关键词: 甘薯资源, 甘薯资源, 筛选, 观赏甘薯, 盆栽

Abstract: To demonstrate the effects of NAA application after removal of the shoot apex on increasing in K+ concentration and decreasing in nicotine concentration in different leaves of tobacco plants under the field conditions, and to provide a evidence for better tobacco production. Field experiments were conducted in three years (1999, 2000 and 2001) in Yunnan province to determine the effects of NAA application after removing the shoot apex on plant growth, K+ and nicotine concentrations in different organs of flue-cured tobacco. The results showed that, excision of the shoot apex caused a net decrease in total K+ content of whole plant, a decrease in K+ concentration while an increase in nicotine concentration in different leaves. Application of NAA onto the cut-surface of the stem after removal of the shoot apex stimulated K+ uptake and distribution into the leaves, resulted in increase in K+ concentration and decrease in nicotine concentration in different leaves. Applying NAA twice (once again two weeks after the first application) could further improve leaf K+ concentration, but cause a slight decrease in leaf dry weights. Keeping plant intact (no removing the shoot apex) resulted lower leaf dry weights and yield, and poor leaf quality, compared with the apex-removed plants, although the leaf K+ concentration was higher in intact plants. NAA application one time after removal of the shoot apex was enough for increasing in K+ concentration and decreasing in nicotine concentration in tobacco leaves.