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Intensity of Bud Dormancy in Douglas‐fir and Its Relation to Scale Removal and Rooting Ability
Author(s) -
ROBERTS A. N.,
TOMASOVIC B. J.,
FUCHIGAMI L. H.
Publication year - 1974
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.1399-3054.1974.tb03693.x
Subject(s) - dormancy , douglas fir , cutting , biology , bud , horticulture , botany , annual growth cycle of grapevines , shoot , germination
Uniform 1‐ or 2‐year‐old rooted cuttings of 3 Douglas‐fir, Pseudotsuga menziesii (Mirb.) Franco, clones were grown under natural conditions in containers from July 1, 1971 to February 15, 1972. At 2‐week intervals, plants from this natural temperature and daylength environment were moved into controlled, long day (LD‐18 h) and short day (SD‐9 h) environments to measure the intensity of bud dormancy from its inception to termination based on number of days to bud break and percentage of expanding buds on a given date. Growth responses to bud scale removal were also helpful in describing the degree and nature of bud dormancy. The cessation of initiatory activity at the bud apex, reflected in the needle number of the subsequent growth flush, corresponded to a September peak of bud dormancy based on the number of days to bud break in the LD environment. Similarly, the cold requirement for breaking bud dormancy was measurable in the SD environment. The use of such rest intensity indices is illustrated in the close relationship established between bud dormancy development and stem cutting rooting ability.