Journal of Experimental Botany, 59(12): 3215-3228 (Sept 2008)
Regulation of floral initiation in horticultural trees
John D. Wilkie, Margaret Sedgley, Trevor Olesen

Environmental control of floral initiation

A range of subtropical and tropical tree species can be induced to flower by exposure to low temperature: mango, lychee (Menzel and Simpson, 1995), macadamia (Macadamia integrifolia Maiden and Betche) (Nakata, 1976), avocado (Persea americana Mill.) (Buttrose and Alexander, 1978) and orange (Citrus sinensis L.) (Moss, 1976). Olive (Olea europaea L.), an evergreen tree generally grown in Mediterranean environments, can also be induced to flower under cool conditions (Hackett and Hartmann, 1964). One major difference between cool temperature induction in subtropical and tropical trees, and vernalization in herbaceous species, is the temperature required: subtropical and tropical trees often require temperatures around 15–20 °C whereas vernalization in herbaceous species requires temperatures between –1 °C and 10 °C.

With respect to temperate deciduous species, high temperatures (up to 30 °C) increased inflorescence production in grapevine, Vitis vinifera L., while temperatures of 21 °C and below increased tendril production (Buttrose, 1970), but for southern high bush blueberry (Vaccinium corymbosum L.), 28 °C inhibited floral induction compared with 21 °C (Spann et al., 2004).