Ultrastructural study of chilling injury in roots of Episcia reptans (Mart.).

Chilling the roots of the ultra-chill-sensitive plant Episcia reptans at 5-15° C for 1-50 h produced ultrastructural changes such as mitochondrial swelling, tonoplast discontinuity and sub-cellular deposition of two types of crystalline compounds. One deposit, found by pepsin digestion to be proteinaceous, was associated with the tonoplast and its structure changed with time. The other deposit occurred in the cytoplasm, had a non-variable structure and was not digested by pepsin.