Early detection of the effects of warm storage on conifer seedlings using physiological tests

Abstract

Four species of conifer seedlings were more tolerant of pre-planting within-package warm storage than suggested by the literature and physiological tests were highly predictive of incipient damage and growth potential. Bareroot white pine ( Pinus strobus L.), red pine ( Pinus resinosa Ait.), white spruce ( Picea glauca (Moench.) Voss), and black spruce ( Picea mariana (Mill.) B.S.P.) seedlings in sealed polyethylene bags were stored at 15°C from 5 to 13 days or at 30°C from 12 h to 4 days. Seedling performance potential was evaluated after warm storage based on height increment, survival, and foliar damage in a 7-week greenhouse growth trial. White pine, white spruce, and black spruce seedlings were unaffected by storage at 15°C storage for up to 13 days whereas red pine tolerated up to 5 days storage at 15°C without damage or loss of growth. Red pine, black spruce, and white spruce could tolerate at least 12 h storage at 30°C with no appreciable loss of performance potential while white pine suffered impairment even with the shortest period of storage (12 h) at 30°C. The survival and growth of seedlings was accurately predicted by within-package ethanol concentration, shoot tip electrolyte leakage, chlorophyll fluorescence, and root growth potential.