The objective of this work was to estimate the cardinal temperatures and to quantify the thermal requirements for the initial development of seedlings of the native tree species Citharexylum myrianthum and Bixa orellana. A field experiment was carried out in a completely randomized design, in a 2?12 factorial arrangement (2 tree species and 12 sowing dates), with five replicates. The base, optimum, and maximum temperatures for the development of C. myrianthum were 11.4, 18.1, and 36.6°C, and, for B. orellana, 12.0, 18.4, and 46.4°C. The thermal requirements for the development of C. myrianthum was 66.7°C day per leaf, and, for B. orellana, 82.5°C day per leaf. In the initial development, B. orellana shows a large thermal amplitude and is tolerant to extreme temperatures, while C. myrianthum shows a large thermal amplitude, but a lower thermal requirement and a more rapid development than B. orellana.

The aim of this study was to estimate cardinal temperatures (base, optimum, and maximum), and simulate the vegetative development of guava crop through phyllochron (linear) and Wang and Engel (nonlinear) models at the seedling phase. The experiment was conducted in Itajubá, MG, Brazil (22° 24’ 46.43” S 45° 26’ 48.94” W), for two years in a completely randomized design with twelve sowing dates and five experimental units per treatment, totaling sixty experimental units. The cardinal temperatures were estimated using twelve methods described in the literature and the values were: base, 10.9 °C, optimum, 17.3 °C and maximum, 51.2 °C. The phyllochron model was superior to Wang and Engel’s model for simulation of vegetative growth of guava, with root mean square error of 1.5 leaves.

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Recebido em agosto/2014; Aceito em fevereiro/2015. RESUMO. O presente trabalho objetivou avaliar a utilização do resíduo orgânico da agroindústria processadora de bananas na composição de substratos em comparação com outros substratos para produção de mudas de Platycyamus regnellii Benth. O experimento foi realizado em casa de vegetação, avaliando-se seis substratos dispostos em blocos casualizados, constando de: solo, areia e compostagem da casca de banana (S1); solo, areia e compostagem de cascas de vegetais diversos sem adição de banana (S2); solo, areia e farinha proveniente de cascas de banana após secagem (S3); solo, areia e esterco bovino seco e peneirado (S4), todos na proporção 3:2:1; solo e areia na proporção 3:2 com adição de 150g de fertilizante NPK 4.14.8 (S5) e tratamento controle: solo e areia na proporção 2:1 (S6). A compostagem da casca de bananas mostrou-se eficiente para produção de mudas de P. regnellii, enquanto o emprego da farinha de cascas de banana na composição de substrato comprometeu o desenvolvimento das mudas.

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