Effects of low temperature on the growth of blackcurrant cultivars

Abstract

The effects of prolonged exposure to low temperature above freezing at the onset of growth of three blackcurrant ( Ribes nigrum L.) cultivars were examined by growing plants at 5°C and 12°C for 7 weeks. Those growing at 5°C had reduced rates of both leaf appearance and leaf expansion. In the cultivar ‘Ben More’, low temperature also delayed bud break by 33 days. Base temperature for leaf appearance and growth differed, and was lower in the chilling-tolerant cultivar ‘Ben Lomond’ than the chilling-sensitive cultivars ‘Baldwin’ and ‘Ben More’. Low temperature reduced stomatal conductance in ‘Ben Lomond’ but not in ‘Baldwin’. Photo-inhibition was greater in leaves of plants grown at 5°C than at 12°C, but the effect of low temperature did not differ between cultivars. Photosynthetic rate, measured at 15°C and 5% CO 2, was unaffected by the temperature at which plants were grown.