The use of a novel stabilizing substrate for the in vitro cultivation of cauliflower (Brassica oleracea L. var. botrytis)
A new stabilizing substrate derived from cellulose crystallite aggregates (CCA) is presented in its use for tissue culture and regeneration of cauliflower (Brassica oleracea L.), particularly at the stage of root formation. The material is suitable instead of agar for the large scale propagation of cultured plants. Frequently growth promoting effects are being observed with the medium.
THE PICEA ABIES SHOOT APICAL MERISTEM IN CULTURE. I. AGAR AND AUTOCLAVING EFFECTS
A B S T R A C T Shoot apical meristems of Picea abies seedliings can be cultured on a relatively simple, defined, basal medium. Dome-like explants initially about 200,u tall, without externally obvious primordia, and having dry weights of about 3 Ag, usually initiate 5-10 new primordia within a week. They typically show 10- to 30-fold dry weight increases in three weeks. None of the 5,000 meristems cultured has produced any basal callus. Growth is strongly influenced by both the type and concentration of agar used to gel the medium. Dry weight yield increases as agar concentration decreases. This is probably partly due to increased diffusion rates of enzymes or other large molecules through more dilute agar gels but possibly also partly ascribable to unknown agarborne inhibitors. About half of the agar concentration effect can be eliminated by substituting glucose and fructose for sucrose in the medium. This suggests that diffusion of invertase through the agar gel in this medium may be a growth limiting factor. Growth of cultures is also promoted by autoclaving sucrose in the presence of the agar. The basis of this effect is not yet understood. ISOLATED shoot apical meristems of Picea abies and some other conifers can be grown on relatively simple culture media. No primordia need be included with the explant and the latter, indeed, need not include even the entire apical dome. New primordia normally appear during the first week of culture. Their initiation and development can be observed and can be modified by experimental treatment. We have already cultured more than 5,000 such meristems, usually for 3 weeks, but sometimes as long as 6 months. Dry weight increases in 3 weeks have been as great as 37-fold. The historical, technical, and philosophical background of this approach to the study of woody plant development has been discussed earlier (Romberger, 1963, 1966a, 1969; Romberger, Varnell, and Tabor, 1970). Our long range goal is understanding the control of morphogenesis and development at the shoot apex. However, this paper is primarily concerned with the considerable effects of agar type and concentration, and with effects of different methods of preparing the basal medium. The existence of such effects demands that we attempt to understand their basis before proceeding to studies of those more obvious environmental and biochemical factors which are potential morphogens and growth regulators.
Impact of acetaldehyde‐ and pyruvic acid‐bound sulphur dioxide on wine lactic acid bacteria
Aims:  To investigate the impact of acetaldehyde‐ and pyruvic acid‐bound sulphur dioxide on wine lactic acid bacteria (LAB).