32 research outputs found

    Salt stress and exogenous application of hydrogen peroxide on photosynthetic parameters of soursop

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    ABSTRACT This study aimed to evaluate the gas exchanges and photosynthetic pigments of soursop seedlings cv. ‘Morada Nova’ irrigated with saline waters and subjected to exogenous application of hydrogen peroxide by seed soaking and foliar spraying. The study was carried out using plastic bags under greenhouse conditions at the Center of Technology and Natural Resources of the Federal University of Campina Grande, PB, Brazil, using a eutrophic Regolithic Neosol of sandy loam texture. Treatments were arranged in a randomized block design, in 5 x 5 factorial scheme, which consisted of five levels of electrical conductivity – ECw (0.7; 1.4; 2.1; 2.8 and 3.5 dS m-1) of irrigation water and five concentrations of hydrogen peroxide - H2O2 (0, 25, 50, 75 and 100 µM), with four replicates and three plants per plot. As the salt stress increased, there were reductions in internal CO2 concentration, instantaneous carboxylation efficiency and water use efficiency, and instantaneous carboxylation efficiency was the most sensitive variable. Hydrogen peroxide at concentrations of 25 and 50 µM attenuated the deleterious effects of water salinity on stomatal conductance, CO2 assimilation rate and chlorophyll a content, and the concentration of 25 µM was the most efficient. The content of chlorophyll b and carotenoids of soursop cv. ‘Morada Nova’ had the deleterious effects caused by the salinity of irrigation water mitigated by the exogenous application of hydrogen peroxide in the concentration of 25 μM

    Life-Space Mobility and Objectively Measured Movement Behavior in Older Adults with Hypertension after Receiving COVID-19 Vaccination

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    This study examined the changes in life-space (LS) mobility and objectively measured movement behavior in older adults with hypertension after receiving the COVID-19 vaccine and their associations with housing type. A total of 32 participants were included in this exploratory longitudinal study with a 1-year follow-up. LS mobility and accelerometer-based physical activity (PA) and sedentary behavior (SB) were assessed before and ~2 months after receiving COVID-19 vaccination. Participants residing in apartment/row housing showed an increase in LS mobility composite score (β = 14, p < 0.05). In addition, they showed an increase in light PA on weekdays and the weekend (β = 3.5%; β = 6.5%; p < 0.05) and a decrease in SB on weekdays and the weekend (β = −3.7%; β = −6.6%; p < 0.05). Furthermore, changes in SB pattern were found (less time spent in bouts of ≥10 and 30 min, more breaks/day and breaks/hour). Significant associations were found between changes in LS mobility composite score and PA (positive association) and SB (negative association) in older adults residing in apartment/row housing (p < 0.05). Older adults with hypertension, particularly those who resided in houses with limited outdoor space (apartment/row housing), showed positive changes in LS mobility and objectively measured movement behavior in a period after receiving the COVID-19 vaccine and characterized by social distancing policies without mobility restrictions when compared with the period of social distancing policies with high mobility restrictions and without vaccine
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