ИСТИНА

A few species (e.g. A. atroviolacea, A. opaca, A. phanluongii) have roots with only single distinguishable layer of the endodermis. However, central cylinder in root of each of these species shows low degree of lignification. The vascular bundle consists of separate arrays of lignified tissue of xylem (xylem parenchyma is not lignified) and has large central mass of parenchyma (Fig. D). The central cylinder of other species, which have multilayered endodermis, contains continuous massive of lignified tissue with small cylinder of parenchyma in the center (ring-like) or without parenchyma (round-like) (Fig. A, B). Probably, such differences of root anatomy are a result of higher or lower degree of general xeromorphism in different species and have no evolutionary significance.