Status hídrico, partição de íons e trocas gasosas em plântulas de Erythrina velutina sob estresse salino durante o estabelecimento tardio
Considering that the Caatinga is a highly anthropized and salt-affected biome, it is imperative to elucidate how woody pioneer species respond to salt stress during the initial developmental phases as this knowledge could be useful to the restoration of degraded areas. In this sense, the aim of this...
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| Formato: | bachelorThesis |
| Idioma: | pt_BR |
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Universidade Federal do Rio Grande do Norte
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| Endereço do item: | https://repositorio.ufrn.br/handle/123456789/47261 |
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| Resumo: | Considering that the Caatinga is a highly anthropized and salt-affected biome, it is imperative to elucidate how woody pioneer species respond to salt stress during the initial developmental phases as this knowledge could be useful to the restoration of degraded areas. In this sense, the aim of this work is to verify the effect of salinity on growth, water status, Na+ and K+ partitioning and gas exchanges in Erythrina velutina Wild. seedlings during late establishment. The seeds harvested from ten mother trees were escarified, desinfected and germinated in towel paper under controlled conditions and the seedlings were hydroponically cultivated in distilled water in a greenhouse for 8 d. The hydroponic medium was changed to 100 mM NaCl or distilled water as the control, and the seedlings were maintained under the same conditions for 3 d. The salt treatment was not capable to cause seedling mortality, but the seedlings showed three distinct morphological responses, including shoot growth reduction, leaf wilting or leaf necrotic spots, accompanied by a decrease in dry weight and water relative content in the cordiform leaves. Salt stress caused Na+ accumulation and altered K+ partitioning in the different seedling parts, but the K+/Na+ ratio remained closest to 1.0 only in the cotyledons. The exposure to salinity also reduced stomatal conductance, net CO2 uptake and transpiration, and it increased leaf temperature and internal CO2 concentration in the cordiform leaves during the day course. Taking into account the results, it is not recommended the use of E. velutina to restore degraded areas affected by high salinity, as this stress could lead to seedling mortality due to both osmotic and ionic effects that promote carbon starvation. |
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