556 PB 371 EFFECTS OF SUBLETHAL HEAT STRESS 0N ENDODOPMANCY AND ECODORMANCY OF PEACH AND HYBRID POPLAR

in HortScience
View More View Less
  • 1 USDA-ARS. Kearneysville, WV
  • | 2 Christian Albrecht Universität, Kiel, Germany
  • | 3 Horticulture Dep't.. OSU, Cowallis, Oregon

Sublethal heat stress has been shown to decrease or eliminate deep supercooling of flower buds in woody plants and to release plants from endodormancy. Experiments were conducted to characterize the effect of heat stress on endodormancy and ecodormancy in peach (cv Loring) and two hybrid poplars. Protein synthesis (de novo) and patterns of protein expression were also monitored. In order to determine optimum treatment temperatures, shoots, collected September-March, were exposed to a range of temperatures (35-60 C) under wet or dry conditions for 1-6 h. Shoots were then placed in the greenhouse and cumulative budbreak was monitored over 4 weeks. Samples of bud and bark tissues were collected during and up to 72 h after heat treatment for SDS-PAGE analysis. Data indicate: 1) twigs must be immersed in water for the heat treatments to be effective; 2) heat treatments resulted in a release from endodormancy and a decrease in thermal units needed for budbreak during ecodormancy; 3) 40 C for 2-4 h was optimum in fall and late winter whereas 45 C was the optimum temperature to induce budbreak in midwinter; 4) optimum temperature for peach floral buds (37.5 C/2h) was lower than for vegetative buds (40 C/4h), and 5) heat treatments also decreased cold hardiness. Protein synthesis decreased significantly following heat treatment but was significantly greater than controls (room temp) 24-48 h after heat treatment.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 48 14 2
PDF Downloads 70 25 3