Reza Soleimani, Hasan Tofighi , Hosseinali Alikhani,
Volume 2, Issue 3 (12-2015)
Abstract
This investigation was carried out to evaluate Indole acetic acid (IAA) production by isolated bacteria from drought and salinity affected soils. Four hundred bacteria were isolated from soils with different levels of electrical conductivity (EC) and sodium adsorption ratio (SAR). Then the ability of these bacteria to produce IAA and the effects of different amounts of tryptophan and drought-salinity tensions on IAA production were analyzed. Results indicated that the effects of drought and salinity tensions on variability of IAA production were statistically significant. One of the bacterial species isolated from saline-sodic soils, Arthrobacter siccitolerans, was IAA producer and data comparison indicated that under drought stress conditions it produced IAA 84.3% higher than isolate RS11. While isolated RS11 produced highest rate of IAA (10.42 µg.ml-1) under normal conditions. Also, A.siccitolerans continued to produce IAA until the EC was 40 dS.m-1 and OP (Osmosis pressure) was -20 bar. The amount of IAA production per unit of applied tryptophan in this bacterium was 0.1 and in others it was lesser. According to experiments, the relative preference of this bacterium was verified and proposed for field experiments in drought, salinity and salinity-sodicity affected soils.
Nader Chaparzadeh, Roya Saeedifar, Leila Zarandi-Miandoab , Mohammad Pazhang,
Volume 4, Issue 2 (9-2017)
Abstract
In recent years, the involvement of nitric oxide (NO) in numerous physiological processes, particularly the mitigation of stress-induced negative effects on plants, has been clarified. Under salinity conditions, plants are subjected to a secondary oxidative stress. The present work was designed to examine the exogenous application of nitric oxide (NO), in the form of its donor sodium nitroprusside (SNP), in mitigating the deleterious effects of salinity on Zygoph-yllum fabago L. plants. SNP (200 µM) was applied to plants growing medium under saline (200 and 400 mM NaCl) and non-saline conditions. Growth, oxidative stress markers [cell membrane stability index (MSI) and H2O2 conc-entration], antioxidant enzymes activities [peroxidase (POX, EC 1.11.1.7) and catalase (CAT, EC 1.11.1.6)], as well as the contents of some antioxidant compounds (flavonoids and carotenoids) were determined. Salinity lowered the shoot and root dry weights, while it enhanced peroxidase and catalase activities. High salinity increased H2O2; however, it de-creased the carotenoids content of leaves. Exogenous NO enhanced the growth, MSI, flavonoids and carotenoids co-ntents of salinized plants. In salinity plus SNP treated plants, H2O2 concentration and the activities of the examined en-zymes were reduced. Data suggest that a cooperative process is performed by the antioxidant systems in Syrian bean ca-per in order to cope with salinity. Also, the application of exogenous NO was found to be useful in the mitigation of salinity-induced oxidative stress in plants.
Leila Zarandi-Miandoab, Nader Chaparzadeh, Hamid Fekri-Shali,
Volume 8, Issue 2 (7-2021)
Abstract
In order to investigate the effects of salinity and magnesium (Mg) on the growth parameters, physiological characteristics and content of some metabolites in Syrian bean-caper (Zygophyllum fabago) plants, a factorial experiment with completely randomized design was performed and carried out in perlite with Hoagland solution. The treatments were combinations of two levels of salinity (0 and 300 mM NaCl) and three levels of Mg concentration (2, 4 and 8 mM; 0, 2 and 6 mM over the standard Mg content of Hoagland medium, 2mM, respectively). The simultaneous effect of salinity and Mg did not change the fresh weight of the plants, but increased the dry weight by 50%. Salinity reduced the leaf area, but the presence of Mg improved and even increased the leaf area of the plants. The Mg reduced NAR, while increased LAR and RLGR. Salinity decreased the RLGR. The simultaneous effect of salinity and Mg increased and improved RGR, LWR, RLGR. The tolerance index in saline treatments increased with the presence of Mg, but the R/S ratio showed a significant increase only in salinity condition, however, the presence of Mg moderated it. Salinity reduced the photosynthetic pigments, while the presence of Mg ameliorated the decrease. As a result, salinity and Mg increased the total sugar content of the leaf and reduced the total sugar content of the root. Salinity and Mg reduced the total protein content of all the organs of the plant specimens studied. In general, salinity had a negative effect on the physiological parameters of the Zygophyllum fabago plants, while the application of supplementary Mg improved the growth indices and increased the plants tolerance against salinity.
Akbar Forghani, Amir Hossein Forghani, Maryam Altafi, Kazem Hashemi Majd, Omid Sofalian,
Volume 8, Issue 3 (10-2021)
Abstract
Most of agricultural lands in Iran are located in arid and semi-arid regions and are considered as saline soils. In order to investigate the interaction of salinity as well as potassium and calcium on the growth and yield of tomato plants, a factorial experiment was perfected in the form of randomized complete blocks, in hydroponic conditions, with three replicates per treatment. Experimental factors include salinity at three levels (0, 20, and 40 mM NaCl), potassium content form chloride, nitrate (0 and 15 mM), and calcium from chloride, and nitrate (with 0 and 10 mM (. The studied growth factors, including plant height, stem diameter, number of leaves, flowers and fruits and leaf chlorophyll decreased with increase NaCl. Treatment plants with Ca (NO3)2 at 40 mM NaCl, increased the shoot and root dry weight by 55% and 95%, respectively. In addition, application of Ca (NO3)2 in the medium with maximum salinity concentration resulted in an increase of 75% in chlorophyll content. The analysis of data showed that the increase of salinity was accompanied with increase sodium content level of tomato plants. However, the root potassium was observed to decrease. On the contrast to the root, potassium content showed no change in the organs from the root upwards. Also, the use of Ca (NO3)2 with 40 mM NaCl reduced Na+ content by 23% compared with plants treated only with 40 mM NaCl. According to the results, it seems that application of Ca (NO3)2 may improve chlorophyll content, dry weight, and modulate ion hemostasis and decreased the negative of salt stress in tomato plants.
