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Abstract
Hypocotyl and cotyledon expiants of 85 cultivars and lines of cucumber were screened for adventitious shoot and root formation in tissue culture. Tissue was cut from 7-day-old seedlings and grown on a medium consisting of Murashige-Skoog salts and vitamins with 1 mg/liter each of 6-ben-zylamino purine (BA) and naphthaleneacetic acid (NAA), and 3% sucrose added. No shoots were formed from hypocotyl pieces, while 28 of the 85 lines formed shoots from cotyledon tissue. Thirty-two lines formed at least one root in culture, and there was no difference in the frequency of root formation between cotyledon and hypocotyl tissue. There was no correlation between root and shoot formation. The best 2 lines, PI 279463 and PI 401732, had 53% and 40% of the cotyledon pieces forming shoots, respectively.
Abstract
Wounding freshly harvested or cured sweet potato [Ipomoea batatas (L.) Lam.] roots by either breaking, or cutting them in half stimulated C2H4 production in all 13 cultivars and selections examined. Ethylene production was stimulated within 1 day of wounding and generally continued to increase for 7 days before decreasing. At the peak of production, wounded freshly harvested roots produced about 22 times more C2H4 than controls, while C2H4 production from wounded cured roots of the same cultivar or selection increased about 86 times. Wounding stimulated CO2 production by about 72% over the controls. There were marked cultivar differences in the maximum rate of wound-induced C2H4 production.