Variation in leaf structures of micropropagated rhubarb (Rheum rhaponticum L.) PC49

Alterations in leaf trichomes, stomatal characteristics and epidermal cellular features were investigated in micropropagated rhubarb (Rheum rhaponticum L.) PC49. The results showed that micropropagated regenerants had produced significantly lower stomatal index, but larger epidermal cell size than conventional plants. In addition, altered trichome morphology and abnormal stomata, e.g. twin-stomata were constantly noted only in micropropagated plants. The microscopic observation demonstrated a substantially larger intercellular space in palisade and mesophyll only in leaves of micropropagated plants. But the results showed no difference in chloroplast number and chlorophyll content between micropropagated and conventional plants. All the abnormalities suggest somaclonal variation may have occurred in micropropagated rhubarb PC49.