不同外植体对马蹄金愈伤组织诱导及分化的影响

从不同外植体的生长时间、切取方式和光照条件诸因素探讨了对草坪地被植物马蹄金Dichondra repens愈伤组织诱导及分化的影响作用。结果表明：下胚轴和子叶的生长时间只对愈伤组织诱导的始愈时间和生长势有影响，生长期越短，则始愈时间缩短，愈伤组织生长势强，而对出愈率、愈伤组织状态和愈伤组织分化率无明显作用；光照和黑暗培养只对下胚轴诱导愈伤组织的生长状态有影响而对子叶诱导愈伤组织无作用；外植体的不同切取方式对愈伤组织诱导的始愈时间有影响，经切取后可缩短始愈时间；仅从完整子叶离体培养诱导愈伤组织获得了再生植株，其分化频率为13．9％～18．6％。

Effect of different explants on Dichondra repens callus induction and differentiation

The influence of growing time, cutting-out method a nd illumination condition of explants on the induction and differentiation of call uses was studied in Dichondra repens, a groundcover turfgrass. The results indicated that the growing time of the lower hypocotyl and cotyledon only signif icantly affected the initial healing stage and growth vigour of the callus induc tion, with shorter growing time leading to shorter initial healing time and incr ease in growth vigour of the callus. The growing time showed no obvious affect on the induction frequency, quality character or differentiation frequency of ca lluses. Illumination or darkness during culture only effected the growth state of callus induced from the lower hypocotyls, but did not affect cotyledon induce d callus. The different cutting-out methods of explants affected the initial h ealing time of callus inductions, and could lead to time reduction. Regenerated plantlets were only obtained from calluses induced from whole cotyledons using in vitro culture, and the differentiation frequency was from 13.9% to 18.6%.