Moshe Sagi

• Professor
• Professor (Full) at Ben-Gurion University of the Negev

Among the three active aldehyde oxidases in Arabidopsis thaliana leaves (AAO1‐3), AAO3, which catalyzes the oxidation of abscisic‐aldehyde to abscisic‐acid, was shown recently to function as a reactive aldehyde detoxifier. Notably, aao2KO mutants exhibited less senescence symptoms and lower aldehyde accumulation, such as acrolein, benzaldehyde, and...

Plants generate reactive oxygen species (ROS) during different metabolic processes, which play an essential role in coordinating growth and response. ROS levels are sensitive to environmental stresses and are often used as a marker for stress in plants. While various methods can detect ROS changes, histochemical staining with nitroblue tetrazolium...

Among the three active aldehyde oxidases in Arabidopsis thaliana leaves (AAO1-3), AAO3, which catalyzes the oxidation of abscisic-aldehyde to abscisic-acid, was shown recently to function as a reactive aldehyde detoxifier. Notably, aao2KO mutants exhibited less senescence symptoms and lower aldehyde accumulation, such as acrolein, benzaldehyde, and...

Purpose Ureides, allantoin and allantoate, are N-rich compounds used for N transport in nodulated ureide legumes. Here, we investigated their role in response of Phaseolus vulgaris and Pisum sativum, representing ureide and amide legumes, respectively, to Cd toxicity. Methods First, ureide content and ureide metabolism in P. vulgaris and P. sativu...

Groundwater salinization is a problem affecting access to water in many world regions. Though desalination by conventional reverse osmosis (RO) can upgrade groundwater quality for drinking, its disadvantages include unmanaged brine discharge and accelerated groundwater depletion. Here, we propose a new approach combining RO, forward osmosis (FO), a...

Salinity negatively influences crop growth, but several salt-tolerant plant species (halophytes) are viable crops. Sarcocornia fruticosa (ecotypes EL and VM) is currently cultivated, but there is demand for new crop candidates and higher biomass production. Salicornia brachiata Roxb. and Arthrocneum macrostachyum L. are considered novel crops, and...

Exploiting consistent differences in radiation and average air temperature between two experimental vineyards (Ramat Negev, RN and Mitzpe Ramon, MR), we examined the impact of climate variations on total carotenoids, redox status, and phenylpropanoid metabolism in the berries of 10 white wine grapevine (Vitis vinifera) cultivars across three consec...

The roles of cytosolic O-acetylserine-(thiol)-lyase A (OASTLA), chloroplast-localized OASTLB and mitochondrion OASTLC in plant selenate resistance were studied in Arabidopsis. Impairment in OASTLA and OASTLB resulted in reduced biomass, chlorophyll and soluble protein levels compared with selenate treated impaired OASTLC and Wild-Type plants. The g...

Pathogenic fungi cause major postharvest losses. During storage and ripening, fruit becomes highly susceptible to fungi that cause postharvest disease. Fungicides are effective treatments to limit disease. However, due to increased public concern for their possible side effects, there is a need to develop new strategies to control postharvest funga...

Sarcocornia A. J. Scott is a halophytic edible succulent plant belonging to the Amaranthaceae family. To date, the genus includes 28 species distributed worldwide in saline environments, usually salt marshes. Sarcocornia (Scott) is similar to Salicornia (L.), which has a recognized commercial value in morphological and taxonomical traits. Species o...

To examine a role of purine degraded metabolites in response to wounding or UV-C stress, the Arabidopsis wild-type (WT) and Atxdh1 KO mutants, defective in xanthine dehydrogenase1 (XDH1), were exposed to wounding and UV-C irradiation stress. In Atxdh1 mutant, wounding or UV-C stresses resulted in lower fresh-weight, increased senescence symptoms an...

The Arabidopsis thaliana aldehyde oxidase 3 (AAO3) catalyzes the oxidation of abscisic aldehyde (ABal) to abscisic acid (ABA). Besides ABal, plants generate other aldehydes that can be toxic above a certain threshold. AAO3 knockout mutants (aao3) exhibited earlier senescence but equivalent relative water content compared to wild-type during normal...

To examine a role of purine degraded metabolites in response to wounding or UV-C stress, the Arabidopsis wild-type and Atxdh1 KO mutants, defective in xanthine dehydrogenase1 (XDH1), were exposed to wounding and UV-C irradiation stress. In Atxdh1 mutant, wounding or UV-C stresses resulted in lower fresh-weight, increased senescence symptoms and hig...

Molybdenum cofactor containing sulfite oxidase (SO) enzyme is an important player in protecting plants against exogenous toxic sulfite. It was also demonstrated that SO activity is essential to cope with rising dark-induced endogenous sulfite levels and maintain optimal carbon and sulfur metabolism in tomato plants exposed to extended dark stress....

Chloroplast-localized adenosine-5'-phosphosulphate reductase (APR) generates sulfite and plays a pivotal role in sulfate reduction to cysteine. The peroxisome-localized sulfite oxidase (SO), oxidizes excess sulfite to sulfate. Wild-type (WT), SO RNA-interference (SO Ri) and SO overexpression (SO OE) Arabidopsis mutants were infiltrated with sulfite...

The role of the cytosolic O-acetylserine-(thiol) lyase A (OASTLA), chloroplastic OASTLB and mitochondrion OASTLC in plant resistance/sensitivity to selenate was studied in Arabidopsis plants. Impairment in OASTLA and B resulted in reduced biomass, chlorophyll and soluble protein levels compared with impaired OASTL C and Wild-Type treated with selen...

Increasing plant tolerance to sulfites/SO2 can lead to the development of tolerant crops to biotic and abiotic stresses. Plant sulfite oxidase (SO) is a molybdo-enzyme that oxidizes excess SO2/sulfite into non-toxic sulfate. The effect of toxic sulfite on leaves and fruits was studied in tomato plants with different SO expression: wild-type, SO ove...

Halophytic plants are, by definition, well adapted to saline soils. However, even halophytes can face nutritional imbalance and the accumulation of high levels of compounds such as oxalic acid (OA), and nitrate (NO3⁻). These compounds compromise the potential nutritional health benefits associated with salt-tolerant plants such as Portulaca olerace...

Halophytic plants are, by definition, well adapted to saline soils. However, even halophytes can face nutritional imbalance and accumulation of high levels of compounds such as oxalic acid (OA), and nitrate (NO3¯). These compounds compromise the potential nutritional health benefits associated with salt tolerant plants such as Portulaca oleracea. T...

M. Sagi), yventura@bgu.ac.il (Y. Ventura). Abstract Plant sulfite oxidase) SO(is a molybdo-enzyme responsible for the oxidation of excess SO2/sulfite into non-toxic sulfate. The effect of toxic sulfite level on leaves and fruits was studied in tomato plants with different SO expression levels: wild-type (WT), SO overexpression (OE) and SO RNA inter...

The identification and understanding of metabolic pathways is a key aspect in crop improvement and drug design. The common approach for their detection is based on gene annotation and ontology. Correlation-based network analysis, where metabolites are arranged into network formation, is used as a complentary tool. Here, we demonstrate the detection...

The nitrogen (N)-rich ureides allantoin and allantoate, which are products of purine catabolism, play a role in N delivery in Leguminosae. Here, we examined their role as a N source in non-legume plants using Arabidopsis (Arabidopsis thaliana) plants mutated in XANTHINE DEHYDROGENASE1 (AtXDH1), a catalytic bottleneck in purine catabolism. Older lea...

It is generally known that when the grain is primed, saturated with a solution of biologically important elements and subsequently dried, the aleurone layer selectively permits ions of various metals. It is also known that in the case of a deficiency of molybdenum in the soil, a non-molybdenum inactive population of molecules of xanthine dehydrogen...

This study deals with the effect of zinc oxide nanoparticles (ZnO NPs) on halophyte from the genus Salicornia. The presence of ZnO nanoparticles (100 and 1000 mg/L) in the solid culture medium resulted in the negative effects on plant growth in the concentration-dependent manner. The shoot length of plant cultivated with 1000 mg/L ZnO NPs decreased...

The nitrogen rich ureides allantoin and allantoate, are known to play a role in nitrogen delivery in 49 Leguminosae, in addition to their role as reactive oxygen species scavengers. However, their role as a 50 nitrogen source in non-legume plants has not been shown. Xanthine dehydrogenase1 (AtXDH1) activity 51 is a catalytic bottleneck step in puri...

Salicornia andSarcocorniaare almost identical halophytes whose edible succulent shoots hold promise for commercial production in saline water. Enhanced sulfur nutrition may be beneficial to crops naturally grown on high sulfate. However, little is known about sulfate nutrition in halophytes. Here we show thatSalicornia europaea(ecotype RN) exhibits...

In response to oxidative stress the biosynthesis of the ROS scavenger, glutathione is induced. This requires the induction of the sulfate reduction pathway for an adequate supply of cysteine, the precursor for glutathione. Cysteine also acts as the sulfur donor for the sulfuration of the molybdenum cofactor, crucial for the last step of ABA biosynt...

The amino acid cysteine plays a major role in plant response to abiotic stress by being the donor of elemental sulfur for the sulfuration of the molybdenum cofactor, otherwise the last step of ABA biosynthesis, the oxidation of abscisic aldehyde, is inactivated. Additionally, cysteine serves as a precursor for the biosynthesis of glutathione, the r...

The Arabidopsis aldehyde oxidases are a multigene family of four AAOs (1-4) that oxidize a variety of aldehydes, amongst them abscisic aldehyde, which is oxidized to the phytohormone abscisic acid.Toxic aldehydes are generated in plants both under normal conditions and in response to stress.The detoxification of such aldehydes by oxidation is attri...

Selenium assimilation in plants is facilitated by several enzymes that participate in the transport and assimilation of sulfate. Manipulation of genes that function in sulfur metabolism dramatically affects selenium toxicity and accumulation. However, it has been proposed that selenite is not reduced by sulfite reductase. Instead, selenite can be n...

Plant sulfite oxidase [SO; E.C.1.8.3.1] has been shown to be a key player in protecting plants against exogenous toxic sulfite. Recently we showed that SO activity is essential to cope with rising dark-induced endogenous sulfite levels in tomato plants (Lycopersicon esculentum/Solanum lycopersicum Mill. cv. Rheinlands Ruhm). Here we uncover the ram...

Plant growth is strongly. Amongst is the reactive oxygen species (ROS) resulting not only tissue damage, but also may play a role in plant signal transduction. Arabidopsis plants with compromised XDH1 (Atxdh1) had less leaf damage when exposed to stress such as salinity, UV, application of the phyto-hormone ABA and nutrient starvation. Interestingl...

Crested wheatgrass (Agropyron cristatum) is a novel halophyte crop for sustainable agriculture in Northern Kazakhstan. This study investigated the effect of molybdenum (Mo) as molybdate (Na2MoO4·2H2O) and its chemical antagonist tungsten (W) as tungstate (Na2WO4·2H2O) on plant response to salinity treatment. The results showed that the treatment of...

The fresh water shortage in agriculture is an increasing problem worldwide, therefore the possibility of cultivating crops under saline conditions is of high importance. Crithmum maritimum, a halophytic plant naturally found on rocky coastlines of the Atlantic Ocean and the Mediterranean Sea, has a long history of human consumption and recently was...

Background: Freshwater comprises about a mere 2·5% of total global water, of which approximately two-thirds is locked into glaciers at the polar ice caps and on mountains. In conjunction with this, in many instances irrigation with freshwater causes an increase in soil salinity due to overirrigation of agricultural land, inefficient water use and...

Sulfite reductase (SiR) is an essential enzyme of the sulfate assimilation reductive pathway, which catalyzes the reduction of sulfite to sulfide. Here we show that tomato plants (Solanum lycopersicum L.) with impaired SiR expression due to RNA interference (SIR Ri) developed early leaf senescence. The visual chlorophyll degradation in leaves of SI...

Aster tripolium L. is a salt marsh halophyte that has recently gained interest as a cash crop vegetable. Leaf yield and quality were investigated in plants grown with salinity in experiments with Perlite in pots and in plots on dune sand. Plants were repetitively harvested in a 14-day cycle. A. tripolium irrigated with 50 mM NaCl exhibited the high...

Increasing soil salinization and the growing scarcity of fresh water dictate the need for a creative solution to attain sustainable crop production. To accomplish this aim, the domestication of inherently salt tolerant plant species with economic value is proposed as a straightforward methodology. Most studies investigating salt tolerance mechanism...

Plant sulfite reductase (SiR, EC 1.8.7.1) catalyzes the reduction of sulfite to sulfide in the reductive sulfate assimilation pathway. Comparison of SiR expression in tomato (Lycopersicon esculentum/Solanum lycopersicum Mill, cv. Rheinlands Ruhm) and Arabidopsis thaliana plants revealed that SiR is expressed in a different tissue-dependent manner t...

Little is known about the homeostasis of sulfite levels, a cytotoxic by-product of plant sulfur turnover. By employing extended dark, to induce catabolic pathways, we followed key elements of the sulfite network enzymes that include adenosine-5'-phosphosulfate reductase (APR) and the sulfite scavengers, sulfite oxidase (SO), sulfite reductase, UDP-...

Plant sulfite oxidase (SO) is a molybdenum cofactor (Moco) containing enzyme located in the peroxisomes. SO is thought to play a role in removing excess sulfite that accumulates upon decomposition of sulfur-containing amino acids or sulfated compounds. SO in plants is the major enzyme responsible for detoxifying the atmospheric or artificially elev...

Adenosine 5'-phosphosulfate (APS) reductase (APR; EC 1.8.4.9) catalyzes the two-electron reduction of APS to sulfite and AMP, a key step in the sulfate assimilation pathway in higher plants. In spite of the importance of this enzyme, methods currently available for detection of APR activity rely on radioactive labeling and can only be performed in...

Sulfur is the sixth most abundant element in life and an important building block of proteins and cellular metabolites. Plants like bacteria can synthesize their sulfur-containing biomolecules from sulfate, where sulfite is an intermediate of the sulfur assimilation pathway. Above a certain threshold SO(2)/sulfite is cytotoxic and is rapidly metabo...

Sulfite reductase (SiR; EC 1.8.7.1), an essential enzyme in the sulfate reduction pathway, catalyzes the reduction of sulfite to sulfide, as an intermediate for cysteine biosynthesis. The commonly used kinetic assay for the detection of in vitro SiR activity in plants is based on a coupled reaction, in which the sulfide produced is converted to cys...

a b s t r a c t Salicornia is a new vegetable crop that can be irrigated with highly saline water, even at salt concentrations equivalent to full-strength seawater. During leafy vegetable cultivation, the onset of the reproductive phase is an undesired phenomenon that reduces yield and quality and prevents year-round cultivation. Knowledge about th...

The halophyte Salicornia was recently introduced as a fresh vegetable crop that thrives in extreme salt conditions. Two annual Salicornia and two perennial Sarcocornia ecotypes were investigated for yield production and nutritional value in response to different seawater concentrations in the irrigation solution. A harvest schedule based on a three...

The growth of crop plants on full-strength seawater constitutes a major challenge because of the high salt content and the limited availability of essential microelements such as molybdenum. For cultivation of the halophyte Salicornia as seawater-grown crop, the effect of molybdate application on total yield production and the activities of the two...

Colletotrichum pathogens of fruit and leaves are known ammonium secretors. Here, we show that Colletotrichum coccodes virulence, as measured by tomato (Solanum lycopersicum cv. Motelle) fruit tissue necrosis, correlates with the amount of ammonium secreted. Ammonium application to fruit tissue induced hydrogen peroxide (H(2)O(2)) accumulation. To e...

In our recent paper in The Plant Journal,1 we described the remobilization of purine metabolites during natural and dark induced senescence in wild type and Atxdh1 mutant lines impaired in xanthine dehydrogenase (XDH), a pivotal enzyme in the purine catabolism pathway. In the light of these observations and additional evidence shown here, we discus...

The remobilization of metabolites during stress and senescence plays an important role in optimal plant adaptation to the environment. The plant molybdenum co-factor (MoCo) and flavin-containing enzyme xanthine dehydrogenase (XDH; EC 1.2.1.37) are pivotal for purine remobilization, and catalyze the conversion of the purine catabolic products hypoxa...

The gaseous pollutant SO(2) readily reacts with water to form sulfite that impacts deleteriously on animal and plant health. By modulating the level of sulfite oxidase (SO) that catalyzes the transformation of sulfites to the non-toxic sulfate, we show that Arabidopsis and tomato plants can be rendered resistant or susceptible to SO(2)/sulfite. Pla...

Reactive oxygen species (ROS) play a crucial role in many cellular responses and signaling pathways, including the oxidative burst defense response to pathogens. We have examined very early events in cryptogein-induced ROS production in tobacco (Nicotiana tabacum) Bright Yellow-2 suspension cells. Using Amplex Red and Amplex Ultra Red reagents, whi...

NADPH oxidases (NOX) catalyze the production of superoxides, a type of reactive oxygen species (ROS). The dramatic induction of ROS production by human NOX2 in activated blood phagocytic cells and its role in promoting pathogen killing has long motivated research in this area (Babior et al., 2002). In plants, the NOX homologs have been named respir...

The effects of three irrigation salinity levels (1.8, 3.3, and 4.8 dS/m) on ion accumulation and relative turgidity of Cabernet Sauvignon (Vitis vinifea) grapes on ‘Rugerri’ and ‘Salt Creek’ rootstocks were studied in order to introduce more saline water in the Negev Desert of Israel. Leaf samples were taken four times during the summer of 1997 and...

The influence of salinity on the activity of nitrate reductase (NR, EC 1.6.6.1) and the level of the molybdenum cofactor (MoCo) as affected by the source and concentration of nitrogen was studied in annual ryegrass (Lolium multiflorum cv. Westerwoldicum). Plants grown in sand were irrigated with nutrient solution with an electrical conductivity of...

In the Negev Desert of Israel, saline water is used to irrigate grapevines (Cabernet Sauvignon grafted on Roggeri) with the premise that the vine is only moderately salt sensitive. The objectives of the research were to study the effect of salinity on major production factors of the grapevine. Irrigation was applied with water of three salinity lev...

The plant molybdenum-cofactor (Moco) and flavin-containing enzymes, xanthine dehydrogenase (XDH; EC 1.2.1.37) and aldehyde oxidase (AO; EC 1.2.3.1) are thought to play important metabolic roles in purine metabolism and hormone biosynthesis, respectively. Their animal counterparts contribute to reactive oxygen species (ROS) production in numerous pa...

Brackish water (7 dS m−1) is frequently utilized to drip-irrigate crops in the Negev desert of Israel, the practice being to use deep sandy soils (96% sand) to avoid soil salinization. When muskmelon (Cucumis melo L.), a moderately salt-sensitive crop species, was grown using brackish irrigation under these conditions, yields declined due to a sign...

Production of spring potato (Solanum tuberosum L. cv. Désirée) on a deep sandy soil in the central highland of the Negev desert of Israel under drip irrigation with saline water (up to 6.2 dS m−1) was studied in the years 1992–1997. The objective of the study was to determine the effects of saline water irrigation on potato production in an arid en...

The requirement for hydrogen peroxide (H2O2) generation and action during stomatal closure induced by darkness and abscisic acid (ABA) was investigated in pea (Pisum sativum L.). Stomatal closure induced by darkness or ABA was inhibited by the H2O2-scavenging enzyme catalase or the antioxidant N-acetyl cysteine (NAC), or by diphenylene iodonium (DP...

Drought is a major abiotic stress that limits plant growth and crop productivity. A spontaneous wilty mutant (eibi1) hypersensitive to drought was identified from wild barley (Hordeum spontaneum Koch). eibi1 showed the highest relative water loss rate among the known wilty mutants, which indicates that eibi1 is one of the most drought-sensitive mut...

The influence of molybdate and tungstate in the nutrient growth medium on the activities of the molybdo-enzymes, aldehyde oxidase (AO) and xanthine dehydrogenase (XDH) in barley (Hordeum vulgare L.) plants was studied. Root AO and XDH activities were enhanced with increasing concentrations of molybdate in the nutrient medium, while AO and XDH activ...

Plant respiratory burst oxidase homologs (Rboh) are homologs of the human neutrophil pathogen-related gp91(phox). Antisense technology was employed to ascertain the biological function of Lycopersicon esculentum (tomato) Rboh. Lines with diminished Rboh activity showed a reduced level of reactive oxygen species (ROS) in the leaf, implying a role fo...

Grafted plants of flacca, an ABA-deficient mutant of tomato (Lycopersicon esculentum), and the wild-type variety Rheinlands Ruhm were grown with and without salinity stress to test the roles of roots and shoots in the regulation of plant growth. Fourteen days after exposure to 200 mM NaCl, shoot and root fresh weight, endogenous ABA concentrations,...

The effects of endogenous and exogenous abscisic acid (ABA) on the growth of flacca, a specific ABA-deficient mutant of tomato (Lycopersicon esculentum), and the wild-type variety Rheinlands Ruhm (RR) were investigated under conditions in which the effects of stomatal behavior on growth were minimized. Two experimental systems were used: (1) germin...

Tomato fruit cracking occurs both during ripening and after harvest. Cracked fruits cannot be marketed and the cracks form sites for fungal penetration and infection. An assay based on immersion of the fruit in water was developed to study factors involved in fruit cracking. Adding calcium to the water reduced cracking whereas chelating agents incr...

ABA is a plant signalling-molecule that plays a key role in regulating stomatal response, stress-tolerance responses, and coordinated growth of roots and shoots. Knowledge of the relationship between endogenous ABA level and plant growth is essential for improving plant growth and productivity. The wild-type tomato Rheinlands Ruhm (RR) and its flac...

The molybdenum cofactor (MoCo)-containing enzymes aldehyde oxidase (AO; EC 1.2.3.1) and xanthine dehydrogenase (XDH; EC 1.2.1.37) require for activity a sulfuration step that inserts a terminal sulfur ligand into the MoCo. The tomato flacca mutation was originally isolated as a wilty phenotype due to a lack of abscisic acid (ABA) that is related to...

Genes encoding homologs of the gp91(phox) subunit of the plasma membrane NADPH oxidase complex have been identified in plants and are hypothesized to be a source of reactive oxygen species during defense responses. However, the direct involvement of the gene products in superoxide (O(2)(-)) production has yet to be shown. A novel activity gel assay...

Light distribution, canopy structure, and yield were studied in vertically grown greenhouse 'Galia' melon. Plants were at three densities and two levels of irrigation water salinity, topped to fixed numbers of leaves, and allowed one fruit. The objectives were to determine whether productivity is light limited, to characterize the light environment...

The flacca tomato (Lycopersicon esculentum) mutant displays a wilty phenotype as a result of abscisic acid (ABA) deficiency. The Mo cofactor (MoCo)-containing aldehyde oxidases (AO; EC 1.2.3.1) are thought to play a role in the final oxidation step required for ABA biosynthesis. AO and related MoCo-containing enzymes xanthine dehydrogenase (XDH; EC...

The flacca tomato (Lycopersicon esculentum) mutant displays a wilty phenotype as a result of abscisic acid (ABA) deficiency. The Mo cofactor (MoCo)-containing aldehyde oxidases (AO; EC 1.2.3.1) are thought to play a role in the final oxidation step required for ABA biosynthesis. AO and related MoCo-containing enzymes xan-thine dehydrogenase (XDH; E...

Tomato plants (Lycopersicon esculentum (L.) Mill. cv. F144) were irrigated with low concentrations of mixed salts; the highest level (E.C. 7 dS m-1) simulated conditions used to produce quality tomatoes in the Negev highlands. CO2 enrichment (to 1200 μmol mol-1, given during the daytime) increased plant growth at the early stage of development. How...

The influence of salinity and nitrogen source on xanthine dehydrogenase (XDH; EC 1.2.1.37) and aldehyde oxidase (AO; EC 1.2.3.1) was studied in annual ryegrass (Lolium multiflormn cv. Westerwoldicum). The activities of AO and XDH in the roots and shoots of ryegrass plants increased with salinity and NH4+ concentration. The salinity-enhanced activit...

Salinity improve tomato fruit quality by enhancing hexose accumulation. To study the involvement of the carbohydrate influx into fruits under saline conditions, we have studied carbohydrate metabolism in leaves and the partitioning of photosynthetic 14C in fruits of tomato plants exposed to 0, 50, or 100 mM NaCl. Carbohydrate content and the activi...

The influence of NH4+ And NO3− on the activity of nitrate reductase (NR; EC 1. 6.6.1) and the level of the molybdenum cofactor (MoCo) was studied in annual ryegrass (Lolium multiflorum cv Westerwoldicum). Addition of 4.5 mM NH4+ to plants grown with NO3− increased NR activity in the shoots, but decreased it in the root. Total MoCo increased in both...

The molybdenum cofactor (MoCo) is a component of aldehyde oxidase (AO EC 1.2.3.1), xanthine dehydrogenase (XDH EC 1.2.1.37) and nitrate reductase (NR, EC 1.6.6.1). The activity of AO, which catalyses the last step of the synthesis of abscisic acid (ABA), was studied in leaves and roots of barley (Hordeum vulgare L.) plants grown on nitrate or ammon...

The concentration of organic acids, organic nitrogen (N), nitrate (NO3), and total cations increased in annual ryegrass [Lolium multiflorum Lam.) with salinity and N concentration in the growth medium. Increasing salinity and N in the growth medium induced changes in the level of key enzymes of N assimilation and organic acids: nitrate reductase (N...

Studies on the effects of salinity and nitrogen (N) fertilization on ionic balance, biomass, and organic N production of annual ryegrass (Lolium multiflorum Lam.) were conducted. Plants grown in sand were irrigated with nutrient solution with an electrical conductivity of 2 or 11.2 dS#lbm, and N in the form of sodium nitrate (NaNO3), ammonium nitra...

Two barley genotypes, the wild type and the narla, nar7w mutant, impaired in two structural genes of the nitrate reductase (NR) apoproteins, exhibited a considerable level of molybdenum cofactor (MoCo) when grown in the absence of NO3. Increasing concentrations of nitrate in the nutrient solutions did not affect MoCo content in shoots and roots of...

The molybdenum cofactor (MoCo) is the prosthetic group of several enzymes in higher plants including nitrate reductase (NR, EC 1.6.6.1). The traditional assay of MoCo includes its release from binding proteins, followed by its complementation with the NR (EC 1.6.6.3) apoprotein of the nit-I mutant of Neurospora crassa and the assay of the assembled...

A double-emitter source (DES) irrigation system was designed, using trickle instead of sprinkler irrigation. Two trickle laterals and their emitters connected to two tanks of stock solutions are coupled together to form a double-joint lateral. The emitters of the two lines have different and varying discharges to obtain various mixings between the...

Experiments with tomato (Lycopersicon esculentum (L.) Mill. cv. F144) grown in a greenhouse show that salinity (electric conductivity 6-7 dS m-1) and bicarbonate fertilization enhanced the accumulation of total solids in the fruits. Short term experiments with tomato seedlings were carried out simultaneously to study the effect of salinity (NaCl) a...

The salt tolerance of 14 sweet corn (Zea mays L.) cultivars differing in days for silking and days for grain filling was evaluated under field conditions in an arid environment. Plants were drip irrigated with fresh (ECi=1.2 dS m−1) and brackish (ECi=6.2 dS m−1) water. Brackish water irrigation started 20 days after planting following the applicati...