Sucrose and light effects on in vitro cultures of potato, chokecherry and saskatoon berry during low temperature storage

Cultures of potato (Solanum tuberosum) cv. Atlantic, chokecherry ( Prunus v irginiana L.) cv. Garrington and saskatoon berry (Amelancher alnifolia Nutt .) cv. Northline grown in vitro for 3 weeks at 24/22 degreesC, 16-h photope riod, 150 mu mol m(-2) s(-1) photosynthetic photon flux density (PPFD) mixe d fluorescent/incandescent light were stored for 6, 9 and 12 weeks at 4 deg reesC under 0 (darkness) and 3 mu mol m(-)2 s(-)1 PPFD (690 nm red light co ntinuous illumination). Growth regulators free MSMO medium either with or w ithout 30 g l(-1) sucrose was used to store the cultures. All cultures reta ined capacity to re-grow after storage. Tested factors, sucrose, light and the length of the storage period had an impact on shoot quality and re-grow th capacity of the cultures. For either light treatment sucrose was essenti al for the low temperature maintenance of vigorous stock plants of potato, if stored for over 6 weeks. Chokecherry and saskatoon cultures stored well without sucrose; although chokecherry benefited from sucrose in the storage medium when the stock cultures were kept at the low temperature for 12 wee ks. Low light significantly improved quality of the stored potato cultures, but had very little effect on both chokecherry and saskatoon berry culture s. The woody plant cultures grew during storage, and the longer the stock p lants were stored, the more vigorous cultures they generated. The results i ndicate that growers can successfully use their existing facilities, small refrigerators and coolers with low light intensity, set at 4 degreesC, for short term storage of potato, chokecherry and saskatoon berry cultures. The potato cultures, which are known to be sensitive to prolonged low temperat ure storage, should be frequently monitored and subcultured as required. On the other hand, the woody plant stock cultures do not require any special attention when kept at 4 degreesC and re-grow the most vigorous shoots if s tored for at least 12 weeks.