Crescimento e desenvolvimento do algodoeiro em função de doses de silício e ácido salicílico

Abstract

The herbaceous cotton (Gossypium hirsutum L. race Latifolium Hutch) is one of the top ten species domesticated by human beings. Its main product is the fiber that wears almost half of humanity. It is also a source of protein, the fifth oilseed of the world and the second of Brazil, and the third source of biodiesel in our country with excellent quality oil, which is very good for human consumption and for the production of biofuels, and good chemical stability. Among the limiting factors for the cotton plant development stands mineral nutrition considering that there is little information available for this cultivar about the use of silicon, as a beneficial element and also the use of new plant hormones, that is the case of salicylic acid, used isolated and in combination. The objective of this research to identify and quantify the isolated and in combination effects of these two products on growth and biochemical aspects of herbaceous cotton, cultivar BRS 8H, that is quite drought resistant and produces an average of excellent intrinsic quality fiber. The experiment was conducted in semi-controlled conditions (greenhouse) in Campina Grande, Paraiba, on the premises of Embrapa Algodão in 20 liters capacity vessels. It was used a completely randomized design with three replications and 16 treatments, in a 4 x 4 factorial analysis scheme, having as factor four silicon concentrations: 0; 40; 80 e 120 g L-1 and four salicylic acid concentrations: : 0; 5; 10 e 15 mM. It was measured several variables of growth, such as non-destructive analysis (leaf area, stem diameter and plant height) at various periods of the cycle of the plant besides dry weight, leaf area ratio, leaf weight ratio, specific leaf area and biochemical aspects (total chlorophyll content and peroxidase activity). The cotton plant cv. BRS 8H when grown under foliar application of silicon (SI), and salicylic acid (SA) isolated and in combination, showed significant changes in growth and biochemical aspects, which highlights the need for further research with larger amplitude range of these factors order to obtain more conclusive results for the tested variables.