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Promotion of flowering in the Pinaceae by gibberellins
Author(s) -
WHEELER N. C.,
WAMPLE R. L.,
PHARIS R. P.
Publication year - 1980
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1980.tb04111.x
Subject(s) - gibberellin , girdling , strobilus , biology , horticulture , botany , auxin , gibberellic acid , seed orchard , germination , gene , biochemistry
Significant female flowering of 6‐ to 11‐year‐old seedlings and grafted ramets of sexually mature scions of lodgepole pine ( Pinus contorta Dougl.) was promoted by both topical and spray applications of a gibberellin (GA) A 4/7 mixture (1.6 to c . 5 mg per plant in total) during that period (June to September) when sexual differentiation of lateral primordia would be expected to take place. Girdling was used in most experiments to enhance the GA 4/7 effect, as was the auxin, naphthaleneacetic acid (NAA). Average frequency of flowering branches on treated plants over all experiments ranged from 27 to 59% (control ranged from 0 to 36%) and average number of female strobili was increased from 2‐ to 6‐fold by growth regulator treatment, relative to controls. Within an experiment, clonal or family frequency of flowering for treated plants ranged from 11 to 67% (controls were 0 to 28%), and number of female strobili was increased from 2‐ to 14‐fold by growth regulator treatment, relative to controls. Movement of the flowering stimulus from the point of application was apparent in several experiments, the response in adjacent branches being correlated positively with increasing dosage of GA 4/7 . Significant male flowering occurred only in one experiment, girdling and GA 4/7 treatment being promotive factors. The use of spray applications of GA 4/7 + NAA is warranted to induce early and enhanced flowering in lodgepole pine seedlings and vegetative propagules for genetic improvement programs.