Efeitos da salinidade e da composiÃÃo iÃnica da Ãgua de irrigaÃÃo sobre o desenvolvimento de plantas de feijÃo-de-corda / Effects of salinity and ionic composition of the water irrigation on the development of cowpea plants [Vigna unguiculata(L.)].

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

12/03/2007

RESUMO

The use of the inadequate water in irrigation can be prejudicial to the plants. The objective of this work was to evaluate the effect of salinity and chemical composition of irrigation water on plant growth, mineral nutrition, gas exchange, and organic solutes contents of cowpea plants [Vigna unguiculata (L.) Walp.]. Plants were cultivated in plastic pots, using 22 kg of soil at greenhouse conditions and subjected to four different salt stress concentrations (0.5; 1.5; 3.0; and 4.5 dS m-1) in irrigation water. These different salt concentrations were obtained by adding NaCl, CaCl2.2H2O and MgCl2.6H2O (A1), a mixture of chloride, sulphate, carbonates, and bi-carbonates salts (A2), or alone NaCl (A3). A completely randomized design, in a factorial arrangement (3 x 4), with five replicates was adopted. During the experimental period, the following responses were evaluated: transpiration rate, stomatal conductance, net photosynthesis, chlorophyll contents. After 48 days after sowing they were measured total leaf area and fresh and dry masses of leaves, stems and roots. The contents of inorganic (Na, Cl, K, Ca, P, Cu, Fe, Mn, and Zn) and organic (proline, protein, carbohydrates e N-amino soluble) solutes were also determined. The salinity of irrigation water caused reduction in the biomass production, leaf growth and gas exchange, but it was not observed effects of the chemical composition of water on these parameters. However, the ionic composition of irrigation water affected the contents of mineral nutrients, especially the contents of micronutrients. On the other hand, it was not found significant relationships between organic solutes contents and the levels of salinity or chemical composition of the water. The results suggest that chemical composition of irrigation water is an important factor, since it could affect mineral nutrients uptake, which can cause negative effects on plant metabolism and productivity.

ASSUNTO(S)

irrigacao e drenagem vigna unguiculata estresse salino irrigaÃÃo tolerÃncia à salinidade vigna unguiculata salt stress irrigation salt tolerance

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