N-acetyl-cysteine mitigates arsenic stress in lettuce: Molecular, biochemical, and physiological perspective.

Agricultural land contaminated with heavy metals such as non-biodegradable arsenic (As) has become a serious global problem as it adversely affects agricultural productivity, food security and human health. Therefore, in this study, we investigated how the administration of N-acetyl-cysteine (NAC), regulates the physio-biochemical and gene expression level to reduce As toxicity in lettuce. According to our results, different NAC levels (125, 250 and 500 µM) significantly alleviated the growth inhibition and toxicity induced by As stress (20 mg/L). Shoot fresh weight, root fresh weight, shoot dry weight and root dry weight (33.05%, 55.34%, 17.97% and 46.20%, respectively) were decreased in plants grown in As-contaminated soils compared to lettuce plants grown in soils without the addition of As. However, NAC applications together with As stress increased these growth parameters. While the highest increase in shoot fresh and dry weight (58.31% and 37.85%, respectively) was observed in 250 µM NAC application, the highest increase in root fresh and dry weight (75.97% and 63.07%, respectively) was observed in 125 µM NAC application in plants grown in As-polluted soils. NAC application decreased the amount of ROS, MDA and H2O2 that increased with As stress, and decreased oxidative damage by regulating hormone levels, antioxidant and enzymes involved in nitrogen metabolism. According to gene expression profiles, LsHIPP28 and LsABC3 genes have shown important roles in reducing As toxicity in leaves. This study will provide insight for future studies on how NAC applications develop resistance to As stress in lettuce.

The impacts of nanoplastic toxicity on the accumulation, hormonal regulation and tolerance mechanisms in a potential hyperaccumulator - Lemna minor L.

Plastic pollution, which is currently one of the most striking problems of our time, raises concerns about the dispersal of micro and nano-sized plastic particles in ecosystems and their toxic effects on living organisms. This study was designed to reveal the toxic effects of polystyrene nanoplastic (PS NP) exposure on the freshwater macrophyte Lemna minor. In addition, elucidating the interaction of this aquatic plant, which is used extensively in the phytoremediation of water contaminants and wastewater treatment facilities, with nanoplastics will guide the development of remediation techniques. For this purpose, we examined nanoplastic accumulation, oxidative stress markers, photosynthetic efficiency, antioxidant system activity and phytohormonal changes in L. minor leaves subjected to PS NP stress (P-1, 100 mg L-1; P-2, 200 mg L-1 PS NP). Our results showed no evidence of PS NP-induced oxidative damage in P-1 group plants, although PS NP accumulation reached 56 µg g-1 in the leaves. Also, no significant changes in chlorophyll a fluorescence parameters were observed in this group, indicating unaffected photosynthetic efficiency. PS NP exposure triggered the antioxidant system in L. minor plants and resulted in a 3- and 4.6-fold increase in superoxide dismutase (SOD) activity in the P-1 and P-2 groups. On the other hand, high-dose PS NP treatment resulted in insufficient antioxidant activity in the P-2 group and increased hydrogen peroxide (H2O2) and lipid peroxidation (TBARS contents) by 25 % and 17 % compared to the control plants. Furthermore, PS NP exposure triggered abscisic acid biosynthesis (two-fold in the P-1 and three-fold in the P-2 group), which is also involved in regulating the stress response. In conclusion, L. minor plants tolerated NP accumulation without growth suppression, oxidative stress damage and limitations in photosynthetic capacity and have the potential to be used in remediation studies of NP-contaminated waters.

Variation in phenolic, antioxidant and vitamin amounts among some medicinal plants and investigation by PCA analysis: Lamiaceae family / Variación en las cantidades de fenoles, antioxidantes y vitaminas entre algunas plantas medicinales e investigación poranálisis PCA: familia Lamiaceae

Aromatic and medicinal plants are of great importance to determine the contents of the active compounds of plant origin and to evaluate them depending on variety and climate factors in order to determine the phenolic, antioxidant enzyme activity, vitamin contents in species belonging to the Lamiaceae family. Examination of the characteristics of different species, the highest peroxidase (POD) enzyme activity, ascorbate peroxidase (AxPOD), total antioxidant (TA), malondialdehyte (MDA), caffeic acids (CA), vitamin C contents,and chloric acid (ChA) were obtained in the M. longifoliaspecies. The highest vitamin E and catalase (CAT) were determined in the S. hortensisspecies but the highest total phenolic (TP), superoxide dismutase (SOD) enzyme, hydrogen peroxide (H2O2) and chlorogenic acid (ChgA) were determined in the S. spicigeraspecies. As a result of PCA analysis, it can be said that Mentha longifolia(L.) Hudson and Satureja spicigeraspecies have significant value in terms of biochemical and phenolic content.

Las plantas aromáticas y medicinales son de gran importancia para determinar el contenido de los compuestos activos de origen vegetal y evaluarlos en función de la variedad y factores climáticos con el fin de determinar la actividad enzimática fenólica, antioxidante, contenido vitamínico en especies pertenecientes a la familia Lamiaceae. El examen de las características de diferentes especies, la mayor actividad enzimática de peroxidasa (POD), ascorbato peroxidasa (AxPOD), antioxidante total (TA), malondialdehído (MDA), ácidos cafeicos (CA), contenido de vitamina C y ácido clorhídrico (ChA) se obtuvieron en la especie M. longifolia. La mayor cantidad de vitamina E y catalasa (CAT) se determinó en la especie S. hortensis, pero la mayor cantidad total de enzima fenólica (TP), superóxido dismutasa (SOD), peróxido de hidrógeno (H2O2) y ácido clorogénico (ChgA) se determinó en la especie S. spicigera. Como resultado del análisis de PCA, se puede decir que las especies Mentha longifolia(L.) Hudson y Satureja spicigeratienen un valor significativo en términos de contenido bioquímico y fenólico.

Seasonal variation of total phenolic, antioxidant activity and minerals in fresh tea shoots (Camellia sinensis var. sinensis).

Seasonal variation of total phenolics, antioxidant activity and minerals in fresh tea shoots, consisting of one apical bud and two adjoining leaves sampled from Muradiye, Tuglali, Gundogdu, Enstitu 9, Hamzabey, Hayrat and Pazar 20 clones grown in Eastern Black Sea region in Turkey was investigated during three harvest season (May, July and September) in both 2006 and 2007 years. The total phenolics of all clones were lower in cool months of May in both years (average 33.00-90.27 mg GAE/g dry weight basis). Thereafter, the levels of total phenolics increased throughout the warmer months from July to September. Antioxidant activity determined by beta-carotene bleaching assay showed similar trends which increased from 1st harvest (May) to 3rd harvest (September). All clones showed nearly 100% antioxidant activity at 2nd and 3rd harvest season which higher than standard synthetic antioxidant BHA (butylated hydroxyanisole). However, seasonal variation of minerals (N, P, K, Ca, Mg, Na, Fe, Cu, Mn, Zn) showed different results according to clones used. These results seem to suggest that the harvest time is crucial to determining the antioxidant potential of fresh tea shoots.