Abstract: (1)Case studies are made in the Three Gorges Reservoir to learn the effects of regulatingwater rising on the natural reproduction of “domestic fish” in the mid-reaches of the Chang-jiang River.(2)According to practical survey,the relationship between amount of fry andfluctuation of water level is F=1.596+9.912H;and the relationship between water level andflux in Yichang station during last May to early June is H=47.374Q^0.0582-37.483.(3) The proper time for water discharge in durations of artificial regulation is from last May to earlyJune;its proper amount is about 0.5m water rising per day,lasting for 4—6 days.(4)Areasonable control of water discharge in the Three Gorges Reservoir has no negative influen-ce on flood control,power generation and navigations.

Key words: Chinese fir, Productivity, Allelopathy, Phenolics, Autotoxicity