以9个蝴蝶兰品种的花梗和无菌苗叶片为试材,研究了不同品种间不定芽诱导率及增殖系数的差异,并选出增殖系数高、中、低的3个代表性品种‘内山姑娘’、‘梦幻兄弟’和‘万花筒’,对不定芽增殖条件进行优化,并对培养过程中褐变严重的品种‘内山姑娘’进行了热激处理抑制褐变的研究.结果表明:(1)相同条件下,不同蝴蝶兰品种间不定芽诱导率和增殖(分化)系数存在显著差异,且花梗芽诱导率和繁殖系数高的品种,其叶片的不定芽诱导率和分化系数也较高.(2)6-BA是影响蝴蝶兰不定芽增殖的主要因素,椰汁次之.培养基1/2MS+7.0 mg· L-16-BA+0.2 mg·L-1 NAA+100 mL·L-1椰汁适于‘内山姑娘’和‘梦幻兄弟’品种的不定芽增殖,1/2MS+5.0 mg·L-1 6-BA+0.2 mg·L-1 NAA+50 mL·L-1椰汁适合‘万花筒’品种的不定芽增殖.(3) 40℃热激处理9 min恢复48 h后再切割接种能够显著减轻蝴蝶兰‘内山姑娘’叶片的褐变程度,热激处理后叶片组培过程中的褐变指数、总酚含量以及苯丙氨酸解氨酶(PAL)活性均显著低于对照,且三者的两两之间均具有极显著正相关关系,证明短时间的热激处理可降低酚合成酶PAL的活性,减少酚类化合物的积累,从而减轻组培过程中的褐变伤害.%Adventitious buds were induced from peduncle buds and leaves of nine Phalaenopsis varieties on the same media, so as to compare the differences of shoot induction rates and propagation coefficients a-mong varieties. On the basis of above results, three representative varieties, 'Neyshan guniang', 'Brother Dream "L" ' and 'Kaleidoscope'were selected, which had the maximum, medium and minimum propagation coefficient,respectively,to optimize the adventitious bud propagation condition. Meanwhile,the effects of heat-shock treatment on explants browning were studied with the highest browning degree variety 'Neyshan guniang'. The results showed that:(l)There were significant differences on adventitious bud induction rates among different varieties, and so were propagation/differentiation coefficients. In the experiment, it had been observed that high flower stalk bud induction rates and propagation coefficients were accompanied with high leaf in vitro shoot induction rates and differentiation coefficients. (2)The major influence factor of shoot proliferation in vitro was 6-benzylaminopurine (6-BA) , followed by coconut milk. The suitable medium for adventitious bud propagation of 'Neyshan guniang' and 'Brother Dream "L" ' was 1/2 MS+7.0mg·L-1 6-BA + 0. 2 mg · L-1 NAA+100 mL · L-1 coconut milk,and the medium 1/2MS+ 5. 0 mg · L-1 6-BA+0. 2 mg · L-1 NAA + 50 mL · L-1 coconut milk was appropriate for the adventitious bud propagation of 'Kaleidoscope'. (3)Explants browning could be significantly inhibited by heat shock at 40°C for 9 min. Browning index,total phenol content and PAL activity were significantly below against CK in leaves cultured after heat shock treatments, and they had very significantly positive correlation. These proved that short time of heat-shock could reduce PAL activity and phenol compounds accumulation,thus reduce brown injury in the process of culture.
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