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Type: Artigo de periódico
Title: No·-releasing Substances That Induce Growth Elongation In Maize Root Segments
Author: Gouvea C.M.C.P.
Souza J.F.
Magalhaes A.C.N.
Martins I.S.
Abstract: Root segments of maize were incubated in different solutions containing substances that non-enzymatically release nitric oxide, such as sodium nitrite (SN), sodium nitroprusside (SNP), nitrosoglutathione (NGLU) and nitrosocysteine (NCYS). We found that all of these substances induced root tip expansion in a dose-dependent manner. The decreasing order of potency for root-induced elongation was: 10 -7 M SN, pH 4.5; 10 -11 M NCYS, 10 -10 M SNP, 10 -9 M NGLU and 10 -7 M SN, pH 7.0. Nitric oxide scavenger such as methylene blue prevented the elongation induced by NO·-releasing substances, but had no effect on indole-3-acetic acid (IAA)-induced cell expansion. Our results suggest that nitric oxide is the putative elongation inducer and that IAA and NO·-releasing substances conceivably share common steps in the signal transduction pathway, since both elicited the same plant response. Vanadate, a plasmamembrane ATPase inhibitor, significantly reversed IAA-induced elongation when supplied at 10 μM concentration. IAA-induced elongation was strongly enhanced by 10 nM BAY K 8644, an agonist of voltage dependent Ca 2+ channels. Promotion of root elongation in the absence of IAA occurred only at higher concentrations of BAY K. Vanadate and BAY K had no influence on the NCYS-induced elongation suggesting that the common steps in the signalling of IAA and NCYS are not at the level of the plasmamembrane.
Rights: fechado
Identifier DOI: 10.1023/A:1005837012203
Date Issue: 1997
Appears in Collections:Unicamp - Artigos e Outros Documentos

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