Fennel is a medicinal and aromatic plant that is commonly used in Brazilian cuisine and in the manufacture of cosmetics. The exogenous application of salicylic acid (SA) can act on the hormonal action stimulating plant growth and development and the induction of plant defense responses under stressful conditions. The objective of this study was to determine the effect of the foliar application of SA on the production of biomass and synthesis of secondary compounds in fennel plants. For this purpose, an experiment was carried out in potted plants in a greenhouse with the application of SA at concentrations of 0, 0.25, 0.50 and 1.00 mM, 20 days and 90 days after transplanting the seedlings to the pots. The effect of SA on the metabolism of the fennel plants was evaluated using growth and biochemical parameters. The exogenous application of SA increased the plant shoots dry weight at the concentration of 0.50 mM, whereas an improved dry root mass and root/shoot ratio was achieved with the concentration of 0.25 mM. The elicitor effect was observed at 0.25 mM of SA, resulting in greater economic value of the biomass due to the higher production of secondary compounds, such as phenolic compounds and flavonoids. In addition, an increase in antioxidant activity of the plant extracts and of the essential oil content of the species was obtained at the concentration of 1.00 mM. Keywords: Fennel; Antioxidant activity; Phenolic compounds; Essential oil; Secondary metabolism. ResumoO funcho é uma planta medicinal, condimentar e ornamental, utilizada na culinária brasileira e na fabricação de cosméticos e de fitoterápicos. A aplicação exógena do ácido salicílico (AS) pode agir na ação hormonal, estimulando o crescimento e o desenvolvimento vegetal, e na indução das respostas de defesa das plantas. O objetivo deste trabalho foi determinar o efeito da aplicação foliar de AS sobre a produção de biomassa e a síntese de compostos secundários em plantas de funcho, uma espécie medicinal produzida comercialmente como matéria-prima para a indústria mundial de fitomedicamentos. O experimento foi conduzido em plantas envasadas em estufa, sem controle de umidade e temperatura. A aplicação do AS foi efetuada nas concentrações 0; 0,25; 0,50 e 1,00 mM, aos 20 dias e 90 dias após o transplante das mudas para os vasos. O efeito do AS sobre o metabolismo das plantas de funcho foi avaliado através de parâmetros biométricos de crescimento e bioquímicos. Conclui-se que a aplicação exógena de AS constitui-se em técnica de manejo vantajosa para a obtenção de aumento na biomassa das plantas de funcho: massa seca da parte aérea, na concentração de 0,50 mM, e massa seca de raízes e razão raiz/parte aérea, na concentração de 0,25 mM. O efeito elicitor foi obtido na concentração de 0,25 mM de AS, resultando em maior valor econômico da matéria-prima, devido ao aumento na produção de compostos secundários, tais como fenóis totais e flavonoides, além de um concomitante aumento na atividade antioxidante do extrato vegetal e no teor do óleo essencial ...

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Cotton cultivation in Brazil tends to occur mostly in the rainy season, and at the time of developing the crop there are often prolonged periods of low solar radiation. The objective of this work was to evaluate the root development of cotton cultivars subjected to shading in the initial phase. The experiment was carried out in a greenhouse, using rhizotrons. The experimental design was a 2x2 factorial in randomized blocks with five replications. The treatments were composed of cotton cultivars TMG 1WS (early) and TMG 8WS (late) and luminosity conditions: non-shaded and shaded (50% reduction of luminosity). There were no interactions between the factors “shading” and “cultivars” for any parameter evaluated. Shading reduced total and lateral root growth from the 21 days after emergence (DAE) and the main root at 24DAE. Shading caused reductions in length (60%), surface (65%), mean diameter (15%), root volume (69%), root dry matter mass (83%) and shoot (64%), as well as decreasing the content (36%) and the accumulation of carbohydrates in the shoot (73%). Shading at early cotton development reduces the shoot carbohydrates production, affecting dry matter accumulation and root growth, and this response is independent of the cultivar.

Salicylic acid (SA) is a phenolic compound present in plants and has multiple functions, including hormonal effect on stimulus of plant growth and development and induction of plant defense responses under conditions of biotic and abiotic stresses. Studies related to SA's elicitor action on the synthesis of secondary metabolite in medicinal plants have been conducted in order to increase the economic value of these species. The objective of this study was to determine the effect of SA foliar application on biomass production and the synthesis of secondary compounds in yarrow (Achillea millefolium L.-Asteraceae). The experiment was conducted in potted plants under greenhouse conditions. The SA application was done at concentrations of 0, 0.25, 0.50 and 1.00 mM 20 days after transplanting the seedlings to pots. The effect of SA on the metabolism of yarrow plants was evaluated through biometric parameters of growth and biochemical parameters. The SA at 0.50 mM resulted in linear increases in biomass accumulation of roots, total dry mass, ratio root/shoot and chlorophyll a and chlorophyll a+b content in yarrow plants.The application of SA at 0.50 and 1.00 mM was most effective in eliciting the production of essential oils and total phenols, with a consequent improvement of the antioxidant activity of the plant extract. It can be concluded that SA application constitutes an advantageous management practice for commercial production of Achillea millefolium, increasing the nutraceutical and medicinal values of this species.

Sweet potato [Ipomoea batatas (L.) Lam.] has wide adaptability to different climatic conditions. However, its yield can be affected by prolonged periods of drought. Application of exogenous jasmonates can modulate several physiological and biochemical processes, improving plant tolerance to abiotic stress. This study sought to evaluate the role of exogenous application of methyl jasmonate (MeJA) in attenuating the adverse effects of drought stress by physiobiochemical analyses and their impact during the early initiation of tuberous roots. The experimental design was completely randomized and arranged in a 2 × 2 factorial, comprised of two concentrations of a MeJA plant regulator [without (0 µmol•L-1) and with (13 µmol•L-1) application] and two water regimes (optimum and drought conditions, corresponding to a field capacity of 100 and 40%, respectively). Plants treated with MeJA showed a reduction in total leaf area and leaf dry biomass but increased adventitious root dry biomass. In addition, MeJA application in sweet potato plants affected photosynthetic performance and increased and antioxidant phenolic compounds, carotenoids, anthocyanins, and proline. The evaluated response mechanisms showed that the severity of drought was more prominent than the positive effects of MeJA, since the increases on antioxidant pigments and secondary metabolites were not sufficient to mitigate stress caused by drought, which was reflected in the reduced tuberous root production.

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Genetic, biochemical and physiological parameters can be changed by applying seaweed extract-based products. However, there is scarce information about the influence of seaweed extract on yarrow performance (Achillea millefolium L.), which is widely used in the folk medicine. Therefore, this study aimed to evaluate the effects of Ascophyllum nodosum extract on plant development (leaf and root biomass, and leaf area), physiological indexes (leaf weight ratio, and root: leaf ratio), secondary metabolite (phenolic compounds) content and antioxidant activity of yarrow. The experiment was carried out in a completely randomized design with 4 treatments (seaweed extract concentrations 0, 3, 6 and 9 mL L-1) and 10 replications. The higher concentration of seaweed extract caused higher total dry weight of plants (from 17.8 to 19%), especially due to increases in the root biomass (up to 28.5%). Only plants that received the highest concentration of seaweed-based product presented increments in the number of leaves when compared to the control plants (18.3 %). Furthermore, the use of A. nodosum extract 9 mL L-1 provided increases in the antioxidant activity and content of phenolic compounds in leaves (up to 30.44%). In conclusion, application of A. nodosum is a potential tool strategy to improve the quality of raw material from yarrow plants, since it increased the phenolic compound content and antioxidant activity in leaves, which are the plant organs commonly used in folk medicine.