Sheila Isabel do Carmo Pinto

Eficiência nutricional de clones de eucalipto na fase de mudas cultivados em solução nutritiva

The objectives of this study were to evaluate the biomass production and nutritional efficiency of seedlings of eucalyptus clones in nutrient solution, to characterize the macronutrient uptake, translocation and utilization efficiency. The experiment was carried out in a greenhouse using seedlings of six eucalyptus clones (58, 386, GG100, I042, I144, and VM1), grown in nutrient solution. The treatments, represented by the six clones, were distributed in a completely randomized design, with four replications. The eucalyptus clones differed from each other in biomass production and in nutritional efficiency. Differences were detected in the uptake efficiency, translocation and utilization of the macronutrients in relation to the different eucalyptus clones, as well as in function of the nutrient. In a general way, the clones can be ranked for nutritional efficiency in the following sequence: I144 > 386 > 58 ≈ GG100 > VM1 > I042. Clone I144 was most efficient, mainly for N, P, K, Mg and S, with higher uptake and utilization efficiency of these nutrients in biomass production. Clone I042 was inefficient in uptake and utilization of all macronutrients, compromising biomass production. VM1 stood out among the other clones as the most efficient in the translocation of all macronutrients to the aerial part of the eucalyptus seedlings. The differences identified in this study in terms of nutritional efficiency of eucalyptus clones in the seedling phase suggest the possibility of selection of eucalyptus genotypes for distinct soil fertility conditions.

Caracterização genética de Calophyllum brasiliense Camb. em duas populações de mata ciliar

Calophyllum brasiliense Camb. is a predominant species in areas with high water saturation such as the riparian forests in southern Minas Gerais State. The objective of this research was to study the genetic variability of C. brasiliense populations. Twenty individuals were sampled from two populations located in Funil Dam in Lavras-MG. Isozyme eletrophoresis analysis provided evidence of 17 alleles distributed in 8 loci, which were represented in five enzymatic systems: α-esterase, β esterase, acid phosphatase, malate dehydrogenase and transaminase oxalacetatum glutamate. The diversity indexes showed a low number of alleles per loci in both populations, pop I (1.75) and pop II (1.50). The polymorphic loci percentage (P) were 37.5% and 50% in populations I and II respectively. The mean heterozygosities were 0.119 and 0.111, while the expected was 0.131 and 0.112. The number of migrants ( ) between populations was 2.70. The estimated effective size was 18 individuals for population I, and 19 for population II.

Crescimento e nutrição mineral de mudas de cedro australiano (Toona ciliata) sob omissão de nutrientes

In order to evaluate nutritional requirements and the effect of nutrient deprivation on the development of seedlings of Australian cedar (Toona ciliata M. Roem var. australis), a greenhouse experiment was conducted. The substrate used was a dystroferric red latosol with low nutrient availability, using 15 treatments and applying the missing element technique. The experiment included two complete treatments (one provided N, P, K, S, B, Cu, Zn with limestone while another provided N, P, K, Ca, Mg, S, B, Cu and Zn without limestone), besides deprivation of each nutrient (-N, -P, -K, -Ca, -Mg, -S, -B, -Cu and -Zn), one treatment with combined deprivation of B, Cu and Zn, one treatment applying limestone only, one treatment applying N, P, K, S, B, Cu and Zn, without limestone, and one absolute control treatment (natural soil). The following characteristics were evaluated: height, diameter, shoot dry matter and root dry matter, and nutrient content in the shoot dry matter after 150 days. Australian cedar plants have high nutritional requirements, and nutrients P, N, S, Ca, K, Mg and Cu, in that order, were found to be limiting factors to plant development. B and Zn deprivation did not affect plant development. Limestone application was essential for the development of Australian cedar plants. Initial deficiency symptoms were found to be the result of S, limestone and N deprivation.

Silício como amenizador da fitotoxicidade de zinco em plantas jovens de Eucalyptus urophylla cultivadas em solução nutritiva

Zn is an essential micronutrient for the growth and metabolism of plants, but when present in toxic levels in the environment, it can affect the the development of plants. Among the several beneficial effects of silicon (Si), it presents an effect in the decrease or elimination of the adverse effects of heavy metals in the environment. The objective of this work was to evaluate the effect of Si in the alleviation of Zn toxicity on the growth and mineral nutrition of Eucalyptus urophylla seedlings cultivated in nutrient solution. Seedlings of Eucalyptus urophylla were grown in pots containing 3L of Clark nutrient solution, in a 6 x 2 factorial design, using six Zn concentrations (0, 2, 50, 150, 300 and 450 µmol L-1 as ZnSO4 7H2O) and two of Si (0 and 1.78 mmol L-1 of Si as potassium silicate). After eight weeks, plant morphologic traits, dry matter production and content and nutrient utilization were evaluated. The increase of Zn concentrations in the nutrient solution provided higher toxicity in the roots than in the shoots. The addition of the Si alleviated the negative effect of the excess Zn on plant growth, but presented little effect on the nutrient content in these tissues. The silicon addition in the nutrient solution provided a more efficient use of P, Ca, Mg and S for the Eucalyptus urophylla plants.