Changes in indole-3-acetic acid and abscisic acid concentrations during development of the Ginkgo biloba L-ovule

Seasonal changes in the concentrations of indole-3-acetic acid (IAA) and ab scisic acid (ABA) in the endosperm and integument of the ovule of Ginkgo bi loba L. were analysed by GC-MS using [d(5)]-IAA and [d(6)]-ABA as internal standards. The concentration of IAA in the endosperm increased rapidly duri ng the period of rapid growth, and was closely correlated with the growth r ate of the ovule. The concentration of IAA in the integument was much lower than that in the endosperm, but also changed similarly. The concentration of ABA in the endosperm showed a peak after the cessation of rapid growth, and decreased during the fertilization period. The concentration of ABA in the integument also increased after the cessation of rapid growth, though s lowly.