Seed germination of a South American forest tree described by linear thermal time models

Effect of reduced water potential on seed germination of a forest tree: a hydrotime approach

“…The results provide a preliminary approach on hydrotime models, by testing the basic assumptions of the models and linear relationships with water potential (Bradford, 1995). Likewise, most model presupposes were followed by P. dubium seeds under different temperatures, described by thermal time models (Daibes and Cardoso, 2018). Temperature and water potential show important interactions to describe germination parameters under laboratory conditions (Alvarado and Bradford, 2002).…”

“…Seeds were obtained from a certified producer located in the municipality of Porto Ferreira (21°3'S; 47°2'W; state of São Paulo, Brazil). The harvesting site shows average temperatures from 19 to 25 °C and mean annual precipitation of 1500 mm (Daibes and Cardoso, 2018). The species has a widespread distribution throughout South America, mostly occurring in seasonal forests from the Paraguai-Paraná Basin to the state of Bahia (Barneby, 1996).…”

“…Then, seeds were individually scarified with a sandpaper to overcome physical dormancy. Once scarified, seeds were expected to behave as non-dormant seeds in the germination trials (Daibes and Cardoso, 2018). Different water potentials were obtained by aqueous solutions of PEG 6000 (polyethylene glycol), ranging from zero (distilled water) to -1.5 MPa (0; -0.3; -0.5; -0.7; -0.9; -1.1; -1.3; -1.5).…”

“…Three replicates of twenty seeds were used in each water potential treatment, and germination tests were conducted in germination chambers under the constant temperature of 25 °C, considered within the range of optimal conditions for seed germination of the species (Daibes and Cardoso, 2018). Because P. dubium seeds are non-photoblastic, all germination trials were conducted in the dark.…”

“…Some studies evaluated the role of Ψ on seed germination of Brazilian species (Botelho and Perez, 2001;Fonseca and Perez, 2003;Rego et al, 2007), but rarely explaining whether germination would fit the presupposes of hydrotime models (Cardoso and Pereira, 2008;Oliveira et al, 2019). Most attention regards to the role of temperature, rather than water potential, as described by thermal time models in neotropical species (Cardoso and Pereira, 2009;Pires et al, 2009;Daibes and Cardoso, 2018;Duarte et al, 2018).…”