Production of anthocyanins was studied in shoot cultures of carob at high (45.9 μmol s-1m-2) and low (9.2 μmol s-1m-2) irradiance levels and in darkness in relation to carbohydrate nutrition. Anthocyanin production was stimulated by light, but it also occurred in etiolated shoot cultures which developed in darkness. Anthocyanins were present in both leaves and shoot tips. The major factor affecting anthocyanin production was carbohydrate nutrition, with sucrose as a choice superior to fructose and glucose. The carbohydrate effect was clearly osmotic in nature, since anthocyanin production increased even at supraoptimal concentrations detrimental to the growth of shoot cultures. This conclusion was further confirmed in experiments in which sucrose was partly replaced with the sugar alcohols sorbitol and mannitol

A procedure for the micropropagation of Chimonanthus praecox (L) Link, wintersweet, has been developed using buds from adult trees excised in spring. Shoot cultures established on Murashige and Skoog (1962) medium supplemented with 0.5 mg l −1 6-benzyladenine (BAP) and 0.1 mg l −1 indole-3-butyric acid (IBA) were difficult to maintain in vitro through extended periods of time due to browning of the medium, shoot and leaf necrosis, and hyperhydricity. A treatment combining the use of 0.1% w/v activated charcoal and addition of a double phase agar-solidified/liquid medium improved propagation, enabling a successful in vitro propagation scheme to be developed. Optimal shoot multiplication occurred on medium containing 0.5 mg l −1 BAP, and rooting on medium with 2.0 mg l −1 IBA for 7 d, followed by transfer to hormone-free medium. Rooted plantlets were easily acclimated in a glasshouse and replanted and cultured outdoors.