Cardinal temperatures and thermal requirements for the initial development of two Brazilian native species

Abstract

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.

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

“…Both species presented different duration and phyllochron values during sowing dates (p<0.05), which indicates the influence of photoperiod (Rosa et al, 2009;Lisboa et al, 2012;Ferreira et al, 2019). The angular coefficients (a) of linear regressions between mean phyllochronand mean photoperiod were significant for both species, proving that there is influence of photoperiod on the phyllochron of C. citriodora and E urophylla.…”

“…Different environmental conditions, such as those occurring during the 11 sowing dates (Table 1), affected the leaf appearance rate and, consequently, the leaf development rate and are important in plant development studies (Ferreira et al 2019). The presence of an inverse relationship between air temperature and duration of the seedling phase indicated that lower air temperature extends the seedling phase in both species.…”

“…However, there is no confirmation of the influence of photoperiod on LD in forest species, such as eucalyptus (Rawal et al, 2015). This information could help improving the quality of seedlings and increase the probability of success in the implantation and establishment of forests (Martins et al, 2007;Rawal et al, 2014;Ferreira et al, 2019).…”

“…Studies on the quantification and modeling of leaf development are important for scientific and practical reasons. They are a basis for the selection of species and cultivars more adapted to specific climatic conditions, evaluation of plant response in scenarios of climate changes (Streck et al, 2011;Ferreira et al, 2019) and may be useful to nurserymen in choosing strategies to optimize seedling production (Martins et al, 2007). In addition, by-products obtained in this study such as 3-PG and PnET are used in modeling of forest growth and yield (Xie et al, 2017).…”

“…TT is based on the daily accumulation of air temperature and its relation with cardinal temperatures (Freitas et al, 2017), and can be calculated by several methods. Different methods can result in different TT values, especially in periods when temperatures are below or above cardinal temperatures (Rosa et al, 2009;Ferreira et al, 2019), influencing LD quantification.…”