Análise da formação de nódulos radiculares e fixação de nitrogénio em seis variedades de feijão-nhemba (Vigna unguiculata (L) Walp.)sob stress hidrico

Abstract

This experiment was conducted in the greenhouse of the Department of Biological Sciences of the Eduardo Mondlane University (UEM) and aimed to analyze the effect of water stress on the formation of reticular nodules and nitrogen fixation in six varieties (IT82E-18, IT82D812, Massava -nhassenje, Namarua, Tete-2 and mottled Timbawene) of cowpea (Vigna unguiculata (L.) Walp). The plants were subjected to two treatments: control, in which plants were always kept irrigated every three days: and the stress treatment in which irrigation was suspended for 15 days. During the experiment, three harvests were carried out: on the fourth, seventh and tenth weeks. The number, the fresh weight of the nodules, nitrogen fixation and the protein concentration were determined. In the fourth week almost all varieties fixed the nodules, in the seventh the number of nodules increased and in the tenth it decreased slightly under the conditions of water stress. .A positive relationship was found between the number of nodules and the fresh weight. a positive relationship was also found between the number of nodules formed and nitrogen fixation. All six bean varieties subjected to water stress formed nodules, especially the Tete-2 variety, which formed the largest number of nodules. The Massava-nhassenje variety showed a higher percentage of nitrogen fixation in the nodules and the Namarua variety showed a higher protein concentration under water stress conditions. (TRADUÇÃO NOSSA)