Germination of Prosopis juliflora (Sw.) D.C. seeds at different osmotic potentials and temperatures

Abstract

The effects of osmolytes, osmotic potential (Ψs), temperature, and their interactions on the germinability, germination rate, and other germination parameters of the invasive shrub Prosopis juliflora, which grows in the semiarid environmental conditions of the Caatinga in northeast Brazil, were evaluated. To study the effects of polyethylene glycol (PEG) and NaCl stress and temperature on germination, two separate experiments were carried out at the Plant Ecophysiology Laboratory of the Federal University of Pernambuco in 2011. The overall germinability decreased significantly with increases in both PEG (one-way ANOVA, F4,75 = 111.21, P ≤ 0.001) and NaCl (one-way ANOVA, F4,75 = 12.82, P ≤ 0.001); however, the effects were more accentuated with PEG than NaCl. The PEGtreated seeds maintained their germinability, even when they were subjected to a Ψs = −1 MPa after being rinsed and allowed to germinate on deionized water. In contrast, NaCl-treated seeds usually lost their ability to germinate; this fact was possibly linked to the accumulation of Na + and Cl − in the cells, which may have contributed to a loss of membrane function that led to the death of the embryos. Although numerous studies describing seed germination in the presence of osmolytes have been conducted, studies that show the interactions between osmolytes, osmotic potentials, and temperature are scarce. The present study is the first to describe these interactions for P. juliflora seeds.

‘Jurema-de-embira’ seed germination under water stress and at different temperatures

“…The reduction of germination due to the increase in water deficit was also observed by Miranda et al (2014) in seeds of Prosopis juliflora (Sw.) D.C. These authors reported that, at the highest temperatures (35 and 40 ºC), the reduction was faster than at the lowest temperatures (25 and 30 ºC).…”

GerminaQuant: a new tool for germination measurements

“…The output results were compared with those generated by the spreadsheet described by Miranda et al (2014), Ranal et al (2009) and Joosen et al (2010). Feedback from users is welcome and will be used to improve the program and to correct unforeseen flaws.…”

“…Currently, there is a lack of information about the start time, rate, and uniformity of germination, which are essentially important for normally distributed seed population and for seed companies. This feature could be solved by the introduction of the mean germination time (MGT), uncertainty (U), and synchrony (Z) of germination (Miranda et al, 2014;Ranal and Santana, 2006). However, in this type of experiment the number of germination assays required is immense, which can lead to human error or misjudgment of seed treatments.…”

“…There are, however, some freely spreadsheets which in stricto sensu are not really a software but a set of spreadsheets developed on Microsoft ® Excel package. On this category are included the spreadsheets developed by Ranal et al (2009), Joosen et al (2010 and Miranda et al (2014). The major limitation of the spreadsheets proposed by Miranda et al (2014) and Ranal et al (2009) is the impossibility of working with different treatments in the same file at the same time; each treatment or situation must be interpreted in different spreadsheets which are time consuming in addition to being tedious.…”

“…On this category are included the spreadsheets developed by Ranal et al (2009), Joosen et al (2010 and Miranda et al (2014). The major limitation of the spreadsheets proposed by Miranda et al (2014) and Ranal et al (2009) is the impossibility of working with different treatments in the same file at the same time; each treatment or situation must be interpreted in different spreadsheets which are time consuming in addition to being tedious. The spreadsheets proposed by Joosen et al (2010) would be the only, therefore allowing the calculation of two or more treatments at the same time.…”