Anatomical variation in Citrus leaves from in-vitro and greenhouse plants: Scanning Electron Microscopic studies

Microshoots from proliferating cultures of Citrus reticulata Blanco were rooted in MS medium supplemented with paclobutrazol (0.25–4.0 mg/litre). Scanning electron microscope studies were carried out on mature leaves of 3-month-old greenhouse plants and an equal number of expanded leaves from in-vitro rooted plantlets after 1 month in the rooting medium. The structure of cell wall bordering the stomatal pore from in-vitro rooted plants and from greenhouse grown plants were observed. Three types of stomata, i.e. normal, abnormal and immature were observed in leaves. Normal stomata had kidney-shaped cell with one outer ledge over the stomatal pore and external periclinal cell walls without deformation. Immature stomata were characterized structurally by crescent-shaped guard cells and closed pores. The characteristics of abnormal stomata were the cuticular ledge forming the guard cell and stomata reduced to only one guard cell.