蜡梅愈伤组织诱导及褐化抑制的最佳培养条件OA

To address the problems of low callus induction rate and severe explant browning in the tissue culture of Chimonanthus praecox,and to optimize its culture conditions and anti-browning strategies,sterile seedlings induced from mature fruits of red-flowered C.praecox were used as experimental materials.The effects of multiple factors,including explant type,basal medium,shading duration,donor seedling age,and plant growth regulator(PGR)ratios,on callus induction rate and browning were systematically analyzed.Meanwhile,the inhibitory effects of two anti-browning agents,namely polyvinylpyr-rolidone(PVP)and ascorbic acid(ASA),were evaluated.The results showed that the optimal culture conditions were as follows:cotyledons from 35-day-old seedlings were used as explants,cultured on Woody Plant Medium(WPM)supple-mented with 1.0 mg/L naphthaleneacetic acid(NAA)and 0.10 mg/L 6-benzylaminopurine(6-BA)under shading for 28 days.Under these conditions,the callus induction rate reached 100%after 40 days of culture.In addition,when 5 mg/L ASA was added to the medium,the browning rate was significantly reduced to 54%with a browning index of 0.22,and the activities of polyphenol oxidase(PPO)and phenylalanine ammonia-lyase(PAL)were also significantly inhibited.It was further clarified that PPO activity is the key factor causing browning in C.praecox.