Seed Activation and Seed Germination Under Moisture Stress

Abstract

SUMMARYSeeds of calabrese and carrot were held at 10°C or 20°C for periods of up to 21 days in water or polyethylene glycol '6000' solutions of from -5 to -20 bars. Seeds were subsequently placed to germinate in a favourable environment or were first dehydrated before transfer to this environment. The seeds' ability to germinate was virtually unaffected by any of the temperature, water potential or duration treatments. Increasing water stress progressively reduced the levels of water content and oxygen uptake rates after initial imbibition, and delayed the onset of germination with the accompanying increase in these factors. At -15 and -20 bars, water content remained approximately constant throughout the experiment but oxygen uptake rates fell after day 6. The results have a direct bearing both on the seed 'priming' treatment used to accelerate seed germination and on the tolerance to drought of seeds in the field.

Germination, osmotic adjustment, and antioxidant enzyme activities of gibberellin-pretreated Picea asperata seeds under water stress

“…Water stress may result in delayed and reduced germination or may prevent germination completely (Hegarty 1977). The results obtained in the present study demonstrated that decreased water potential resulted in a delay and reduction of germination percentage (Fig.…”

Influence of sowing techniques and pesticide application on the emergence and the establishment of bean plants (Phaseolus vulgaris L.)

“…The damage of pathogens can cause faults in the crops' emergence [14] so differences ought to exist between pesticide applications, as fungicide applications reduce damping-off [13] and insecticide applications protect the seed against bean seed fly attack [21,22]. However, in this work no differences were found for the number of plants emerged between pesticide applications.…”

Estratégias de seleção para germinação de sementes de cenoura em condições de temperaturas elevadas

“…Estresses abióticos podem resultar no atraso ou mesmo na inibição completa da germinação de sementes de hortaliças (Hegarty, 1977). A germinação das sementes de cenoura (Daucus carota L.) ocorre em temperaturas de 8 a 35 ºC, e a velocidade e uniformidade de germinação variam com a temperatura dentro desses limites.…”