Abstract
Reproductive organ development in plants is regulated by endogenous and exogenous factors. At 25C with a 14-h photoperiod in a phytotron, male strobili of Cryptomeria japonica showed delayed development. Here, the effects of changing temperatures on the morphogenesis of male cones were examined. Two year-old saplings were treated with GA3 in mid-July to induce male strobilus formation and these plants were grown in a phytotron at 30/25C (day/night) with a natural photoperiod. At the 7th week after GA3 treatment, some saplings were transferred to a lower temperature (20/15C), and some of them were subsequently transferred to the field at the 13th week. Histological observation showed that the delayed development of male strobili under the high temperature treatment was recovered in the lower-temperature environment. Pollen production was normal in those saplings transferred to the field. The pattern of gene expression in the male cones under different temperatures will also be presented.
