Effect of paclobutrazol on germination and metabolism of ethylene in seeds of Stylosanthes humilis H.B.K. / Efeito do paclobutrazol na germinação e no metabolismo do etileno em sementes de Stylosanthes humilis H.B.K.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

Germination of non-dormant seeds of Townsville stylo (Stylosanthes humilis HBK), a tropical annual forrage legume was decreased by the growth retardant paclobutrazol (PBZ) [(2RS, 3RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1H-1,2,4- triazol-1-yl)pentan-3-ol] suspensions. This effect was reverted by 2-chloroethylphosphonic acid, an ethylene-releasing substance, and 1-amino-1-cyclopropane-1-carboxylic acid (ACC), the immediate ethylene precursor in its biosynthetic pathway. A delay in ethylene emanation by non-dorment seeds and a significant decrease in the production of that gaseous regulador by dormant seeds were observed when they were treated with PBZ. The retardant also led non-dormant seeds to show significant lower free ACC content, a similar effect also exhibited by dormant seeds treated simultaneously with the retardant plus selenourea. In vitro activity of ACC oxidase of that enzyme was observed in the first 48 h exposure to the inhibitor. In vitro activity of ACC oxidase was decreased from 36 h onwards following incubation of non-dormant seeds with PBZ, but this phenomenn occurred after the germination decrease.

ASSUNTO(S)

germinação fisiologia de plantas cultivadas germination paclobutrazol paclobutrazol ethylene etileno stylosanthe estilosante

ACESSO AO ARTIGO

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