Influência de temperatura, luz e giberelina na germinação de sementes de Thlaspi caerulescens J. Presl & C. Presl (Brassicaceae)

Abstract

Influence of temperature, light and giberelic acid on seed germination of Thlaspi caerulescens J & C Presl (Brassicaceae)Thlaspi caerulescens is a natural zinc (Zn), cadmium (Cd) and nickel (Ni) hyperaccumulator, a model species to study heavy metal hyperaccumulation and tolerance. However, the quick loss of viability under storage and the low production of seeds under non temperate climates justify the need to identify conditions to maximize germination and seed vigor. In order to characterize better conditions for germination, seeds of T. caerulescens were incubated under a photoperiod of 8h light/16h dark (15 mmol.m -2 .s -1 ) or in darkness, at temperatures of 10, 15, 20 and 25°C. The assays were performed with germination paper wetted with 0,05% giberelic acid or distillated water. Percentage of germination (G%), and germination speed index (GSI) were evaluated. The highest percentage of germination (66%) was recorded for the treatments with GA at the temperatures of 15 and 20ºC. The highest GSI was recorded for the treatments with GA at 15º and 20ºC, independent of the light effect. The highest germination and germination speed index for T. caerulescens were obtained with the GA 3 treatment, under light, and temperatures between 15 and 20ºC.

Seed stratification, gibberellic acid and temperature in obtaining rootstock in the persimmon

“…A temperatura é um fator que influencia as reações bioquímicas que regulam o metabolismo necessário para iniciar o crescimento do embrião e, em consequência, a porcentagem e a velocidade de germinação. A temperatura ótima para a germinação é aquela na qual a semente expressa o seu potencial máximo em originar plântulas normais no menor tempo possível (GUIMARÃES et al, 2010).…”