Freitas, Cleverson Henrique de  Martins, Fabrina Bolzan  <br/><br/>
Thermal Requirements and Photoperiod Influence in the Leaf Development of Two Forest Species 

<br/><br/> Publicação on-line; 20 ref.; 4 tables; 1 illus.; Summary (En) 
<br/><br/> <br/><br/>ABSTRACT<br/><br/>The aim of this work was to evaluate the effect of thermal time methods and to identify the<br/>phyllochron and photoperiod response in seedlings of two forest species: Corymbia citriodora and<br/>Eucalyptus urophylla. A field experiment was installed under a completely randomized design,<br/>in a 2 × 11 factorial scheme, with two forest species and eleven sowing dates (E). Phyllochron is<br/>influenced by thermal time methods. The best thermal time method is the one that considers the<br/>base and optimum temperature and compares them with daily extreme temperatures. In addition,<br/>the influence of photoperiod and air temperature on phyllochron values was also verified. The lowest<br/>value occurred in E1 (Corymbia citriodora: 24.6 and Eucalyptus urophylla: 13.2 °C day leaf-1)<br/>and the highest in E10 (Corymbia citriodora: 46.4 °C day leaf-1) and E7 (Eucalyptus urophylla:<br/>29.2 °C day leaf-1), suggesting that the phyllochron is influenced by sowing dates.<br/><br/>Keywords: Corymbia citriodora, Eucalyptus urophylla, phyllochron, degree days, daylength. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>EUCALYPTUS UROPHYLLA<br/>FOTOPERIODISMO<br/>FISIOLOGIA VEGETAL