scholarly journals Phenotypic Plasticity of Drought Tolerance Traits in a Widespread Eucalypt (Eucalyptus obliqua)

Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1371
Author(s):  
Carola Pritzkow ◽  
Christopher Szota ◽  
Virginia G. Williamson ◽  
Stefan K. Arndt
Keyword(s):  
Drought Stress ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Morphological Traits ◽  
Leaf Water ◽  
Severe Drought ◽  
Short Term ◽  
Sapwood Area ◽  
Eastern Australia ◽  
Throughfall Reduction

Long-term studies of tree responses to drought stress help us to understand the capacity of species to adapt to their environment. In this study, we investigated how Eucalyptus obliqua adjusts physiological and morphological traits in response to seasonal and multi-year droughts. We monitored physiological and morphological traits over multiple years in undisturbed control and throughfall reduction plots in a eucalypt forest in south-eastern Australia. The throughfall reduction treatment did not induce significantly lower soil moisture in the throughfall reduction plots compared with the control plots. However, natural variability in precipitation and evaporative demand induced drought stress of varying intensity each summer in all plots. We observed a significant relationship between seasonal precipitation and leaf pre-dawn water potential (ΨPD), with less precipitation over summer, resulting in a decline in ΨPD and drought stress when ΨPD fell below −0.75 MPa. Eucalyptus obliqua responded to short-term summer drought through rapid leaf osmotic adjustment which lowered the leaf water potential at the turgor loss point beyond the minimum leaf water potential. Morphological adjustments, such as the reduction of leaf area to sapwood area (higher Huber Value) were moderate during the measurement period and only occurred under severe drought stress (pre-dawn water potential < −1.2 MPa). Overall, E. obliqua responded to short-term mild drought stress through physiological trait plasticity, while morphological adjustment only occurred under a more severe water deficit.

scholarly journals Interactive effects of elevated CO2 and drought stress on leaf water potential and growth in Caragana intermedia

Trees ◽  
2005 ◽  
Vol 19 (6) ◽  
pp. 712-721 ◽  
Author(s):  
Chun-Wang Xiao ◽  
Osbert J. Sun ◽  
Guang-Sheng Zhou ◽  
Jing-Zhu Zhao ◽  
Gang Wu
Keyword(s):  
Drought Stress ◽  
Water Potential ◽  
Elevated Co2 ◽  
Leaf Water Potential ◽  
Leaf Water ◽  
Interactive Effects ◽  
Caragana Intermedia

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.

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.

scholarly journals Impact of Drought Stress on the Accumulation of Capsaicinoids in Capsicum Cultivars with Different Initial Capsaicinoid Levels

HortScience ◽  
2012 ◽  
Vol 47 (9) ◽  
pp. 1204-1209 ◽  
Author(s):  
Paongpetch Phimchan ◽  
Suchila Techawongstien ◽  
Saksit Chanthai ◽  
Paul W. Bosland
Keyword(s):  
Drought Stress ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Leaf Water ◽  
Growth And Yield ◽  
Yield Response ◽  
Hot Pepper ◽  
Environment Interaction ◽  
Relative Water ◽  
Drought Stress Condition

Capsaicinoids are the alkaloids in hot pepper that cause the sensation of heat when eaten and are affected by a genetic and environment interaction. Drought stress is well recognized as an environmental condition that influences capsaicinoid accumulation. This investigation identified the responses of capsaicinoid accumulation in hot pepper cultivars under drought stress condition. A total of nine cultivars with a different initial pungency level, i.e., low, medium, and high, was subjected to gradual drought stress during the flowering stage. Plants in this drought stress group were supplied with reduced water applications of 25%, 50%, and 75% by volume at 10, 20, and 30 days after flowering (DAF), respectively. Leaf water potential and relative water content were recorded to measure the level of drought stress. The results indicated that all cultivars were subjected to drought stress because of their decrease in leaf water potential and changes in physiological characteristics, e.g., growth and yield performance. In addition, leaf area and shoot-to-root ratio were good criteria for identifying hot pepper cultivars under drought stress because their responses were correlated with the stress level and yield components. Yield performances of the high pungency group did not decrease under drought stress, whereas those of the low pungency group did decrease. In conclusion, capsaicinoid levels increased for all cultivars studied when subjected to drought stress, except for the cultivars in the high pungency group. A yield response under drought stress for the medium pungency group varied and was not found to be associated with drought stress.

scholarly journals Leaf Physiological Responses to Drought Stress and Community Assembly in an Asian Savanna

Forests ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1119
Author(s):  
Thuy T. Nguyen ◽  
Stefan K. Arndt ◽  
Patrick J. Baker
Keyword(s):  
Drought Stress ◽  
Southeast Asia ◽  
Water Potential ◽  
Water Relations ◽  
Leaf Water Potential ◽  
Forest Type ◽  
Adaptive Strategies ◽  
Leaf Water ◽  
Turgor Loss Point ◽  
Drought Avoidance

Deciduous dipterocarp forest (DDF) is the most extensive forest type in continental Southeast Asia, but across much of its range is functionally more similar to tropical savannas than tropical forests. We investigated water relations and drought responses of the four dominant tree species (two Shorea and two Dipterocarpus species) of the DDF in central Vietnam to determine how they responded to prolonged periods of drought stress. We quantified leaf water relations in nursery- and field-grown seedlings of the four species and conducted a dry-down experiment on 258 seedlings to study leaf water potential and morphological responses of the seedlings following the drought stress. The two Shorea and two Dipterocarpus species differed significantly in leaf water potential at turgor loss point and osmotic potential at full turgor, but they showed similar responses to drought stress. All species shed leaves and suffered from stem loss when exposed to water potentials lower than their turgor loss point (approximately −1.7 MPa for Dipterocarpus and −2.6 MPa for Shorea species). Upon rewatering, all species resprouted vigorously regardless of the degree of leaf or stem loss, resulting in only 2% whole-plant mortality rate. Our results suggest that none of the four deciduous dipterocarp species is drought tolerant in terms of their water relations; instead, they employ drought-adaptive strategies such as leaf shedding and vigorous resprouting. Given that all species showed similar drought avoidance and drought-adaptive strategies, it is unlikely that seasonal drought directly influences the patterns of species assembly in the DDF of Southeast Asia.

scholarly journals Characteristics of Leaf Water Potential and Photosynthetic Rate of Blueberry Plants Grown Under Drought Stress

2011 ◽  
Vol 10 (4) ◽  
pp. 485-490 ◽  
Author(s):  
Naomi Horiuchi ◽  
Naoko Kameari ◽  
Jingai Che ◽  
Sakae Suzuki ◽  
Tadashi Hirasawa ◽  
...  
Keyword(s):  
Drought Stress ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Photosynthetic Rate ◽  
Leaf Water

An Analysis of the Effects of Repeated Short-Term Soil Water Deficits on Stomatal Conductance to Carbon Dioxide and Leaf Photosynthesis by the Legume Macroptilium atropurpureum Cv. Siratro

1981 ◽  
Vol 8 (3) ◽  
pp. 347 ◽  
Author(s):  
MJ Fisher ◽  
DA Charles-Edwards ◽  
MM Ludlow
Keyword(s):  
Stomatal Conductance ◽  
Water Potential ◽  
Soil Water ◽  
Water Deficit ◽  
Leaf Water Potential ◽  
Leaf Water ◽  
Mathematical Function ◽  
Leaf Photosynthesis ◽  
Short Term ◽  
Macroptilium Atropurpureum

The response was measured of stomatal conductance and leaf photosynthesis to changing leaf water potential in the legume siratro subjected to a sequence of I-week cycles of increasing soil water deficit followed by watering. The response of stomatal conductance was described using a continuous mathematical function, which is more robust and accurate than the usual discontinuous linear function used to analyse such data. After seven successive cycles of water deficit, there was no apparent adjustment of the short-term response of leaf conductance to leaf water potential.

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