Nitrogen Application Alleviates the Adverse Effects of Defoliation Stress on Lolium perenne L. by Enhancing the Antioxidant System and Promoting Photosynthesis

Perennial grasses undergo compensatory growth after defoliation. Nitrate is the main nitrogen source for the growth of perennial ryegrass and plays a significant role in plant resistance to stress. The aim of the study was to understand the physiological mechanism of ryegrass in response to defoliation stress under different nitrate supplies and to explore possible ways to alleviate defoliation stress. We performed pot experiments where 12-week-old ryegrass plants grown in low (0.05 mM KNO3) or moderate nitrate (5 mM KNO3) conditions were defoliated and subsequently supplied with different concentrations of nitrate following defoliation treatments. During the regrowth stage, the regrowth rate, biomass, photosynthetic parameters, and the response of the antioxidant system to low or moderate nitrate supply of ryegrass were investigated. The results showed that moderate nitrate supply after defoliation increased the content of photosynthetic pigments in ryegrass and improved its photosynthetic efficiency. In addition, adding moderate nitrate after defoliation increased the activity of antioxidant enzymes and the accumulation of osmotic regulating substances, thereby enhancing plant resistance, effectively reducing the damage to plants caused by defoliation stress, and promoting plant regrowth, especially for plants grown in a low nitrate environment before defoliation. Therefore, this study showed that the addition of exogenous nitrate could counteract some of the adverse effects of defoliation stress on the growth and development of ryegrass

Effect of Resveratrol-Based Nutritional Supplement on Choroidal Thickness: A Pilot Study.

PurposeThe effect of an oral trans-resveratrol-based supplement (Longevinex®) on choroidal thickness, measured using optical coherence tomography (OCT) enhanced depth imaging, was investigated in a prospective study.Materials and methods34 young, healthy participants were randomly divided into two age- and gender-matched groups. They were then assigned in a randomized fashion to treat with either a trans-resveratrol-based group (Longevinex®, Las Vegas) or placebo. All participants underwent ocular imaging with spectral domain (SD)-OCT (Spectralis; Heidelberg Engineering, Heidelberg) at the baseline and then again 1 h following treatment. The choroidal thickness was measured in a masked fashion at the fovea and at four additional points, located at 500 μm and 1000 μm nasal to the fovea and 500 μm and 1000 μm temporal to the fovea.ResultsIn the resveratrol group, the foveal choroidal thickness at the baseline was 267.73 ± 84.19 μm (mean ± SD); it increased to 284.57 ± 92.39 μm 1 h after drug treatment (p = 0.033). The mean choroidal thickness was also significantly increased at each of the four extrafoveal points (all p < 0.05). In the control group, the mean baseline choroidal thickness at the fovea was 269.73 ± 71.40 μm (mean ± SD) and it was 268.43 ± 70.15 μm (mean ± SD) 1 h after the placebo was administered (p = 0.183); there were also no significant differences in choroidal thickness at the four additional points (all p > 0.05) Conclusion: A significant increase in choroidal thickness following oral administration of a trans-resveratrol-based supplement was observed. There was no change in choroidal thickness in the placebo-treated control group. We speculate that the increased choroidal thickness is the result of choroidal vessel vasodilation

Effect of Resveratrol-Based Nutritional Supplement on Choroidal Thickness: A Pilot Study.

PurposeThe effect of an oral trans-resveratrol-based supplement (Longevinex®) on choroidal thickness, measured using optical coherence tomography (OCT) enhanced depth imaging, was investigated in a prospective study.Materials and methods34 young, healthy participants were randomly divided into two age- and gender-matched groups. They were then assigned in a randomized fashion to treat with either a trans-resveratrol-based group (Longevinex®, Las Vegas) or placebo. All participants underwent ocular imaging with spectral domain (SD)-OCT (Spectralis; Heidelberg Engineering, Heidelberg) at the baseline and then again 1 h following treatment. The choroidal thickness was measured in a masked fashion at the fovea and at four additional points, located at 500 μm and 1000 μm nasal to the fovea and 500 μm and 1000 μm temporal to the fovea.ResultsIn the resveratrol group, the foveal choroidal thickness at the baseline was 267.73 ± 84.19 μm (mean ± SD); it increased to 284.57 ± 92.39 μm 1 h after drug treatment (p = 0.033). The mean choroidal thickness was also significantly increased at each of the four extrafoveal points (all p < 0.05). In the control group, the mean baseline choroidal thickness at the fovea was 269.73 ± 71.40 μm (mean ± SD) and it was 268.43 ± 70.15 μm (mean ± SD) 1 h after the placebo was administered (p = 0.183); there were also no significant differences in choroidal thickness at the four additional points (all p > 0.05) Conclusion: A significant increase in choroidal thickness following oral administration of a trans-resveratrol-based supplement was observed. There was no change in choroidal thickness in the placebo-treated control group. We speculate that the increased choroidal thickness is the result of choroidal vessel vasodilation

Tissue Distribution of trans-Resveratrol and Its Metabolites after Oral Administration in Human Eyes

Purpose. This study was performed to measure the concentration of trans-resveratrol and its three metabolites in human eyes. Methods. The patients who underwent pars plana vitrectomy for rhegmatogenous retinal detachment were included. The participants were orally given trans-resveratrol-based supplement (Longevinex®). A suitable amount of conjunctiva, aqueous humor, and vitreous humor were obtained during the operation. High-performance liquid chromatography (HPLC) with mass spectrometry (LC/MS/MS) was used to detect the concentration of trans-resveratrol and its three metabolites in the various samples. Results. The average concentration of resveratrol in the conjunctiva was 17.19 ± 15.32 nmol/g (mean ± SD). The concentration of resveratrol in the aqueous humor was close to the limit of detection, but its metabolites could be quantified. The concentrations of resveratrol metabolites in the aqueous humor can be detected. In the vitreous humor, the average concentration of resveratrol-3-O-sulfate was 62.95 ± 41.97 nmol/L. The sulfate conjugations of resveratrol were recovered in the conjunctiva, aqueous humor, and vitreous humor. Conclusions. Resveratrol and its three metabolites can be detected in the ocular tissues after oral administration. Although the concentration of parent resveratrol was low in the eyes, its metabolites could be detected and may have a role in the treatment of ocular diseases

Effect of Resveratrol-Based Nutritional Supplement on Choroidal Thickness: A Pilot Study

PurposeThe effect of an oral trans-resveratrol-based supplement (Longevinex®) on choroidal thickness, measured using optical coherence tomography (OCT) enhanced depth imaging, was investigated in a prospective study.Materials and methods34 young, healthy participants were randomly divided into two age- and gender-matched groups. They were then assigned in a randomized fashion to treat with either a trans-resveratrol-based group (Longevinex®, Las Vegas) or placebo. All participants underwent ocular imaging with spectral domain (SD)-OCT (Spectralis; Heidelberg Engineering, Heidelberg) at the baseline and then again 1 h following treatment. The choroidal thickness was measured in a masked fashion at the fovea and at four additional points, located at 500 μm and 1000 μm nasal to the fovea and 500 μm and 1000 μm temporal to the fovea.ResultsIn the resveratrol group, the foveal choroidal thickness at the baseline was 267.73 ± 84.19 μm (mean ± SD); it increased to 284.57 ± 92.39 μm 1 h after drug treatment (p = 0.033). The mean choroidal thickness was also significantly increased at each of the four extrafoveal points (all p < 0.05). In the control group, the mean baseline choroidal thickness at the fovea was 269.73 ± 71.40 μm (mean ± SD) and it was 268.43 ± 70.15 μm (mean ± SD) 1 h after the placebo was administered (p = 0.183); there were also no significant differences in choroidal thickness at the four additional points (all p > 0.05) Conclusion: A significant increase in choroidal thickness following oral administration of a trans-resveratrol-based supplement was observed. There was no change in choroidal thickness in the placebo-treated control group. We speculate that the increased choroidal thickness is the result of choroidal vessel vasodilation