Efeito do cloreto de sódio (NaCl) no crescimento do feijão nhemba (Vigna unguiculata) e feijão jugo (Vigna subterranea)

Abstract

The present work was carried out in the greenhouse of the Nursery of the Department of Biological Sciences, on the Main Campus of the Eduardo Mondlane University, between September and November 2004. The main objective of this experiment was: "To study the effect of sodium chloride (NaCl) ) on the growth of Nhemba Beans (Vigna unguiculata) and Jugo Beans (Vigna subterranea)" Jugo Beans (Vigna subterranea) and Nhemba Beans (Vigna unguiculata) are dicotyledons of the Fabaceae family and belong to the same genus (Vigna). These are crops with enormous food importance in the arid and semi-arid regions of Africa and Asia. For the experiment, 90 seeds of each species were used, subdivided into 5 treatments, the first being the control and the remaining four different concentrations of the NaCl salt. The NaCl concentrations used were: 5mM, 10mM and 100mM. In the laboratory, sampling was done by destructive analysis of 6 plants from each treatment, every 4 weeks after the start of the experiment. The plants were separated into root, stem and leaves. Then all growth parameters were measured. The fresh and dry weights of Nhemba Beans were not affected by the concentrations of 5 mM, 10 mM and 50 mM NaCl. On the contrary, the total fresh and dry weights of Jugo Beans were only not affected by the concentration of 5 mM of NaCl. Relative Growth Rate (TCR), Apparent Assimilation Rate (TAA), Leaf Area Ratio (RAF) and Leaf Dry Weight Ratio (RPsF) for Nhemba Beans and Relative Growth Rate (TCR), Assimilation Rate apparent (TAA), Leaf area ratio (RAF), Root dry weight ratio (RPsR) and Root weight by area ratio (RPR/A) for Jugo beans, were negatively influenced by NaCl during the experiment. while the root length, number of nodules and leaves, absolute growth rate (TCA), root dry weight ratio (RPsR) and root weight to area ratio (RPR/A) for Nhemba beans and, root length, leaf area, absolute growth rate (ACT) and leaf dry weight ratio (RPsF) for Jugo beans, in general, were positively affected by low NaCl concentrations. Nhemba Bean was more tolerant to the effect of NaCl in relation to Jugo Bean