title: Nitric oxide increases tolerance responses to moderate water deficit in leaves of Phaseolus vulgaris and Vigna unguiculata bean species.
abstract: Drought stress is one of the most intensively studied and widespread constraints, and nitric oxide (NO) is a key signaling molecule involved in the mediation of abiotic stresses in plants. We demonstrated that a sprayed solution of NO from donor sodium nitroprusside increased drought stress tolerance responses in both sensitive (Phaseolus vulgaris) and tolerant (Vigna unguiculata) beans. In intact plants subjected to halting irrigation, NO increased the leaf relative water content and stomatal conductance in both species. After cutting leaf discs and washing them, NO induced increased electrolyte leakage, which was more evident in the tolerant species. These leaf discs were then subjected to different water deficits, simulating moderate and severe drought stress conditions through polyethylene glycol solutions. NO supplied at moderate drought stress revealed a reduced membrane injury index in sensitive species. In hydrated discs and at this level of water deficit, NO increased the electron transport rate in both species, and a reduction of these rates was observed at severe stress levels. Taken together, it can be shown that NO has an effective role in ameliorating drought stress effects, activating tolerance responses at moderate water deficit levels and in both bean species which present differential drought tolerance.
authors: Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas, Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte, 31270-901 MG Brazil.
authors: Lucas Martins
authors: LM
authors: Zimmer-Prados
authors: Universidade Federal de Uberlândia, Instituto de Biologia, Rua Ceará, s/n, Uberlândia, 38400-902 MG Brazil.
authors: Ana Sílvia Franco Pinheiro
authors: AS
authors: Moreira
authors: Empresa Brasileira de Pesquisa Agropecuária, EMBRAPA, Av. Olegário Maciel, 450, 36015-350 Juiz de Fora, MG Brazil.
authors: Jose Ronaldo
authors: JR
authors: Magalhaes
authors: Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas, Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte, 31270-901 MG Brazil.
authors: Marcel Giovanni Costa
authors: MG
authors: França
keywords: Bean cultivars; Chlorophyll fluorescence; Hydric deficit; Leaf discs; PEG