Alterações fisiológicas e morfológicas da mamoneira sob efeito de doses de torta de mamona e níquel.

Abstract

In the semiarid, the cultivation grown of castor bean emerges as alternative in the economic, environmental and social sectors, employment generation and generating income, strengthening the agricultural economy and the rural sector. Fertilization is an agricultural practice, that provides nutrients to the soil and improve its physical and chemical properties of. Thus, the castor beazcake, as a fertilization alternative, presents significant amounts of N, P and K, and act increasing the capacity of water storage; in other way, nickel is an important element for plants, whose deficiency prevents the action of urease, increasing the accumulation of urea in the leaves. Thus the aim, of this work was, to analyze the influence of castor bean cake and nickel on growth and physiological behavior of castor bean 'BRS Energia'. The study was accomplished at the Embrapa Cotton, Campina Grande, PB, in a completely randomized design, organized in a 4 x 4 factorial scheme, four doses of nickel (0.0, 4.0, 8.0, 12 mL of the solution in concentration of 50 mg L"1) applied in the leaves, four doses of castor bean cake (0.0, 1.0, 2.0 and 3.0 t ha"1) with four replications. The behavior of growth: stem diameter, plant height, leaf area, leaves, stems and roots dry matter; physiological behaviors: fluorescence, relative chlorophyll index and gas exchange were evaluated. The data were subjected to analysis of variance and regression. The castor bean cake influenced the growth parameters, dry matter, quantum efficiency of photosystem I I , relative chlorophyll index and gas exchange. It was reported that there was no changes in the growth, leaf area, dry weight of stem and roots, fluorescence nor in relative chlorophyll index in response to application of nickel. In turn, the application of castor bean cake reduced transpiration, stomatal conductance, instantaneous water use efficiency and instantaneous carboxylation efficiency.