Variability in seed cone production and functional response of seed predators to seed cone availability: support for the predator satiation hypothesis

Black spruce (Piceamariana (Mill.) B.S.P.) grafts growing in a seed orchard were sprayed with gibberellin A4/7, and grafts and trees in families growing in arboreta were sprayed with gibberellin A4/7 and (or) vitamin E from vegetative bud burst to the end of shoot elongation. Gibberellin A4/7 was very effective in promoting seed cones and 400 mg/L appeared optimal. Vitamin E at 1000 mg/L was not effective. Vegetative bud burst occurred in mid-May and shoot elongation ended in late June. Needle primordia were visible on the apices of newly formed buds at the end of June. Reproductive buds had fewer bud scales than vegetative buds. It appeared that potential reproductive buds terminated their bud scale initiation earlier. Gibberellin A4/7 application to promote seed-cone production should be carried out before bud-type differentiation. This coincides with the end of lateral shoot elongation.

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Evaluation of the functional response of Chrysoperla carnea (Stephens) (Neuroptera:Chrysopidae) larvae feeding on cabbage aphid, Brevicoryne brassicae (L.)(Homoptera: Aphididae) in laboratory

Baghdad Science Journal ◽

10.21123/bsj.9.2.220-228 ◽

2012 ◽

Vol 9 (2) ◽

pp. 220-228

Author(s):

Baghdad Science Journal

Keyword(s):

Functional Response ◽

Attack Rate ◽

Handling Time ◽

Brevicoryne Brassicae ◽

Chrysoperla Carnea ◽

Nymphal Instar ◽

Predator Satiation ◽

Cabbage Aphid ◽

The Stability ◽

Type Ii Functional Response

This study evaluated the functional response of the larva of the predator Chrysoperla carnea by offering varying densities of cabbage aphid, Brevicoryne brassicae (L.) . Results showed conformity with type–II functional response, where the number of prey killed approaches asymptote hyperbolically as prey density increases (declining proportion of prey killed or the inverse density dependent) till it reached the stability stage determined by handling time and predator satiation. Also, the values of attack rate and handling time changed with age progress for both predator and prey. It has been observed an increase in the attack rate and reduction in handling time with the progress of the predator age when feeding on a particular nymphal instar. The attack rates of the predator was 1.779,3.406 and 4.219 ,while handling time was 0.015,0.010 and 0.008 (days) for 1st,2nd,3rd larval instars respectively, when fed on 1st nymphal instar. Also attack rates decreased and increases handling time with the progress in the prey. The attack rates were 1.779, 1.392, 1.096 and 1.059, due to an increase in size of the predator and in the growing efficiency in hunting the prey as well as in the increase in size of the prey and in developing its ability to defend itself and escape.

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Cost of reproduction in Douglas-fir

Canadian Journal of Botany ◽

10.1139/b92-179 ◽

1992 ◽

Vol 70 (7) ◽

pp. 1429-1432 ◽

Cited By ~ 42

Author(s):

Yousry A. El-Kassaby ◽

Hugh J. Barclay

Keyword(s):

Pseudotsuga Menziesii ◽

Annual Ring ◽

Ring Width ◽

Energy Allocation ◽

Douglas Fir ◽

Environmental Correlations ◽

Annual Ring Width ◽

Trade Off ◽

Cone Production ◽

Seed Cone

The balance between allocating energy resources to reproduction or growth has considerable theoretical interest. Conflicting ecological requirements and evolutionary pressures often necessitate a trade-off in energy allocation. We obtained measurements on seed-cone production and annual ring width of 365 Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees from 29 open-pollinated families for 8 years. Phenotypic, genetic, and environmental correlations were computed for seed-cone production and ring width for each year. Five of the eight environmental correlations were negative (range −0.077 to −0.305), reflecting the reality of the trade-off in physiological terms. Six of the eight genetic correlations were negative (range −0.199 to −0.776), indicating that a trade-off exists at the genetic level between energy allocation to reproduction and to somatic growth. These findings agree with the current theory of life-history evolution. Key words: Pseudotsuga menziesii, cone production, annual ring width, genetic correlation.

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Promotion of flowering in western hemlock by gibberellin A4/7 applied at different stages of bud and shoot development

Canadian Journal of Forest Research ◽

10.1139/x89-160 ◽

1989 ◽

Vol 19 (8) ◽

pp. 1051-1058 ◽

Cited By ~ 4

Author(s):

John N. Owens ◽

Anna M. Colangeli

Keyword(s):

Effective Treatment ◽

Shoot Elongation ◽

Shoot Development ◽

Western Hemlock ◽

Bud Burst ◽

Cone Production ◽

Seed Cone ◽

Pollen Cone ◽

Vegetative Bud

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.

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Gibberellin A4/7 enhanced flowering in Pinuscaribaea var. hondurensis

Canadian Journal of Forest Research ◽

10.1139/x91-111 ◽

1991 ◽

Vol 21 (6) ◽

pp. 788-793 ◽

Cited By ~ 6

Author(s):

Derek L. S. Harrison ◽

Mike U. Slee

Keyword(s):

Single Treatment ◽

Bud Development ◽

Cone Production ◽

Seed Cone ◽

Pollen Cone ◽

Sexually Mature

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.

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Some Factors Influencing Cone Production on Young Black Spruce in New Brunswick

The Forestry Chronicle ◽

10.5558/tfc57267-6 ◽

1981 ◽

Vol 57 (6) ◽

pp. 267-269 ◽

Cited By ~ 6

Author(s):

J. D. Simpson ◽

G. R. Powell

Keyword(s):

New Brunswick ◽

Picea Mariana ◽

Black Spruce ◽

Tree Height ◽

Tree Age ◽

Cone Production ◽

Factors Influencing ◽

Seed Cone ◽

Pollen Cone

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.

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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

Canadian Journal of Forest Research ◽

10.1139/x86-058 ◽

1986 ◽

Vol 16 (2) ◽

pp. 340-345 ◽

Cited By ~ 10

Author(s):

Richard P. Pharis ◽

Debra Tomchuk ◽

Frederick D. Beall ◽

R. Marie Rauter ◽

Gyula Kiss

Keyword(s):

Fold Increase ◽

White Spruce ◽

Naphthaleneacetic Acid ◽

Female Cone ◽

Cone Production ◽

Seed Cone ◽

Sporadic Flowering ◽

Old Trees ◽

Pollen Cone ◽

Temperature Water

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.

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Reproductive development and insect damage on white and black spruce seed trees treated with ammonium nitrate and carbofuran

Canadian Journal of Forest Research ◽

10.1139/x93-226 ◽

1993 ◽

Vol 23 (9) ◽

pp. 1786-1792

Author(s):

W.H. Fogal ◽

S.M. Lopushanski ◽

H.O. Schooley ◽

D.A. Winston

Keyword(s):

Ammonium Nitrate ◽

Black Spruce ◽

Spruce Budworm ◽

Reproductive Development ◽

White Spruce ◽

High Rate ◽

Insect Damage ◽

Cone Production ◽

Seed Cone ◽

Needle Senescence

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.

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Hormonal enhancement of cone production in Douglas-fir grafts and seedlings

Canadian Journal of Forest Research ◽

10.1139/x79-034 ◽

1979 ◽

Vol 9 (2) ◽

pp. 193-200 ◽

Cited By ~ 15

Author(s):

George S. Puritch ◽

Eleanor E. McMullan ◽

Michael D. Meagher ◽

Clarence S. Simmons

Keyword(s):

Seed Germination ◽

Gibberellic Acid ◽

Douglas Fir ◽

Naphthaleneacetic Acid ◽

Viable Seed ◽

Seed Orchards ◽

Cone Production ◽

Seed Cone ◽

Pollen Cone ◽

Production Response

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.

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Patterns of seed-cone and pollen-cone production in young Piceamariana trees

Canadian Journal of Forest Research ◽

10.1139/x89-054 ◽

1989 ◽

Vol 19 (3) ◽

pp. 359-364 ◽

Cited By ~ 18

Author(s):

G. E. Caron ◽

G. R. Powell

Keyword(s):

Black Spruce ◽

Annual Production ◽

Tree Age ◽

Cone Production ◽

Seed Cone ◽

Warm Weather ◽

Old Trees ◽

Pollen Cone

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.

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