Changes Of The Activity Of Enzyme And The Content Of Plant Hormones During Regeneration Of Rieger Begonias

The aim of this investigation was to establish plant regeneration system in vitro from R.Begonia leaves,and to research the relationship between morphogenesis and the activity of enzyme,and to find the content of plant hormones during bud differentiation.The results as follows:1 The explants showed the efficient induction of bud differentiation in MS medium supplemented with 0.4 mg/1 6-BA,0.1 mg/l NAA,30 g/l sugar and 6 g/l agar,when culturing with 1500 lx illumination light for 14 days,then 2000 lx illumination light for18 days.The rate of bud multiplication was maximal when fascicular bud was cultured in MS medium containing 0.3 mg/1 6-BA,0.1 mg/l NAA,30 g/l sugar and 6 g/l agar,culturing with 2000 lx illumination light.Root induction was better on half-strength MS media having 0.1 mg/1 6-BA,15g/l sugar and 3g/l agar.Rooted plantlets were successfully acclimatized when the media contained an half of pearlite and the other half of peat soil.The survival rate was 100%.2 The content of protein increased firstly,and then reduced during dedifferentiation from leaves of R.Begonia,Which was reverse in the process of redifferentiation.The content of soluble sugars declined in the whole process.3 The activity of peroxidase increased rapidly in 3～15 days,during bud differentiation from leaves of R.begonia,which reached to maximum(896.27 U/(g.min)·FW) on the 15th day,and then declined dramatically in 15～24 days.The activity of catalase increased firstly,then showed a downward trend in 1～15 and 15～24 days,and reached to maximum(13.05 mg/(g·min) FW) on the 3rd day.The activity of superoxide dismutase increased in the beginning,then reduced during dedifferentiation from leaves of R.begonia.The trend was just the reverse of that in redifferentiation.The activity of polyphenol oxidase increased in the beginning,and then reduced during bud differentiation from leaves of R.begonia.4 The content of IAA reduced continuously in the process of bud differentiation from leaves of R.Begonia.The content of GA₃ reduced in the beginning,and increased until the callus was formed,then keeping the high level.The change of the content of ZT was similar to "M" shape. The content of ZT increased at the beginning of redifferentiation,and then kept at the high level. The content of ABA declined,and kept at the low level in the whole process of bud differentiation.The ratio of ZT/IAA increased slowly in the early stage of dedifferentiation,then rose firstly and declined rapidly in the late stage of dedifferentiation(9～15 d).The ratio of ZT/IAA raised in redifferentiation.Both the ratio of ABA/IAA and ABA/ZT was slight in the whole process.The change of GA₃/ZT was significant.Both 6-BA and NAA increased firstly, and then reduced during dedifferentiation from leaves of R.begonia.The content of 6-BA increased at first,then maintained at a steady state in the redifferentiation.The concentration of NAA maintained at a steady state after a slight reduce.The content of NAA in the whole process was always higher than that of 6-BA.