56 



most horizontal in orientation to minimize droplet movement. Treated 

 leaves were marked with small gummed labels for ease of identificaton. 

 Plants were placed at random in the growth chamber. 



Four plants treated with GA 3 and 2,4-D and four treated with 2,4-D 

 only were harvested at 1, 3, and 6-day intervals. The above procedure 

 was replicated for the six-day treatment series only. The presence of 

 necrotic tissue, daughter plants, and flower spikes was noted. Plants 

 were then separated into the following fractions: treated lamina, 

 petiole of treated leaf, individual leaves, daughter plants, meristem 

 and youngest leaf, and roots. Plant parts were placed in paper bags 

 and placed in a forced-air drying oven for 72 h at 65 C. Dried plant 

 parts were weighed separately to the nearest 0.01 mg and wrapped in a 



low-ash, unscented, ungummed cigarette papers. Weighed samples were 



14 

 combusted in a Packard TRICARB sample oxidizer to collect C0~ for 



assaying radioactivity. Oxidizer sample burn time was set at 1.5 



minutes; however, all samples were completely combusted within 0.5 



minute. Six milliliters of 0XIS0RB 2 and 10 ml of OXIPREP (New England 



14 

 Nuclear Ltd., Boston (USA)) were used to absorb the CO2 and serve as 



a scintillation fluor, respectively. Radioactivity was assayed by a 



PACKARD TRICARB scintillation spectrometer. Samples were counted for 



10 min and counts per minute (cpm) were converted to disintegrations 



per minute (dpm) based on a linear regression obtained from a quench 



curve. The quench curve was obtained by oxidizing blank samples of 



varying weights. After combustion, known levels of radioactivity were 



added to the scintillation fluor and the counting efficiency was 



obtained. All results were reported as dpm/mg of plant material and 



