Polyp morphogenesis in a scyphozoan: Evidence for a head inhibitor from the presumptive foot end in vegetative buds ofCassiopeia andromeda

The relative contribution of various temperatures to dormancy completion of lateral vegetative apple [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.] buds was studied quantitatively on whole container-grown trees. Trees were exposed continuously to 10 different temperatures and also to daily alternating temperatures in a 24-hour cycle. In addition, fully chilled vertically and horizontally positioned shoots were compared under forcing conditions. No budbreak occurred in shoots chilled above 12.5 °C. There was a steep increase in budbreak as the chilling temperature fell from 12.5 to 7.5 °C. There was little difference in the level of budbreak on shoots chilled between 7.5 and 0 °C. The relative contribution of temperature to chilling accumulation in apple found in our study differs from what has been proposed for stone fruit and for apple in previous studies, especially at temperatures <6 °C. The length of exposure to forcing conditions required to initiate budbreak diminished as the chilling temperature was reduced. No additional bud-break was apparent on shoots chilled longer than 2100 chilling hours. The chilling requirement found here for lateral vegetative buds is much higher than that needed for terminal vegetative and flower buds. Trees that were exposed to daily alternating temperatures had lower levels of budbreak when the high temperature in the diurnal cycle was greater than 14 °C. Practically no budbreak was apparent on trees that were exposed to diurnal cycles with a high temperature of 20 °C for 8 hours. Budbreak on horizontally positioned trees was more than twice that on the vertically positioned trees, emphasizing the magnitude of the apical dominance effect and its strong masking of the chilling effect on lateral buds in vertically grown apple trees. Based on the data collected here we propose a new response curve for vegetative budbreak in `Golden Delicious·apple, within a temperature range between 0 to 15 °C.

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RELATIONSHIPS BETWEEN ATTACK RATES AND SURVIVAL OF WESTERN SPRUCE BUDWORM, CHORISTONEURA OCCIDENTALIS FREEMAN (LEPIDOPTERA: TORTRICIDAE), AND BUD DEVELOPMENT OF DOUGLAS-FIR, PSEUDOTSUGA MENZIESII (MIRB.) FRANCO

The Canadian Entomologist ◽

10.4039/ent124347-2 ◽

1992 ◽

Vol 124 (2) ◽

pp. 347-358 ◽

Cited By ~ 21

Author(s):

Roy F. Shepherd

Keyword(s):

Close Association ◽

Spruce Budworm ◽

Larval Survival ◽

Douglas Fir ◽

Choristoneura Occidentalis ◽

Western Spruce Budworm ◽

Bud Development ◽

Feeding Sites ◽

Vegetative Buds ◽

Wide Range

AbstractIndividual larvae of western spruce budworm (Choristoneura occidentalis Freeman) were observed from overwintering emergence to pupation at six locations spread over a wide range of altitudes and thus climate. A weekly census of 100 lower-crown buds per plot indicated large differences in rates of bud development and larval survival among locations.Emerging second-instar larvae attempted to mine swelling buds of Douglas-fir. If the buds were hard and tight, larvae mined 1-year-old needles until penetrable buds were available. Larvae dispersed over the crowns with only one larva becoming established in each bud; thus, many early-emerging and surplus larvae could not find suitable feeding sites and disappeared. Within the protective bud, survival was high. After buds flushed and larvae became exposed, densities dropped, probably due to increased predation and decreased food quality. Correlations indicated a close association between larval survival for the exposed period between bud flush and pupation, and overall larval survival.Douglas-fir trees responded to initial bud removal, but not to needle removal, by inducing latent buds in the axils of needles to grow into active vegetative buds ready to develop and flush the next spring. The number of these new vegetative buds formed was greatest when the initial buds were removed early in the season before flush, and decreased thereafter. Trees with vigorous crowns had the greatest response to defoliation by inducing the largest number of latent buds into becoming active vegetative buds; these were found mainly on the 2- and 3-year-old internodes.

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Bud development in mountain hemlock (Tsuga mertensiana). I. Vegetative bud and shoot development

Canadian Journal of Botany ◽

10.1139/b84-071 ◽

1984 ◽

Vol 62 (3) ◽

pp. 475-483 ◽

Cited By ~ 3

Author(s):

John N. Owens

Keyword(s):

Growth Cycle ◽

Shoot Development ◽

Bud Development ◽

Vegetative Buds ◽

Lateral Shoots ◽

Tsuga Mertensiana ◽

Terminal Buds ◽

Lateral Branches ◽

Relationship Of ◽

Vegetative Bud

Vegetative buds of mature Tsuga mertensiana (Bong) Carr. (mountain hemlock) were studied throughout the annual growth cycle. Cell divisions began in vegetative buds in mid-April and shoots and leaves elongated within the bud scales causing the buds to burst in late June. Lateral shoots completed elongation by the end of July. Vegetative terminal apices from lateral branches began bud-scale initiation when bud dormancy ended. All bud scales were initiated by the end of July. Leaf primordial initiation occurred from that time until mid-October when vegetative buds again became dormant. Axillary buds were initiated on the elongating shoots in early June then followed the same phenology as vegetative terminal buds. Vegetative bud and shoot development are compared with that of western hemlock and certain other members of the Pinaceae. The relationship of bud development to shoot development is discussed for mountain hemlock and other conifers having a similar pattern of vegetative bud development.

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Control of morphogenetic pathways in thin cell layers of tobacco by pH

Canadian Journal of Botany ◽

10.1139/b89-087 ◽

1989 ◽

Vol 67 (3) ◽

pp. 650-654 ◽

Cited By ~ 17

Author(s):

A. Cousson ◽

P. Toubart ◽

K. Tran Thanh Van

Keyword(s):

Butyric Acid ◽

De Novo ◽

Culture Media ◽

Callus Formation ◽

Medium Ph ◽

Vegetative Buds ◽

Cell Layers ◽

Initial Medium ◽

Vegetative Bud

Thin cell layer explants of tobacco were floated in vitro on the surface of liquid culture media. The initial exogenous concentrations of indolyl-3-butyric acid, and kinetin, the initial medium pH, and the explant density were varied. Various patterns of de novo and direct differentiation without any intermediate callus (flower, vegetative bud, root) as well as the absence of morphogenesis and callus formation without any subsequent organogenesis were separately controlled on 100% of the explants. On the same exogenous combination of glucose, indolyl-3-butyric acid, and kinetin, changes in initial medium pH changed the pattern of morphogenesis. For a given initial exogenous indolyl-3-butyric acid concentration, vegetative buds were obtained at either pH 6.1 or 7.8, whereas a mixture of flowers and vegetative buds was obtained at pH 6.8. Furthermore, changes in explant density changed the morphogenetic response. It is suggested that the effects of the initial medium pH and explant density on morphogenesis may be related partially to modifications of the physicochemical properties of the cell wall and (or) plasmalemma.

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Plant Regeneration Through Meristem Culture from Vegetative Buds of Mulberry (Morus bombycis Koidz.) Stored in Liquid Nitrogen

Annals of Botany ◽

10.1093/oxfordjournals.aob.a087638 ◽

1988 ◽

Vol 62 (1) ◽

pp. 79-82 ◽

Cited By ~ 29

Author(s):

HARUMI YAKUWA ◽

SEIBI OKA

Keyword(s):

Plant Regeneration ◽

Liquid Nitrogen ◽

Meristem Culture ◽

Vegetative Buds

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WINTER GROWTH IN THE VEGETATIVE BUDS OF THE WAGENER APPLE

Canadian Journal of Research ◽

10.1139/cjr40c-054 ◽

1940 ◽

Vol 18c (12) ◽

pp. 585-590 ◽

Cited By ~ 3

Author(s):

Hugh P. Bell

Keyword(s):

Statistical Analysis ◽

Longitudinal Section ◽

Continuous Growth ◽

Vegetative Buds

Vegetative buds of the apple were collected from September 26, 1938, to March 18, 1939. The median longitudinal section of each bud was measured. The data collected suggested that a slow but continuous growth in length within the bud proceeds throughout the winter months. The figures were subjected to statistical analysis and found to be significant.

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Seasonal studies of vegetative buds of Helianthus tuberosus: concentration of nuclei in phase G1 during winter dormancy

Canadian Journal of Botany ◽

10.1139/b81-252 ◽

1981 ◽

Vol 59 (10) ◽

pp. 1918-1927 ◽

Cited By ~ 9

Author(s):

S. S. Tepfer ◽

Arlette Nougarède ◽

Pierre Rondet

Keyword(s):

Mitotic Activity ◽

Mitotic Index ◽

Developmental Stages ◽

Central Zone ◽

Winter Period ◽

Helianthus Tuberosus ◽

Winter Dormancy ◽

Feulgen Staining ◽

Vegetative Buds ◽

Terminal Buds

The following vegetative buds were studied at several developmental stages during the course of the year: from November through February dormant terminal buds of subterranean tubers; in March, newly reactivated buds of young shoots; in June, terminal buds of horizontal underground stolons that will form tubers; and in July, the terminal buds of erect aerial shoots. Microdensitometric studies of DNA levels after Feulgen staining showed that during the winter period of dormancy, from November through February, the temporary arrest of growth and morphogenesis is accompanied by a concentration of nuclei in phase G1 (2C level) of a diploid cycle for all nuclei in the terminal meristems of the tubers. In March, reactivation occurs uniformly throughout the meristem without any zonal differences. The G1 phase remains predominant in the cycle and mitotic activity increases uniformly. In the meristems of young underground stolons, beginning in the month of June, signs of concentration at the 2C level again are perceptible. The nuclei of the apical meristems of erect shoots are also diploid at 2C and 4C. In the very large nuclei in the central zone of the tunica where the mitotic index is very low, the distribution of DNA levels shows that nuclei are present at all phases of the cycle. These results are discussed and compared with other species in temporary dormancy and in regard to the concept of nonpolysomatic species.

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