Evaluation of the effects of changes in nitrogen supply in Amaranthus cruentus l. plants

Abstract

The Amaranthus is a plant of great economic valuebecause both their leaves as its seeds can be used as food, but little is known in Brazilian agriculture. Its leaves and seeds are rich in protein, vitamins and minerals. In countries where it is grown, the leaves are eaten as vegetables and their seeds used as cereal or processed into flour and used in the bakery and biscuits industry, resulting in more nutritious food. The availability of nitrogen is an important factor for the growth andproductivity of plants and its alteration can also induce qualitative changes. The nitrogenn is an essential constituint of aminoacids nucleic acids and protein. It is estimated that 65 of foliar pretein occur in the chloroplasts. To the biochemical level, good nitrogen supply increases the protein concentration and the activity of enzymes involved in the carbon dioxide reduction. Therefore, limited availability of nitrogen compromises the supply of carbohydrate for plantgrowth. The elucidation of the effects of nitrogen availability in the culture of Amaranthus is of great importance to agriculture. In this sense, the aim of this project isto evaluate the nature of the changes induced by the variation in the supply of nitrogen as ammonium nitrate (in 70% Long Ashton Solution; HEWITT, 1966) in the production of biomass, photosynthetic characteristics and leaf chemicalcomposition. Chemical changes in the leaves will be evaluated by determining the levels of photosynthetic pigments, betacyanins,total nitrogen and nitrate.