Transcriptome and structure analysis in root of Casuarina equisetifolia under NaCl treatment

Background High soil salinity seriously affects plant growth and development. Excessive salt ions mainly cause damage by inducing osmotic stress, ion toxicity, and oxidation stress. Casuarina equisetifolia is a highly salt-tolerant plant, commonly grown as wind belts in coastal areas with sandy soils. However, little is known about its physiology and the molecular mechanism of its response to salt stress. Results Eight-week-old C. equisetifolia seedlings grown from rooted cuttings were exposed to salt stress for varying durations (0, 1, 6, 24, and 168 h under 200 mM NaCl) and their ion contents, cellular structure, and transcriptomes were analyzed. Potassium concentration decreased slowly between 1 h and 24 h after initiation of salt treatment, while the content of potassium was significantly lower after 168 h of salt treatment. Root epidermal cells were shed and a more compact layer of cells formed as the treatment duration increased. Salt stress led to deformation of cells and damage to mitochondria in the epidermis and endodermis, whereas stele cells suffered less damage. Transcriptome analysis identified 10,378 differentially expressed genes (DEGs), with more genes showing differential expression after 24 h and 168 h of exposure than after shorter durations of exposure to salinity. Signal transduction and ion transport genes such as HKT and CHX were enriched among DEGs in the early stages (1 h or 6 h) of salt stress, while expression of genes involved in programmed cell death was significantly upregulated at 168 h, corresponding to changes in ion contents and cell structure of roots. Oxidative stress and detoxification genes were also expressed differentially and were enriched among DEGs at different stages. Conclusions These results not only elucidate the mechanism and the molecular pathway governing salt tolerance, but also serve as a basis for identifying gene function related to salt stress in C. equisetifolia.

Growth and Characteristics of Two Different Epichloë sinensis Strains Under Different Cultures

In the present study, two Epichloë sinensis endophyte strains isolated from different Festuca sinensis ecotypes were inoculated on potato dextrose agar (PDA) and potato dextrose broth (PDB) media with or without (control) exogenous additives. After 4weeks of growth, the growth (colony diameter, hyphal diameter, and mycelial biomass) and other characteristics (pH and antioxidant capacity of culture filtrate, mycelial ion contents, and hormone contents) were measured. The results showed that the culture conditions had significant effects (p<0.05) on the hyphal diameter, mycelial biomass, and hormone content of the two strains. The mycelial biomass of the two strains in PDB was significantly higher (p<0.05) than that on PDA. Except for strain 1 with indole-3-acetic acid (IAA) treatment and strain 84F with control and VB1 treatments, the hyphal diameter of the two strains in PDB under the other treatments was significantly higher (p<0.05) than that on PDA. In most cases, the IAA, cytokinins (CTK), abscisic acid (ABA), and gibberlic acid (GA) contents in the mycelia on PDA of the two strains were significantly higher (p<0.05) than those in PDB. The two E. sinensis strains exhibited significantly different performances (p<0.05) under the five treatments. The indices, including colony diameter, mycelial biomass, scavenging ability of superoxide anion radicals and hydroxyl radicals, pH of culture filtrate, ion contents, hyphal diameter, and IAA, CTK, GA, and ABA contents were significantly different (p<0.05) between the two strains, although the performance was inconsistent. Exogenous additives had significant effects (p<0.05) on the performance of the two E. sinensis strains. Indole-3-acetic acid and VB1 treatments significantly promoted (p<0.05) the growth of the two strains on both PDA and PDB. Indole-3-acetic acid treatment also significantly increased the hyphal diameters of the two strains in PDB (p<0.05). Indole-3-acetic acid and VB1 treatments significantly reduced (p<0.05) the antioxidant ability of these two strains in PDB. NaCl and ZnCl2 treatments had significant inhibitory effects (p<0.05) on fungal growth and promotion effects on the antioxidant ability of the two strains. The treatments also had significant effects (p<0.05) on hyphal diameters and ion and hormone contents, although the effects varied with different indices.

Phytopharmacological Assessment of Some Medicinal Plants of Thal Desert of Pakistan

The presence of secondary metabolites and various ions in a plant determines its phytophamacological potential. Desert plants are adapted to stressful environmet by synthesizing secondary metabolites and ions accumulation as osmoticum.The present study was conducted to evaluate the pharmacological potential of Thal desert plants in term of their metabolites and nutrient ions concentrations. Five specimens of seasonally available herbs and three of trees of Thal desert plants were colected. After collection specimens were analysed for alkaloids, terpenoids, tannins, sugar and ion contents. The data were analyzed statistically and means were compared by Duncan’s Multiple Range Test. Among the herbs Panicum antidotale root showed highest terpenoid, K+ ion and Ca+ ion contents. The herb Aerva javanica stem showed lowest alkaloid, tannin, soluble sugar, phosphorus, potassium and calcium contents. Among trees specimens, Tamarix aphylla leaves showed highest soluble sugar, phosphorous, potassium and calcium contents. Stem of Acacia modesta showed the lowest alkaloid, terpenoid, phosphorous and potassium contents.

Regulated Salinity Eustress in A Floating Hydroponic Module of Sequentially Harvested Lettuce Modulates Phytochemical Constitution, Plant Resilience, and Post-Harvest Nutraceutical Quality

A mild salinity stress (eustress) may modulate the induction of the plant defense system in horticultural crops and the synthesis of phytochemical components able to enhance plant resilience, post-harvest performance, and the nutraceutical quality of produce. However, the choice of the correct eustress type and dose to induce the synthesis of these protective phytochemicals is pivotal to avoid potential interference with plant growth and productivity. In order to study how green and red lettuce (Lactuca sativa L.) plants equilibrate the nutritional and nutraceutical components of quality with yield components, we applied iso-osmotic concentrations of three different salts (20 mM NaCl, 20 mM KCl, and 13.3 mM CaCl2, with a final total ionic concentration of 40 mM) in combination with two successive harvests in a floating raft system. The biometric parameters, mineral composition, bioactive compounds, and antioxidant activity of both cultivars were analyzed. The green cultivar had a superior response concerning biometric traits and productivity compared to the red one during the first cut but lower phytochemical content (e.g., ascorbic acid). The effect of cut order, independently of cultivar and salinity treatments, demonstrated that at the first harvest plants could redirect metabolism by increasing the lipophilic antioxidant content (LAA) at the expense of plant yield, therefore increasing plant resilience and post-harvest nutraceutical quality; whereas, at the second harvest, plants reverted principally to tissue expansion. The treatments with iso-osmotic salt concentrations did not affect K and Mg ion contents but further increased LAA and resulted only in a moderate decrease of fresh yield. The lettuce nitrate content was reduced during the second cut only when lettuce plants were treated with NaCl and especially CaCl2.

Effects of Bi3+ Ion-Doped on the Microstructure and Photoluminescence of La0.97Pr0.03VO4 Phosphor

The objective of this paper is to enhance the emission intensity of La0.97Pr0.03VO4 single-phased white light emitting phosphor. The Bi3+ ion-doped La0.97Pr0.03VO4 single-phased white light emitting phosphors are synthesized using a sol-gel method. The structure and photoluminescence properties of (La0.97-yBiy)Pr0.03VO4 (y = 0-0.05) phosphor are also examined. The XRD results show that the structure of La0.97Pr0.03VO4 phosphors with different concentrations of Bi3+ ion doping keeps the monoclinic structure. The SEM results show that the phosphor particles become smoother when the Bi3+ ion is doped. The excitation band for La0.97Pr0.03VO4 phosphor exhibits a blue shift from 320 nm to 308 nm as the Bi3+ ion contents are increased. The maximum emission intensity is achieved for a Bi3+ ion content of 0.5 mol%, which is about 30% greater than that with no Bi3+ ion doped. The CIE chromaticity coordinates are all located in the near white light region for different Bi3+ ion-doped La0.97Pr0.03VO4 phosphors.

GhNHX3D, a Vacuolar-Localized Na+/H+ Antiporter, Positively Regulates Salt Response in Upland Cotton

Vacuolar sodium/proton (Na+/H+) antiporters (NHXs) can stabilize ion contents to improve the salt tolerance of plants. Here, GhNHX3D was cloned and characterized from upland cotton (Gossypium hirsutum). Phylogenetic and sequence analyses showed that GhNHX3D belongs to the vacuolar-type NHXs. The GhNHX3D-enhanced green fluorescent protein (eGFP) fusion protein localized on the vacuolar membrane when transiently expressed in Arabidopsis protoplasts. The quantitative real-time PCR (qRT-PCR) analysis showed that GhNHX3D was induced rapidly in response to salt stress in cotton leaves, and its transcript levels increased with the aggravation of salt stress. The introduction of GhNHX3D into the salt-sensitive yeast mutant ATX3 improved its salt tolerance. Furthermore, silencing of GhNHX3D in cotton plants by virus-induced gene silencing (VIGS) increased the Na+ levels in the leaves, stems, and roots and decreased the K+ content in the roots, leading to greater salt sensitivity. Our results indicate that GhNHX3D is a member of the vacuolar NHX family and can confer salt tolerance by adjusting the steady-state balance of cellular Na+ and K+ ions.

Characteristics Analysis and Corrosion Inhibition in Typical Produced Water of Jidong Oilfield

The composition of oilfield water is complex and diverse. The development and application of corrosion inhibitors can effectively inhibit the corrosion of pipelines and equipment by oilfield water. The ions in produced water of Jidong Oilfield were determined by instrumental analysis and chemical analysis. Triazine prepared from ethanolamine and formaldehyde as corrosion inhibitor was evaluated by weight loss method. The corrosion inhibition experiments were carried out in ancient water samples, and the effects of concentration and temperature on corrosion inhibition were investigated. Finally, corrosion inhibitors were applied to the corrosion inhibition of produced water with different compositions in Jidong Oilfield, the corrosion inhibition of steel sheet was evaluated under different salinity conditions, and the effects of various ion contents in typical water samples and salinity on corrosion inhibition were analyzed. The experimental results show that the corrosion inhibition effect of triazine is better, and the product can be used in various water samples in oilfield with the inhibition efficiency above 85%.

Cation and Zn Accumulation in Brown Seeds of the Euhalophyte Suaeda salsa Improves Germination Under Saline Conditions

Salinity inhibits plant growth due to salt ion accumulation in plant cells and reduced absorption of other nutrients such as metal ions; however halophyte plants have evolved mechanisms to survive and thrive in high-salt conditions. The euhalophyte Suaeda salsa generates dimorphic seeds (black and brown), which show marked differences in germination and seedling growth under high-salt conditions. However, it is unclear whether their ionic status differs. Here, to provide insight on the role of ions in salt tolerance, we used inductively coupled plasma mass spectrometry to measure the ion contents in the dimorphic seeds from S. salsa plants treated with or without NaCl. We measured the macroelements Na, K, Mg, and Ca, and the microelements Mn, Fe, Zn, Cu, and Mo. NaCl-treated S. salsa plants produced seeds with significantly reduced metallic element contents and significantly increased Na+ contents. The brown seeds of S. salsa plants treated with 0 and 200 mM NaCl had much higher contents of K+, Ca2+, and Fe2+ compared with the black seeds. However, the S. salsa seeds (both black and brown) from NaCl-treated plants were significantly larger, and had higher germination rate and higher seedling salt tolerance compared with seeds from plants not treated with NaCl. Interestingly, we measured significantly higher Zn2+ contents in the brown seeds from plants treated with NaCl compared with the black seeds. This suggests that the high contents of Zn2+ and other cations affected seed development and salt tolerance during germination under high-salt conditions. These observations provide insight into the mechanisms of salt tolerance in this halophyte and inform efforts to increase salt tolerance in salt-sensitive species.