龙眼的茎尖培养

SHOOT APEX CULTURE OF LONGAN (DIMOCARPUS LONGAN LOUR.) TREES

以网室内6年生的龙眼实生苗、嫁接苗的顶芽和侧芽为外植体，采用两步法，排除了污染与褐变．第一步建立了无菌培养物，经30d培养诱导出腋芽．第二步是从腋芽上取2mm长茎尖进行培养，试验采用对茎尖死亡率、萌芽率、展叶数和培养净重四个衡量指标因素进行综合评判．筛选出茎尖培养效果最好的是以MS附加0．3mgL^-16－BA．0．1mgL~－1IAA和3％蔗糖的培养基；茎尖增殖最适宜的激素及其浓度是0．1－0．2mgL~－16－BA，0．1－0．5mgL~－1KT及0－0．3mgL~－1IAA，其增殖倍数达3．05倍．在生根培养中，IBA优于NAA，液体优于固体，生根效果最好的培养基是用0．01mgL~－16－BA＋1．0mgL~－1 IBA，生根率达34．1％．

Procedures were developed for the micropropagation of longan (Dimocarpus longanLour.) using lateral and terminal shoots from seedlings and graftings of 6-year-old treesgrown in reticular plot. Shoot apex culture was established in two steps: sterilized explantswere first cultured for 30 days, then the 2 mm long segments of shoot apexes from axillarybuds were taken and cultured on induction and multiplication media. Four indexes wereused to evaluate the growth of cultures, i.e. the death rate, induction rate, leaf number,and the fresh weight. Of the media and explants examined, the best culture establishmentwas obtained with shoot apexes cultured on MS medium supplemented with 0.3 mg L^-16-BA, 0.1 mg L^-1 IAA and 3% sugar. Optimum hormones for shoot apex multiplicationwere 0.1 -0.2 mg L^-1 6-BA, 0.1 -0.5 mg L^-1 KT and 0-0.3 mg L^-1 IAA, the multiplicationrate being 3.05 times. Treatment in liquid culture with 0.01 mg L^-1 6-BA and 1.0 mg L^-1IBA in combination was best for rooting, the rooting percentage reaching to 34.1%.