Abstract: Changing dynamics of four endogenous hormones in normal and aborted ovules of
hazelnut（Corylus heterophylla Fisch）was analyzed during fruit development stage，and following ABA
and its synthesis inhibitor sodium tungstate solution spraying treatments were carried out to study the
effects of ABA on ovules filling process. The results showed that：（1）Content changing curves of IAA，
GA₃ and ZR in normal filled ovules were approximately single peak shaped，and their peak value appeared
on 80th，90th and 100th day after blooming，respectively. Compared during the same developing period，
content of IAA and GA₃ in aborted ovules were lower than that in filled ovules in most cases，while higher
ZR content was found to exist in aborted ovules. Eighty to 110 days after blooming was a key period for
rapid growth of hazelnut ovule. During the stage，ABA content in developing ovules was significantly higher than that in abortive one.（2）20.0 and 50.0 mg · L^-1 ABA treatments promoted fresh weight of kernel，
shell and nut to different degrees，while sodium tungstate had an opposite effects on the above indexes
compared with ABA treatments. The results above indicated that ABA was involved in the regulation
process of ovule filling in hazelnut.

Key words: hazelnut, ovule, abscisic acid, sodium tungstate