Physiological Aspects of Racomitrium crispipilum Taylor A. (Jaeger) during Dry Season in Páramo de Chingaza, Colombia

2009 ◽  
Vol 30 (1) ◽  
pp. 1-7
Author(s):  
Andrés Felipe Barón ◽  
Walther García ◽  
Luz Marina Melgarejo ◽  
Luis Carlos Montenegro
Keyword(s):  
Water Deficit ◽  
Soluble Protein ◽  
Water Shortage ◽  
Dry Mass ◽  
Dry Season ◽  
Mountain Range ◽  
Relative Water ◽  
The Hours ◽  
Peroxidase Enzyme ◽  
Response To Water

In order to study the response to water deficit of the moss Racomitrium crispipilum (Taylor) A. Jaeger, a bryophyte typical of open sites and expose to water shortage, measurements of its soluble protein and proline contents, and enzymatic activity of catalase and peroxidase were made. Sampling was done in the Páramo de Chingaza, eastern mountain range of Colombia, in the zone of Lagunas de Buitrago during the dry season. We determined that R. crispipilum diminish its relative water content (RWC) from 50% to 4% of its dry mass (DM) (i.e. to <10% of its capacity), without losing the ability to synthesize proteins in the rehydration. Declining RWC was associated with declining soluble protein content and increased activities of catalase and peroxidase. Enzyme activities peacked in the hours at which R. crispipilum exhibited its minimum RWC (21.02 U mg protein-1 min-1 for catalase and 172.66 for peroxidase). Proline was found to be high during the hours of maximum RWC and the earliest hours of diminishing RWC, between 60 and 87.07 mg g dry mass-1 and declines to 18.98 during the afternoon. The results reported in this study give the first evidence that the activities of catalase and peroxidase increase in this species in response to conditions of water deficit. This is likely to be an important component in the mechanism by which this moss tolerates drought periods.

Relationships between physiological traits and productivity of sugarcane in response to water deficit

2012 ◽  
Vol 152 (1) ◽  
pp. 104-118 ◽  
Author(s):  
M. DE A. SILVA ◽  
J. L. JIFON ◽  
J. A. G. DA SILVA ◽  
C. M. DOS SANTOS ◽  
V. SHARMA
Keyword(s):  
Water Deficit ◽  
Field Studies ◽  
Water Deficit Stress ◽  
Chlorophyll Contents ◽  
Physiological Variables ◽  
Drought Tolerant ◽  
Relative Water ◽  
Leaf Relative Water Content ◽  
Sugarcane Productivity ◽  
Response To Water

SUMMARYThe relationships between physiological variables and sugarcane productivity under water deficit conditions were investigated in field studies during 2005 and 2006 in Weslaco, Texas, USA. A total of 78 genotypes and two commercial varieties were studied, one of which was drought-tolerant (TCP93-4245) and the other drought-sensitive (TCP87-3388). All genotypes were subjected to two irrigation regimes: a control well-watered treatment (wet) and a moderate water-deficit stress (dry) treatment for a period of 90 days. Maximum quantum efficiency of photosystem II (Fv/Fm), estimated chlorophyll content (SPAD index), leaf temperature (LT), leaf relative water content (RWC) and productivity were measured. The productivity of all genotypes was, on average, affected negatively; however, certain genotypes did not suffer significant reduction. Under water deficit, the productivity of the genotypes was positively and significantly correlated with Fv/Fm, SPAD index and RWC, while LT had a negative correlation. These findings suggest that genotypes exhibiting traits of high RWC values, high chlorophyll contents and high photosynthetic radiation use efficiency under low moisture availability should be targeted for selection and variety development in programmes aimed at improving sugarcane for drought prone environments.

scholarly journals Trigonelline Accumulation in Leaves of Panicum virgatum Seedlings

2014 ◽  
Vol 9 (8) ◽  
pp. 1934578X1400900 ◽  
Author(s):  
Lauren M. Schwartz ◽  
Andrew J. Wood ◽  
David J. Gibson
Keyword(s):  
Water Deficit ◽  
Tallgrass Prairie ◽  
Panicum Virgatum ◽  
Water Deficit Stress ◽  
Significant Difference ◽  
Moisture Treatment ◽  
Relative Water ◽  
Tallgrass Prairies ◽  
Response To Water ◽  
Physiological Markers

Panicum virgatum is a dominant, native, perennial species found in the tallgrass prairie. In this study, we report the biosynthesis and accumulation of trigonelline (TRG) in leaves of P. virgatum in response to water-deficit stress. Once established, half of the seedlings underwent a drought stress treatment while the other half were watered daily (control). Relative water content (RWC) and trigonelline (TRG) concentrations were determined. RWC showed an interaction between moisture treatment and time, in which upland cultivars had the highest mean RWC compared with the lowland cultivars. The moisture treatments showed a significant difference in TRG concentration across all P. virgatum cultivars, which ranged from 0.5–31.8 μg/gFW−1. There was a divergence in TRG accumulation between upland and lowland cultivars in relation to RWC. This study is the first to report TRG accumulation in the grass P. virgatum, and to test for differences in TRG with respect to water-deficit stress among cultivars. The effect of soil moisture levels on cultivars may be important in making an informed selection and the response of P. virgatum and other dominant grasses should be considered as a potential filter in tallgrass prairies for restoration. Physiological markers such as TRG and RWC can aid in this decision making process.

Phenology, leaf gas exchange, growth, and seed yield in contrasting Medicago truncatula and Medicago laciniata populations during prolonged water deficit and recovery

Botany ◽  
2012 ◽  
Vol 90 (2) ◽  
pp. 79-91 ◽  
Author(s):  
Nasreddine Yousfi ◽  
Ines Slama ◽  
Chedly Abdelly
Keyword(s):  
Water Deficit ◽  
Medicago Truncatula ◽  
Seed Yield ◽  
Growth Parameters ◽  
Leaf Gas Exchange ◽  
Seed Mass ◽  
Field Capacity ◽  
Water Shortage ◽  
Relative Water ◽  
Leaf Relative Water Content

The aims of this study were to investigate the effect of prolonged water stress and recovery on phenology, growth, and seed yield in Tunisian contrasting populations of Medicago truncatula and Medicago laciniata . After ample irrigation for 24 days, the plants of each population were divided into two lots: the first lot was irrigated at 100% field capacity (FC), and the second at only 45% FC. After 24 days of treatment, one lot of dehydrated plants was rewatered at 100% FC, while the other was maintained at 45% FC. Interspecific and intraspecific differences were found in phenological responses to water deficit. All growth parameters were more reduced in M. truncatula populations than in M. laciniata populations. The water shortage tolerance of M. laciniata populations was associated with a lower metabolic impairment of photosynthesis and maintenance of relatively higher leaf relative water content. Seed yield was also more reduced in M. truncatula populations compared with M. laciniata populations. In M. laciniata, seed mass was a compensation mechanism to sustain seed yield under drought conditions. Seed yield variation between populations under water deficit was explained mainly by variation in seed number per plant.

scholarly journals Variability among Young Table Grape Cultivars in Response to Water Deficit and Water Use Efficiency

Agronomy ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 135 ◽  
Author(s):  
Carolin Weiler ◽  
Nikolaus Merkt ◽  
Jens Hartung ◽  
Simone Graeff-Hönninger
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Water Deficit ◽  
Water Use ◽  
Dry Mass ◽  
Table Grape ◽  
Water Limitation ◽  
Use Efficiency ◽  
Response To Water ◽  
Grape Cultivars

Climate change will lead to higher frequencies and durations of water limitations during the growing season, which may affect table grape yield. The aim of this experiment was to determine the variability among 3-year old table grape cultivars under the influence of prolonged water deficit during fruit development on gas exchange, growth, and water use efficiency. Six own rooted, potted table grape cultivars (cv. ‘Muscat Bleu’, ‘Fanny’, ‘Nero’, ‘Palatina’, ‘Crimson Seedless’ and ‘Thompson Seedless’) were subjected to three water deficit treatments (Control treatment with daily irrigation to 75% of available water capacity (AWC), moderate (50% AWC), and severe water deficit treatment (25% AWC)) for three consecutive years during vegetative growth/fruit development. Water deficit reduced assimilation, stomatal conductance, and transpiration, and increased water use efficiencies (WUE) with severity of water limitation. While leaf area and number of leaves were not affected by treatments in any of the tested cultivars, the response of specific leaf area to water deficit depended on the cultivar. Plant dry mass decreased with increasing water limitation. Overall, high variability of cultivars to gas exchange and water use efficiencies in response to water limitation was observed. ’Palatina’ was the cultivar having a high productivity (high net assimilation) and low water use (low stomatal conductance) and the cultivar ‘Fanny’ was characterized by the highest amount of total annual dry mass as well as the highest total dry mass production per water supplied during the experiment (WUEDM). Hence, ‘Fanny’ and ‘Palatina’ have shown to be cultivars able to cope with water limiting conditions and should be extensively tested in further studies.

scholarly journals Changes in carbohydrates accumulation in Viguiera discolor Baker in response to water deficit

Hoehnea ◽  
2019 ◽  
Vol 46 (4) ◽  
Author(s):  
Rodrigo Fazani Esteves Sanches ◽  
Ana Paula Oliveira da Silva ◽  
Vanessa Pires da Costa ◽  
Maria Ângela Machado de Carvalho ◽  
Emerson Alves da Silva
Keyword(s):  
Water Deficit ◽  
Osmotic Adjustment ◽  
Water Status ◽  
Soluble Sugars ◽  
Water Suppression ◽  
Adaptive Responses ◽  
Close Relationship ◽  
Relative Water ◽  
Influence Of Water ◽  
Response To Water

ABSTRACT Water stress is an environmental factor that can regulate growth, limit production and lead to physiological and biochemical changes. Plants present a series of adaptive responses to drought, such as osmotic adjustment, in which carbohydrates play an important role. To evaluate the influence of water deficit on carbohydrates accumulation in V. discolor, the plants were divided into two groups: daily watering and water suppression for 14 days being re-watering after this period. Leaves and roots were collected at 0, 3, 6, 9, 12, 15 and 18 days, for ecophysiological and biochemical analyzes. Variations in carbohydrate contents in V. discolor showed a close relationship with changes in the plant water status, with higher concentrations of soluble sugars, total fructans, oligosaccharides, reducing sugars coinciding with the lower values of soil moisture and leaf water potentials and relative water content. In the tuberous roots, there is an increase in carbohydrate concentrations after re-watering. The increase of these low molecular weight carbohydrates is involved in osmotic adjustment and therefore acts to protect against dehydration.

scholarly journals Drought responses and their effects on radial stem growth of two co-occurring conifer species in the Mediterranean mountain range

2020 ◽  
Vol 77 (4) ◽  
Author(s):  
Aylin Güney ◽  
Roman Zweifel ◽  
Semra Türkan ◽  
Reiner Zimmermann ◽  
Magnus Wachendorf ◽  
...  
Keyword(s):  
Water Deficit ◽  
Growth Rates ◽  
Water Shortage ◽  
Stem Growth ◽  
Growth Strategy ◽  
Mountain Range ◽  
Summer Drought ◽  
Cedrus Libani ◽  
Juniperus Excelsa ◽  
Species Specific

Abstract Key message Patterns of stem radial variations showed thatCedrus libaniA. Rich. was less limited by summer drought than co-occurringJuniperus excelsaM. Bieb.Cedrus libanirecovered faster from tree water deficit and showed significantly higher radial growth rates and annual stem increments thanJ. excelsa. However, the ability ofJ. excelsato grow more hours per year may indicate a potential benefit in more extreme conditions. Context Knowledge about species-specific drought responses is needed to manage productive forests in drought prone areas. Under water shortage, trees commonly show stem shrinkage, which is assumed to inhibit growth. Aims We investigated whether the two co-existing conifers Juniperus excelsa M. Bieb. and Cedrus libani A. Rich. (growing at the Taurus Mountains, SW-Turkey) show differences in water relations and stem growth in order to evaluate their respective drought tolerance. Methods Stem radius changes were hourly monitored over 2 years using high-resolution point dendrometers. Radial stem growth, tree water deficit-induced stem shrinkage, and maximum daily shrinkage were extracted from stem radius change measurements, investigated for their patterns, and related to environmental conditions. Results Cedrus libani recovered from tree water deficit under higher temperature and vapor pressure deficit than J. excelsa. The number of hours during which stem growth occurred was higher for J. excelsa; however, growth rates and annual increments were significantly lower than in C. libani. Both species showed highest maximum daily shrinkage during the driest months indicating the ability to maintain gas exchange all year round. Conclusion Juniperus excelsa showed a more conservative growth strategy while C. libani was less limited by summer drought and showed more annual stem increment under the conditions investigated.

scholarly journals Elevated Nitrogen Priming Induced Oxinitro-Responses and Water Deficit Tolerance in Rice

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 381
Author(s):  
Kamolchanok Umnajkitikorn ◽  
Mitsutaka Fukudome ◽  
Toshiki Uchiumi ◽  
Neung Teaumroong
Keyword(s):  
Nitric Oxide ◽  
Water Deficit ◽  
Plant Stress ◽  
Antioxidant Defense System ◽  
Water Shortage ◽  
Rice Plants ◽  
Dissolved Nitrogen ◽  
Relative Water ◽  
Nitrogen Concentrations ◽  
Root Nitrogen

Under water deficit conditions, the essential macronutrient nitrogen becomes limited as a result of reduced dissolved nitrogen and root nitrogen uptake. An elevated nitrogen level might be able to mitigate these effects, integrated with the idea of using nitric oxide as abiotic stress tolerant inducers. In this study, we evaluated the potential of using elevated nitrogen priming prior to water shortage to mitigate plant stress through nitric oxide accumulation. We grew rice plants in 300 mg L−1 nitrogen for 10 weeks, then we primed plants with four different nitrogen concentrations: 100, 300 (control), 500 and 1000 mg L−1 nitrogen prior to inducing water deficit conditions. Plants primed with 500 mg L−1 nitrogen possessed a higher photosynthetic rate, relative water content, electrolyte leakage and lipid peroxidation under water deficit conditions, compared to control plants. The induction of water deficit tolerance was supported with the activation of antioxidant defense system, induced by the accumulation of nitric oxide in leaves and roots of rice plants. We originally demonstrated the accumulation of nitric oxide in leaves of rice plants. The elevated nitrogen priming can be used to enhance water deficit tolerance in irrigated paddy fields, instead of nitric oxide donors.

scholarly journals Free proline accumulation in sugarcane under water restriction and spittlebug infestation

2008 ◽  
Vol 65 (6) ◽  
pp. 628-633 ◽  
Author(s):  
Eduardo Rossini Guimarães ◽  
Miguel Angelo Mutton ◽  
Márcia Justino Rossini Mutton ◽  
Maria Inês Tiraboschi Ferro ◽  
Gisele Cristina Ravaneli ◽  
...  
Keyword(s):  
Water Deficit ◽  
Xylem Sap ◽  
Compatible Solutes ◽  
Water Shortage ◽  
Saccharum Officinarum ◽  
Dry Mass ◽  
Proline Accumulation ◽  
Free Proline ◽  
Water Restriction ◽  
Root Cells

Mahanarva fimbriolata (Stål) (Hemiptera: Cercopidae) has become a key pest in the sugarcane (Saccharum officinarum) fields of center-south Brazil. Although some control technologies have shown to be efficient, the damage promoted by this spittlebug species and its interaction with sugarcane are poorly characterized. At high infestation levels the symptoms are similar to those of severe water restriction. This work was conducted to determine whether the stress promoted by spittlebug infestation can be measured in terms of free proline accumulation. The water restriction tolerance of two sugarcane genotypes was also compared. Two experiments were set up in a greenhouse and arranged in a completely randomized design in a 2 x 2 x 4 factorial, with two cultivars (SP80-1816 and RB72454), two stress levels (control and ten nymphs per plant or 50% water restriction), and four sampling dates. The water deficit caused by spittlebug nymphs sucking xylem sap does not result in proline accumulation, illustrating that there are different mechanisms to sense when the water deficit is caused by insect feeding or water potential variation in root cells. The cultivar RB72454 accumulates more free-proline, and the dry mass accumulation and stalk growth are less affected in this cultivar under water restriction. The levels of compatible solutes probably cannot be used to measure spittlebug infestation stress in sugarcane and RB72454 is more tolerant to water shortage than SP80-1816.

Effects of Water Deficit on Leaf Development in Tobacco

1975 ◽  
Vol 2 (3) ◽  
pp. 291 ◽  
Author(s):  
BF Clough ◽  
FL Milthorpe
Keyword(s):  
Water Deficit ◽  
Water Shortage ◽  
Cell Number ◽  
Similar Response ◽  
Leaf Initiation ◽  
Small Water ◽  
Palisade Cells ◽  
Reduced Rate ◽  
Simple Logistic ◽  
Response To Water

Leaf initiation, leaf area, and the numbers and areas of palisade cells in developing leaves at five nodes were followed during a period in which tobacco plants were deprived of water. The rate of leaf initiation in well-watered plants was constant with time, but was rapidly reduced by a small water deficit and ceased at leaf water potentials of less than - 750 J kg-1. Cell expansion showed a similar response to water shortage, but cell division was much less sensitive, continuing although at a reduced rate even after leaf expansion had ceased. The expansion of a leaf on a well-watered plant could be described by a simple logistic relation with time from unfolding. The course of cell number and size during expansion could be accounted for by assuming that cells always divided at the same size, that the proportion of cells passing into a further cycle of division decreased as a negative logistic of time and that all cells expanded in the same manner, i.e, over 4 days at a rate which fell linearly with time.

scholarly journals Overexpression of Bacterial mtlD Gene in Peanut Improves Drought Tolerance through Accumulation of Mannitol

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Tengale Dipak Bhauso ◽  
Thankappan Radhakrishnan ◽  
Abhay Kumar ◽  
Gyan Prakash Mishra ◽  
Jentilal Ramjibhai Dobaria ◽  
...  
Keyword(s):  
Water Deficit ◽  
Radical Scavenging ◽  
Water Deficit Stress ◽  
Gene Coding ◽  
Global Environmental ◽  
Relative Water ◽  
Transgenic Lines ◽  
Improved Performance ◽  
Radical Scavenging Ability ◽  
Response To Water

In the changing global environmental scenarios, water scarcity and recurrent drought impose huge reductions to the peanut (Arachis hypogaea L.) crop yield. In plants, osmotic adjustments associated with efficient free radical scavenging ability during abiotic stress are important components of stress tolerance mechanisms. Mannitol, a compatible solute, is known to scavenge hydroxyl radicals generated during various abiotic stresses, thereby conferring tolerance to water-deficit stress in many plant species. However, peanut plant is not known to synthesize mannitol. Therefore, bacterial mtlD gene coding for mannitol 1-phosphate dehydrogenase under the control of constitutive promoter CaMV35S was introduced and overexpressed in the peanut cv. GG 20 using Agrobacterium tumefaciens-mediated transformation. A total of eight independent transgenic events were confirmed at molecular level by PCR, Southern blotting, and RT-PCR. Transgenic lines had increased amount of mannitol and exhibited enhanced tolerance in response to water-deficit stress. Improved performance of the mtlD transgenics was indicated by excised-leaf water loss assay and relative water content under water-deficit stress. Better performance of transgenics was due to the ability of the plants to synthesize mannitol. However, regulation of mtlD gene expression in transgenic plants remains to be elucidated.

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