The relative stabilities of IAA and IBA under various tissue culture procedures were determined. IBA was significantly more stable than IAA to autoclaving. IBA was also found to be more stable than IAA in liquid Murashige and Skoog medium (MS) under growth chamber conditions. The stabilities of IBA and IAA were similar in agar-solidified MS. Light provided by cool-white fluorescent bulbs promoted degradation of IAA and IBA in both liquid and agar media. Activated charcoal in concentrations as high as 5% was found to adsorb more than 97% of IAA and IBA in liquid MS. These results have important implications for the preparation, storage, and handling of IBA and IAA in plant tissue culture. Chemical names used: indole-3-acetic acid (IAA); indole-3-butyric acid (IBA).
Scott J. Nissen and Ellen G. Sutter
Daniel K. MacKinnon, Dale Shaner, Scott Nissen and Phil Westra
A study was conducted with a wettable powder formulation of 1-methylcyclopropene (1-MCP) to determine the effects of surfactants, spray volume, nozzle type, and rain fastness on the efficacy of 1-MCP to protect tomato plants from the epinastic effects of ethephon. 1-MCP at 25 and 50 g·ha−1 protected tomato plants from 250 and 500 g·ha−1 of ethephon. Of the three best surfactants tested, two (Dyne-Amic and Silwet L-77) contained silicone and one (Herbimax) an emulsified petroleum oil. The efficacy of 1-MCP increased with an increase in spray volume from 150 L·ha−1 to 400 L·ha−1, suggesting that an increase in leaf coverage leads to greater protection and that the translocation of 1-MCP is limited within tomato plants. There was no significant effect of spray nozzle type on 1-MCP activity. 1-MCP appeared to be rainfast within 15 min after application.