PT - JOURNAL ARTICLE AU - Robert J. Weaver AU - Stanley B. Mccune TI - Bioassay for Testing Activity of Gibberellins on Grape Shoots AID - 10.5344/ajev.1959.10.4.185 DP - 1959 Jan 01 TA - American Journal of Enology and Viticulture PG - 185--190 VI - 10 IP - 4 4099 - http://www.ajevonline.org/content/10/4/185.short 4100 - http://www.ajevonline.org/content/10/4/185.full SO - Am J Enol Vitic.1959 Jan 01; 10 AB - 1. The apical 6 inches of Zinfandel and Thompson Seedless shoots were sprayed with GA3 from 0.01 to 10,000 ppm. A pin was put through the shoot 2 inches from the apex. About 12 days after treatment the length, fresh and dry weights of stems and leaf blades separately, and total weight of shoots were determined for the growth occurring after spraying. The increase in total fresh weight of the shoot was judged to be the best criterion in this bioassay.2. GA, and GA3 at 25 ppm sprayed on shoots of Muscat of Alexandria were found to result in about equal shoot response.3. To study translocation drops containing 0.1 to 1,000 µg were applied to the base of the upper surface of the first mature leaf from the apex. Measurement of subsequent shoot growth showed that fresh weight of new shoot growth was a good criterion for the amount of gibberellin that reached the shoot tip from the leaf. Results were similar when entire leaves were dipped in solutions ranging from 1 to 10,000 ppm.