Efeito da toxicidade de sulfato de alumínio no crescimento e morfologia de duas variedades locais de feijão-nhemba (Vigna unguiculata (L.) Walp.)

Abstract

Food toxicity is one of the biggest problems for plant growth in acidic soils. In Mozambique, southern coastal areas are characterized by having highly acidic soils and high levels of exchangeable aluminum. The present study examined the phenological and physiological responses of two local varieties of cowpea ("Namarua" and "Massava-nhassenje") when subjected to different concentrations of aluminum (0.015, 0.030 and 0.045mM) and the control without adding aluminum. To carry out the experiment, plants with 8 days old were grown in pots, in the greenhouse of the Department of Biological Sciences. Afterwards, these plants were transferred to aquariums containing Clark's nutrient solution with pH 4.3 and with different concentrations of aluminum for 15 days, in the Ecology laboratory of the Department of Biological Sciences. Both varieties showed signs of phytotoxic effects of aluminum two days after its addition, such as curled and yellowed leaves, poorly developed root hairs and the production of a mucilaginous layer. These signs have been more accentuated in the "Namarua" variety over time. In the second week there were leaf necrosis and plant death in the control treatments, 0.015 and 0.030mM of aluminum in the "Namarua" variety and in the control treatments and 0.015mM in the "Massava-nhassenje" variety. The growth parameters TCR and TAA were the most affected, with significant differences between the two varieties and between the different treatments (p <0.05), the variety "Massava-nhassenje" was more tolerant than the variety "Namarua" considered sensitive to the effects of aluminum. (TRADUÇÃO NOSSA)