Seed germination and dormancy break in Eragrostis polytricha, a native Brazilian grass species with potential for recovery of degraded lands

Abstract

Ferruginous Rocky Outcrops have high levels of species richness and endemism, but have been threatened by several anthropic actions, especially mining. Eragrostis polytricha, a common grass species in the vegetation of these outcrops, has shown promising features for use in the recovery of mining areas. However, in order to fully understand the species' potential for such use, its requirements for germination, seed dormancy break and seedling development must be determined. Thus, we aimed to: (1) assess the temperature conditions needed for seeds of E. polytricha to germinate; (2) evaluate the effects of KNO₃ in breaking seed dormancy; and (3) analyze the germination efficiency of seeds that are still in spikelets. The experiment included seven treatments: 15-35 ºC with KNO₃, 20-30 ºC with KNO₃, 15 ºC with KNO₃, 25 ºC with KNO₃, 35 ºC with KNO₃, 20-30 ºC with water, and 20-30 ºC with KNO₃ using spikelets. The treatments with alternating temperatures associated with KNO 3 yielded the highest germination rates, suggesting that these two factors combined can break seed dormancy. Seeds inside spikelets exhibited a high germination percentage, and thus represent an interesting alternative for seedling production.

Strategies for reintroduction and conservation of Gymnopogon doellii, an endemic grass at risk of extinction

“…Dormancy among caryopses of native grass species has been previously reported (Ramos et al 2017(Ramos et al , 2019Saraiva et al 2020) and different cues, as smoke and heat shock (Ramos et al 2019) as well as KNO 3 and alternating temperatures (Carmona et al 1998;Saraiva et al 2020) were reported to improve their germination. Caryopses of G. doellii are dormant at harvest, but alternating temperature treatments, coupled or not with KNO 3 and light were shown to considerably improve germination (Carmona et al 1997).…”

GA3 and growing medium influence papaya seed germination and seedling growth

“…Osmopriming with chemical agents such as calcium nitrate and potassium nitrate stimulates seed germination by generating a water potential balance between the seeds and the solution via osmosis [8,9] . Pretreatment with potassium nitrate reduced dormancy and improved seed germination [10,11] . Gibberellic acid is a plant hormone that is essential for fruit plant growth and yield.…”