Catalpa bignonioides Walt. (Indian Bean): In Vitro Culture, Regeneration of Plants, and the Formation of Iridoids and Phenolic Acids

Abstract

The genus Catalpa L. belongs to the family Bignoniaceae and comprises 13 species of deciduous trees (Engler 1964). The plants are found in East Asia, North America (extending northward into Missouri and Indiana) and the West Indies. Catalpa trees are usually grown for their attractive, white, pink, or yellow flowers, which appear during the summer (the flowering time is July and August), and their large (10–20 cm in length) heart-shaped leaves. Leaves are opposite, long petioled. Bisexual flowers are organized into terminal pannicles. The corolla is campanulate in form. There are five stamens, two of them are represented by staminodes. The fruits are long (20–35 cm), cylindrical capsules including numerous flat seeds, tomentose at both ends. The fruits remain on the branches throughout the winter (Belot 1985; Seneta 1987). Catalpa plants require fresh soil, rich in nutrients. They are phytophilous and thermophilous plants; the immature shoot tips die in winter (Csapody and Toth 1982). Catalpa has proved to be very decorative — an excellent tree for planting in parks or streets due to its tolerance to city pollution (Seneta 1987).