*2.5. Stomata Analysis*

The middle third portion of the third and fourth fully expanded leaves were cut into approximately 1 cm × 1 cm sections. Impressions of the leaves were obtained by placing leaf sections on top of a thin layer of super glue (Elmer's Products, Inc., Westerville, OH, USA), spread over microscope glass slides, and removing the leaf after drying. Impressions were obtained for both the adaxial and abaxial surfaces of the leaves. Stomata observations were performed under an optical Leica DMLB microscope (Leica microsystems, Buffalo, NY, USA) at 200× magnification. Images were recorded using a SPOT 4.7 digital camera coupled to the microscope and analyzed using the SPOT basic software (SPOT Imaging, Diagnostic Instruments, Inc., Sterling Heights, MI, USA). The number of stomata was counted under the microscope for both the abaxial and adaxial surfaces of leaves. Three different areas of 5 mm in diameter were selected as replicates for observations for each light treatment. Results were expressed as a means of counts of the three areas per mm2. The length and width of three randomly selected stomata were measured for both the adaxial and abaxial surfaces of each leaf in three different sections of each selected leaf. Five random plantlets were selected per treatment.
