Polypeptide markers for low temperature stress during seed germination in sunflower

Sunflower seeds behaved as chilling and freezing sensitive and also exhibited acclimation under low seed moisture content (< 1%). At high seed moisture content (approx. 22 %) they tolerated chilling stress but failed to acclimate under freezing temperatures. Pre-imbibitional chilling (5 degrees C) or freezing (-5 or -10 degrees C) stress significantly enhanced total soluble protein (TSP) content. Chilling treatment after imbibition (in contrast to pre-imbibition) enhanced germination and this was accompanied by increase in 30, 24 and 21.9 kDa TSPs content (3 d after germination). Freezing at -5 and -10 degrees C suppressed seed germination and increased content of 78 and 56.2 kDa wall bound proteins. Chilling acclimation decreased 35.4, 33.9, 29.5, 23.4 and 21.4 kDa TSPs.