In vitro Root Initiation of ‘ Champi Sirindhorn ’

Abstract

A study of root initiation of ‘Champi Sirindhorn’ (Magnolia sirindhorniae Noot. & Chalermglin), a newly discovered plant in Thailand since 1999, was made by using modified USK II medium supplemented with varying IBA levels from 0 to14 mg l-1. Root initiation was observed after 17 days of culture, in contrast to MS medium, in which, no root formation was observed even after 60 days. Treatment without IBA gave the lowest yield of 5 - 10% of root initiation while the highest yield was up to 90% at 4 mg l-1 IBA after 24 days of culture and at the end of the experiment, 32 days of culture, the averages of root number and root length were 4.89 roots/explant and 26.15 mm/root, respectively. The maximum averages of 9.19 roots/explant and a total root length of 172.75 mm/explant were obtained from the treatment with 12 mg l-1. The control treatment yielded the longest root of 34.25 mm, the lowest average shoot length/explant, and the lowest increased in shoot growth at the end of the experiment.