A cDNA clone encoding a putative EBF-like protein （DCEBF1）was obtained from total RNA isolated from senescing carnation （Dianthus caryophyllus L.） petals using reverse transcription PCR and rapid-amplification of cDNA ends techniques. The cDNA contained an open reading frame of l 878 bp corresponding to 625 amino acids. Results of Northern blot indicated DCEBFI expression was enhanced by endogenous and exogenous ethylene, and was inhibited by STS in petals and ovaries. Upon wounding treatment, DCEBF1 showed a quick increase in mRNA accumulation which was positively correlated with the increase in ethylene production. The levels of DCEBF1 mRNA increased in both petals and ovaries by sucrose treatment compared with the control.
FU Zhao-diWANG Hui-nanLIU Juan-xuZENG Hong-xueZHANG JiaoKUANG Xiao-congYU Yi-xun
This research aims at developing a plant regeneration system from leaf and petiole explants of Anthurium andraeanum Hort., thereby establish a foundation for mass production and transformation. Using tissue culture technique, the conditions for callus induction, protocorm-like body （PLB） formation and plant regeneration from leaf explants and petiole of A. andraeanum, such as basal medium and plant growth regulator, were investigated. Totipotent callus was induced on a 1/2-strength MS medium containing 0.90 μmol L^-1 2,4-dichlorophenoxyacetic acid （2,4-D） and 8.88μmol L^-1 N6-benzyladenine （BA）. The callus exhibited complete hormone autonomy for growth and differentiation of PLBs. This callus proliferated well and was maintained by subculturing on 1/2 MS medium containing 0.90 μmol L^-1 2,4-D and 4.44 μmol L^-1 BA. On average, 8 protocorm-like bodies could be obtained from a piece of 4 mm callus after being transferred to the 1/2 MS medium with 4.44 μmol L^-1 BA after 8 wk of culture. The regenerated PLBs formed shoots and roots on 1/2 MS medium. After 24 wk of culture on these medium, well-developed plantlets for potting were produced. An efficient micropropagation method was established for indirect PLB formation and plant regeneration from leaf and petiole ofA. andraeanum.
The regenerated plantlets of Acacia auriculiformis were obtained by the method of re-differentiation of the callus from the hypocotyls explants.The effects of plant regulator compositions on the induction of callus and the differentiation of adventitious buds in vitro culture were studied.The optimum medium for callus induction was MS medium containing 1.0 or 1.5 mg ·L-1 2,4-D and 0.5 mg ·L-1 KT and 100% the callus induction frequency was obtained.The optimum medium for re-differentiation of callus was MS medium containing 1.5 mg ·L-1 6-BA and 0.2 mg ·L-1 NAA and 84.7% of adventitious shoot regeneration frequency with 5.83 shoots per explants was obtained.In addition,the optimum medium for the adventitious buds induced from the hypocotyls explants without transferring the callus was MS medium containing 2.0 mg ·L-1 6-BA,0.1 mg ·L-1 NAA and 0.2 mg ·L-1 KT.Excised shoots were effectively elongated in MS medium without appending any hormones.Elongated shoots of 3.0 cm rooted when they were transferred to MS medium containing 0.1 mg ·L-1 IAA and 0.2 mg ·L-1 NAA after 30 days and developed into healthy plantlets,which resulted in a rooting rate of 85 %.The results of this study will facilitate the application of genetic transformation methods in A.auriculiformis.
