Recovery of plants from "Near-Lethal" stress

Area of Science:

• Plant physiology
• Stress tolerance in woody plants
• Environmental stress responses

Background:

• Red-osier dogwood (Cornus sericea L.) is a common woody plant.
• Understanding plant recovery from sublethal stress is crucial for ecological and horticultural applications.

Purpose of the Study:

• To investigate the dieback and recovery of red-osier dogwood after near-lethal heat stress.
• To determine the effect of post-stress environment (PSE) conditions on plant survival and recovery.

Main Methods:

• Dormant red-osier dogwood stems were subjected to 47°C for 1 hour in October, November, or December.
• Stems were then exposed to different post-stress environments: constant 0°C, 23°C, or natural conditions.
• Plant injury, dieback, and recovery were monitored over time.

Main Results:

• Near-lethal heat stress in October followed by 0°C PSE was lethal, causing plant death within 9 weeks.
• Dieback occurred in November and December stressed plants at 0°C PSE after 12 and 15 weeks, respectively.
• Post-stress temperatures above 10°C following October heat stress allowed for plant recovery, while 0°C or 5°C were lethal.

Conclusions:

• The timing of near-lethal heat stress and the subsequent post-stress environment significantly impact red-osier dogwood survival.
• Cold post-stress temperatures exacerbate injury from prior heat stress, while warmer temperatures facilitate recovery.
• Other near-lethal stresses like freezing also cause dieback under cold PSE.