A PORTABLE SYSTEM TO QUANTIFY SEEDLING DAMAGE USING STRESS-INDUCED VOLATILE EMISSIONS

This paper describes a portable gas analysis system that was used to q uantify stress-induced ethanol in black spruce (Picea mariana (Mill.) B.S.P.). Operationally fall-lifted black spruce seedlings, packaged in polyethylene-lined kraft bags, were placed in a greenhouse to simulat e conditions in the field, where stock may be exposed to elevated temp eratures. The maximum temperature in the greenhouse was 36 degrees C, and the duration of heat treatment exposure ranged from 3 h to 7 days. After exposure to the heat stress event, the ethanol concentration in the bags of seedlings was measured using a portable gas analysis syst em. A sample of 20 seedlings were then potted and placed in a controll ed-environment room for a 14-day growth period. At the conclusion of t he growth period the seedlings were removed from the pots and the numb er of white roots >1 cm were counted. The terminal buds were dissected to determine viability, and the degree of foliage browning was estima ted. The experiment was repeated four times. Ethanol concentration was significantly correlated with subsequent root growth potential, folia ge viability, and terminal bud viability.