Authors:Nehla Labidi, Manel Ammari, Sana Snoussi, Najoua Messelini, Fatma Gharbi, and C. Abdelly
The halophyte Crithmum maritimum thrives in cracks of calcareous rocks or cliffs at seashores, a situation which associates limited phosphorus availability and high salinity. In order to understand the common patterns of colonization and zonation of this species, seedlings were cultivated for 34 d in inert sandy soil irrigated with a nutrient solution containing or not phosphorus at moderate (50 mM) or high (250 mM) NaCl level. Net assimilation rate and consequently relative growth rate increased in response to P deprivation at moderate saline level, but not at high salinity level. Parallelly, CO2 fixation rate, rubisco capacity, transpiration rate and stomatal conductance were diminished by P deprivation at moderate NaCl level. Intercellular CO2 concentration was therefore not affected. Chlororophyll fluorescence analysis revealed that photosynthetic systems were insensitive to change in P availability at moderate salinity level: neither pigment content, nor effective and maximum quantum yield, photochemical and non photochemical quenching, and electron transport rate were affected by P deprivation. On the contrary, at high salinity level when net photosynthesis, rubisco capacity and the quantum yields of PS2 were severely affected, P deprivation strongly augmented electron transport rate. Stomatal aperture and more modest increase in net photosynthesis, rubisco capacity, photosystem II effective quantum yield and photochemical quenching accompanied this response. This study shows the tolerance of C. maritimum to the phosphorus deprivation combined to moderate or to high saline level which may explain the common patterns of colonization and zonation of this species.
Authors:I. Prasad, N. Kulshreshtha, A. R. Chinchmalatpure, and D. K. Sharma
Soil salinity is one of the major environmental constraints in increasing agricultural crop production, especially wheat production in India. Screening of diverse germplasm in representative growing conditions is prerequisite for exploring traits with stable expression imparting salinity tolerance. A study was undertaken during 2011–2012 for characterizing wheat germplasm in three environments representing growing conditions of crop in Northern parts of India, estimating inter-relationship among traits and evaluating stability of trait conferring salinity tolerance. Significant value of mean square for observed trait across the environments signified presence of large variability in genotypes. Significant yield reduction was recorded in almost all genotypes in saline environment compared to non-saline condition. Ratio of potassium and sodium ion in leaf tissue (KNA); a key salt tolerance traits was found to be significantly correlated with biomass, SPAD value and plant height. Due to the presence of significant genotype × environment interaction (G × E) for KNA, additive main effect and multiplicative interaction (AMMI) model was utilized to study stability of KNA among genotypes and environments. IPCA1 and IPCA2 were found to be significant and explained more than 99 per cent of variation due to G × E. KRICHAUFF was having maximum trait value with specific adaptation while DUCULA 4 and KRL 19 were having general adaptability. AMMI2 biplot revealed high stability of Kharchia 65 and KRL 99 across environments. E1 (timely sown, non-saline soil) recorded maximum site mean while E2 (timely sown, sodic soil) was having minimum interaction with genotypes (AMMI1 = 1.383). Thus, our studies suggest that AMMI model is also useful for estimating adaptability of traits other than yield utilized for breeding salt tolerant wheat varieties.
A method for the determination of uranium and 210Po in high salinity water samples has been elaborated. Both radionuclides are preconcentrated from 0.5 dm3 saline media by co-precipitation with hydrated manganese dioxide, followed by dissolution of the precipitate in 200 mL of
1 M HCl. Uranium isotopes 235U and 238U can be directly determined by ICP MS method with a detection limit of 0.01 ppb for 238U. Prior to a selective determination of 210Po, the majority of other naturally occurring α-emitting radionuclides (uranium, thorium and protactinium) can be stripped
from this solution by their extraction with a 50% solution of HDEHP in toluene. Finally, 210Po is simply separated by direct transfer to an extractive scintillator containing 5% of trioctylphosphine oxide in Ultima
Gold F cocktail and determined by an α/β separation liquid scintillation technique with detection limit below 0.1 mBq/dm3.
Authors:A. Boustani, F. Fatehi, and R. Azizinezhad
Salinity is a major constraint to crop productivity and mechanisms of plant responses to salinity stress are extremely complex. “Hordeum marinum” is a salt tolerant barley species, which could be a good source to evaluate salt-tolerance patterns. Proteomics is a powerful technique to identify proteins involved in plant adaptation to stresses. We applied a proteomic approach to better understanding the mechanism of plant responses to salinity in a salt-tolerant genotype of barley. At the 4-leaf stage, plants were exposed to 0 (control treatment) or 300 mM NaCl (salt treatment). Salt treatment was maintained for 3 weeks. Total proteins of leaf 4 were extracted and separated by two-dimensional gel electrophoresis. More than 290 protein spots were reproducibly detected. Of these, 20 spots showed significant changes to salt treatment compared to the control: 19 spots were upregulated and 1 spot was absent. Using MALDI-TOF/TOF MS, we identified 20 cellular proteins which represented 11 different proteins and were classified into five categories. These proteins were involved in various cellular functions. Upregulation of proteins which involved in protein processing (ribosomal protein, cullin family, cp31AHv protein and RNA recognition motif (RRM) superfamily), photosynthesis (Ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) and Ribulose bisphosphate carboxylase/oxygenase activase (rubisco activase)), energy metabolism (cytosolic malate dehydrogenase (cyMDH) and fructokinase), oxygen species scavenging and defense (cystatin and thioredoxin) may increase plant adaptation to salt stress.
In order to evaluate the effect of Azosprillium inoculation and molybdenum application on common barley grown in saline condition, a greenhouse experiment was conducted at Azad university, branch of Eghlid, Iran. The experimental design was factorial based on complete randomized design with four replications. The first factor comprised of four salinity treatments (1 as control, 5, 10 and 15 ds m−1), second factor comprised the levels of Mo application (1: treated and 2: untreated = control) and the third factor included two levels of Azosprillum inoculation (inoculated and uninoculated = control). The measured parameters were chlorophyll fluorescence, photosynthesis (Ps) rates, carbohydrates, nitrate, ammonium and protein content, nitrogenase activity, grain yield (GY) and yield components. The results showed that salinity decreased GY in all levels. GY reduction in inoculated treatment was lower (12.9%) than uninoculated treatment (29.7%). GY reduction was highly related to the reduction of grain number (GN) rather than reduction in ear mX2. Inoculation and application of Mo reduced harmful effects of salinity especially on mean kernel weight and grain number. Soluble saccharides and protein contents increased with increasing salinity. Inoculation and Mo application significantly increased the content of fructan and sucrose respectively. The mean values of Fv/Fm and photosynthesis rate reduced in the salinity treatments compared to the control. Inoculation and Mo application significantly increased photosynthesis rates at all salinity levels. The highest plant N content was obtained from inoculated, control salinity treatment by applying Mo. In inoculated barley roots with application of Mo, nitrogenase activity (NA) was not severely inhibited by salinity. Data also showed that Mo application positively affected nitrogenase activity. Inoculation, caused plant to cope on the stress, effectively by increasing fructan content and NO3/NH4 ratio and lower decrease in whole plant N content and Fv/Fm ratio. Generally, Azosprillium inoculation helped plants perform better under salinity treatments and Mo application ameliorated plant nitrogen status.
Authors:S.L. Krishnamurthy, S.K. Sharma, R.K. Gautam, and V. Kumar
Effects of salinity on correlation, path and stress indices, yield and its components were studied in a set of 34 promising rice genotypes collected from various national and international organizations. These genotypes were evaluated in a randomized complete block design with three replications during the wet seasons (kharif) of 2009 and 2010 in normal (ECiw ∼ 1.2 dS/m) and salinity stress (ECiw ∼ 10 dS/m) environments in micro plots at Central Soil Salinity Research Institute (CSSRI), Karnal, India. Grain yield per plant showed positive significant association with plant height, total tillers, productive tillers, panicle length, and biological yield per plant and harvest index under normal environment, whereas grain yield showed positive significant association with biological yield and harvest index under salinity stress. These results clearly indicate that selection of high yielding genotypes would be entirely different under normal and saline environments. The stress susceptibility index (SSI) values for grain yield ranged from 0.35 (HKR 127) to 1.55 (TR-2000-008), whereas the stress tolerance index (STI) values for grain yield ranged from 0.07 (PR 118) to 1.09 (HKR 120). The genotypes HKR 120, HKR 47 and CSR-RIL-197 exhibited higher values of stress tolerance index (STI) in salinity. Under salinity, negative and significant association was shown by SSI and grain yield in contrast to positive and significant association shown by STI and grain yield. These associations could be useful in identifying salt tolerant and sensitive high yielding genotypes. The stress susceptible and stress tolerance indices suggest that the genotypes developed for salinity tolerance could exhibit higher tolerance, adaptability and suitability. Harvest index and biological yield traits emerged as the ideal traits for improvement through selection and could be used to increase the rice productivity under saline stress environments.
hydrogeologically closed Carpathian Basin
particular importance in the salinization/alkalization processes. In the
poorly-drained low-lying areas the capillary flow transports high amounts of
water soluble salts from the shallow, „stagnant” groundwater with high salt
concentration and unfavourable sodium-carbonate(bicarbonate) type ion
composition to the overlying soil horizons. Due to the strongly alkaline soil
solution, the Ca and Mg salts (mostly carbonates and bicarbonates) are not
soluble and Na
became absolutely predominant in the migrating soil
solution which leads to high ESP even at relatively low salt concentration.
saturation of heavy-textured soils with high amount of
expanding clay minerals results in unfavourable physical-hydrophysical
extreme moisture regime
of these soils, which are their
main ecological constrains and the limiting factors of their fertility,
productivity and agricultural utility. The simultaneous hazard of waterlogging
or overmoistening, and drought sensitivity in extensive lowland areas,
sometimes in the same places within a short period, necessitates a precise,
“double function” soil moisture control against their harmful
ecological/economical/social consequences. Most of the environmental constrains
(including salinity/alkalinity/sodicity) can be efficiently controlled:
prevented, eliminated, or - at least - moderated. But this needs permanent care
and proper actions: adequate soil and water conservation practices based on a
comprehensive soil/land degradation assessment. It includes continuous
registration of facts and changes (monitoring); exact and quantitative knowledge
on the existing soil processes, their influencing factors and mechanisms.
Clays high in Mg content occur frequently in the high saline environment of salt lakes in southern Tunisia. The DTA curves
of these clays show a striking endothermic-exothermic reaction in the temperature range of 800–820�C. A strong correlation
is observed between the intensity of these coupled reactions and the Mg content of the initial clay sample. The initial endothermic
reaction is interpreted as the melting/dehydroxylation of the Mg-bearing smectites. The subsequent exothermic peak is interpreted
as caused by the crystallisation of the new Mg-silicate phase enstatite. Therefore, the DTA is considered as a suitable method
for the identification and relative quantification of high Mg clay minerals (e.g. trioctahedral smectites). Variations of
the Mg content of the studied samples were well detectable by means of DTA, disclosing a distinct distribution pattern of
the salt lake clays. Clues to bulk chemical composition of the initial clay assemblage can also be found in the results of
the X-ray analysis of the firing products.