A comparative study on leaf stomatal characters in some cultivars of longan.

The shapes,distribution and size of stomata in five longan,Dimocarpus longan Lour,cultivar leaves were compared under scanning electron microscope and light microscope.The stomatal structure of longan leaves was quite special.Almost all stomasta were covered by protuberances of the epidermis cells and therefore invisible except for those located near leaf vein.The stomatal density of longan leaves ranged from 376.6 to 451.4 per square millimeter.Cultivar ‘Dawuyuan' showed the highest density of stomata whereas cultivars‘Shuangmamu'and‘Shixia' showed the lowest.The stomatal length ranged from 11.7 to 22.5 micrometers among different cultivars.Cultivar ‘Shuangmamu had the longest stomata while ‘Chuliang’ howed the shortest stomata.