FREEZE-THAW INJURY IS ENHANCED BY POSTTHAW LEACHING IN WATER

Turnip (Brassica rapa L.) root tissue was exposed to freeze-thaw stresses of -7, -9, -11 and -19 degrees C. The post-thawed tissues were either subjected to leaching in deionized water for 2 h or left at 100% humidity. Tissue survival was then assayed by vital staining using modified 2,3,5-triphenyltetrazolium chloride (TTC) staining in 0.2 M phosphate buffer. Tissue survival was significantly lower for leached samples than for non-leached samples. It is concluded that freeze-thaw injury in plant tissues is enhanced by post-thaw leaching in water. The 0.05 M phosphate buffer commonly used for TTC staining also damaged freeze-thaw injured tissue.