FREEZE-THAW INJURY IS ENHANCED BY POSTTHAW LEACHING IN WATER

Turnip (Brassica rapa L.) root tissue was exposed to freeze-thaw stres ses of -7, -9, -11 and -19 degrees C. The post-thawed tissues were eit her subjected to leaching in deionized water for 2 h or left at 100% h umidity. Tissue survival was then assayed by vital staining using modi fied 2,3,5-triphenyltetrazolium chloride (TTC) staining in 0.2 M phosp hate buffer. Tissue survival was significantly lower for leached sampl es than for non-leached samples. It is concluded that freeze-thaw inju ry in plant tissues is enhanced by post-thaw leaching in water. The 0. 05 M phosphate buffer commonly used for TTC staining also damaged free ze-thaw injured tissue.