Chromium Stress Mitigation by Polyamine-Brassinosteroid Application Involves Phytohormonal and Physiological Strategies in Raphanus sativus L.

Brassinosteroids (BRs) and polyamines (PAs) are well-established growth regulators playing key roles in stress management among plants. In the present study, we evaluated the effects of epibrassinolide (EBL, an active BR) and spermidine (Spd, an active PA) on the tolerance of radish to oxidative stress induced by Cr (VI) metal. Our investigation aimed to study the impacts of EBL (10−9 M) and/or Spd (1 mM) on the biochemical and physiological responses of radish (Raphanus sativus L.) under Cr-stress. Applications of EBL and/or Spd were found to improve growth of Cr-stressed seedlings in terms of root length, shoot length and fresh weight. Our data also indicated that applications of EBL and Spd have significant impacts, particularly when applied together, on the endogenous titers of PAs, free and bound forms of IAA and ABA in seedlings treated with Cr-stress. Additionally, co-applications of EBL and Spd modulated more remarkably the titers of antioxidants (glutathione, ascorbic acid, proline, glycine betaine and total phenol) and activities of antioxidant enzymes (guaicol peroxidase, catalase, superoxide dismutase and glutathione reductase) in Cr-stressed plants than their individual applications. Attenuation of Cr-stress by EBL and/or Spd (more efficient with EBL and Spd combination) was also supported by enhanced values of stress indices, such as phytochelatins, photosynthetic pigments and total soluble sugars, and reduction in malondialdehyde and H2O2 levels in Cr-treated seedlings. Diminution of ROS production and enhanced ROS scavenging capacities were also noted for EBL and/or Spd under Cr-stress. However, no significant reduction in Cr uptake was observed for co-application of EBL and Spd when compared to their individual treatments in Cr-stressed seedlings. Taken together, our results demonstrate that co-applications of EBL and Spd are more effective than their independent treatments in lowering the Cr-induced oxidative stress in radish, leading to improved growth of radish seedlings under Cr-stress

Nanoparticles and biochar with adsorbed plant growth-promoting rhizobacteria alleviate Fusarium wilt damage on tomato and watermelon

The addition of biochars and nanoparticles with adsorbed Azotobacter vinelandii and Bacillus megaterium alleviated damage from Fusarium infection in both tomato (Solanum lycopersicum) and watermelon (Citrullus lanatus) plants. Tomato and watermelon plants were grown in greenhouse for 28 and 30 days (respectively) and were treated with either nanoparticles (chitosan-coated mesoporous silica or nanoclay) or varying biochars (biochar produced by pyrolysis, gasification and pyrogasification). Treatments with nanoparticles and biochars were applied in two variants - with or without adsorbed plant-growth promoting bacteria (PGPR). Chitosan-coated mesoporous silica nanoparticles with adsorbed bacteria increased chlorophyll content in infected tomato and watermelon plants (1.12 times and 1.63 times, respectively) to a greater extent than nanoclay with adsorbed bacteria (1.10 times and 1.38 times, respectively). However, the impact on other endpoints (viability of plant cells, phosphorus and nitrogen content, as well antioxidative status) was species-specific. In all cases, plants treated with adsorbed bacteria responded better than plants without bacteria. For example, the content of antioxidative compounds in diseased watermelon plants increased nearly 46% upon addition of Aries biochar and by approximately 52% upon addition of Aries biochar with adsorbed bacteria. The overall effect on disease suppression was due to combination of the antifungal effects of both nanoparticles (and biochars) and plant-growth promoting bacteria. These findings suggest that nanoparticles or biochars with adsorbed PGPR could be viewed as a novel and sustainable solution for management of Fusarium wilt

Gender differences in cardiovascular functions during exercise: a brief review

Exercise is a major challenge for the cardiovascular apparatus, since it has to provide adequate oxygen supply to exercising muscles and to guarantee arterial blood pressure regulation. Several adjustments, such as heart rate increase, contractility enhancement, and venous return modulation are made to accomplish this task. Furthermore, regular physical training induces several physiological adaptations due to an increase in parasympathetic and a decrease in sympathetic tone and to chronic increases in cardiac pre-load and after-load. There are gender-related physiological and morphological differences in the cardiovascular adjustments and adaptations to physical exercise in humans. In this review, we briefly summarize these differences. Moreover, differences in ECG pattern between sexes are discusse