Nutritional and Sexual Responses of Jack Pine to Ammonium Nitrate and Gibberellins

Author： Fogal W. H. Larocque G. R. Lopushanski S. M. Schooley H. O. Anderson M. L. Edwards I. K. Coleman S. J. Wolynetz M. S.

Publisher： Society of American Foresters

ISSN： 0015-749X

Source： Forest Science, Vol.45, Iss.1, 1999-02, pp. : 136-153

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Abstract

The nutritional and sexual responses of jack pine (Pinus banksiana Lamb.) seed orchard trees to NH₄NO₃ fertilization and GA_4/7 foliar sprays were examined in seedling and grafted orchards at an Ontario location where soils were low N acidic sandy loams and in a Saskatchewan grafted orchard on high N calcareous sandy clay loams. High seed strobilus abortion and low pollen strobilus production and seed yields characterized the Saskatchewan trees. NH₄NO₃ fertilizer increased soil NH₄⁺ and NO₃^- at both locations, current-year needle N and Mg in Ontario, Fe in Saskatchewan, and Ca at both locations, seed strobilus initiation and seed yields in Ontario; it decreased K in Saskatchewan. GA_4/7 increased needle senescence and current-year needle N and P at both locations, K at Saskatchewan, seed and pollen strobilus initiation in Ontario, seed strobilus initiation and abortion in Saskatchewan, and seed yields per tree in Ontario; it decreased Ca at both locations, Mg at Saskatchewan, and diameter increments the year following treatments in Ontario. NH₄NO₃ and GA_4/7 treatments did not interact for strobilus counts. Sexual expression varied with clones in Saskatchewan but not with families in Ontario. Clones interacted with GA_4/7 but not NH₄NO₃ for seed strobilus initiation. For. Sci. 45(1):136-153.