Cold Induced Changes of Chlorophyll Fluorescence in Intact Needles of Picea abies Correlated with Damage of the Membranes

1991

S. 61-71

32 Lit. Ang.

Unselbständiges Werk

200052482

Effect of cold stress on chlorophyll fluorescence yield of intact needles of Norway spruce (Picea abies (L.) Karst.) during decreasing temperature (10 Grad to -50 Grad C), and the induction kinetics of fluorescence at 20 Grad C, before and after a freeze-thaw cycle were investigated. In vivo chlorophyll fluorescence yield of needles depended substantially on the side and physiological stages of the needles, and correlated with freezing injury of cellular membranes defined as ion leakage. The decrease of fluorscence quenching Fq occurred near the temperatures of freezing supercooled tissue water. Fluorescence-termpature curves showed characteristic low-temperature break points, for cold-hardened spruce at -32 Grad C and dehardened spruce at -20,5 Grad C. The break points on fluorescence-temperature plots are discussed in relation to phase transitions of chloroplast membranes and their injury.