Pear (pyrus) Leaves And Petiole Regeneration System Established

Pear (pyrus) scion cultivars 'Dang shan su', 'Zao su', 'Ba yue hong' and 'Crystal' were chosen as the materials. Several factors that affect shoot culture and adventitious bud regeneration from leaf and petiole were examined. The regenerate systems of pear were developed from different explants.The regenerate system of four pear cultivars were set up from shoot. The shoot from indoor bud was more effective than from growing tree . For the indoor shoot, the proper treatment time of HgCl2 was from six to seven minutes. The suitable bud induction medium of shoot was 1/2 MS + BA 0.5 mg·L-1+IBA 0.2 mg·L-1. MS + BA 0.5 mg·L-1+IBA 0.1 ～ 0.2 mg·L-1 was suitable for shoot multiplication. The basal medium greatly affected the multiplication and growth of shoot, MS medium was the suitable basal medium. The genotype was a chief factor on shoot multiplication. Effect of sugars on shoot multiplication had not the great variability. Dark culture significantly enhanced the rooting efficiency. The rooting frequency of 'Bayue Hong' pear was 61.2% and the highest on the medium 1/2 MS0 + BA 0.5 mg·L-1+IBA0.2 mg·L-1.Adventitious bud was regenerated from in vitro leaf of four pear cultivars. It was for first time that we obtained adventitious bud regeneration from leaf of 'Dangshan su', 'Zao su', and 'Bayue hong' pear . The efficient adventitious bud regeneration system were developed for 'Bayue hong' and 'Crystal' pear. Under optimal conditions, bud regeneration frequencies of 'Bayue Hong' and 'Crystal' was 100% and 77.8%, with the mean number of bud per leaf was 5.78 and 3.17, respectively. The genotype was a key factor on bud regeneration from leaf of pear. The regeneration efficiency of 'Bayue hong' was more higher than others. Dark culture was not necessary for adventitious bud regeneration from leaf. But a dark period of 20 days at the beginning of regeneration significantly enhanced the regeneration efficiency of pear. NN69 medium is the suitable basal medium. No effect on regeneration efficiency of leaf was found by substituting equal concentration glucose for sucrose in NN69 medium, while replacing sucrose with granulated sugar greatly reduced regeneration efficiency. The cytokinin and auxin was also a key factor on bud regeneration from leaf of pear. The suitable concentration is BA 5.0 mg·L-1, IAA 0.5 mg·L-1 for bud regeneration from leaf of 'Bayue hong' pear. Compared to BA and ZT, TDZ was a potent exogenous cytokinin for the bud regeneration from leaf of pear, ZT had not effect on the bud regeneration from leaf of pear. The combination of TDZ with IAA,IBA or NAA may significantly affected the regeneration efficiency of pear. IBA is suitable for bud regeneration from leaf of 'Bayue hong' pear, but IAA is suitable for regeneration of 'Crystal' pear. Using leaf from upper part of shoots and plating leaf with abaxial downside significantly enhanced the regeneration efficiency of pear. Adding up AgNO3 0.5mg.L-1 in medium significantly enhanced the regeneration efficiency of 'Ba yue hong' pear.Adventitious bud was regenerated from petiole of 'Ba yue hong', 'zao su', and 'Crystal' pear for the first time. The regeneration frequency and mean number of bud per petiole of 'Ba yue hong' were 45.5% and 0.79 on NN69+TDZ 1.0 mg·L-1+IBA 0.5mg·L-1, The frequency and bud per petiole of 'Crystal' were 42.4% and 1.0 on NN69+TDZ 1.0 mg·L-1+IAA 0.5 mg· L-1, respectively. TDZ was suitable for bud regeneration from petiole of pear, ZT Had no effect on bud regeneration from petiole of pear The combination of TDZ and IBA,IAA or NAA greatly affected bud regeneration from petiole of pear. AgNO3 (0.1～1.5 mg·L-1) enhanced the regeneration efficiency of petiole of pear.