpureum ◽  
Leaf Differentiation

Macroptilium atropurpureum cv. Siratro was grown in large soil beds in a glasshouse with a water table at constant height below. Water stresses of dawn leaf water potential of - 1.0 MPa (medium stress) or of - 1.5 MPa (severe stress) were developed over 14 or 28 days, either singly or repeated after 42 days of rewatering. These stresses caused some death of terminal shoots and abscission of old leaves, but rapid rates of leaf differentiation restored leaf density to the levels of the control plants upon rewatering. A subsidiary experiment showed lower levels of leaf water potential in young leaves near the apex than in leaves subtending inflorescences.Persistent increases in the rate of floral bud appearance occurred upon rewatering, but the ratio of floral buds surviving to form an inflorescence with flowers was reduced both during and after the imposition of stress. A single cycle of medium stress increased seed yield 36% relative to the control plants, due to increased inflorescence and flower density. Repetition of water stress after 42 days was disadvantageous, and the effects of longer intervals between stress merit investigation. Severe stress of - 1.5 MPa was not beneficial to seed production.

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.

Effects of water stress and soil type on photosynthesis, leaf water potential and yield of olive trees (Olea europaea L. cv. Chemlali Sfax)

2007 ◽  
Vol 47 (12) ◽  
pp. 1484 ◽  
Author(s):  
B. Ben Rouina ◽  
A. Trigui ◽  
R. d'Andria ◽  
M. Boukhris ◽  
M. Chaïeb
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Sandy Soil ◽  
Clay Soil ◽  
Sandy Loam ◽  
Leaf Water ◽  
Severe Drought ◽  
Relative Water ◽  
Olive Trees

In Tunisia, olives are grown under severe rain-fed, arid conditions. To determine the behaviour of olive trees (cv. Chemlali Sfax) during the severe drought affecting Tunisian arid areas in 2002, a range of physiological parameters were investigated in three adjacent orchards. Two olive orchards were rain-fed, one located on a sandy soil, and the other on a sandy-loam clay soil. A third orchard was also located on sandy soil, but received remedial irrigation (415 mm of water per year; ~40% of olive evapotranspiration). Predawn leaf water potential (Ψpd) did not fall below –1.52 MPa for irrigated olive trees. However, a large decrease in Ψpd was observed for rain-fed olive trees in the same period with Ψpd measured at about –3.2 MPa on sandy soil and –3.6 MPa on sandy-loam clay soil. At the same time, the minimal leaf water potential recorded at midday (Ψmin) decreased to –4.15 MPa and –4.71 MPa in the rain-fed trees for sandy and sandy-loam clay soil, respectively. For irrigated trees, the Ψmin was –1.95 MPa. These results were associated with relative water content, which varied from 80% for irrigated trees to 54 and 43.6%, respectively, for rain-fed trees and trees subjected to severe drought. In August, when the relative water content values were less than 50%, a progressive desiccation in the outer layer of canopy and death of terminal shoots were observed in trees, which grew on the sandy-loam clay soil. Furthermore, low soil water availability also affected (negatively) the net photosynthetic rate in rain-fed orchards (10.3 µmol/m2.s for irrigated trees v. 5.3 µmol/m2.s in rain-fed trees on sandy soil) and stomatal conductance (98.5 mmol/m2.s v. 69.3 mmol/m2.s). However, it improved water use efficiency (7.6 v. 4.7 µmol CO2/mmol H2O), which increased by more than 50% in both groups of rain-fed trees compared with the irrigated ones. We can conclude that olive trees respond to drought by showing significant changes in their physiological and biological mechanisms. These results also help our understanding of how olive trees cope with water stress in the field and how marginal soils can restrict growth and lower yields.

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