Modeling the Three Phases of the Soaking Kinetics of Seeds

Abstract

Core Ideas The soaking kinetics of seeds of six cultivated species was modeled.Morphological and physical properties of seeds affected the water absorption.Two models were adapted in order to capture the third phase of the soaking process. Several models can be used to describe the seed soaking curve, which, under optimal conditions, occurs according to a three‐phase pattern. Among these models, the Peleg model stands out by its wide use. However, phase III (of germination itself) is not captured by this and other common models in seed soaking curves. The soaking curves of pea (Pisum sativum L.), lentil (Lens culinaris Medik.), onion (Allium cepa L.), welsh onion (A. fistulosum L.), maize (Zea mays L.), and millet [Pennisetum glaucum (L.) R. Br.] seeds, diverging for physical and morphological properties, were obtained with the following objectives: (i) to propose models to fully describe the kinetics of soaking of seeds, capturing the three stages of the process; (ii) to identify the most appropriate model for each species; (iii) to identify the phases of the soaking process; (iv) to relate physical and morphological properties of seeds, such as bulk density, sphericity, with the soaking kinetics. Five models were fitted: third degree polynomial, Peleg model, logistic model, an adaptation of the logistic model and an adaptation of the Peleg model, both adaptations with the addition of an exponential term with two parameters. The species P. sativum (pea) and L. culinares (lentil) did not present the third stage of the process. In this case, the Peleg model shall be used. On the other hand, the other species presented the three phases. The adaptation of the Peleg equation was quite effective in modeling the seed soaking curve of those species. The water absorption capacity is negatively correlated with the seed's sphericity and density.

Seed and fruit size affect soaking and physiological seed quality in Campomanesia adamantium?

“…values greater or equal to 90% (Table 5) show that the soaking of the small and medium seeds was efficiently modeled by the logistic model, adapted from Silva et al (2018). Large seeds were fit to the reparametrized Peleg model (suggested by Silva et al, 2018), with R² and R² adj. values greater than 65%.…”

“…Preliminary tests were carried out and the logistic model was fit for S and M seeds, as proposed by Silva et al (2018):…”

“…Large seeds were fit to the Peleg model (Peleg, 1988). The model was reparametrized as described by Silva et al (2018):…”

“…Confidence bands were constructed (95%) to perform statistical comparisons among the soaking curves of the three seed sizes (Silva et al, 2018). The models were fit to the nls () function using the R environment for statistical computations.…”

“…Phase III is characterized by a resumption of embryonic growth and emergence of the primary root. However, the occurrence and duration of each phase is species specific (Marcos-Filho, 2015) and depends on several factor including seed size (Silva et al, 2018). Leão-Araújo et al (2019b) concluded that the reparameterized Peleg model efficiently describes soaking in C. adamantium seeds and that phase II is short while phase III is not characterized by elevated water uptake.…”