The physiological screening and fingerprint profile, with the aid of quantified biochemical compounds in different stress tissue of the selected traditional rice lines are the first attempt to make their overall multi-informative pro- filing in relation to osmotic stress tolerance. Osmotic stresses, mainly drought and salinity, adversely affected the germination percentage as well as shoot and root length of germinated seedlings which are necessary to have optimum plant growth for crop production. Chlo- rophyll and protein contents were declined in increasing stress doses compared to the control; whereas proline was accumulated at the higher concentration in the ma- ture leaves with an elevated stress dose. The 45 sets of SSR markers provide a positive assessment by their abil- ity to produce unique DNA fingerprinting profile of tra- ditional rice genotypes leading to their genetic relation- ship and diversity. Microsatellite profiling combined with physiological and biochemical screening revealed that Malik Sail and Rani Sail showed full germination at both osmotic stress (due to PEG and NaCl) conditions and were recommended as tolerant genotypes; whereas Laxmi Sail, Mihinagra Sail, Ratan Sail and Raghu Sail were proved to be susceptible to drought and salinity stress for all aspects. The obtained data can be used for varietal identification and the construction of a database of such vulnerable rice landraces of West Bengal. This investigation would be more significant and useful if it
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This study concludes that large increase in proline and P5CS activity in tolerant sorghum cultivars may be considered as an important adaptive characteristic under water stress. RAPD analysis of genomic DNA revealed that the primers OPE-03 and OPC-19 synthesised unique fragments only in tolerant cultivars and can be used in further study for selection of segregating populations.
In order to define the expression patterns of the three TaDREB1 homologues and their relationship with osmotic stress tolerance, semi-quantitative RT-PCR analysis was carried out to determine the expression levels of TaDREB1-A, TaDREB1-B, and TaDREB1-D in two wheat genotypes differing in seed germination osmotic stress tol- erance, using the ACTIN gene as an internal control. The results showed that the transcriptions of TaDREB1-A and TaDREB1-B genes were not detected in dry seeds and seeds treated with − 1.00 MPa mannitol for 12, 24 and 36 h via agarose gel electrophoresis. However, the expression level of TaDREB1-D had the tendency to increase gradually and then decrease when treated with − 1.00 MPa mannitol for 0 h, 12 h, 24 h and 36 h. Higher transcript expression level was detected in seeds treated by mannitol than in dry seeds. The highest transcript expression level came from osmotic stress-resistant line 08–1783 for 24 h treatment and from osmotic stress-sensitive variety Zhangye 1 after 12 h treat- ment (Fig. 3).
Thirteen different inbred lines in relation to the type of grain and life cycles were characterized by testing for osmotic stress associated with salinity. The identification of tolerant genotypes would be an effective strategy to overcome the saline stress. Osmotic stress reduces immediately the ex- pansion of the roots and young leaves which determine a reduction in the size of the plant. A com- pletely randomized design was adopted to test seedlings under controlled conditions of light and temperature. Two treatments were used: 0 mM NaCl (as control) and 100 mM NaCl. After 15 days of complete salinization, the seedlings were harvested and several morphological traits were meas- ured. The morphological traits of growth were leaf growth (Ar1, Ar2, Ar3 and Ar4), dry masses of shoot and root (SDM and RDM, respectively). Also, traits associated with water economy were registered: leaf water loss (LWL) and relative water content (RWC). The morphological traits were expressed in relative terms, while the traits associated with the economy of water were expressed in absolute terms. Uni and multivariate techniques were applied to identify genotypes with diver- gent behaviors to osmotic stress tolerance. Also, a Tolerance Index was employed to identify su- perior genotypes. Four clusters were obtained after applying a Cluster Analysis and Principal Component Analysis (PCA). The genotypes were compared to each other with a test of DMS. The results obtained with different statistical techniques converged. Some variables presented a dif- ferential weight classification of genotypes. The morphological traits like RDM, SDM, Ar3, Ar4 and Ar5 were the most discriminating. Tolerance Index allowed to classify genotypes, thus SC2 and AD3 lines were that reached highest value of the index and therefore would be tolerant lines, while AF3 and LP3 had a low index and were seen as sensible.
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To investigate plant reactions towards osmotic stress (site salinity), we applied freezing point osmometry. As the osmotic potential within a plant is comprised of ionic and non-ionic osmotica in different combinations and ratios (Rhodes et al., 2002) electrical conductivity (EC) is not applicable for plants since it exclusively targets the ionic osmotica in a solvent (Mitlöhner & Kopp, 2007). However, within the plant the non-ionic osmotica, i.e. glycine betaine, proline and sucrose increase with high external salinity. These substances exhibit protective and ion-compensating effects and bear a high share of the total osmotic concentration for many species under ex- treme conditions (Greenway & Munns, 1980). Hence, our approach is to use freezing point osmometry, which seizes the concentration of osmotically active particles independent of their ionic or non-ionic character (Swee- ney & Beuchat, 1993). Plants change in osmotic potential parallel to that of the soil (Mitlöhner & Kopp, 2007). Failure of osmotic balance results in loss of turgidity, cell dehydration and, ultimately, death of cells (Gorham, 1995). Intracellular osmotic potential can decrease as a result of an accumulation of solutes or a decrease in cell water content (Turner, 1970) in which the former is considered as active (true) osmotic adjustment. Since the osmotic potential is highly variable among species, it can be used to compare the osmotic stress tolerance of species within their natural distributions (Abrams, 1988; Gebre et al., 1998) and reflect the concentration of dis- solved salts, sugars and organic acids in the cells (Mitlöhner & Koepp, 2007).
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Rho5p binds to Ste50p, and a potential role for Rho5p in the regulation of the osmotic stress response is suggested by the synthetic osmotic sensitivity of an ⌬ ste50 RHO5(Q91H) mu- tant. We have previously shown that the association between the RA domain of Ste50p and the C terminus of Opy2p results in the membrane localization of both Ste50p and its SAM domain-associated partner Ste11p under conditions of osmotic stress (62). The binding of Rho5p to Ste50p suggests another possible interaction and another role for Ste50p in coordinat- ing the osmotic stress response. One explanation is that Rho5p may act as a direct negative regulator of HOG pathway signal- ing, and the combination of increased Rho5p-dependent inhi- bition with reduced pathway activation due to the ⌬ ste50 mu- tation results in a synthetic osmotic lethality. A second explanation is that the synthetic effects are indirect due to the FIG. 4. Rho5p is ubiquitinated. (A) GST-Rho5p purified from congenic wild-type (WT) and proteasome-impaired (pre1-1) strains was assayed for ubiquitination by probing with the anti-ubiquitin antibody. The levels of GST-Rho5p were monitored by the anti-GST antibody. (B) GST- Rho5p was expressed singly or in combination with HA-tagged ubiquitin and was subsequently purified and separated by SDS-PAGE. The presence of HA-ubiquitin was assayed by an anti-ubiquitin antibody. (C) Impaired proteasome function impairs growth of Rho5-expressing strains. Vectors containing wild-type RHO5 (pGAL-RHO5) and activated rho5 (pGAL-RHO5 Q91H ) were transformed into strains compromised for
under low salinity conditions suggests that the polyp stage is probably an estuarine inhabitant. Cubozoans that have coastal or estuarine polyp stages have previously been reported for two species; C. fleckeri polyps were located in situ attached to the underside of rocks near a river mouth in Queensland , and polyps of C. marsupialis were once located attached to bivalve shells in a mangrove habitat in Puerto Rico . To date, these are the only two discoveries of cubozoan polyps in situ globally, however at least one other Australian cubozoan polyp, those of C. bronzie, has also been suggested to be estuarine . The possibility that C. barnesi has an estuarine polyp stage has not previously been considered primarily due to their distinctly oce- anic medusa stage [5,6,34] compared to species which are known to be primarily coastal, such as C. fleckeri and C. bronzie [2,3,50–52]. There have been no reported sightings, or documented stings caused by C. barnesi from estuaries; however this does not discount the possible presence of medusae in these areas when they are newly detached and small. It is currently unknown how the polyps enter low salinity habitats and nothing is known about the osmotic tolerance of the medusa stage or where or when the medusae spawn. In speculation, due to there being no reports of adult C. barnesi medusae within estuarine systems, it is plausible that the eggs, that are known to have a long encapsulated planula stage from six days to six months , are transported inshore on currents. Future research is required on the medusa stage, such as determining their osmotic tolerance, to better understand how the life cycle is completed in situ.
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Na+ was distributed equally between the mesophyll and epidermis in Wollaroi, with the Na+ concentration in both cell types increasing as leaf Na+ increased. However, Franklin appeared to have a greater capacity for storage of Na+ in mesophyll vacuoles, partitioning slightly greater Na+ (-10%) to the mesophyll compared to Wollaroi. Also using X-ray microanalysis, Huang and van Steveninck (1989) found similar concentrations of Na+ in the epidermis and mesophyll of two barley cultivars (differing in salt tolerance) grown for 1 d in 50 and 100 mM NaCl, but twice the Na+ in the mesophyll of both genotypes after 4 d in 50 mM NaCl. Similarly, using the same technique, Leigh and Storey (1993) encountered more mesophyll than epidermal cells with detectable levels of Na+. However, studies using different techniques have offered contrasting results. Karley et al., (2000a) measured 10 fold higher Na+ concentrations in isolated protoplasts from barley epidermal cells (41 mM) than from mesophyll cells (3 mM). These measurements were taken from leaves of non salt-stressed plants and are at odds with Dietz et al. (1992) who, using the same technique, found similarly low levels in protoplasts from both mesophyll and epidermal cells. Using a microcapillary to extract sap from single cells, Fricke et al. (1996) generally found higher Na+ concentrations in epidermal vacuoles than mesophyll vacuoles of salt-stressed barley seedlings. This discrepancy may have resulted from the exclusive sampling of mesophyll cells from a particular cellular location (cells lining the stomatal cavity), as the microcapillary was inserted through the stomatal pore. The diversity of results summarised in the above mentioned studies, probably reflects the range of techniques and experimental conditions used.
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Heat stress is a major environmental constraint to crop production. Terminal heat stress is defined as a rise in temperature that occurs between heading and maturity. When this stress matches with the reproductive phase of the wheat plant, it affects anthesis and grain filling, resulting in a severe reduction in yield . High temperatures at the time of flowering cause floret sterility via pollen dehiscence , decrease photosynthetic capacity by drying the green tissues, and reduce starch biosynthesis [1,3]. These in turn result in a negative effect on grain number and weight [4-7]. The optimum growing temperature for wheat during pollination and grain filling phases is 21°C [8,9], and for each increase of 1°C above it is estimated a decline of 4.1% to 6.4% in yield . Environmental temperatures have been increasing over the last century and more frequent heat waves are predicted in the next decades [11-13]. Therefore, breeding for tolerance to chronic as well as short term heat stress is a major objective worldwide [14-19]. Breeding selection would benefit by a good understanding of traits associated with tolerance to high temperatures, as well as the identification of the genomic regions controlling these traits.
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The above studies did not simultaneously consider electro-osmotic transport in non-Newtonian fluids. In recent years this area has become increasingly attractive to researchers owing to newly fabricated electro-rheological fluids which can combine desirable electro-kinetic and non-Newtonian effects in microscale devices. Several theoretical investigations have therefore been reported using a variety of robust non-Newtonian formulations. Li et al.  derived closed-form solutions for the electrical potential distribution in rotating electro-osmotic flow of an incompressible third grade Reiner-Rivlin fluids in a microchannel, observing that with increasing dimensionless electro-kinetic width, increasing Reynolds number and non- Newtonian parameter, the flow is decelerated and volumetric flow rates reduced. Siddiqui and Lakhtakia  investigated transient electro-osmotic flow of an Eringen micropolar fluid in a rectangular microchannel with height significantly greater than the Debye length, noting that under a spatially uniform electric field (applied as an impulse of finite magnitude), decay times of the fluid velocity are markedly lesser for micropolar fluids than Newtonian fluids. Afonso et al.  used the Phan-Thien–Tanner (PTT) constitutive equation to simulate electro-osmotic viscoelastic flow in a channel with pressure gradient and asymmetric boundary conditions (different zeta potentials at the walls). Sousa et al.  further studied electro-osmosis and pressure gradient forcing in PTT viscoelastic microchannel Poiseuille skimming flows. Tang et al.  used a lattice Boltzmann method to computationally simulate the electroosmotic power-law rheological flow in micro-channels, showing that power-law index markedly alters the electroosmotic flow pattern and that shear thinning fluids constrain the electrical double layer effect in a small zone nearer
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103 Brassica leaves at reproductive growth stages by water stress. Vartanian, et al. (1992) observed high proline accumulation through water shortage, reaching up to 4.6% of total dry matter. Proline accumulation during drought stress is an adaptive response that enhances survival and tissue water status (Chu et al. 1974).
In order to identify drought tolerant cultivars, three dimensional plots based on Yp, Ys, GMP and STI were drawn (Fig. 2 and 3). Three dimensional plots are presented to show the interrelationships among these three variables to separate the cultivars of group A (high yielding cultivars in both stress and non-stress conditions) from the other groups (B, C and D), and to illustrate the advantage of STI and GMP indices as selection criterion for identifying high- yielding and stress tolerant cultivars. In three dimensional plots, 4, 7, 8, 19, 16, 19 and 17 were included in A group, these accessions revealed stable grain yield in stress and non-stress conditions. The genotypes 20, 14, 18, 11, 9, 15, 13 were in D group that performed poorly in both conditions. Cluster analysis showed that the cultivars, based on indices tended to group into three groups: tolerant, semi-tolerant and sensitive genotypes. (Fig. 4). In this analysis, the first group had the highest Yp, Ys, STI, MP, GMP, YI, DI, K1STI, K2STI, and SNPI and was thus considered to be the most desirable cluster for both growth conditions (tolerant group). The second group had mean indicators values (Semi- sensitive/ semi-tolerant). In the third group, all cultivars had high SSI, thus they were susceptible to drought and only suitable for irrigated conditions.
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excess and low salinity levels are a concern; The growth of many salt-sensitive plant species is inhibited by low salinity and excess salt in the soil can reduce osmotic potential to such an extent that crops cannot take up enough water . Thus, finding strategies to address salt stress is a global matter that can ensure agricultural success and sustainable food production. Although the plants display marked differences in their salt tolerance degree, they share a similar salt inclusion strategy to deal with excessive salinity . In this process, the leaf tissues are adapted to accumulate large
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Fig. 1 Phenotypes of the osgf14b mutant, complementation and OsGF14b-OE lines under drought stress treatment at the seedling stage. a Expression analysis of OsGF14b in the osgf14b mutant, complementation and OsGF14b-OE lines. The rice Actin1 gene was used as the internal control. Error bars represent the SE of three biological replicates. b The osgf14b mutant showed increased drought resistance. The 5.5- to 6.5-leaf stage seedlings of DJ, osgf14b and complementation lines (about 20 seedlings for each genotype) were subjected to drought stress without water for 12 d and then recovered for 7 d. The seedlings with newly growing leaf blades were counted as surviving plants and the survival rates were recorded. Error bars represent the SE of three biological replicates (**, P < 0.01, by Student ’ s t-test). c The OsGF14b-OE lines were more sensitive to drought stress treatment. The 5.5- to 6.5-leaf stage seedlings of Nip and OsGF14b-OE lines (about 10 seedlings for each genotype) were subjected to drought stress without water for 8 d and then recovered for 7 d. The seedlings with newly growing leaf blades were counted as surviving plants and the survival rates were recorded. Error bars represent the SE of three replicates (*, P < 0.05, by Student ’ s t-test). d-g The H 2 O 2 , MDA, proline and soluble sugar content in the WT and transgenic plants (mutant and OE) under normal growth and drought stress conditions. Error
(sodium chloride). However, according to , the calcium chloride as osmotic agent, was not as efficient as mannitol. Regarding the potassium and sodium chlorides, work previously reported that solutions of these salts exhibit toxicity to bean seeds from −0.6 MPa, not being recommended as water deficiency simulators . The effects of osmotic potential on seeds and seedlings depend on the initial seed quality and type of solute used when they are subjected to the same degree of water deficit .
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The capability of animal cells to maintain cell volume and structural dynamics are prerequisite for cellular life. This is particularly important for euryhaline fishes, as they must maintain water and ion homeostasis in their gills during migration. Numerous cellular events occur during osmotic stress, such as changes in the activities of cellular receptors and reorganization of the cellular cytoskeleton architecture [1,2]. Fiol and Kultz proposed the concept of an “osmosen- sory signal transduction network” in order to summarize cellular events during osmoregulation in fishes. The authors divided the osmoregulatory process into three parts: osmo- sensors, signal transducers, and effectors. Cellular sensors detect external osmolality changes and stimulate various signaling molecules, which induce effectors to compensate for the osmotic challenge . Researchers have spent de- cades attempting to understand the underlying osmoregula- tory mechanism in fishes. However, due to the complicated factors involved in the process, (for example, how changes in external ion contents or internal hormonal levels affect osmotic responses), it is still unknown which factors or molecules are critical to the process. Using traditional methods, such as microarray, subtractive hybridization, and
Plant breeding focused on water deficiency can exploit different strategies, including developing cultivars with increased water-stress tolerance or agronomic efficiency of water use (WUE). The concept of tolerance is defined as the plant’s ability to support, survive and reproduce under stress conditions (Maia et al., 2011). From an agronomic point of view, tolerance (T) can be defined as the ratio of crop yield produced under stress compared to yield under ideal cultivation conditions (Mitra, 2001; Miti et al., 2010). In turn, WUE is related to the greater ability of a genotype to produce under low water availability and is computed as the ratio between grain yield (kg) per unit of available water resource (L of applied, transpired or evapotranspired water (Tambussi et al., 2007; Jákli et al., 2018).
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challenge. Thus, the time frame of this response is relatively slow, but it coincides with the critical period for adaptation to a salinity change in the killifish (Marshal et al., 1999). Furthermore, within this time period, the present results document a series of events that culminate in providing hepatocytes with active TH. Indeed, both in vivo and in vitro experiments showed a sequential correlation between the peak in translocation of putative OREBP to the nucleus, the increase D2 transcription, and the subsequent rise in enzymatic activity. Recently, the mammalian liver has been recognized as an important osmosensing and osmosignaling organ. Mammalian hepatocyte swelling or shrinkage triggers an array of intracellular transduction signals that are integrated with those that are hormone- and metabolic-dependant (for a review, see Schliess and Haussinger, 2006). In elasmobranch osmoregulation, the liver is the main provider of organic osmolytes including urea (Hazon et al., 2003). The osmoregulatory role of the teleostean liver has been less documented (Fiess et al., 2007). Osmoregulation is a highly expensive physiological process in terms of metabolic energy. In fish it has been suggested to require from 20% to 50% of the total energy expenditure, and is greater in freshwater than in seawater (Boef and Payan, 2001; Fiess et al., 2007). In addition to supplying glucose and organic osmolytes (Fiess et al., 2007), fish liver contains the largest pool of glutamine, which is the major source of ammonia as well as an important blood carrier for this nitrogenous waste product (for reviews, see Wood, 1993; Haberle et al., 2006). Two key enzymes involved in glutamine and ammonia metabolism are glutamine synthetase and glutamate dehydrogenase, which interestingly, at least in mammals, are both TH-dependent (Doulabi et al., 2002). In this context it is paradoxical that the current dogma considers the role of TH in osmoregulation to be indirect. Indeed TH have been thought to support long-term adaptive responses mediated by growth hormone, prolactin and cortisol, among other classical osmoregulatory messengers (Sakamoto and McCormick, 2006). However, previous studies from our laboratory (Orozco et al., 1998; Orozco et al., 2002b) and recent studies in the seabream gill (Klaren et al., 2007), strongly suggest a more direct involvement of TH in the hydro-osmotic balance in fish. Furthermore, our present results support the suggestion that a putative hypo-osmotic, OREBP-mediated increase in hepatic D2 activity could be an important endocrine component for the maintenance of hydro-osmotic homeostasis in fish. Thus, we hypothesize that the local intra-hepatic T 3
Canopy temperature is related to plant water stress because the evaporative cooling involved in transpiration may cool leaves below ambient air temperature. If soil water is limiting, plant water stress develops, transpira- tion decreases and the canopy temperature rises. Plants with adequate supply of water maintained their canopy temperature below the air temperature, whereas the plants with inadequate supply of water exhibited their cano- py temperature above the air temperature . Blum et al.,  used canopy temperatures of drought stressed wheat genotypes to characterize yield stability under various moisture conditions. Many researchers also used canopy temperature as tool of screening against drought in many crops like, Sorghum ; potato ; wheat ; tomato  and cotton .
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The main objective of any wheat breeding program is to create varieties with high yield potential, possessing a complex of biological and agricultural quality, resistant to biotic and abiotic stress factors and suitable for low input (Rachovska et al., 2003; Dimova et al., 2006; Ivanova and Tzenov, 2009b; Tzenov et al., 2009; Bozhanova et al, 2009a). By approaching the limits of biological productivity and as a result of global climate change, the need for new sources material to create new varieties that meet the climate change has greatly increased. The efforts of researchers have been directed to searching for new sources of gene plasm, as carriers of ecological plasticity and stress tolerance in the highest degree. Identification of