Pre- and post-flasking factors affecting establishment of Cordyline 'Purple Tower' from tissue culture

Abstract

Cordyline 'Purple Tower' has dark purple leaves, and is a strong growing hybrid from C. banksii in the Agavaceae. There are 15 Cordyline species with five, including C. banksii, endemic to New Zealand. The species australis, banksii, and fruticosa are often raised by tissue culture. In 1990, 600,000 C. fruticosa were grown in the Netherlands using micropropagation, making it the eighth most important pot plant in Europe. The micropropagation of C. fruticosa has been most frequently described. This species was found to have high bud production and a high percentage ofviable in vitro buds at 24°C during the day and 18 to 24°C at night. In tissue culture, sucrose is primarily used as an energy source for developing explants. But large amounts of sucrose reduce chlorophyll and bisphosphate carboxylase activity thus loweringthe plantlet's photosyntheticrate. These changes are irreversible and continued growth ofthe plantlet is dependent on the formation ofnewleaves. The extra sucrose increases the osmotic potential ofthe medium, which can produce plantlets with high intracellular solutes. These plantlets remain turgid and are better able to survive transplanting to another environment.