The effects of day and night temperatures during early growth of winter oilseed rape (Brassica napus L var oleifera cv Gorczanski) seedlings on their morphology and cold acclimation responses

Studies on the effects of temperature during the early stage of growth on frost resistance of winter rape seedlings under controlled conditions were performed. It was found that cold acclimation responses of plants were affected to a great extent by the conditions of the seedlings early growth. During this period, when the day temperatures were reduced to the range from +10 degrees C to + 15 degrees C, a process termed "prehardening" was observed. During prehardening plants formed leaf rosettes. Their ability to develop frost resistance during acclimation at +2 degrees C also increased. Frost resistance of these plants was comparable with the resistance of plants growing in autumn under field conditions.