The effect of short-term high (+ 40 °C, 2 h) (HT) and positive low-temperature (+ 4 C, 2 h) (LT) stresses on leaf micromorphology and ultrastructure of mesophyll cells in winter rye was investigated. After HT, leaf blade relief became reticulate, while under control conditions and after low-temperature stress, leaf blade relief was folded. The ultrastructure of the leaf mesophyll cells of control plants was nominal: in the chl...