<i>in vitro</i>培養におけるイチゴ果実の発育におよぼす数種の植物生長調節物質の影響

Abstract

Fruits of strawberry, Fragaria × ananassa (Duch), cv. ′Hohkoh-wase′, one day prior to anthesis, were cultured in vitro to determine the roles of seeds in fruit development in relation to plant growth regulators.1. Fruits from which carpels were removed enlarged normally as intact fruits with carpels on the medium with α-naphthaleneacetamide (NAAm). The ripening of intact fruits with carpels on the NAAm medium was suppressed in comparison to that of fruits without carpels.2. When fruits with or without carpels were cultured on the medium with gibberellic acid (GA3), in either fruit, only the basal portion, which was originally devoid of carpels, swelled, but the upper portion, where there were carpels originally, showed no growth. With addition of GA3 to the NAAm medium, fruits with carpels enlarged into normal shape and their growth and ripening were promoted in comparison to those of fruits on the NAAm medium.3. When fruits with or without carpels were cultured on the medium with N6-benzyladenine (BA) and NAAm, the growth and ripening were suppressed in either fruit as the concentration of BA increased.4. When fruits with carpels were cultured on the medium with maleic hydrazide (MH) and NAAm, the browning of the carpels became severe as the concentration of MH increased, and the growth and ripening were promoted.Based on these results, it is suggested that auxin is more essential for the growth of strawberry fruits than gibberellin, and the carpel is the production site of cytokinin, which suppresses the growth and ripening of strawberry fruits.