Journal Article

Effects of cone-induction treatments on black spruce (<i>Picea mariana</i>) current-year needle development and gas exchange properties

Ronald F. Smith and Michael S. Greenwood

in Tree Physiology

Volume 17, issue 6, pages 407-414
Published in print June 1997 | ISSN: 0829-318X
Published online June 1997 | e-ISSN: 1758-4469 | DOI:
Effects of cone-induction treatments on black spruce (Picea mariana) current-year needle development and gas exchange properties

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Both drought and root pruning (RP) increased the number of cones induced when black spruce (Picea mariana (Mill.) B.S.P.) grafts were injected with gibberellins A4/7 (GA), but their effects on predawn shoot water potential and current-year needle development differed. Drought decreased predawn shoot water potential (Ψpd), but only during the period when irrigation was withheld, and it had no effect on the growth or gas exchange properties of current-year needles. Conversely, root pruning had little effect on Ψpd, but it resulted in trees with smaller current-year needles that had lower nitrogen and chlorophyll concentrations and reduced rates of gas exchange up to the later stages of shoot elongation compared with needles of control trees. These findings are discussed in relation to potential effects on the development of induced cones in the following growth cycle.

Keywords: drought; GA4/7; photosynthesis; pollen-cone production; root pruning; seed-cone production; shoot water potential; stomatal conductance

Journal Article.  0 words. 

Subjects: Plant Sciences and Forestry

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