Promotion of flowering in white spruce (Piceaglauca) by gibberellin A4/7, auxin (naphthaleneacetic acid), and the adjunct cultural treatments of girdling and Ca(NO3)2 fertilization

1986 ◽  
Vol 16 (2) ◽  
pp. 340-345 ◽  
Author(s):  
Richard P. Pharis ◽  
Debra Tomchuk ◽  
Frederick D. Beall ◽  
R. Marie Rauter ◽  
Gyula Kiss

Flowering (production of seed cone buds) of white spruce (Piceaglauca (Moench) Voss) grafts and of 55-year-old trees was significantly promoted by the application of gibberellin A4/7 (GA4/7). Use of GA4/7 accompanied by the adjunct cultural treatment of nondestructive girdling was especially effective. When GA4/7 was injected into a branch, the flowering stimulus was translocated upwards, thereby yielding up to a fivefold increase (72 female cone buds per propagule) in flowering. Clonal propagules sprayed to drip off with GA4/7 + auxin (naphtaleneacetic acid) averaged 116 female cone buds per propagule (a 12-fold increase over controls) with a 100% frequency of flowering. Pollen cone bud production and number of male flowering plants also tended to increase with the most successful flowering treatments. When GA4/7 was applied to 55-year-old trees with nondestructive, overlapping stem girdles and auxin, treatments were significantly effective (6- to 27-fold increases, respectively). When GA4/7 + Ca(NO3)2 was applied to 55-year-old trees, there was a tendency (nonsignificant) to increase (4- to 16-fold) flowering, relative to GA4/7 alone. White spruce, because of its very sporadic flowering and usually nominal response to GA4/7 alone, should be classed as a "recalcitrant conifer species." Use of the GA4/7 plus appropriate adjunct cultural treatments (high temperature, water stress, girdling) and (or) auxin is, thus, recommended if significant flowering and seed cone production is desired.

1979 ◽  
Vol 9 (2) ◽  
pp. 193-200 ◽  
Author(s):  
George S. Puritch ◽  
Eleanor E. McMullan ◽  
Michael D. Meagher ◽  
Clarence S. Simmons

Gibberellic acid (GA) and naphthaleneacetic acid (NAA) were applied alone and in combination to both girdled and nongirdled branches of Douglas-fir in four seed orchards (two containing seedlings and two containing grafts). GA significantly increased seed-cone buds and cones and caused a nonsignificant increase in pollen-cone buds. Cone production was not significantly affected by girdling or the application of NAA. Trees treated with the combination of GA + NAA responded similarly to those treated with GA alone. Cone production response to GA varied according to the orchard locations, with better response in the normally more productive orchards. The percentage of trees flowering was increased by GA. Hormone treatments had no effect on seeds per cone but they significantly reduced filled seed per cone. Owing to increased cone number, however, the GA treatments greatly increased the yield of viable seed. NAA increased the percentage of seed germinating and the rate of seed germination, while GA had no effect.


1989 ◽  
Vol 19 (3) ◽  
pp. 359-364 ◽  
Author(s):  
G. E. Caron ◽  
G. R. Powell

Production of seed cones from 1978 to 1987 and of pollen cones from 1980 to 1982 by young black spruce (Piceamariana (Mill.) B.S.P.) trees was recorded in five plantations aged 8, 10, 12, 14, and 16 years in 1980. Variations in cone production and percentages of trees bearing cones were assessed in relation to changing tree age and cone numbers per tree. The first seed cones and pollen cones were noted on 7- and 10-year-old trees, respectively. After ages 10–12 for seed cones and 12–14 for pollen cones there were substantial yearly fluctuations of average numbers of cones per tree. Similarly, the percentages of trees bearing cones fluctuated among years, but differences between poorer and better years decreased as the proportion of bearing trees gradually increased. Up to age 14, the number of seed cones borne per tree was generally higher than the number of pollen cones. Thereafter, pollen-cone production was always higher than seed-cone production and reached 6.6 pollen cones per seed cone by age 18. Pollen cone bearing trees were good indicators of seed cone bearing trees at all ages. Most 12-year-old and older seed cone bearing trees were good indicators of pollen cone bearing trees. Annual production of seed cones was correlated with warm weather in early May and early July, and with relatively low rainfall in early June of the previous year.


1989 ◽  
Vol 19 (8) ◽  
pp. 1051-1058 ◽  
Author(s):  
John N. Owens ◽  
Anna M. Colangeli

Cone buds were induced on container-grown and field-grown western hemlock (Tsugaheterophylla (Raf.) Sarg.) clones during a 3-year period to study the effects of time and duration of gibberellin A4/7 treatment on cone induction, sexuality of cones, and to relate these results to bud and shoot development. The most effective treatment times preceded anatomical differentiation. The most abundant pollen cones and seed cones were produced when trees were sprayed with gibberellin A4/7 before vegetative bud burst and early shoot elongation. Two to three weekly gibberellin A4/7 applications starting at preswollen and swollen-bud stages were adequate for pollen-cone production. Pollen-cone production decreased when the applications were started at vegetative bud burst or during early shoot elongation. A minimum of three weekly applications were required for seed-cone production, and applications were equally effective when started at preswollen, swollen, and vegetative bud burst stages. Seed-cone production decreased when three weekly applications were started during early shoot elongation; however, this was overcome by increasing the number of applications.


1991 ◽  
Vol 21 (6) ◽  
pp. 788-793 ◽  
Author(s):  
Derek L. S. Harrison ◽  
Mike U. Slee

Gibberellin A4/7 was applied to field-grown grafts of sexually mature poor and good flowering clones of Pinuscaribaea Morelet var. hondurensis. Barr. & Golf. Continuous applications of gibberellin A4/7 over a 6-week period significantly enhanced seed-cone production in poor flowering clones but had no effect on good flowering clones. Poor flowering clones also showed slight decreases in pollen-cone production with gibberellin A4/7, while clones that normally flowered well did not. Gibberellin A4/7 increased final shoot lengths in the lower (male) and upper (female) crown region of both poor and good flowering clones. A series of timed gibberellin A4/7 applications suggested that a single treatment near the onset of reproductive bud development may be used to enhance seed-cone production.


1981 ◽  
Vol 57 (6) ◽  
pp. 267-269 ◽  
Author(s):  
J. D. Simpson ◽  
G. R. Powell

Ten young black spruce (Picea mariana [Mill.] B.S.P.) plantations in northern and central New Brunswick were examined to de termine the influence of aspect, slope, tree age and tree height on pollen-cone and seed-cone production. It was found that a greater proportion of trees growing on southerly aspects produced pollen cones and seed cones than trees growing on northerly aspects. Trees growing on southerly aspects bore 2.5 and 5 times more seed cones and pollen cones, respectively, than trees growing on northerly aspects. Cone production on south-sloping sites was approximately double that on level sites. The number of seed cones was most significantly correlated with tree height. The number of pollen cones was most significantly correlated with number of seed cones.


1993 ◽  
Vol 23 (9) ◽  
pp. 1786-1792
Author(s):  
W.H. Fogal ◽  
S.M. Lopushanski ◽  
H.O. Schooley ◽  
D.A. Winston

Granular ammonium nitrate and carbofuran were applied to soil beneath white spruce (Piceaglauca (Moench) Voss) and black spruce (Piceamariana (Mill.) B.S.P.) seed trees to stimulate reproductive development and protect them from defoliating and cone-feeding insects. Rates of carbofuran application were 0, 10.8, or 21.6 g/cm DBH for white spruce, and 0, 5, or 10 g/cm DBH for black spruce. Both species received 0,224, or 448 kg N/ha of ammonium nitrate. Trees were assessed for defoliation by the eastern spruce budworm (Choristoneurafumiferana Clem.), cone insect damage, seed-cone bud production, cone production, seed yields, and needle senescence for 3 years in white spruce, and 2 years in black spruce. On white spruce, carbofuran reduced defoliation and number of spruce budworm at both application rates in the year of treatment and at the high rate in the second year; no protection was observed in the third year. Seed-cone bud production was stimulated by carbofuran for 3 years following treatment. Needle senescence was increased by carbofuran. Ammonium nitrate decreased needle senescence but had no effects on other assessment variables. On black spruce, carbofuran did not reduce spruce budworm numbers or protect cones in the year of application but, in the year after treatment, both foliage and cones were protected. Defoliation was reduced by the low rate of applied ammonium nitrate. Treatments did not influence the number of seed-cone buds or cones or amount of needle senescence in black spruce.


1988 ◽  
Vol 18 (1) ◽  
pp. 43-53 ◽  
Author(s):  
Conor O'Reilly ◽  
John N. Owens

Reproductive growth and development were studied in 1983 in seven provenances of Pinuscontorta Dougl. ssp. latifolia Engelm. growing in a provenance trial near Prince George, B.C. Stages of pollen release and seed-cone receptivity were scored by indices of cone development. Pollen- and seed-cone numbers were estimated and the distribution of seed cones within the upper crown and on annual growth increments of fourth-whorl branches was assessed. Pollen-and seed-cone bud development was followed in sectioned long-shoot buds taken at 2- to 3-week intervals. The times of maximum seed-cone receptivity and pollen release differed slightly among provenances, indicating that there was a high chance of cross-pollination. Differences among provenances in pollen-cone numbers were large, but smaller differences in seed-cone numbers were noted. No mature pollen cones or developing pollen-cone buds were found in the Yukon provenance. Seed-cone production varied with whorl position and was influenced by polycyclic long-shoot development. Potential pollen-cone buds were initiated from May until late June. Pollen cones first differentiated in early to mid July in all provenances. Potential seed-cone apices were noted from mid-June to late July and differentiation occurred in mid-July to early August, depending on provenance. Seed-cone bud development began first in the northern provenances.


1985 ◽  
Vol 15 (4) ◽  
pp. 743-746 ◽  
Author(s):  
Robert D. Marquard ◽  
James W. Hanover

The floral response of 6-year-old seedling white spruce (Piceaglauca (Moench) Voss.) was evaluated after treatment in 1981 with the gibberellin mixture of A4 and A7 (GA4/7), napthaleneacetic acid (NAA), and root-pruning. To evaluate the effectiveness of biennial treatment, trees treated in 1981 were again treated in 1983 and compared with a second group of trees treated only in 1983. Trees treated in 1981 with 500 mg•L−1 GA4/7 plus 25 mg•L−1 NAA and root-pruning averaged 42 female strobili per tree and control trees remained vegetative. Root-pruning significantly reduced terminal shoot growth and shoot water potential. No male strobili were produced on study trees. Trees treated in 1981 and again in 1983 were as productive (based on female counts) as trees treated only in 1983. Two treatments in 1983 significantly enhanced female strobilus production over the control: (i) 500 mg•L−1 GA4/7 alone and (ii) 250 mg•L−1 GA4/7 plus root-pruning. These treatments averaged 150 and 192 female strobili per tree, respectively; control trees averaged 30. Biennial treatment with GA4/7 and root-pruning can effectively continue to increase female cone production of white spruce.


1985 ◽  
Vol 61 (3) ◽  
pp. 223-228 ◽  
Author(s):  
C. C. Ying ◽  
J. C. Murphy ◽  
S. Andersen

Cone production records over a 12-year period from two clonebanks (SCA and SK) indicate that Red Rock is a suitable location for lodgepole pine seed orchards for central interior British Columbia. Both seed and pollen cone production increased rapidly every year and reached their peak in 1982, 10 years after their establishment; a sharp decline occurred in 1983, but cone production recovered to the 1982 level in 1984, On an average, in 1982, the two clonebanks produced 237 seed cones and 186 pollen cones per living graft. Clonal differences were large, and a good cone producer continued to produce more cones year after year. Regular pollen cone production lagged behind seed cone production by about 5 years. Clones from the Yukon and northern British Columbia started to produce seed cones earlier than those of more southern origins; but the latter, despite being less precocious, eventually outproduced the northern ones. Southward transfer of lodgepole pine grafts is not necessarily beneficial to cone production. Average mature cone length was 41 mm, width 24 mm, and weight 7.1 g; average number of seeds per cone was 23 and 100-seed weight was 0.4 mg. Clonal differences were also large for these traits. Key Words: lodgepole pine, clonebank, seed cone, pollen cone, central British Columbia.


Sign in / Sign up

Export Citation Format

Share Document