Enhanced nutrient uptake in salt-stressed Mentha piperita using magnetically treated water

Biochemical properties and pigment contents of Satureja genotypes affected by plant growth regulators and temperature stress

There is little data, to our knowledge, on the biochemical properties of different Satureja sp. genotypes affected by plant growth regulators (PGR) under temperature stress. A split plot research on the basis of a complete randomized block design with three replicates examining temperature stress (planting dates, 8th of April, May and June) (main factor), and the factorial combination of plant growth regulators (PGR, control (CO), gibberellic acid (GA), fertilization (MI), and amino acid (A)), and genotypes (Khuzestani, Mutika, and Bakhtiari) on plant biochemical properties, was conducted. Plant pigment contents (chlorophyll a, and b and carotenoids (car)), antioxidant activity (catalase (CAT), ascorbate peroxidase (APX) and guaiacol peroxidase (GP)), and leaf protein were determined. Treatments significantly and differently affected the genotypes performance. PD3 and PD1resulted in significantly higher activity of APX (0.059 U. mg-1) and GP (0.190 U. mg-1), respectively (P ≤ 0.05). Temperature stress significantly affected plant CAT activity (U. mg-1) at PD1 (0.084) and PD3 (0.820). Higher temperature significantly enhanced leaf Pro, MI increased plant APX (0.054) and CAT activities (0.111 U. mg-1) significantly, and GA resulted in the highest and significantly different GP activity (0.186 U. mL-1). Treatments T1 and T3 significantly enhanced Chla and Car content, and MI resulted in significantly higher Chlb content (0.085 mg g-1 leaf fresh weight). Car and CAT are the two most sensitive biochemical traits under temperature stress and can more effectively regulate Satureja growth and activity. It is possible to alleviate temperature stress on Satureja biochemical properties by the tested PGR.

Effects of the Powder from Hoggery Desulfurization Tanks on the Salinity Resistance of Lettuce

Lettuce is an important vegetable cultivated worldwide, even in regions with highly saline soils. A large amount of research discusses the application of sulfur on the increase of antioxidation in plants. The powder from hoggery desulfurization tanks contained high amounts of sulfur and small amounts of other nutrients for plants. This powder can be added to liquid fertilizer to create high-sulfur liquid fertilizer (HSLF). This study observed the cell morphologies of lettuce root apices under salt stress after the application of HSLF. Lettuce plants were cultivated in hydroponic solutions containing one of two NaCl (0 and 40 mM) and three HSLF (0.0, 1.5, and 3.0 g L−1) concentrations. Salinity reduced the K+/Na+ ratio in the plant leaves; however, this reduction was smaller in the HSLF-treated plants. Except for phosphate and potassium, nutrient absorption is inhibited under conditions of high salinity. Using scanning electron microscopy, we observed apices more integrated on cell roots after increasing HSLF supplement under non-salt-stressed conditions. In addition, the cells were repaired after increasing the supplement of HSLF under the condition of 40 mM NaCl. Although salt stress reduced plant growth, the reductions were minimized in the HSLF-treated plants. The application of HSLF potentially alleviated salt injury in lettuce root apices and was probably associated with the improvement of phosphorus and potassium absorption and increasing K+/Na+ ratios in lettuce plants.

Tomato (Solanum lycopersicum) growth and fruit quality affected by organic fertilization and ozonated water

The use of modern and safe techniques to increase plant growth and yield is of significance. There is little data, to our knowledge, on the use of organic fertilization and ozonated water (ozone (O3) affecting tomato (Solanum lycopersicum) growth and quality. Different tomato growth and fruit quality parameters including yield, fruit number, leaf fresh and dry weight, leaf and inflorescence number, plant height and stem diameter, distance from the first inflorescence to the collar, total soluble solids, total acidity, chlorophyll a, chlorophyll b, and total were determined. O3 treatment resulted in significant affects in all tomato parameters. One of the interesting results of the present research is the increased concentration of the antioxidant ascorbic acid (vitamin C) in response to ozonation, which can also improve tomato quality. However, organic fertilization and its interaction with the O3 treatment significantly affected only some of the measured tomato parameters. Ozonated water, at proper concentrations, may improve tomato growth and fruit quality, and if combined with organic fertilization, its positive effects may increase.

The physicochemical approaches of altering growth and biochemical properties of medicinal plants in saline soils

Medicinal plants are important sources of biochemical compounds affecting human health. However, because large areas of the world are subjected to different stresses including salinity, it is important to find methods, which may control the growth and biochemical properties of medicinal plants in such conditions. Another aspect of cropping medicinal plants in saline soils is the alteration of their biochemical properties by stress. Due to the significance of planting medicinal plants in saline soils, the objective of the present review article is to investigate and analyze the physicochemical approaches including soil leaching, organic fertilization, mineral nutrition, ozonated water, magnetism, superabsorbent polymers, and zeolite, which may control the effects of salinity stress on the growth and biochemical properties (production of secondary metabolites) of medicinal plants. In our just-published review article, we investigated the biological approaches, which may affect the growth and biochemical properties of medicinal properties in saline soils. Although salinity stress may induce the production of biochemical products in medicinal plants, the use of physicochemical approaches is also recommendable for the improved growth and biochemical properties of medicinal plants in saline soils. More has yet to be indicated on the use of the physicochemical approaches, which may affect the growth and biochemical properties of medicinal plants in salt stress conditions. KEY POINTS: • Growth and physiological alteration of medicinal plants in salt stress conditions. • The physicochemical approaches of such alteration have been reviewed. • More has yet to be indicated on the approaches, which may affect such properties.

The biological approaches of altering the growth and biochemical properties of medicinal plants under salinity stress

Due to their interesting properties for human health, medicinal plants are of worldwide interest, including Iran. More has yet to be investigated and analyzed on the use of methods affecting medicinal plant growth and biochemical properties under stress. The important question about medicinal plants is the purpose of their plantation, determining their growth conditions. The present review article is about the effects of salinity stress on the growth and production of secondary metabolites (SM) in medicinal plants. In stressful conditions including salinity, while the growth of medicinal plants decreases, the production of secondary metabolites (SM) may increase significantly affecting plant medicinal properties. SMs are self-protective substances that medicinal plants quickly accumulate to resist changes in the external environment. Although previous research has indicated the effects of salt stress on the growth and yield of medicinal plants, more has yet to be indicated on how the use of biological methods including plant growth regulators (PGR) and soil microbes (mycorrhizal fungi and plant growth-promoting rhizobacteria, PGPR) may affect the physiology of medicinal plants and the subsequent production of SM in salt stress conditions. The use of modern omics has become significantly important for the identification and characterization of new SM, transcriptomics, genomics, and proteomics of medicinal plants, as well as for the high production of plant-derived medicines. Accordingly, the possible biological mechanisms, which may affect such properties, have been presented. Future research perspectives for the production of medicinal plants in saline fields, using biological methods, have been suggested. KEY POINTS: • The important question about medicinal plants is the purpose of their plantation. • Secondary metabolites (SM) may significantly increase under salinity stress. • Biological methods, affecting the production of SM by stressed medicinal plants.

Soil physicochemical (colloidal) properties affected by ozonated water and organic fertilization

More has to be investigated on the use of ozonated water (O3) for the improvement of growth medium properties. Accordingly, the objective was to examine the effects of O3 (control, 0.5, 1.0, and 2.0 mg L-¹) on soil physicochemical (colloidal) properties using organic fertilization (manure), under non-planted or planted conditions. Different soil physicochemical (colloidal) properties including soil available water (SAW), aggregate stability, soil porosity, pH, salinity (EC), organic carbon (SOC), CaCO₃, and cation exchange capacity (CEC) were determined. The experimental treatments and their interactions significantly (P ≤ 0.05) affected soil physicochemical properties including SAW (4.17-10.98%), aggregate stability and porosity (7.77-57.37%), SOC (0.15-2.09%), and CEC (17.68-42.75 Cmol( +)/kg). Interestingly, the single use of O3 or in combination with manure significantly decreased EC. Although O3 significantly decreased SOC in non-planted soils, it significantly increased SOC in planted soils. O3 may enhance soil physicochemical (colloidal) properties, and if combined with manure in a planted soil, such positive effects may be further enhanced.