Fig. 1From: Preparation and applications of guard cell protoplasts from the leaf epidermis of Solanum lycopersicumGuard cells at different stages of enzymatic digestion in Method L (a–c) and Method S (d–l). a–f Seven fully expanded leaves of the hydroponic plants selected for GCPs isolation (Additional file 1: Fig. S1). g–i Seven fully expanded leaves of the substrate culture plants selected for GCPs isolation. j–l Four fully expanded leaves of the hydroponic plants (younger plants compared with d–f) selected for GCPs isolation. a, d, h, k The status of GCs after 1.5, 0.5, 2 and 0.5 h of digestion in enzyme solution 1. b, e The status of GCs after 2 and 1 h of digestion in enzyme solution 2. c, f, i, l The status of GCs after 3.5, 2.5, 4.5 and 1.5 h of digestion in enzyme solution 2. Scale bars indicate 20 μmBack to article page