在MS附加 0 .5mg·L-16 BA和 0 .15mg·L-1NAA的培养基上 ,三倍体毛白杨幼叶的愈伤组织诱导率可达 87.6 %。蔗糖浓度大小与愈伤组织增长量成正比 ,与褐变开始时间成反比 ,2 %蔗糖下 ,继代周期可长达 6 1d。每日光照 12h的愈伤组织褐化时间可延长至 82d ;少于 12h ,愈伤组织松散 ,褐变开始时间缩短。愈伤组织开始褐化后 ,再分化时间延长 ,分化率降低。不同继代周期对再生试管苗生根无影响。 Callus induction of young triploid poplar leaves reached 87.6% on MS medium supplemented with 0.5 mg · L-16 BA and 0.15 mg · L-1 NAA. The concentration of sucrose is proportional to the amount of callus growth, inversely proportional to the start of browning, and the subculture cycle can be as long as 61 days under 2% sucrose. Callus browning time of 12h daily light can be extended to 82d; less than 12h, callus loose, browning start time shortened. After callus began to brown, the re-differentiation time was prolonged and the differentiation rate was decreased. Different subculture cycles had no effect on rooting of regenerated in vitro plantlets.