Effect of different explants on Dichondra repens callus ind uction 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%.