| High temperatures during lettuce seed imbibition can delay or completely inhibit germination and the endosperm layer appears to restrict the radicle protrusion. The role of endo-beta-mannanase during lettuce seed germination at 35°C and the influence of ethylene in endo-beta-mannanase regulation were investigated. Seeds of 'Dark Green Boston' (DGB) and 'Everglades' (EVE) were germinated in water, or 10 mmol L-1 of 1-aminocyclopropane-1-carboxylic acid (ACC), or 10 mmol L-1 of aminoethoxyvinylglycine (AVG), or 20 mmol L-1 of silver thiosulphate (STS). Seeds were also primed in polyethylene glycol (PEG), or PEG + ACC, PEG + AVG, or PEG + STS. Untreated seeds germinated 100% at 20°C. At 35°C, EVE seeds germinated 100%, whereas DGB seeds germinated only 33%.... |
