Our systems have detected unusual traffic activity from your network. Please complete this reCAPTCHA to demonstrate that it’s you making the requests and not a robot. If you are having trouble seeing or completing this challenge, this page may help. If you continue to experience issues, you can contact JSTOR support.
Block Reference: #24d1817e-761e-11ec-9d71-427a5a577761
Date and time: Sat, 15 Jan 2022 16:13:58 GMT
Having said that, it is important that you realize that I am not in complete agreement with this established model of seed dormancy. Will will evaluate these different views in our classroom discussions. For starters, I view the term dormancy as the "biology of what isn’t":
The Traditional Seed Dormancy Model
Dormancy: a state in which viable seeds, spores or buds fail to germinate under conditions favorable for germination and vegetative growth.
2. Dormancy caused by mechanical restriction of growth by embryo coverings (pericarp, testa, perisperm, endosperm)
-example: cocklebur: upper seed (of two in capsule) radicle is restricted, insufficient thrust to rupture testa and germinate
Variation in dormancy level was tested in seeds of four species, each collected from three populations in 1994 and 1995 (experiment 1). Germination was tested in light and darkness on recently-harvested seeds and on those after-ripened in dry storage for one year. In addition, seeds from each of eight individual plants within each of eight populations were tested for germination when recently harvested and after warm stratification or cold stratification followed by a drying period (experiment 2). Seeds from the two years differed in dormancy level in Silene noctiflora, Sinapis arvensis and Spergula arvensis . Germination percentage differed significantly among populations in Sinapis arvensis and Spergula arvensis in both experiments and in Thlaspi arvense in experiment 2. Furthermore, dormancy level in seeds from different mother plants also varied in the three species tested in experiment 2. Variations at the three levels tested (year, population and mother plant) indicate that these species have a random pattern of variation in dormancy level. It is concluded that variation in seed dormancy among mother plants, populations and years must be taken into account when testing the germination characteristics of a species and also when attempting to model weed seed bank dynamics.