Laticifers

Laticifers 

in plants, the vessels (tubules, cells) containing latex, a milky juice; they are characteristic of certain species of plants of the families Apocynaceae, Euphorbiaceae, Asclepiadaceae, Compositae, Papaveraceae, and others. Laticifers are grouped in two classes: the articulated and the nonarticulated. The former originate as a result of the opening of the septa between the latex cells. Nonarticulated laticifers are formed by the growth and branching of cells that already exist in the plant embryo. Laticifers are usually found in all the plant organs, forming a special system; however, a number of plants, such as Euonymus and Eucommia, have separate, long cell chains that are not joined in a system.

Living laticifers have a parietal layer of cytoplasm, numerous distinctively shaped nuclei, all the other structures of a living cell, and a cellulose casing. The atrophy of old laticifers and the formation of new ones usually occur simultaneously in the plant. When laticifers atrophy, the milky juice coagulates and is converted into a uniform, solid mass. When there are injuries to plants, the milky juice flows out of the living vessels under turgor.

The physiological role of laticifers is not known. The best substantiated theory suggests that the vessels are the receptacles in which the end products of metabolism accumulate. Laticifers probably perform the role of excretory systems in plants.

O. L. CHISTIAKOVA