Thermal Requirements and Photoperiod Influence in the Leaf Development of Two Forest Species

Abstract

The aim of this work was to evaluate the effect of thermal time methods and to identify the phyllochron and photoperiod response in seedlings of two forest species: Corymbia citriodora and Eucalyptus urophylla. A field experiment was installed under a completely randomized design, in a 2 × 11 factorial scheme, with two forest species and eleven sowing dates (E). Phyllochron is influenced by thermal time methods. The best thermal time method is the one that considers the base and optimum temperature and compares them with daily extreme temperatures. In addition, the influence of photoperiod and air temperature on phyllochron values was also verified. The lowest value occurred in E1 (Corymbia citriodora: 24.6 and Eucalyptus urophylla: 13.2 °C day leaf-1) and the highest in E10 (Corymbia citriodora: 46.4 °C day leaf-1) and E7 (Eucalyptus urophylla: 29.2 °C day leaf-1), suggesting that the phyllochron is influenced by sowing dates.

Thermal and photoperiodic requirements of the seedling stage of three tropical forest species

“…(Verbenaceae), and Bixa orellana L. (Bixaceae). The method used to quantify thermal 2019b; Freitas and Martins 2019;Fagundes et al 2021;Reis et al 2021;Martins et al 2022b).…”

“…Air temperature and photoperiod are critical factors for seedling development of tropical forest species (Rawal et al 2014;Ferreira et al 2019a, b;Freitas and Martins 2019;Silva et al 2020;Martins et al 2022b, c). Air temperature influences physiological and metabolic activities, photosynthesis and photorespiration, the transport of solutes, and the balance between transpiration and water consumption (Freitas et al 2017;Ferreira et al 2019a;Martins et al 2022b).…”

“…Air temperature influences physiological and metabolic activities, photosynthesis and photorespiration, the transport of solutes, and the balance between transpiration and water consumption (Freitas et al 2017;Ferreira et al 2019a;Martins et al 2022b). The photoperiod or day length affects the amount of solar radiation and the timing of photosynthesis and biomass production (Rawal et al 2015;Langner et al 2016;Mantai et al 2017;Freitas and Martins 2019).…”

“…The phyllochron is the time between the visible emergence of successive leaf tips, assuming a linear relationship between leaf emergence rate (the phyllochron) and daily thermal accumulation (i.e., thermal time [TT] °C•d); thus, the phyllochron is the cumulative TT between successive leaves (or, number of leaves [NL]) and is thus measured as °C•d per leaf (Streck et al 2011;Ferreira et al 2019a). TT can be calculated using different methods (Rosa et al 2009;Daibes et al 2019;Freitas and Martins 2019), but all require air temperature and the cardinal temperatures, which are called base (T b ), optimum (T opt ), and maximum (T B ) temperatures. These thermal thresholds (T b , T opt and T B ) are specific for each tropical forest species and establish the temperature ranges at which a seedling can develop (Freitas et al 2017;Ferreira et al 2019a, b;Silva et al 2020).…”

“…These thermal thresholds (T b , T opt and T B ) are specific for each tropical forest species and establish the temperature ranges at which a seedling can develop (Freitas et al 2017;Ferreira et al 2019a, b;Silva et al 2020). Each TT method can result in different thermal time values, especially when air temperature is below the T b or above the T B of the species (Rosa et al 2009;Ferreira et al 2019a;Freitas and Martins 2019), thus affecting the phyllochron values (Rosa et al 2009;Martins et al 2022c).…”