Do Dipteryx alata Vogel seedlings recover the quality and the photosynthetic and antioxidant responses in the post-flooding?

Dipteryx alata Vogel is a tree species widely found in Cerrado, settling preferentially in well drained soils. Studies related to ecophysiology of D. alata may contribute to the decision making about using seedlings of this species in projects aimed at the recovery of degraded areas where seasonal flooding happens. This study aimed to assess the effects of flooding on photosynthetic and antioxidant metabolism and quality of D. alata seedlings cultivated or not under flooding during four assessment periods (0, 20, 40, and 60 days), followed by 100 days after the end of each assessment period (0+100, 20+100, 40+100, and 60+100 days), allowing verifying the potential for post-flooding recovery. Flooded plants showed lower photosynthetic efficiency than non-flooded plants, regardless of the periods of exposure. However, this efficiency was recovered in the post-flooding, with values similar to that of the non-flooded seedlings. Moreover, the damage to FV/FM was evidenced by an increase in the period of exposure to flooding, but recovery was also observed at this stage of the photosynthetic metabolism. Seedling quality decreased under flooding, not varying between periods of exposure, but remained lower although the increase observed in the post-flooding period, with no recovery after flooding. The occurrence of hypertrophied lenticels associated with physiological changes and an efficient antioxidant enzyme system might have contributed to the survival and recovery of these seedlings. Thus, this species is sensitive to flooding stress but capable of adjusting and recovering metabolic characteristics at 100 days after the suspension of the water stress, but with no recovery in seedling quality. Thus, we suggested plasticity under the cultivation condition and determined that the time of 100 days is not enough for the complete resumption of growth.

Brassinosteroid Biosynthetic Gene SlCYP90B3 Alleviates Chilling Injury of Tomato (Solanum lycopersicum) Fruits during Cold Storage

Tomato is susceptible to chilling injury during cold storage. In this study, we found that low temperature promoted the expression of brassinosteroid (BR) biosynthetic genes in tomato fruits. The overexpression of SlCYP90B3 (SlCYP90B3-OE), a key BR biosynthetic gene, alleviated the chilling injury with decreased electrical conductivity and malondialdehyde. In SlCYP90B3-OE tomato fruits, the activities of antioxidant enzymes, including ascorbate peroxidase (APX), catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD), were markedly increased, while the activity of membranous lipolytic enzymes, lipoxygenase (LOX), and phospholipase D (PLD), were significantly decreased when compared with the wild-type in response to cold storage. Furthermore, the expression level of the cold-response-system component, SlCBF1, was higher in SlCYP90B3-OE fruits than in the wild-type fruits. These results indicated that SlCYP90B3 might be involved in the chilling tolerance of tomato fruits during cold storage, possibly by regulating the antioxidant enzyme system and SlCBF1 expression.

Exogenously applied nutrients can improve the chickpea productivity under water stress conditions by modulating the antioxidant enzyme system

Water stress is one of the major factor restricting the growth and development of chickpea plants by inducing various morphological and physiological changes. Therefore, the present research activity was designed to improve the chickpea productivity under water stress conditions by modulating antioxidant enzyme system. Experimental treatments comprised of two chickpea genotypes i.e. Bhakhar 2011 (drought tolerant) and DUSHT (drought sensitive), two water stress levels i.e. water stress at flowering stage and water stress at flowering + pod formation + grain filling stage including well watered (control) and three exogenous application of nutrients i.e. KCl 200 ppm, MgCl2, 50 ppm and CaCl2, 10 mM including distilled water (control). Results indicated that water stress at various growth stages adversely affects the growth, yield and quality attributes of both chickpea cultivars. Exogenous application of nutrients improved the growth, yield and antioxidant enzyme activities of both chickpea genotypes even under water stress conditions. However, superior results were obtained with foliar spray of potassium chloride on Bhakhar 2011 under well-watered conditions. Similarly, foliar spray of potassium chloride on chickpea cultivar Bhakhar 2011 cultivated under stress at flowering + pod formation + grain filling stage produced significantly higher contents of superoxide dismutase, peroxidase and catalase. These results suggests that the application of potassium chloride mitigates the adverse effects of water stress and enhanced tolerance in chickpea mainly due to higher antioxidant enzymes activity, demonstrating the protective measures of plant cells in stress conditions.

Exercise Performance Upregulatory Effect of R-α-Lipoic Acid with γ-Cyclodextrin

α-Lipoic acid (ALA) is a vitamin-like substance that is an indispensable supporting factor for a large number of enzymes. Due to its optical activity, ALA has optical isomers RALA and SALA. The major role of RALA is in energy metabolism. However, RALA cannot be used as a pharmaceutical or nutraceutical because it is sensitive to heat and acid conditions. Previous studies have shown that RALA complexed with γ-cyclodextrin (CD) has a higher antioxidant capacity than that of free RALA. The antioxidant enzyme system protects against intense exercise-induced oxidative damage and is related to the physical status of athletes. The aim of this study was to examine the effect of CD/RALA complex supplementation on antioxidant activity and performance during high-intensity exercise. Twenty-four male C3H/HeSlc mice were divided into four groups (n = 6): swimming+distilled water administration (C), swimming+CD/RALA supplementation (CD/RALA), swimming+RALA suplementation (RALA), and swimming+CD supplementation (CD). Blood ammonia elevation due to exercise stress was repressed by CD/RALA supplementation. The oxidative stress in the kidney increased after exercise and was reduced by CD/RALA supplementation. Our findings suggest that CD/RALA supplementation may be useful for improving the exercise performance in athletes.

Effect of Methyl Jasmonate, Cytokinin, and Lavender Oil on Antioxidant Enzyme System of Apricot Fruit (Prunus armeniaca L.)

Various treatments are carried out in order to extend both the shelf life and storage life of fresh fruit and vegetables after harvest and among them non-toxic for humans, environmentally and economically friendly alternative treatments are gained more importance. In the current study, methyl jasmonate (MeJA), cytokinin, and lavender oil which are eco-friendly and safe for human health were applied on apricot fruit. The treated fruit were stored at 0 °C and 90–95% relative humidity for 25 days and catalase (CAT), superoxide dismutase (SOD), and ascorbate peroxidase (APX) enzyme activities and lipid peroxidation of apricots after treatments were studied. According to the findings obtained from the study, it was observed that 5 ppm cytokinin and 1000 ppm lavender oil treatments of apricot fruit gave better APX and CAT enzyme activity, respectively. In addition, better SOD enzyme activity in fruit was obtained with MeJA+lavender oil treatments. As a result, it can be emphasized that the product quality of apricot fruit is preserved as both the eco-friendly application of MeJA, cytokinin, and lavender oil separately from each other and the treatment of combinations between these compounds activate the enzymatic antioxidant defense systems of apricot fruit after harvest.

Effects of Salt Stress on Photosynthetic Fluorescence Characteristics, Antioxidant System, and Osmoregulation of Coreopsis tinctoria Nutt.

Coreopsis tinctoria Nutt. (C. tinctoria) is used in composite tea material and has important medicinal functions. Soil salinization affects the growth and development of C. tinctoria in Xinjiang (China). Here, we discussed the changes in photosynthesis and physiological characteristics of C. tinctoria seedlings treated with different concentrations of NaCl [0 (CK), 50, 100, 150, 200, and 250 mmol·L−1] for 12, 24, and 72 hours. The results showed that the net photosynthetic rate (Pn), stomatal conductance (gS), transpiration rate (Tr), and stomatal inhibition rate (Ls) decreased significantly with increasing concentrations of NaCl. Salt stress promoted the accumulation of peroxidase (POD), catalase (CAT), soluble sugar, soluble protein, and free proline (Pro). A highly significant positive correlation was found between Ls and Fv/Fm; Ls and Fv/Fo; soluble sugar and CAT; soluble sugar and soluble protein. C. tinctoria was most sensitive to the concentrations of 150 to 250 mmol·L−1 NaCl, and its salt stress tolerance was increased by reducing photosynthetic fluorescence parameters, improving the antioxidant enzyme system, and regulating osmotic substances.

Changes in Antioxidative, Oxidoreductive and Detoxification Enzymes during Development of Aphids and Temperature Increase

Temperature, being the main factor that has an influence on insects, causes changes in their development, reproduction, winter survival, life cycles, migration timing, and population dynamics. The effects of stress caused by a temperature increase on insects may depend on many factors, such as the frequency, amplitude, duration of the stress, sex, or the developmental stage of the insect. The aim of the study was to determine the differences in the enzymatic activity of nymphs and adult aphids Aphis pomi, Macrosiphum rosae and Cinara cupressi, and changes in their response to a temperature increase from 20 to 28 °C. The activity of enzymatic markers (superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), β-glucosidase, polyphenol oxidase (PPO) and peroxidase (POD)) in aphid tissues was analysed for three constant temperatures. The results of our research showed that the enzymatic activity of aphids (measured as the activity of antioxidant, detoxifying and oxidoreductive enzymes) was mainly determined by the type of morph. We observed a strong positive correlation between the activity of the detoxifying and oxidoreductive enzymes and aphids’ development, and a negative correlation between the activity of the antioxidant enzymes and aphids’ development. Moreover, the study showed that an increase in temperature caused changes in enzyme activity (especially SOD, CAT and β-glucosidase), which was highest at 28 °C, in both nymphs and adults. Additionally, a strong positive correlation between metabolic activity (heat flow measured by microcalorimeter) and longevity was observed, which confirmed the relationship between these characteristics of aphids. The antioxidant enzyme system is more efficient in aphid nymphs, and during aphid development the activity of antioxidant enzymes decreases. The antioxidant enzyme system in aphids appears to deliver effective protection for nymphs and adults under stressful conditions, such as high temperatures.

Boron Efficient Sugar Beet (Beta Vulgaris L.) Variety Relieve The Symptoms of Boron Deficiency By Enhancing The Antioxidation And Boron Utilization Capacity of The Root System

(Aims) Sugar beet is one of the most sensitive crops to boron and boron deficiency inhibits the root growth and causes hollow symptoms in beets. However, how the roots of boron efficient sugar beet variety adapt to the morphology, physiological, and transcriptome mechanisms of boron deficiency are rarely reported. (Method) Thus, the present study was carried out with B efficient sugar beet variety (H, KWS1197) and B inefficient variety (L, KWS0143), and two B levels i.e., B0.1 (0.1 μM H3BO3, deficiency) and B50 (50 μM H3BO3, control) were designed for hydroponic experiment. (Result) Boron deficiency reduced the total root length, root forks, and root biomass of sugar beet. Compared with L variety, H variety have higher boron transport coefficient, boron distribution ratio above ground, peroxidase and catalase activities, lower malondialdehyde content and reactive oxygen species accumulation. Transcriptome data showed that the two comparison groups, HB0.1 vs HB50 and LB0.1 vs LB50, were enriched for 537 and 257 differentially expressed genes, respectively. The H variety mainly induced and regulated the GO term enrichment associated with antioxidant and stress resistance. On the contrary, the L variety induced cell death and negative regulation of biological and metabolic processes. (Conclusion) B efficient variety specifically up-regulated boron deficiency response genes to activate the antioxidant enzyme system, promoted rational root configuration, and enhance plant growth anti-oxidation and resistance to boron deficiency. The results of this study serve as a theoretical basis of screening candidate genes that respond to boron deficiency and adaptation mechanism of boron deficiency.