Sementes de leguminosas forrageiras sob estresse salino tratadas com ácido salicílico e espermidina
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Data
2016-02-24
Autores
Pizolato Neto, Antonio [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A germinação de sementes é um processo crítico no ciclo vital das plantas superiores e muito susceptível às condições adversas do ambiente, as quais podem causar o estresse oxidativo, resultante do aumento de espécies reativas de oxigênio (ERO), que podem causar danos às proteínas e iniciar a peroxidação lipídica nas membranas celulares. A aplicação do ácido salicílico e espermidina e de grande importância na proteção do tecido vegetal dos efeitos prejudiciais dos estresses, restaurando os padrões normais de crescimento evidenciando a função essencial no metabolismo celular. Diante disso o objetivo deste trabalho foi verificar os efeitos do estresse salino na germinação e no crescimento inicial de duas espécies de leguminosas forrageiras, guandu cv. BRS Mandarim e labe-labe cv. Rongai, avaliando-se os seguintes parâmetros bioquímicos-fisiológicos: i) efeito exógeno do ácido salicílico e da poliamina espermidina; ii) atividade das enzimas superóxido dismutase (SOD), ascorbatoperoxidase (APX) e catalase (CAT). iii) peroxidação lipídica e iv) teores de glicina betaína. O delineamento experimental utilizado foi o inteiramente casualizado no esquema fatorial 2x2x4+1, sendo as duas cultivares, guandu, cv. BRS Mandarim (C1) e labe-labe cv. Rongai (C2); dois tipos de atenuadores (0,5 mM de AS ou Spd); quatro concentrações de cloreto de sódio (NaCl) para induzir diferentes níveis de estresse salino, expressos em mM: 0,0 (S1); 20 (S2); 40 (S3) e 60 (S4). Nas plantas sob salinidade, a Spd e o AS aumentaram o crescimento da parte aérea das espécies, mas diminuíram a germinação e o crescimento de raízes nas plântulas. A Spd aumentou a atividade da CAT, enquanto que o AS aumentou a atividade da SOD e da APX, nas plântulas sob estresse salino. O uso do AS e da Spd ocasionaram no decréscimo de glicina betaína. O labe-labe é menos sensível ao estresse salino estudado que o guandu. Os resultados obtidos neste trabalho mostraram que os compostos (Spd e AS) são benéficos para atenuação do estresse salino em ambas as forrageiras estudadas.
Seed germination is a critical process in the life cycle of superior plants and very susceptible to adverse environmental conditions which can cause oxidative stress, resulting from the increase of reactive oxygen species (EROS), which may cause damage to proteins and initiate lipid peroxidation in cell membranes. The application of salicylic acid and spermidine is a great importance in protecting the plant tissue from the harmful stress effects, restoring the normal growth standards showing the key role in cell metabolism. In view of that, the aim of this study was verify the effects of salt stress on germination and initial growth of two species of forage legumes, pigeonpea cv. BRS Mandarim and lablab bean cv. Rongai evaluating the following biochemical and physiological parameters: i) exogenous effect of salicylic acid and polyamine spermidine; ii) activity of the enzymes superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT); iii)lipid peroxidation; iv) content of glycine betaine. The statistics experimental design was randomized completely in a factorial scheme 2x3x4, the two cultivars, pigeonpea cv. BRS Mandarin (C1) and lablab bean cv. Rongai (C2); Two types of attenuators (0.5 mM AS or Spd); four concentrations of sodium chloride (NaCl) to induce different levels of salt stress, expressed in mM: 0.0 (S1); 20 (S2); 40 (S3) and 60 (S4) . In plants under salinity, the Spd and AS increased the aerial parts of the species, but decreased germination and root growth in seedlings. The Spd increased the CAT activity, while the AS increased the SOD and APX acitivity, in the seedlings under salt stress. The use of AS and Spd caused decrease in glycine betaine. The lablab bean is less sensitive to salt stress than Guandu studied in this experiment. The obtained results in this experiment showed that the compounds (Spd and AS) are beneficial for mitigation of salt stress in both studied forages.
Seed germination is a critical process in the life cycle of superior plants and very susceptible to adverse environmental conditions which can cause oxidative stress, resulting from the increase of reactive oxygen species (EROS), which may cause damage to proteins and initiate lipid peroxidation in cell membranes. The application of salicylic acid and spermidine is a great importance in protecting the plant tissue from the harmful stress effects, restoring the normal growth standards showing the key role in cell metabolism. In view of that, the aim of this study was verify the effects of salt stress on germination and initial growth of two species of forage legumes, pigeonpea cv. BRS Mandarim and lablab bean cv. Rongai evaluating the following biochemical and physiological parameters: i) exogenous effect of salicylic acid and polyamine spermidine; ii) activity of the enzymes superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT); iii)lipid peroxidation; iv) content of glycine betaine. The statistics experimental design was randomized completely in a factorial scheme 2x3x4, the two cultivars, pigeonpea cv. BRS Mandarin (C1) and lablab bean cv. Rongai (C2); Two types of attenuators (0.5 mM AS or Spd); four concentrations of sodium chloride (NaCl) to induce different levels of salt stress, expressed in mM: 0.0 (S1); 20 (S2); 40 (S3) and 60 (S4) . In plants under salinity, the Spd and AS increased the aerial parts of the species, but decreased germination and root growth in seedlings. The Spd increased the CAT activity, while the AS increased the SOD and APX acitivity, in the seedlings under salt stress. The use of AS and Spd caused decrease in glycine betaine. The lablab bean is less sensitive to salt stress than Guandu studied in this experiment. The obtained results in this experiment showed that the compounds (Spd and AS) are beneficial for mitigation of salt stress in both studied forages.
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Palavras-chave
Estresse oxidativo, Cajanus cajan, Lablab purpureus, Poliaminas, Salicilatos, Salinidade, Oxidative stress, Polyamines, Salicylates, Salinity