The Cultivation of Tissues of Cupressus lusitanica in vitro

Conditions for In vitro culture of initial explants of Cupressus lusitanica were determined as the first step of an investigation of physiological differences between tissues obtained from plants, or plant parts, of different ages. Explants proliferated well on a basal agar medium containing only Heller's mineral salts and sucrose. Addition of several vitamins, phytohormones, and coconut water to this basal medium stimulated callus growth only slightly or not at all, and transplanted callus soon died. Proliferation of initial explants was considerably stimulated by increasing the concentration of mineral salts in the medium, and the growth habit changed from compact to friable. Callus could be transplanted to, and maintained on, a high-salt medium enriched by vitamins. Whereas added auxins still stimulated proliferation of initial explants and transplanted callus only slightly, added coconut water was considerably more effective than on basal medium. Thus results confirm observations by others with tobacco tissues: Additions of phytohormones and other organic substances may not exert their potential effects if growth is limited by sub-optimal mineral nutrition.