EFEITO DA TEMPERATURA E DA LUZ NO DESENVOLVIMENTO DE PLÂNTULAS DE MILHO

Abstract

The aim of the present research was to study the effects of temperature and light on seedlings development of two cultivars of corn (Zea mays. L.), Zeneca-8392 and Exeler/Ciba. The experiment was done under climatic chamber conditions with light and temperature control. Eighteen treatments consisted of combinations of constant temperatures (10, 25 and 35 C) or alternate temperatures (10-25, 10-35 and 25-35oC) with different photoperiodic regimes (0, 8 and 24 hours of light). Plants were grown in pots with 16 plant/pot and 5 replications per treatment. Seedling were evaluated for subcrown internode length, coleoptile length and plant height, starting at the four true leave stage. The tratment that promoted the lowest subcrown internode length was the combination of alternate temperature (10-35oC) with constant light for both cultivars. Temperature, light and genotype have some effects on the development of corn seedlings. Plants and subcrown internode etiolation was not only due to light absence but also to combinations of photoperiodic and temperature regimes.