Visiting Fellow on leave from Zhejiang Agricultural Univ., Hangzhou City, People's Republic of China.
Received for publication 25 Jan. 1984. Financial support for this work was provided by an appropriation of funds under the Hatch Act. The authors gratefully aknowledge the generous gifts of phthalimide (AC94377 technical) from A.J. Pavlista, American Cyanamid Co., Princeton, N.J.; of Ethrel (ethephon) (Amchem 68–214 technical) from Amchem Products Inc., Ambler, Pa. (currently from Union Carbide Agricultural Products Co., Inc. Research Triangle Park, N.C.); and of gibberellin A4+7 (a mixture of gibberellin A4 plus A7) from the Imperial Chemical Industries, Yalding, Kent, England. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact.