ARS | Publication request: Establishing Tissue-Cultured Sweetgum Plants in Soil

Submitted to: HortTechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 13, 2005
Publication Date: June 13, 2005
Citation: Tisserat, B. 2005. Establishing tissue-cultured sweetgum plants in soil. HortTechnology. 15:5-9.

Interpretive Summary: Most tissue culture studies seek to improve shooting and growth by altering the nutrient medium by addition of growth regulators or inclusion of minerals and organic formulations. We studied several methods to alter the physical environment interfacing with plant tissue cultures by employing a broad range of CO2 atmospheric environments and altering the method of media application. Knowledge gained from this study can aid researchers in effectively employing optimal physiological environments in future biotechnological and nursery activities. Sweetgum, (Liquidambar stryraciflua L.), an important commercial paper tree in the Southeast U.S., was employed in this study. Various culture systems were tested while employing the same nutrient media in order to determine what influence they may have on sweetgum growth and shooting in vitro. Our results show that a sterile hydroponics system can greatly promote shooting (i.e., 8- to 10-x fold increases) over employing the traditional agar culture vessels. Subsequently, shoots obtained from these studies can be readily rooted at high percentage rates to produce free-living plantlets when given ultra-high CO2 levels (i.e., 10,000 uL CO2 liter**-1) when transferred to soil. This study illustrates that enhanced commercial shooting can be obtained by altering the culture system physical environment rather than altering the nutrient medium composition. These techniques should have immediate application with the forestry commercial nursery industry.

Technical Abstract: Enhanced sweetgum (Liquidambar styraciflua L.) in vitro axillary shooting and shoot establishment in soil is presented. Sweetgum shoots grown in an automated plant culture system (APCS) which mimics hydroponics produced 400 to 500 shoots compared to only 40 shoots produced within Magenta vessels containing agar medium. Employment of a continuous air/CO2 flow-through system improved the survival and growth responses of both vitrified and non-vitrified sweetgum shoots transferred from an APCS to soil. One and two-cm long vitrified shoots were grown within CO2 flow-through system chambers and subjected to 350, 1,500, 3,000, 10,000, and 30,000 uL CO2 liter**-1 for 4 weeks. Ten thousand uL CO2 liter**-1 significantly improved culture survival and overall shoot and root growth compared to plantlets grown at the ambient CO2 levels (i.e., 350 uL CO2 liter**-1).