Mitigation of salinity stress by exogenous application of cytokinin in faba bean (Vicia faba L.)

Soil salinity limits agricultural land use and crop productivity, thereby a major threat to global food safety. Plants treated with several phytohormones including cytokinins were recently proved as a powerful tool to enhance plant’s adaptation against various abiotic stresses. The current study was designed to investigate the potential role of 6-benzyladenine (BA) to improve broad bean (Vicia faba L.) salinity tolerance. The salt-stressed broad bean plantlets were classified into two groups, one of which was sprayed with water and another was sprayed with 200 ppm of BA. Foliar applications of BA to salt-exposed plants promoted the growth performance which was evidenced by enhanced root-shoot fresh and dry biomass. Reduced proline was strongly connected to the enhanced soluble proteins and free amino acids contents, protecting plant osmotic potential following BA treatment in salt-stressed broad bean. BA balanced entire mineral homeostasis and improved mineral absorption and translocation from roots to shoots, shoots to seeds and roots to seeds in salt-stressed plants. Excessive salt accumulation increased malondialdehyde level in leaves creating oxidative stress and disrupting cell membrane whereas BA supplementation reduced lipid peroxidation and improved oxidative defence. BA spray to salinity-stressed plants also compensated oxidative damage by boosting antioxidants defence mechanisms, as increased the enzymatic activity of superoxide dismutase, catalase, peroxidase and ascorbate peroxidase. Moreover, clustering heatmap and principal component analysis revealed that mineral imbalances, osmotic impairments and increased oxidative damage were the major contributors to salts toxicity, on the contrary, BA-augmented mineral homeostasis and higher antioxidant capacity were the reliable markers for creating salinity stress tolerance in broad bean. In conclusion, the exogenous application of BA alleviated the antagonistic effect of salinity and possessed broad bean to positively regulate the osmoprotectants, ion homeostasis, antioxidant activity and finally plant growth and yield, perhaps suggesting these easily-accessible and eco-friendly organic compounds could be powerful tools for the management of broad bean growth as well as the development of plant resiliency in saline prone soils

Cardioprotective molecule and bioactive compounds of some selected vegetables available in Bangladesh

Cardiovascular disease (CVD) is one of the leading causes of death and morbidity as well as imposing a huge economic burden at both country and household level. Upto 90% cardiovascular disease may be preventable if established risk factors are avoided. In this context, dietary nitrate from vegetables was highlighted as a potential candidate for cardio protection. Hence, by supplying dietary nitrate and other bio-active compounds to ease the risk of cardiovascular disease, present research work was carried out. Among the tested vegetables, the highest nitrate content (745 mg/100g) was determined in Indian spinach. In addition, Indian spinach also possesses more chlorophyll (150mg/100g), beta carotene (40mg/100g) and lycopene (34mg/100g) than other tested vegetables in the current study. In case of anti-oxidant content, Indian spinach showed the highest (103mg/100g) vitamin C content. Taken all together, Indian spinach may be a good and cheapest source of cardio protective molecule (nitrate) bioactive compounds to avoid risk of cardiovascular disease

Salicylic acid and thiourea ameliorate the negative impact of salt stress in wheat (Triticum aestivum L.) seedlings by up-regulating photosynthetic pigments, leaf water status, and antioxidant defense system

Salinity is one of the most important abiotic stress inhibiting wheat (Triticum aestivum L.) growth and development. Therefore, finding efficient strategies to prevent salt-induced growth retardation and yield loss is critical for modern agriculture to sustain production. The role of exogenous salicylic acid (SA) and thiourea (TU) in regulating salt tolerance was investigated by evaluating morpho-physiological characteristics and antioxidant response in two wheat genotypes at the seedling stage. In both wheat genotypes, salt stress reduced growth characteristics and leaf water status, photosynthetic pigments, while simultaneously increasing the Na+/K+ ratio, hydrogen peroxide (H2O2), and malondialdehyde (MDA). In contrast, exogenous application of SA and/or TU alone in the salt-stressed plants significantly reduced the negative effects of salt stress and improved the growth performance by up-regulating photosynthetic pigments, leaf water status, and proline content in both genotypes. Besides, when compared to seedlings treated only with salt stress, SA and TU played an important role in maintaining lower Na+/K+ levels and reducing oxidative stress by lowering MDA and H2O2 levels in salt-stressed plants through boosting the activities of antioxidant enzymes such as catalase, ascorbate peroxidase, and peroxidase. In addition, hierarchical clustering and principal component analysis revealed a significant interaction among growth characteristics, chlorophyll content, carotenoid content and antioxidant activity with the salt, SA, and/or TU treatments. The findings suggested that exogenous application of SA or TU could be a useful technique for reducing the negative effects of salinity on wheat growth and development

Inhibition of light-induced stomatal opening by allyl isothiocyanate does not require guard cell cytosolic Ca2+ signaling

The glucosinolate-myrosinase system is a well-known defense system that has been shown to induce stomatal closure in Brassicales. Isothiocyanates are highly reactive hydrolysates of glucosinolates, and an isothiocyanate, allyl isothiocyanate (AITC), induces stomatal closure accompanied by elevation of free cytosolic Ca2+ concentration ([Ca2+](cyt)) in Arabidopsis. It remains unknown whether AITC inhibits light-induced stomatal opening. This study investigated the role of Ca2+ in AITC-induced stomatal closure and inhibition of light-induced stomatal opening. AITC induced stomatal closure and inhibited light-induced stomatal opening in a dose-dependent manner. A Ca2+ channel inhibitor, La3+, a Ca(2+)chelator, EGTA, and an inhibitor of Ca2+ release from internal stores, nicotinamide, inhibited AITC-induced [Ca2+](cyt) elevation and stomatal closure, but did not affect inhibition of light-induced stomatal opening. AITC activated non-selective Ca2+-permeable cation channels and inhibited inward-rectifying K+ (K-in(+)) channels in a Ca2+-independent manner. AITC also inhibited stomatal opening induced by fusicoccin, a plasma membrane H+-ATPase activator, but had no significant effect on fusicoccin-induced phosphorylation of the penultimate threonine of H+-ATPase. Taken together, these results suggest that AITC induces Ca2+ influx and Ca2+ release to elevate [Ca2+](cyt), which is essential for AITC-induced stomatal closure but not for inhibition of K-in(+) channels and light-induced stomatal opening

Citric Acid-Mediated Abiotic Stress Tolerance in Plants

Several recent studies have shown that citric acid/citrate (CA) can confer abiotic stress tolerance to plants. Exogenous CA application leads to improved growth and yield in crop plants under various abiotic stress conditions. Improved physiological outcomes are associated with higher photosynthetic rates, reduced reactive oxygen species, and better osmoregulation. Application of CA also induces antioxidant defense systems, promotes increased chlorophyll content, and affects secondary metabolism to limit plant growth restrictions under stress. In particular, CA has a major impact on relieving heavy metal stress by promoting precipitation, chelation, and sequestration of metal ions. This review summarizes the mechanisms that mediate CA-regulated changes in plants, primarily CA's involvement in the control of physiological and molecular processes in plants under abiotic stress conditions. We also review genetic engineering strategies for CA-mediated abiotic stress tolerance. Finally, we propose a model to explain how CA's position in complex metabolic networks involving the biosynthesis of phytohormones, amino acids, signaling molecules, and other secondary metabolites could explain some of its abiotic stress-ameliorating properties. This review summarizes our current understanding of CA-mediated abiotic stress tolerance and highlights areas where additional research is needed

Evaluation of superpave fine aggregate specification

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Includes bibliographical references (leaves 65-69).Issued also on microfiche from Lange Micrographics.Superpave[] was the final product of the Strategic Highway Research Program's (SHRP) asphalt pavement research effort during 1987-93. Some aspects of the Superpave aggregate specifications are not universally accepted. The validity of the fine aggregate angularity (FAA) requirement is questioned by both the owner agencies and the paving and aggregate industries. The FAA test is based on the assumption that more fractured faces will result in higher void content in the loosely compacted sample; however, this is not always true. The aggregate industry has found that cubical shaped particles, even with 100% fractured faces, may not meet the FAA requirement for high-volume traffic. State agencies are concerned that local materials previously considered acceptable and which have provided good field performance, now cannot meet the Superpave requirements. Twenty three-fine aggregates from different part of the USA were tested using major angularity tests: FAA test, direct shear test, compacted aggregate resistance (CAR) test, image analysis Hough transform, and visual inspection. The results from those tests were compared with the available performance history. The FAA test method does not consistently identify angular, cubical aggregates as high quality materials. There is a fair correlation between the CAR stability value and angle of internal friction (AIF) from direct shear test. No correlation was found between FAA and CAR stability or between FAA and AIF. A good correlation was found between FAA and K-index from Hough transform method. Some cubical crushed aggregates whose FAA values were less than 45 gave very high values of CAR stability, AIF and K-index. The statistical analysis of the SHRP LTPP database reveals that there is no evidence of any good linear relationship between FAA and rutting. Of the methods evaluated, image analysis using Hough transform appears most promising for measuring fine aggregate angularity. Until a replacement method for FAA can be identified, the author recommends that the FAA criteria be lowered from 45. The FAA vs. rutting data analysis should be continued with a larger amount of data as the LTPP SHRP database is expanded

Evaluation of superpave fine aggregate specification

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Includes bibliographical references (leaves 65-69).Issued also on microfiche from Lange Micrographics.Superpave[] was the final product of the Strategic Highway Research Program's (SHRP) asphalt pavement research effort during 1987-93. Some aspects of the Superpave aggregate specifications are not universally accepted. The validity of the fine aggregate angularity (FAA) requirement is questioned by both the owner agencies and the paving and aggregate industries. The FAA test is based on the assumption that more fractured faces will result in higher void content in the loosely compacted sample; however, this is not always true. The aggregate industry has found that cubical shaped particles, even with 100% fractured faces, may not meet the FAA requirement for high-volume traffic. State agencies are concerned that local materials previously considered acceptable and which have provided good field performance, now cannot meet the Superpave requirements. Twenty three-fine aggregates from different part of the USA were tested using major angularity tests: FAA test, direct shear test, compacted aggregate resistance (CAR) test, image analysis Hough transform, and visual inspection. The results from those tests were compared with the available performance history. The FAA test method does not consistently identify angular, cubical aggregates as high quality materials. There is a fair correlation between the CAR stability value and angle of internal friction (AIF) from direct shear test. No correlation was found between FAA and CAR stability or between FAA and AIF. A good correlation was found between FAA and K-index from Hough transform method. Some cubical crushed aggregates whose FAA values were less than 45 gave very high values of CAR stability, AIF and K-index. The statistical analysis of the SHRP LTPP database reveals that there is no evidence of any good linear relationship between FAA and rutting. Of the methods evaluated, image analysis using Hough transform appears most promising for measuring fine aggregate angularity. Until a replacement method for FAA can be identified, the author recommends that the FAA criteria be lowered from 45. The FAA vs. rutting data analysis should be continued with a larger amount of data as the LTPP SHRP database is expanded

Foliar Application of Auxin or Cytokinin Can Confer Salinity Stress Tolerance in Vicia faba L.

Soil salinity severely declines the availability of water and essential minerals to the plants, which hinders growth. The present study evaluates the potential roles of indole-3-acetic acid (IAA) and 6-benzyladenine (BA) for mitigating the adverse effects of soil-salinity in faba bean (Vicia faba L.). Plants were exposed to 150 mM NaCl stress and were sprayed with IAA (1.15 mM) or BA (0.9 mM). Our results revealed that foliar application of IAA or BA improved the growth traits of salinized faba bean due to the increased uptake of K+, Ca2+, and Mg2+ ions, accumulation of free amino acids, soluble sugars, and soluble proteins, and activity of superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase. The principal component analysis (PCA) and heatmap clustering indicated that salinity-exposed plants exhibited lower growth and biomass production, which correlated with higher accumulation of Na+ and malondialdehyde. Moreover, electrophoretic patterns of protein showed new bands in IAA- or BA-treated salt-stressed plants, indicating that IAA or BA treatment can reprogram the metabolic processes to confer salinity tolerance. We also found that IAA has a greater capacity to ameliorate the salt stress than BA, although there is no significant difference in yield between these treatments. Finally, these findings can be helpful for a better understanding of IAA- and BA-mediated salt tolerance mechanisms and increasing production of faba bean in saline soils