WATER EXTRACTION PATTERNS AND DEVELOPMENT OF PLANT WATER DEFICITS IN CORN

1985 ◽  
Vol 65 (4) ◽  
pp. 921-933 ◽  
Author(s):  
L. M. DWYER ◽  
D. W. STEWART
Keyword(s):  
Zea Mays ◽  
Water Stress ◽  
Water Potential ◽  
Water Content ◽  
Soil Water ◽  
Leaf Area ◽  
Water Use ◽  
Zea Mays L ◽  
Leaf Water ◽  
Plant Water

Water extraction patterns and plant water deficits for corn (Zea mays L.) were measured and related to development of aboveground biomass, leaf area and root density under different irrigation schedules in controlled chambers. A multi-layer transpiration model, based on an Ohm’s Law analogy, simulated the water uptake processes and predicted leaf water potential and soil water content through time. Comparison of measurements and model predictions of plant and soil water status tested our understanding of the principles involved in plant water use which resulted in growth differences. The experiment involved 48 planted cylinders plus controls; half were well-watered and maintained at or above field capacity and half were allowed to dry to near the wilting point. Over 6 wk, water stress reduced above-ground biomass and leaf area, but enhanced root growth over that of well-watered plants. This reflected the preferential allocation of photosynthate to the root when soil water became limiting. Measured leaf water potentials fell below the level for stomatal closure of the chamber population. The model also predicted a degree of water stress (midday leaf water potential of −1.48 MPa) that would increase stomatal resistance and restrict transpiration and photosynthesis. Measurements and predictions of soil water content over time were generally in good agreement. The model is therefore considered useful in describing water use patterns under controlled conditions.Key words: Zea mays L., transpiration, water use modelling, plant water stress, dry matter partitioning

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

Influence of Water Stress on Water Relations and Growth of a Tropical (C4) Grass, Panicum maximum var. trichoglume

1975 ◽  
Vol 2 (4) ◽  
pp. 581 ◽  
Author(s):  
TT Ng ◽  
JR Wilson ◽  
MM Ludlow
Keyword(s):  
Growth Rate ◽  
Water Stress ◽  
Water Potential ◽  
Water Content ◽  
Soil Water ◽  
Leaf Area ◽  
Soil Water Content ◽  
Relative Growth Rate ◽  
Leaf Water ◽  
Relative Growth

The effects of recurring cycles of short-term water stress on the water relations and growth of P. maximum var. trichoglume in pots of soil were investigated under controlled conditions. As soil water content decreased there was an increase in the resistance to water movement in the soil-plant system. Leaf stomatal resistance increased and concomitantly transpiration rate decreased when soil water content fell below 37 % (soil water potential of - 1 .0 bars) and leaf water potentials were less than - 6 bars. The leaf water potential at wilting (- 8 to - 10 bars) and the relation between leaf water potential and relative water content changed with leaf position on the tiller. The death of early-formed leaves on the plants was accelerated by water stress but, in contrast, the later-formed leaves died more rapidly in the control (unstressed) treatment so that finally the control plants had a higher proportion of dead leaves. Plant growth was reduced at soil water contents above the permanent wilting point. Reduction in net assimilation rate was the main determinant of lower relative growth rate of stressed plants over the initial cycles of stress but subsequently, as leaf area expansion was reduced, leaf area ratio also had a significant influence. Water stress influenced growth directly, and also indirectly via its effect on plant development (ontogeny). Two techniques were used to separate the direct from the indirect effects on relative growth rate Some published data which suggest a stimulation of growth rate after the relief of stress are re-interpreted and the effect is shown to be due mainly to differences in ontogeny between stressed and control treatments

scholarly journals The importance of cuticular permeance in assessing plant water–use strategies

2020 ◽  
Vol 40 (4) ◽  
pp. 425-432
Author(s):  
Matthew Lanning ◽  
Lixin Wang ◽  
Kimberly A Novick
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Water Use ◽  
Leaf Water Potential ◽  
Stress Responses ◽  
Leaf Water ◽  
Plant Water ◽  
Stomatal Control ◽  
Plant Water Use ◽  
The Impact

Abstract Accurate understanding of plant responses to water stress is increasingly important for quantification of ecosystem carbon and water cycling under future climates. Plant water-use strategies can be characterized across a spectrum of water stress responses, from tight stomatal control (isohydric) to distinctly less stomatal control (anisohydric). A recent and popular classification method of plant water-use strategies utilizes the regression slope of predawn and midday leaf water potentials, σ, to reflect the coupling of soil water availability (predawn leaf water potential) and stomatal dynamics (daily decline in leaf water potential). This type of classification is important in predicting ecosystem drought response and resiliency. However, it fails to explain the relative stomatal responses to drought of Acer sacharrum and Quercus alba, improperly ranking them on the spectrum of isohydricity. We argue this inconsistency may be in part due to the cuticular conductance of different species. We used empirical and modeling evidence to show that plants with more permeable cuticles are more often classified as anisohydric; the σ values of those species were very well correlated with measured cuticular permeance. Furthermore, we found that midday leaf water potential in species with more permeable cuticles would continue to decrease as soils become drier, but not in those with less permeable cuticles. We devised a diagnostic parameter, Γ, to identify circumstances where the impact of cuticular conductance could cause species misclassification. The results suggest that cuticular conductance needs to be considered to better understand plant water-use strategies and to accurately predict forest responses to water stress under future climate scenarios.

scholarly journals Rootstock Genotypes Shape the Response of cv. Pinot gris to Water Deficit

Agronomy ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 75
Author(s):  
Michele Faralli ◽  
Pier Lugi Bianchedi ◽  
Massimo Bertamini ◽  
Claudio Varotto
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Leaf Area ◽  
Water Use ◽  
Leaf Water Potential ◽  
Water Availability ◽  
Leaf Water ◽  
Daily Water ◽  
Shallow Soils ◽  
Reduced Water

Understanding the physiological basis underlying the water stress responses in grapevine is becoming increasingly topical owing to the challenges that climate change will impose to grapevine agriculture. Here we used cv. Pinot gris (clone H1), grafted on a series of tolerant (1103Paulsen; P), sensitive (SO4) and recently selected (Georgikon28; G28, Georgikon121; G121, Zamor17; Z17) rootstocks. Plants were either subjected to reduced water availability (WS) or maintained at pot capacity (WW). Photosynthetic (light response curves), stomatal and in vivo gas exchange analysis were carried out as well as dynamics of daily water use (WU), leaf area accumulation with affordable RGB imaging pipelines and leaf water potential. Significant genotypic variation was recorded between rootstocks for most of the traits analyzed under optimal conditions with P and SO4 showing a more vigorous growth, higher CO2 assimilation rate, stomatal conductance and stomatal density per unit of leaf area than G28, G121, Z17 (p < 0.001). Under WS, rootstocks induced different water stress response in Pinot gris, with G28 and G121 showing a higher sensitivity of water use to reduced water availability (WS) (p = 0.021) and no variation for midday leaf water potential until severe WS. P, Z17 and to some extent SO4 induced a pronounced near-anisohydric response with a general WU maintenance followed by reduction in leaf water potential even at high levels of soil water content. In addition, G28 and G121 showed a less marked slope in the linear relationship between daily water use and VPD (p = 0.008) suggesting elevated sensitivity of transpiration to evaporative demand. This led to an insensitivity for total dry weight biomass of G28 and G121 under WS conditions (p < 0.001). This work provides: (i) an in-depth analysis for a series of preferable traits under WS in Pinot gris; (ii) a characterization of Pinot gris × rootstock interaction and a series of desirable traits under WS induced by several rootstocks; (iii) the potential benefit for the use a series of affordable methods (e.g., RGB imaging) to easily detect dynamic changes in biomass in grapevine and quickly phenotype genotypes with superior responses under WS. In conclusion, the near-isohydric and conservative behavior observed for G28 and G121 coupled with their low vigor suggest them as potential Pinot gris rootstock candidates for sustaining grapevine productivity in shallow soils likely to develop terminal stress conditions.

Plant Water Relation and Drought: Relationship Between Plant Water Potential and Relative Leaf Water Content in Different Tropical Plants

2020 ◽  
Author(s):  
Sydney Kerman ◽  
Kinzie Bailey ◽  
Joost van Haren ◽  
Angelika Kübert ◽  
Kathrin Kühnhammer ◽  
...  
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Water Content ◽  
Negative Relationship ◽  
Leaf Water ◽  
Leaf Water Content ◽  
Plant Water ◽  
Long Term Effects ◽  
Tropical Plants ◽  
Plant Water Potential

&lt;p&gt;As global average temperature continues to increase and precipitation events become less predictable, understanding the long-term effects of drought on ecosystems is of increasing importance. However, it is difficult to study phenomena such as drought due to their unpredictable nature and the fact that it is difficult to tag and track the movement of water and carbon through an entire ecosystem. Within the framework of the controlled ecosystem manipulation experiment (WALD- Water, Atmosphere and Life Dynamics) at Biosphere 2, a deliberate drought in the enclosed tropical rainforest biome presented a unique opportunity to study responses in carbon and water cycling due to water stress. Within the scope of this study, the goal of this project was to examine the effect of prolonged water stress on different species within the rainforest and understand how the plants coped with the stress on an ecosystem level. This was accomplished by weekly plant water potential measurements (WP) before, during, and after the drought, as well as leaf sampling for relative leaf water content (RWC) and xylem sampling for water isotope measurements. For both predawn and midday WP, we found significantly different species responses; for &lt;em&gt;Ceiba pentandra&lt;/em&gt; and &lt;em&gt;Pachira aquatica&lt;/em&gt;, WP did not decrease during the drought, while for&lt;em&gt; Hibiscus tiliaceus&lt;/em&gt; and &lt;em&gt;Hibiscus rosa sinensis&lt;/em&gt;, WP decreased dramatically during the drought. After the additional of moisture from deeper depths, both &lt;em&gt;C. pentandra&lt;/em&gt; and &lt;em&gt;Hura crepitans&lt;/em&gt; (largest trees) responded the fastest by increasing in WP, while &lt;em&gt;H. tiliaceus&lt;/em&gt; and &lt;em&gt;H. rosa sinensis&lt;/em&gt; had the slowest recovery in WP, and only after rewetting from above had occurred. RWC also revealed different responses by different plant species, with &lt;em&gt;Phytolacca dioica&lt;/em&gt; and &lt;em&gt;H. rosa sinensis&lt;/em&gt; showing the highest RWC values throughout the experiment. The relationship between RWC and WP was also not consistent among species, with half of the species exhibiting a positive relationship, while the other half exhibiting a negative relationship. Other factors such as trunk capacitance and or leaf shedding during the drought might explain some of these contrasting relationships. Establishing such associations could lead to the development of tools that remotely assess average leaf water content of an area of forest via spectral reflectance and use those data to approximate the water stress of plants in that area, a very valuable asset when dealing with such geographically extensive phenomena as drought.&amp;#160;&lt;/p&gt;

Water Relations in Cowpea and Pearl Millet Under Soil Water Deficits. II. Water Use and Root Distribution

1992 ◽  
Vol 19 (6) ◽  
pp. 591 ◽  
Author(s):  
CL Petrie ◽  
AE Hall
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Soil Water ◽  
Pearl Millet ◽  
Water Use ◽  
Root Length ◽  
Root Distribution ◽  
Root Length Density ◽  
Leaf Water ◽  
Predawn Leaf Water Potential

Pearl millet [Pennisetum americanum (L.) Leeke] develops lower predawn leaf water potentials than cowpea [Vigna unguiculata (L.) Walp.] when plants are subjected to progressive soil dehydration. Water use and root distribution were studied as possible explanations for this difference using plants grown in pots and in tubes in a glasshouse. In experiments grown in pots, weights of each container were measured daily after initiation of the dry treatment to determine water use, and roots and soil were sampled at the end of the experiment to determine root length density and soil water content. In experiments conducted in 1 m long tubes, plants were grown in either Turface Plus or a Turface Plus/sand mixture which had a high water-holding capacity and could be easily separated from roots. Roots and rooting medium were sampled during the dry treatment. Water content and root length density in the same sample were measured, and root distributions at various depths were determined. Pearl millet (millet) did not use more bulk water than cowpea by the time the difference in predawn leaf water potential developed. Millet root length density was at least twice as great as cowpea, and the decline in predawn leaf water potential was greater in millet, even when its root system was more extensive than that of cowpea.

INDICATORS OF WATER STRESS IN CORN (Zea mays L.)

1984 ◽  
Vol 64 (3) ◽  
pp. 537-546 ◽  
Author(s):  
L. M. DWYER ◽  
D. W. STEWART
Keyword(s):  
Zea Mays ◽  
Water Stress ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Zea Mays L ◽  
Stomatal Resistance ◽  
Leaf Water ◽  
Predawn Leaf Water Potential ◽  
Diurnal Patterns ◽  
Potential Transpiration

Greenhouse experiments were conducted to monitor the response of corn (Zea mays L.) to water stress conditions during and following tasselling, and to compare several indicators of water stress. Daily measurements of soil water content and of evaporative demand were made. The degree of plant water stress was indicated by estimates of minimum daily stomatal resistance, comparison of estimated actual and potential transpiration rates, diurnal patterns of leaf water potential and predawn leaf water potentials taken on lower leaves. Analysis of the series of measurements necessary to estimate minimum daily stomatal resistance, actual to potential transpiration rate ratios, and diurnal patterns of leaf water potential identified periods of relative water stress. The simpler and less time-consuming measurement of predawn leaf water potential compared favorably with these other indicators of water stress. We therefore suggest that predawn leaf water potential is an appropriate diagnostic measurement of water stress with promise for irrigation scheduling, particularly for crops in which irrigation is important for a short but critical period.Key words: Leaf water potential, stomatal resistance, transpiration, vapor pressure deficit, soil water deficit

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