Structural features of the leaf in some cultivated species of the genus Citrus

This article discusses the significance and relevance of studying the vegetative organ of the leaf in addressing various fundamental questions. Citrus crops cultivated worldwide are representatives of the genus Citrus L. This genus, along with its wild and semi-wild relatives (C. trifoliata L. and C. ichangensis Sw.), belongs to the subfamily Aurantioideae Eng. of the family Rutaceae Juss. Almost all are evergreen plants and are considered important fruit crops in tropical and subtropical regions of the world. The classification and systematics of citrus are quite problematic. To this day, there is no universally accepted botanical classification, likely due to the extreme polymorphism of the genus Citrus. The three botanical genera of the most economic and practical significance are Citrus, Fortunella, and Poncirus. The fruits, flowers, and leaves contain a wide range of biologically active substances (organic acids, bioflavonoids, essential oils, and 12 vitamins). Citrus essential oils are widely used to produce natural perfumes and as flavoring ingredients in food, pharmaceutical, and cosmetic products. Leaves from plants such as pomelo, orange variety Uzbekistan, and mandarin variety Medovka were studied. A single leaf type was established — hypostomatic. The mesophyll type of the leaf contains various inclusions, with the presence of water-storing cells and a large number of intercellular spaces. It was found that pomelo has the largest leaf blade height, while mandarin Medovka has the smallest one. The presence of trichomes and glandular hairs was noted in the pomelo representative. The smallest number of stomata was observed in mandarin Medovka, while the largest one was found in orange Uzbekistan.