The aims of study were to evaluate growth and characterize the visual symptoms of macronutrient and micronutrient deficiencies in mangosteens. The seedlings were cultivated in nutritive solution containing all required macronutrient and micronutrients and in solutions with omission of N,

ABSTRACT:The adoption of cover crops in commercial plantations has been shown to be an alternative to promote greater soil protection, enhancement in its structure and aggregation, optimization of accumulation and nutrient cycling to obtain greater production of biomass and higher nitrogen fixation. To determine the accumulation of micronutrients of Pueraria phaseoloides L., according to age, established as a soil cover in industrial oil palm crops, an experiment was carried out at Companhia Agroindustrial (CRAI) in the municipality of Tailândia, State of Pará, in an Oxisol. The experimental design was a randomized block with four replicates. The results allow to conclude that the accumulation of nutrients, except for Mn and Cu in the live Pueraria phaseoloides L. plant cover reduced over the years and those of B, Mn, Zn, and Cu were greater in the dead Pueraria phaseoloides L. plant cover and for Cl it was in the live Pueraria phaseoloides L. plant cover. The decreasing order of total micronutrient extraction was the following: Cl> Mn> B> Zn> Cu.

No abstract

The aim of this work was to evaluate, by the physiological and growth variables, the behavior of paricá seedlings submitted to cadmium aplications. Cadmium is a importante metal due the industrial use, the accumulation in the environment, the high mobility in the soil-plant system, and possibly by changing physiological and growth parameters in plants. Among the plants that can be affected by this metal is the species (Schizolobium amazonicum Huber ex Ducke), known as paricá. Native from the amazona region, presents great social, economic and environmental potential. Among the physiological variables analyzed, cadmium interfered with photosynthesis, stomatal conductance and transpiration, mainly with the increase of the concentrations of this element. Among the correlated variables, the variable intrinsic efficiency of water use (EiUA), presented high in the stress conditions maintaining the minimum of water balance. For the growth variables, the cadmium provided a decrease in the height, diameter, number of leaves and leaflets influencing the low synthesis of photoassimilates. The phytotoxic element was mainly concentrated in the roots, but there was translocation to shoot, signaling a phytoextractive characteristic.

Water stress limits the initial growth and development of maize mass and grain, as well as the physiological process for absorbing the amount of mineral elements. The objective was to evaluate the effect of silicon on germination and growth of corn seedlings submitted to water deficit. The experiment was carried out in the laboratory and the experimental design was completely randomized (factorial 3 × 4), with three concentrations of calcium silicate (0.0; 1.0 and 2.0 mM) and 4 solutions of PEG-6000 to simulate different osmotic potentials (0, 0; -0.3; -0.6; -0.9 MPa). Germination percentage, germination speed index (GSI), mean germination time (MGT), percentage of non-germinated and abnormal germinated, length and dry matter of shoot, root and total seedlings were evaluated. Water deficiency reduced the parameters TG, GSI and MGT. The water deficit reduce the MSPA, MSR and MST with more than 80% reduction in mass from seedlings without deficiency to seedlings with deficiency. For CPA, CR and CT there was a reduction of at least 87%, 70% and 77%, respectively, among seeds without deficiency compared to seeds submitted to deficiency. The use of silicon in corn seeds did not attenuate the stress caused by water deficit simulated by PEG-6000.