Cryoprotection of deacclimating peach flower buds by ethephon alteration of pistil carbohydrate content

Ethephon (2-chloroethylphosphonic acid) applied to 4-year-old "Jerseydawn" peach trees in mid October significantly altered cold hardiness, soluble carbohydrate content, and percentage moisture of flower buds during deacclimation the following spring. From February through bloom, pistils from ethephon-treated trees had lower LT85s, with the greatest difference (6.5 °C) occurring at the pink tip stage of flower development. No differences in LT85s could be detected in December and January, before the end of rest, or at the end of full bloom approaching petal fall. Pistil sorbitol content from ethephon-treated trees was 24% greater in February and 45% greater in March, and raffinose content was greater in bark and flower bud vascular traces in March. Sucrose content of pistils from ethephon-treated trees in April was 75% greater, while glucose content was 50% lower, than that in controls.