AbstractThe effects of prolonged exposure to low temperature above freezing at the onset of growth of 3 black currant (Ribes nigrum) cultivars were examined by growing plants at 5 deg and 12 deg C for 7 weeks. Those growing at 5 deg had reduced rates of both leaf emergence and leaf expansion. In the cultivar Ben More, low temperature also delayed bud break by 33 days. Base temperature for leaf emergence and growth differed, and was lower in the chilling-tolerant cultivar Ben Lomond than in the chilling-sensitive cultivars Baldwin and Ben More. Low temperature reduced stomatal conductance in Ben Lomond but not in Baldwin. Photoinhibition was greater in leaves of plants grown at 5 deg than in those grown at 12 deg , but the effect of low temperature did not differ between cultivars. Photosynthetic rate, measured at 15 deg and 5% CO2, was unaffected by the temperature at which plants were grown.