scholarly journals Effect of Early Water Deficits on Nodulation and Nitrogen Content of Inoculated Soybean

2018 ◽  
Vol 20 (2) ◽  
pp. 11-16
Author(s):  
JA Adjetey ◽  
BNG Nxumalo
Keyword(s):  
Water Stress ◽  
Dry Mass ◽  
Growth Stages ◽  
Mild Stress ◽  
Severe Stress ◽  
Production Potential ◽  
Severe Water Stress ◽  
Kwazulu Natal ◽  
The University ◽  
Mild Water Stress

The study was conducted at the University of KwaZulu-Natal (29o37’ S, 30o23’ E) from May to November 2012 under controlled environment conditions with three water regimes namely: well watered controls, mild water stress to -1.4 MPa and severe water stress to -2.0 MPa, at the V4 (28 DAS) and V5 stages (35 DAS). Severe stress significantly reduced no. of nodule and root mass, leaf area, shoot dry mass and uptake, regardless of the stage. Mild stress on the other hand had little effect on this parameter as plants recovered on re-watering, to attain values similar to the control treatments. The V4 and V5 stages can recover from mild stress, but severe stress at both growth stages reduces nodulation and nitrogen uptake and this can lead to reduction in production potential of soybean.Bangladesh Agron. J. 2017, 20(2): 11-16

SENSITIVITY OF CROP PLANTS TO WATER STRESS AT SPECIFIC DEVELOPMENTAL STAGES: REEVALUATION OF EXPERIMENTAL FINDINGS

1995 ◽  
Vol 43 (2) ◽  
pp. 99-111 ◽  
Author(s):  
Zvi Plaut
Keyword(s):  
Water Stress ◽  
Irrigation Water ◽  
Field Experiments ◽  
Developmental Stages ◽  
Growth Period ◽  
Soluble Solids ◽  
Growth Stages ◽  
Mild Stress ◽  
Uniform Reduction ◽  
Different Growth Stages

It has been suggested that in many crops differences in sensitivity to water stress occur at different growth stages. Since identical amounts of water may be applied, irrespective of whether a crop is exposed to relatively severe and short periods of stress or to extended periods of mild stress, the responses to such differing conditions should be compared. Unfortunately, such a comparison has not been conducted in most studies on sensitivity to water stress at different growth stages. In the present study, based on three field experiments conducted for different purposes, such a comparison was made for three crops: corn, sunflower, and tomato. In corn, distinct responses of ear and kernel yields to the timing of water stress were found. Withdrawal of irrigation water during flowering and cob formation resulted in greater yield losses than during other stages, indicating that this is a critical growth stage. However, slight and uniform reduction of water during the entire growth period resulted in significantly less damage to kernel or ear production, although the total amount of water applied was similar to that under staged withdrawal. In sunflowers, the withdrawal of irrigation water even at noncritical growth stages caused a more marked reduction in grain yield than did a uniform reduction throughout the entire season. In tomatoes, on the other hand, the withdrawal of irrigation water during specific growth stages caused minimal damage to fruit and total soluble solids yield as compared with fully irrigated control; reduction of irrigation water throughout the season brought about a significant decrease in yield. The difference between these crops is interpreted on the basis of the determinance of their floral meristems.

Effects of water stress on photosynthesis，growth and yield in winter wheat

2020 ◽  
Author(s):  
Wenhui Zhao ◽  
Jianjun Wu ◽  
Leizhen Liu ◽  
Jianhua Yang ◽  
Xinyi Han ◽  
...  
Keyword(s):  
Water Stress ◽  
Winter Wheat ◽  
Aboveground Biomass ◽  
Field Capacity ◽  
Grain Weight ◽  
Growth And Yield ◽  
Mild Stress ◽  
Severe Stress ◽  
Fresh Weight ◽  
Water Field

<p>Drought has become one of the major constraints on agricultural development, particularly in areas lacking water. By studying the effects of different water stresses on photosynthesis, growth, yield, water use efficiency (WUE) and other indicators of winter wheat, this study provides scientific irrigation strategies for developing water-saving agriculture. According to the size of the water field capacity, four different water stress levels were set, i.e., 30–40% water field capacity (severe stress), 40–50% (moderate stress), 50–60% (mild stress) and 60–80% (well-watered irrigation), through an automatic irrigation system to create different water stress gradients by controlling the irrigation amount. The results showed that the diurnal and seasonal changes in photosynthetic parameters such as net photosynthetic rate (Pn), intercellular carbon concentration (Ci), stomatal conductance (Gs), and transpiration (E) significantly decreased with water stress intensification. The Pn of mild stress only slightly decreased compared to that of well-watered irrigation and was even higher than after May 16th, resulting in an increase in the dry biomass and 1000-grain weight under mild stress. Under all water stresses, the heights and stem weights of the winter wheat significantly decreased. Moderate and severe stress also significantly reduced the fresh weight of the aboveground biomass, dry weight, spike weight, grain weight, WUE and irrigation water productivity (IWP), while mild stress only slightly decreased the fresh weight of aboveground biomass, spike weight and grain weight. Mild stress increased the WUE and IWP. Thus, mild stress results in the optimal use of water resources without a significant reduction in yield. Therefore, mild stress can be considered as a suitable environment for winter wheat growth in arid areas.</p>

scholarly journals Macadamia responses to mild water stress at different phenological stages

2003 ◽  
Vol 54 (1) ◽  
pp. 67 ◽  
Author(s):  
R. A. Stephenson ◽  
E. C. Gallagher ◽  
V. J. Doogan
Keyword(s):  
Water Stress ◽  
High Stress ◽  
Management Tool ◽  
Mild Stress ◽  
Floral Initiation ◽  
Xylem Water Potential ◽  
Phenological Stages ◽  
Oil Accumulation ◽  
Yield And Quality ◽  
Mild Water Stress

Mild water stress was imposed on bearing macadamia trees in through-draining lysimeters at various phenological stages. Water was withheld until a xylem water potential (Ψx) of –1.5 to 2.0 MPa was reached, this being maintained by partial water replenishment at 2-day intervals. Flowering, nut set, nut development, yield, and quality responses were assessed to identify critical, stress-sensitive stages. Stress during nut maturation was particularly detrimental to both yield and quality, although stress during floral development and the premature nut drop also had adverse effects. Low yields were due to reduced nut number and smaller nuts. Lower photosynthesis (c. 2 μmol CO2/m2.s) at –1.5 MPa would account for reduced yield and poorer quality during nut maturation when energy demands of active oil accumulation are high. Stress at floral initiation was generally not detrimental.Overall, stress restricted growth. The rate of girth growth was significantly lower when stress was applied during the dormant floral initiation stage. When stress coincided with normal periods of vegetative growth, flushing was delayed until after re-watering when greater foliage production was stimulated. Judiciously imposing mild stress may be used to manipulate macadamia phenology, although it may not necessarily conserve water. Further refinement would be needed to develop stress manipulation as a practical and reliable management tool to achieve higher yields. Water should be applied to alleviate stress during critical stages of nut development and maturation. Mild stress after the current crop is mature, however, is unlikely to be detrimental to macadamia yield or quality. It may, in fact, be beneficial through manipulation of flushing patterns that influence yield.

ROOT CHARACTERISTICS IN COWPEA RELATED TO DROUGHT TOLERANCE AT THE SEEDLING STAGE

2003 ◽  
Vol 39 (1) ◽  
pp. 29-38 ◽  
Author(s):  
T. MATSUI ◽  
B. B. SINGH
Keyword(s):  
Water Stress ◽  
Drought Tolerance ◽  
Leaf Area ◽  
Dry Matter ◽  
Stress Conditions ◽  
Root Characteristics ◽  
Severe Water Stress ◽  
Cowpea Varieties ◽  
Root Box ◽  
Mild Water Stress

Cowpea (Vigna unguiculata) has relatively higher drought tolerance than other legume crops. It is widely grown in semi-arid regions, particularly in West Africa. One objective of the present study was to determine the effects of soil moisture stress on the length, dry matter and distribution of the roots of two cowpea varieties with different drought tolerances. Another objective was to evaluate the pin-board root-box as a method for identifying the role of root characteristics in drought tolerance. Two cowpea varieties, IT96D-604 (drought tolerant) and TVu7778 (drought susceptible), were used in this study. There were three watering treatments, T1 (well-watered), T2 (mild water stress) and T3 (severe water stress). Between varieties, there were no significant differences in shoot and root characteristics except for leaf area in T1. Under T2, the shoot:root ratio (S:R ratio) of IT96D-604 was significantly decreased compared with that under T1 as a result of the increase in root dry matter and decrease in leaf area without significant differences in total dry matter. In addition, the root dry matter per leaf area, which indicates the capacity to absorb water, of IT96D-604 was significantly higher than that of TVu7778. Under T3, the total dry matter of TVu7778 was about one third of those of the other treatments for the same variety, whereas that of IT96D-604 was more than half. Regarding root distribution, the centres of root dry matter and root length density of both varieties moved downwards significantly under water-stress conditions compared with those of the well-watered condition. This tendency was more pronounced in IT96D-604 than in TVu7778. Drought tolerance in IT96D-604 was associated with the increase in root dry matter per leaf area under mild water-stress conditions, and downward movement of roots (increasing access and use of soil moisture in deep soil layers) under mild and severe water stress conditions. In addition, the root-box method was versatile and can be used for studying root responses to edaphic factors relevant to root growth.

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.

scholarly journals Morphological responses of a high yielding groundnut cultivar (Arachis hypogaea L. cv. K-134 ) under water stress

2014 ◽  
Vol 2 (01) ◽  
pp. 35-38
Author(s):  
K. V. Madhusudhan ◽  
C. Sudhakar
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Arachis Hypogaea ◽  
Shoot Growth ◽  
Significant Inhibition ◽  
Mild Stress ◽  
Severe Stress ◽  
Arachis Hypogaea L ◽  
Morphological Responses ◽  
Moderate Stress

The present study was undertaken to ascertain the morphological responses of a groundnut cultivar K-134, under different water stress regimes characterized as control, mild, moderate and severe stress represented by 100, 75, 50 and 25% soil moisture levels respectively for eight days. Root length increased over control at mild, moderate stress treatments and inhibited at severe stress conditions on all days of sampling. Severe stress treatments had caused significant inhibition in shoot growth on day-4 and 8. The fresh and dry weights of roots and leaves and leaf area decreased over control in all stress treatments except under mild stress on day-4. The changes in theses parameters were dependent on stress severity and duration.

Responses to water stress of enzyme activities and metabolite levels in relation to sucrose and starch synthesis, the Calvin cycle and the C4 pathway in sugarcane (Saccharum sp.) leaves

1998 ◽  
Vol 25 (2) ◽  
pp. 253 ◽  
Author(s):  
Y.-C. Du ◽  
A. Nose ◽  
K. Wasano ◽  
Y. Uchida
Keyword(s):  
Water Stress ◽  
Enzyme Activities ◽  
Stomatal Closure ◽  
Starch Synthesis ◽  
Calvin Cycle ◽  
Severe Water Stress ◽  
C4 Pathway ◽  
Saccharum Sp ◽  
Almost All ◽  
Mild Water Stress

During a slowly induced water stress, almost all measured activities of enzymes, including the important enzymes associated with the Calvin cycle, the C4 pathway, and sucrose and starch synthesis, and the pool sizes of metabolites, including hexose phosphates, 3-phosphoglycerate, triose phosphates, malate, pyruvate and PEP, in leaves of sugarcane (Saccharum sp. cv. NiF4) were not or only moderately reduced by mild water stress (above –0.9 MPa leaf water potential (Ψw)), and the magnitudes of reductions in those parameters were less than the reductions in photosynthetic rates. We conclude that the biochemical processes of sucrose and starch synthesis, the Calvin cycle and the C4 pathway in sugarcane leaves were not seriously affected by mild water stress, and the changes in those processes were not the cause for the decline in photosynthesis; mild water stress induced decline in photosynthesis is caused by stomatal closure. Under severe water stress (–1.2 MPa leaf Ψw), most metabolite levels and enzyme activities decreased significantly compared with those under mild water stress. But the enzyme activities and metabolite levels relating to sucrose and starch synthesis, and the Calvin cycle still remained at high levels compared with the corresponding photosynthetic rate. PPDK activity and pyruvate content decreased to very low levels. It is suggested that PPDK is a possible limiting enzyme for photosynthesis in leaves of sugarcane under severe water stress.

scholarly journals Effects of Water Stress on Photosynthesis, Yield, and Water Use Efficiency in Winter Wheat

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2127 ◽  
Author(s):  
Wenhui Zhao ◽  
Leizhen Liu ◽  
Qiu Shen ◽  
Jianhua Yang ◽  
Xinyi Han ◽  
...  
Keyword(s):  
Water Stress ◽  
Winter Wheat ◽  
Water Use Efficiency ◽  
Water Use ◽  
Water Productivity ◽  
Photosynthetic Parameters ◽  
Mild Stress ◽  
Severe Stress ◽  
Water Capacity ◽  
Use Efficiency

Drought has become one of the major constraints to agricultural development, particularly in areas that lack water. Studying the effects of different water stresses on the photosynthesis, growth, yield, water use efficiency (WUE) and irrigation water productivity (IWP) of winter wheat will provide data for the development of scientific irrigation strategies for water-saving agricultural methods. According to the size of the field water capacity, four different water stress levels were set, i.e., 30–40% (severe stress), 40–50% (moderate stress), 50–60% (mild stress) and 60–80% (well-watered) of field water capacity, controlling the amount of irrigation through an automatic irrigation system. The results showed that the seasonal changes in photosynthetic parameters, such as net photosynthetic rate (Pn), intercellular carbon concentration (Ci), stomatal conductance (Gs) and transpiration (E), significantly decreased under moderate and severe stress. As a result, the height, biomass and grain size of winter wheat decreased significantly, which led to low WUE and IWP. The Pn of the mild stress group only slightly decreased compared to that of the well-watered group, and was actually higher during the flowering and grain-filling stages, resulting in increases in dry biomass and 1000 grain weight of 2.07% and 1.95%, respectively. Higher WUE and IWP were attributed to higher yields and less water use. Thus, mild stress (60–80% field water capacity) resulted in the optimal use of water resources without a significant reduction in yield in the North China Plain (NCP). Therefore, mild stress can be considered a suitable environment for winter wheat growth in arid areas.

Effect of water stress on dry mass accumulation and allocation in sweet potato based on stable isotope analysis

2015 ◽  
Vol 95 (2) ◽  
pp. 263-271 ◽  
Author(s):  
Hui Zhang ◽  
Lvdan Zhu ◽  
Congzhi Zhang ◽  
Yunwang Ning ◽  
Yongchun Zhang
Keyword(s):  
Water Stress ◽  
Sweet Potato ◽  
Photosynthetic Rate ◽  
Isotope Composition ◽  
Stable Carbon Isotope ◽  
Dry Mass ◽  
Growth Stages ◽  
Rubisco Activity ◽  
Effect Of Water ◽  
Mass Accumulation

Zhang, H., Zhu, L., Zhang, C., Ning, Y. and Zhang, Y. 2015. Effect of water stress on dry mass accumulation and allocation in sweet potato based on stable isotope analysis. Can. J. Plant Sci. 95: 263–271. Pot experiments were conducted to study the effect of water stress on the dry mass accumulation, allocation, ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) activity and stable carbon isotope composition in sweet potato (Ipomoea batatas L.). Three water regimes (50, 75 and 100% field water capacity, respectively) were investigated. Water stress effects on dry mass accumulation, allocation, gas exchange, stable carbon isotope composition and Rubisco enzyme activity were detected in sweet potato at different stages (seedling, vegetative, early maturity, and late maturity). In addition, relationships between Rubisco activity and photosynthetic rate, dry stress allocation and Δ13C under different water regimes were explored. The allocation of dry mass and Δ13C in leaves, petioles, stems and roots exhibited highest level in soil with 100% moisture content at different growth stages. The photosynthetic rate, transpiration, stomatal conductance, and RuBisCo activity of sweet potato at different growth stages also increased with increasing soil water content. The regression equations between the activity of RuBisCo and photosynthetic rate in 50, 75 and 100% field capacity were y=0.675x – 1.846, y=0.798x − 1.370, and y=0.516x+3.887. A positive correlation between dry mass allocation and Δ13C was observed. Water stress could affect dry mass accumulation, allocation, gas exchange, RuBisCo activity, and Δ13C content in sweet potato organs during plant development stages.

Effet d’un assèchement édaphique sur la croissance, l’allocation de biomasse et les relations hydriques chez Casuarina glauca

Botany ◽  
2008 ◽  
Vol 86 (11) ◽  
pp. 1242-1251 ◽  
Author(s):  
Zoubeir Béjaoui ◽  
Ali Albouchi ◽  
Mohammed S. Lamhamedi ◽  
Mohamed Hédi El Aouni
Keyword(s):  
Water Stress ◽  
Water Relations ◽  
Dry Mass ◽  
Control Treatment ◽  
Severe Stress ◽  
Drought Period ◽  
Casuarina Glauca ◽  
Stress Treatment ◽  
A Cell ◽  
Osmotic Potentials

Tunisia has vast land tracts that are marginal, arid, semiarid, or desert (about three quarters of the surface of the country). Reforestation of these regions is one of the methods being used to rehabilitate degraded areas. Casuarina glauca Sieber, a fast-growing tree species that is widely used outside of its native range, was tested in the present study with respect to its degree of acclimatization and hardening in response to drought. Three water regimes, simulating the conditions of the reforestation sites, were applied to C. glauca seedlings. These regimes included a control treatment (T : predawn water potential Ψb = –0.2 MPa), a moderate stress treatment (M : Ψb = –0.5 MPa), and a severe stress treatment (S : Ψb = –1.0 MPa). Water relations parameters, estimated by pressure–volume curves through a repeat pressurization method, as well as accumulated dry mass were measured at the beginning of the experiment and 2, 4, and 6 months following treatment imposition. The total dry mass of M and S plants was significantly affected by the treatments. However, water stress favoured dry mass allocation to roots and decreased the shoot turgid mass / dry mass ratio (TM/DM). The evolution of water relations parameters under M or S regimes revealed an adaptive capacity of C. glauca seedlings, as expressed by a significant decrease of the osmotic potentials at full turgor (Ψπ100) and at the turgor loss point (Ψπ0), an osmotic adjustment in water-stressed plants reaching 0.31 and 0.56 MPa, and a significant increase in εmax reaching 26 % and 68 % of that of the control plants, respectively, at the end of the drought period. A reduction in shoot TM/DM combined with increases in εmax during water stress suggests the presence of a cell wall adjustment. These effects were more pronounced under the severe stress. Our results suggest that preconditioning seedlings to drought under nursery conditions by applying a moderate or severe stress, depending on the conditions of the planting site, for 4 months prior to outplanting, possibly will allow the seedlings to adapt morphologically and physiologically and improve their chance of survival in arid and semiarid zones.

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