scholarly journals Osmotic and Turgor Adjustment in Rosa Foliage Drought-stressed under Varying Irradiance

1990 ◽  
Vol 115 (4) ◽  
pp. 661-667 ◽  
Author(s):  
Robert M. Augé ◽  
Ann J.W. Stodola ◽  
Brian D. Pennell
Keyword(s):  
Soil Moisture ◽  
Elastic Modulus ◽  
Water Stress ◽  
Relative Water Content ◽  
The Other ◽  
Ambient Light ◽  
Moisture Treatment ◽  
Relative Water ◽  
Osmotic Potentials ◽  
Water Contents

The influence of irradiance and drought on osmotic and turgor adjustment was examined in leaves of rose (Rosa hybrida L. `Samantha'). Plants cultured under full ambient light in the greenhouse were placed in shade chambers and, after 2 weeks of acclimation, exposed to drought for 21 days. Treatments consisted of a water stress factor (well-watered and drought-stressed) and an irradiance factor (100%, 70%, and 30% of ambient irradiance). Pressure-volume analyses of leaves indicated that osmotic potentials at full turgor were decreased 0.42, 0.36, and 0.23 MPa by drought in the 100%, 70%, and 30% irradiance treatments, respectively. Plants stressed under 100% and 70% irradiance exhibited similar osmotic adjustments. Plants under 30% irradiance had higher osmotic potentials at full turgor under well-watered conditions than plants in the other two irradiance treatments and showed only 55% as much adjustment to drought. In each irradiance treatment, drought induced an increase in elastic modulus and a decrease in relative water content at zero turgor. Turgor pressures were higher across a range of relative water contents in plants in the two higher irradiance treatments under both soil moisture treatments. Turgor also was higher at any particular water potential at 100% and 70% irradiance than 30% irradiance, within each soil moisture treatment. Heavy, but not mild, shading inhibited osmotic and turgor adjustments in leaves during drought.

scholarly journals Water Relations of Leaves of `Sonia' Rose Plants Grown in Soilless Greenhouse Conditions

HortScience ◽  
1994 ◽  
Vol 29 (6) ◽  
pp. 627-630 ◽  
Author(s):  
L. Urban ◽  
R. Brun ◽  
P. Pyrrha
Keyword(s):  
Electrical Conductivity ◽  
High Pressure ◽  
Elastic Modulus ◽  
Relative Humidity ◽  
Water Content ◽  
Relative Water Content ◽  
Drainage Water ◽  
The Other ◽  
Percentage Points ◽  
Relative Water

Rose plants (Rosa hybrids cv. Sonia) were grown in rockwool in two heated greenhouses: one with relative humidity (RH) control (RH >70%) provided by high-pressure mist, the other protected against overheating using a movable screen without RH control. Two electrical conductivity (EC) rates were applied: high (EC of drainage water ≈ 3.8 mS·cm-1) and low (EC of drainage water ≈1.8 mS·cm-1). Under these conditions, water deficit in plants was due mainly to climate, and not to EC. The relative water content of sample leaves picked at noon (RWCnoon) was one to two percentage points higher in the greenhouse with RH control and dropped by 6% to 7% in summer. RWCnoon was unaffected by differences in EC. The average elastic modulus (E) and the relative water content threshold for turgor loss (RWC0) were reduced in the greenhouse with RH control. ϵ was increased in the high EC treatment, but RWC0 remained unaffected.

Water stress affects the productivity, growth components, competitiveness and water relations of phalaris and white clover growing in a mixed pasture

1992 ◽  
Vol 43 (3) ◽  
pp. 659 ◽  
Author(s):  
L Guobin ◽  
DR Kemp ◽  
GB Liu
Keyword(s):  
Water Stress ◽  
Soil Water ◽  
White Clover ◽  
Leaf Growth ◽  
Leaf Water ◽  
Water Potentials ◽  
Relative Water ◽  
Dry Conditions ◽  
Leaf Appearance ◽  
Water Contents

The effect of water stress during summer and recovery after rain on herbage accumulation, leaf growth components, stomatal conductance and leaf water relations of white clover (Trifolium repens cv. Haifa) and phalaris (Phalaris aquatica cv. Australian Commercial) was studied in an established mixed pasture under dryland (dry) or irrigated (wet) conditions. Soil water deficits under dry conditions reached 150 mm and soil water potentials in the top 20 cm declined to nearly -2 MPa after 50 days of dry weather. Water stress severely restricted growth of both species but then after rain fell, white clover growth rates exceeded those of phalaris. Under irrigation, white clover produced twice the herbage mass of phalaris but under dry conditions herbage production was similar from both species. Leaf appearance rates per tiller or stolon were slightly higher for white clover than phalaris but were reduced by 20% under water stress in both species. Leaf or petiole extension rates were more sensitive to water stress than leaf appearance rates and declined by 75% in phalaris and 90% in white clover. The ratio of leaf or petiole extension rates on dry/wet treatments was similar for both species in relation to leaf relative water contents, but in relation to leaf water potentials phalaris maintained higher leaf growth rates. Phalaris maintained a higher leaf relative water content in relation to leaf water potentials than did white clover and also maintained higher leaf water potentials in relation to the soil water potential in the top 20 cm. Stomata1 conductances for both species declined by 80-90% with increasing water stress, and both species showed similar stomatal responses to bulk leaf water potentials and leaf relative water contents. It is suggested that the poorer performance of white clover under water stress may be due principally to a shallower root system than phalaris and not due to any underlying major physiological differences. The white clover cultivar used in this study came from the mediterranean region and showed some different responses to water stress than previously published evidence on white clover. This suggests genetic variation in responses to water stress may exist within white clover. To maintain white clover in a pasture under dry conditions it is suggested that grazing practices aim to retain a high proportion of growing points.

scholarly journals Growth and physiological response of two biomass sorghum (Sorghum bicolor (L.) Moench) genotypes bred for different environments, to contrasting levels of soil moisture

2015 ◽  
Vol 10 (4) ◽  
pp. 208 ◽  
Author(s):  
Lorenzo Barbanti ◽  
Ahmad Sher ◽  
Giuseppe Di Girolamo ◽  
Elio Cirillo ◽  
Muhammad Ansar
Keyword(s):  
Soil Moisture ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Water Content ◽  
Aboveground Biomass ◽  
Relative Water Content ◽  
Physiological Response ◽  
Field Capacity ◽  
Biomass Sorghum ◽  
Relative Water

A better understanding of plant mechanisms in response to drought is a strong premise to achieving high yields while saving unnecessary water. This is especially true in the case of biomass crops for non-food uses (energy, fibre and forage), grown with limited water supply. In this frame, we investigated growth and physiological response of two genotypes of biomass sorghum (<em>Sorghum bicolor</em> (L.) Moench) to contrasting levels of soil moisture in a pot experiment carried out in a greenhouse. Two water regimes (high and low water, corresponding to 70% and 30% field capacity) were applied to JS-2002 and Trudan-8 sorghum genotypes, respectively bred for dry sub-tropical and mild temperate conditions. Two harvests were carried out at 73 and 105 days after seeding. Physiological traits (transpiration, photosynthesis and stomatal conductance) were assessed in four dates during growth. Leaf water potential, its components and relative water content were determined at the two harvests. Low watering curbed plant height and aboveground biomass to a similar extent (ca. 􀀀70%) in both genotypes. JS-2002 exhibited a higher proportion of belowground to aboveground biomass, <em>i.e</em>., a morphology better suited to withstand drought. Despite this, JS-2002 was more affected by low water in terms of physiology: during the growing season, the average ratio in transpiration, photosynthesis and stomatal conductance between droughty and well watered plants was, respectively, 0.82, 0.80 and 0.79 in JS-2002; 1.05, 1.08 and 1.03 in Trudan-8. Hence Trudan-8 evidenced a ca. 20% advantage in the three traits. In addition, Trudan-8 could better exploit abundant moisture (70% field capacity), increasing aboveground biomass and water use efficiency. In both genotypes, drought led to very low levels of leaf water potential and relative water content, still supporting photosynthesis. Hence, both morphological and physiological characteristics of sorghum were involved in plant adaptation to drought, in accordance with previous results. Conversely, the common assumption that genotypes best performing under wet conditions are less suited to face drought was contradicted by the results of the two genotypes in our experiment. This discloses a potential to be further exploited in programmes of biomass utilization for various end uses, although further evidence at greenhouse and field level is needed to corroborate this finding.

scholarly journals In vitro screening of rice genotypes using polyethylene glycol under drought stress

2016 ◽  
Vol 27 (2) ◽  
pp. 128-135 ◽  
Author(s):  
J Akte ◽  
S Yasmin ◽  
MJH Bhuiyan ◽  
F Khatun ◽  
J Roy ◽  
...  
Keyword(s):  
Water Stress ◽  
Drought Stress ◽  
Water Content ◽  
Relative Water Content ◽  
Dry Weight ◽  
Proline Accumulation ◽  
Shoot Length ◽  
Fresh Weight ◽  
Relative Water

Five rice varieties viz. Binadhan-4, Binadhan-5, Binadhan-6, Binadhan-10 and Iratom-24 were evaluated in vitro under different water stress conditions. Several parameters such as germination percentage, shoot length, root length, shoot-root ratio, fresh weight, dry weight, turgid weight, relative water content and proline accumulation were studied. Drought condition was created by MS medium supplemented with five treatments of PEG, with a control such as 0%, 1%, 2%, 3% and 4% of PEG. The highest germination (100%) was found in the variety Binadhan-10 under low water stress conditions induced by 1% PEG. Similarly, the highest percentage of germination was found in all varieties under control condition (0% PEG). The lowest percentage of germination was obtained in the variety Iratom-24. But under severe stress (4% PEG), the highest percentage of germination was found only in the variety Binadhan-10. Moreover, the variety Binadhan-10 was found to be the best at 4% PEG for shoot length, root length, shoot-root ratio, relative water content and also the best at 1% PEG for fresh weight, dry weight, turgid weight. Water stress decreased relative water content and increased proline accumulation in rice. The highest relative water content was recorded in the variety Binadhan-10 and the lowest value recorded in the variety Binadhan-5. The highest proline content was obtained from the binadhan-6 at the highest treatment (4% PEG). Binadhan-10 showed the best performance almost in all the parameters under drought stress because of its own nature of tolerancy.Progressive Agriculture 27 (2): 128-135, 2016

Visual assessment of total plant relative water content, with the aid of photographic standards, as a guide to scheduling irrigation

1974 ◽  
Vol 14 (66) ◽  
pp. 76
Author(s):  
GJ Luke
Keyword(s):  
Water Stress ◽  
Water Status ◽  
Visual Assessment ◽  
Whole Plant ◽  
Accurate Indication ◽  
Relative Water ◽  
Total Plant ◽  
Scheduling Irrigation ◽  
Maize Plants ◽  
Water Contents

The relative water contents (RWC) of the top and bottom leaves of maize plants were measured. The RWC of the top leaf was higher than that of the bottom leaf when the plant was under water stress. Photographic standards based on the RWC of the whole plant were developed and tested against plants in the field. The results showed that the standards give an accurate indication of the plant's water status. Standards based on the upper leaf only would result in irrigations too infrequent to prevent severe restrictions to photosynthesis.

scholarly journals Modifications in vapor diffusion resistence of leaves and water relations in barbados cherry plants under water stress

2001 ◽  
Vol 13 (1) ◽  
pp. 75-87 ◽  
Author(s):  
REJANE J. MANSUR C. NOGUEIRA ◽  
JOSÉ ANTÔNIO P. V. DE MORAES ◽  
HÉLIO ALMEIDA BURITY ◽  
EGÍDIO BEZERRA NETO
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Water Content ◽  
Relative Water Content ◽  
Leaf Temperature ◽  
Diffusive Resistance ◽  
Severe Water Stress ◽  
Relative Water ◽  
Proline Concentration ◽  
Prolonged Stress

Young sexually and assexually propagated Barbados cherry plants were submitted to water deficit (20 days without irrigation). During this period the accumulation of proline, water potential of branches, osmotic potential, the relative water content of leaves, the leaf diffusive resistance, the transpiration rate and leaf temperature in the cuvette were determined. In addition, photosynthetically active radiation (PAR) and vapor pressure deficit (VPD) were measured in the porometer cuvette. The concentration of proline for both types of plants began to increase on the fifth day without watering, and reached 38.1 times the concentration in the control plants grown from seeds and 26.4 times the concentration in grafted plants on the tenth day without watering. The lowest levels of leaf water potential in the plants suffering from severe water stress varied from -4.5 to -5.7 MPa, the lowest values being observed in the sexually propagated plants. These plants also showed the highest values for transpiration (0.9 mmol.m-2.s-1) and proline concentration (20.42 mg.g-1 DM), the lowest for relative water content of the leaves (38.4%) and diffusive resistance (940 s.m-1) at the end of the experiment. The Barbados cherry plants developed strategies for surviving drought, with differences between various characteristics, resulting from prolonged stress, which significantly influenced the parameters evaluated, with the exception of leaf temperature.

scholarly journals Comparison of Strawberry F. chilocnsis and F. ×ananassa in Response to Water Stress: I. Leaf Water Potential, Relative Water Content, and Gas Exchange Characteristics

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 601c-601
Author(s):  
Chuhe Chen ◽  
J. Scott Cameron ◽  
Stephen F. Klauer
Keyword(s):  
Water Stress ◽  
Gas Exchange ◽  
Water Potential ◽  
Water Content ◽  
Leaf Water Potential ◽  
Relative Water Content ◽  
Leaf Water ◽  
Severe Water Stress ◽  
Relative Water ◽  
Gas Exchange Characteristics

Leaf water potential (LWP), relative water content (RWC), gas exchange characteristics, and specific leaf weight (SLW) were measured six hours before, during, and after water stress treatment in F. chiloensis and F. ×ananassa grown in growth chambers. The leaves of both species showed significantly lower LWP and RWC as water stress developed. F. ×ananassa had consistency lower LWP under stressed and nonstressed conditions than F. chiloensis. F. ×ananassa had higher RWC under nonstressed conditions, and its RWC decreased more rapidly under water stress than F. chiloensis. In comparison to F. ×ananassa, F. chiloensis had significantly higher CO2 assimilation rate (A), leaf conductance (LC), and SLW, but not transpiration rate (Tr), under stressed and nonstressed conditions. LC was the most sensitive gas exchange characteristic to water stress and decreased first. Later, A and stomatal conductance were reduced under more severe water stress. A very high level of Tr was detected in F. ×ananassa under the most severe water stress and did not regain after stress recovery, suggesting a permanent damage to leaf. The Tr of F. chiloensis was affected less by water stress. Severe water stress resulted in higher SLW of both species.

scholarly journals Effect of weather variability on growth and yield of wheat crop under semi-arid region of India

2021 ◽  
Vol 22 (2) ◽  
pp. 124-131
Author(s):  
ANANTA VASHISTH ◽  
AVINASH GOYAL ◽  
P. KRISHANAN
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Grain Yield ◽  
Water Content ◽  
Relative Water Content ◽  
Significant Positive Correlation ◽  
Weather Conditions ◽  
Grain Filling ◽  
Phenological Stages ◽  
Relative Water

For generating different weather conditions during various phenological stages, experiments were conducted on two varieties of wheat (HD-2967 and HD-3086) sown on three different dates at the research farm of IARI, New Delhi during rabi 2015-16 and 2016-17. Soil temperature, soil moisture, leaf area index, biomass, chlorophyll content, radiation interceptions were measured during different crop growth stages. Number of days taken for each phenological stage was observed and thermal time for different phenological stages were calculated. Results showed that first sown crop had higher value of crop growth parameters and yield as compared to second and third sown crop.HD-3086 had higher value of LAI, biomass and yield than HD-2967. Grain yield had significant positive correlation with growing degree days during grain filling stage. Soil temperature measured at 2.21 PMat 5, 10, 15, 20 cm depth had 1-5°C lower value than the air temperature. Soil moisture measured at 0-15, 15-30, 30-45 and 45-60 cm depths had slightly higher soil moisture for HD-3086 as compared to corresponding value in HD-2967 during emergence, flowering and grain filling stages. Percentage relative water content in HD-2967 was found to be higher in first sown crop followed by second and third sown crop. However, in HD-3086, percentage relative water content was found to be higher in first sown crop followed by third and second sown crop. Grain yield had significant positive correlation with relative water content during different phenological stages. HD-3086hadhigherradiation use efficiency as compared to HD-2967 in all weather conditions.

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