ACTIVITY OF THE VASCULAR CAMBIUM IN RELATION TO WOUNDING IN THE BALSAM POPLAR, POPULUS BALSAMIFERA L.

1937 ◽  
Vol 15c (1) ◽  
pp. 7-31 ◽  
Author(s):  
A. B. Brown
Keyword(s):  
Cambial Activity ◽  
Living Cells ◽  
Vascular Cambium ◽  
Limiting Factor ◽  
Populus Balsamifera ◽  
Lower Side ◽  
Balsam Poplar ◽  
Complete Ring ◽  
Type Of Behavior ◽  
Stimulation Of

An investigation of the response of the vascular cambium to wounding in leader shoots of the balsam poplar, Populus balsamifera L., was carried out in the laboratory during the winter months, at which time observations on local wound cambial activity, distinct and apart from normal cambial activity, can be obtained. It was found, in disbudded units, that the greater the amount of living bark distal to a wound, the greater is the development of local cambial activity in relation to the wound. Local wound cambial activity is further promoted by the presence of developing buds and leaves distal to the wound, and the effect can be observed before the basipetal gradient of normal cambial activity emanating from the developing extension growth has reached the wound. Cambial activity in relation to wounding responds to gravity in the same way as normal cambial activity. In horizontally placed leader shoots, cambial activity is greater in relation to a wound on the upper side of the shoot than to a similar wound directly opposite on the lower side. On the basis of these results, it is suggested that a hormone, present in the living bark and also produced by developing buds and leaves, is involved in local wound cambial activity. In all probability this hormone is identical with that which promotes normal cambial activity.It is also suggested that a wound substance, capable of promoting by itself cell division only, is involved in local wound cambial activity. The amount of this wound substance produced is apparently proportional to the extent of dying of the cells of the bark subsequent to wounding. From the lower edge of a complete ring, a very feeble basipetal gradient of cambial activity arises, in which differentiation to form vessels and fibres does not occur, although a few tracheids may be found. This type of behavior has not hitherto been reported, and is interpreted as the result of stimulation of the cambial layers by the wound substance alone. Local cambial activity above a complete ring and in relation to bridged wounds, involves differentiation of more or less typical vessels and fibres, and is interpreted as the result of interaction between the wound substance and the cambial hormone traveling basipetally in the living cells of the bark. The absence or feebler development of cambial activity at certain points in relation to bridged wounds, in contrast to greater development at other points where presumably the concentration of cambial hormone must be less, is interpreted as the result of lack of wound substance or low concentration of it acting as a limiting factor.

STIMULATION OF CAMBIAL ACTIVITY, LOCALLY IN THE REGION OF APPLICATION AND AT A DISTANCE IN RELATION TO A WOUND, BY MEANS OF HETEROAUXIN

1937 ◽  
Vol 15c (9) ◽  
pp. 433-441 ◽  
Author(s):  
A. B. Brown ◽  
R. G. H. Cormack
Keyword(s):  
Cell Division ◽  
Cambial Activity ◽  
Structural Features ◽  
Balsam Poplar ◽  
Considerable Distance ◽  
Xylem Formation ◽  
Xylem Elements ◽  
Stimulation Of

The application of heteroauxin in lanoline (1 mg. of heteroauxin per gm. of lanoline) to the distal end of disbudded cuttings of leader shoots of balsam poplar, stimulated cambial activity for a distance of 1.0–1.5 in. below the point of application. Marked stimulation of local cambial activity, in relation to a bridged ring some considerable distance below the point of application of the heteroauxin, was also obtained. The response at the wound was distinct and separate from the response in the region of application of the heteroauxin, since in the intervening distance no cambial activity had occurred. The experiments were carried out during the winter months, so that the cambium was dormant in material as it came from the field. Cambial activity subsequent to treatment was estimated in terms of xylem formation. The structural features of this new xylem are described and discussed, with particular reference to the question as to whether heteroauxin stimulates cell division only in the cambium or, in addition, is active in differentiation of typical xylem elements.

scholarly journals Cambial Activity and Phenology in Three Understory Species along an Altitude Gradient in Mexico

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 506
Author(s):  
Mayte S. Jiménez-Noriega ◽  
Lauro López-Mata ◽  
Teresa Terrazas
Keyword(s):  
Soil Temperature ◽  
Sierra Nevada ◽  
Cambial Activity ◽  
Life Forms ◽  
Dry Season ◽  
Vascular Cambium ◽  
Phenological Stages ◽  
Altitude Gradient ◽  
The Mean ◽  
Trees And Shrubs

The aims of this study were to evaluate the cambial activity and phenology of three species with different life forms (Alchemilla procumbens, Acaena elongata and Ribes ciliatum) along an altitudinal gradient and to establish which environmental variables (light, soil humidity and temperature) had the greatest influence on cambial activity and phenological stages. Over two years, data on phenology, growth and cambium were gathered every four weeks in three to six sites per species in Sierra Nevada, Mexico. The results showed that Ribes is the only species that terminates cambial activity with leaves senescence and is influenced by the minimum soil temperature. The light environment influenced the vegetative stages in Alchemilla (cryptophyte), while in Acaena (hemicryptophyte), the mean soil temperature explained the findings related to leaf area during the dry season and growth along the gradient. In the three species, the reproductive phase dominated for a longer period at higher elevations, especially in Alchemilla. Only Ribes, the phanerophyte, showed a similar cambial activity to other trees and shrubs. Although cambium reactivates during the dry season, no xylogenesis occurs. The three species varied during the time in which vascular cambium was active, and this was dependent on the altitude. Specifically, the variation was more rhythmic in Ribes and switched on and off in Alchemilla. It is likely that, depending on the life form, vascular cambium may be more or less susceptible to one or more climate factors.

scholarly journals Climate-driven local adaptation of ecophysiology and phenology in balsam poplar, Populus balsamifera L. (Salicaceae)

2011 ◽  
Vol 98 (1) ◽  
pp. 99-108 ◽  
Author(s):  
Stephen R. Keller ◽  
Raju Y. Soolanayakanahally ◽  
Robert D. Guy ◽  
Salim N. Silim ◽  
Matthew S. Olson ◽  
...  
Keyword(s):  
Local Adaptation ◽  
Populus Balsamifera ◽  
Balsam Poplar

Effects of balsam poplar (Populus balsamifera) tannins and low molecular weight phenolics on microbial activity in taiga floodplain soil: implications for changes in N cycling during succession

1996 ◽  
Vol 74 (1) ◽  
pp. 84-90 ◽  
Author(s):  
Joshua P. Schimel ◽  
Keith Van Cleve ◽  
Rex G. Cates ◽  
Thomas P. Clausen ◽  
Paul B. Reichardt
Keyword(s):  
Molecular Weight ◽  
Secondary Compounds ◽  
N Cycling ◽  
Low Molecular Weight ◽  
N Fixation ◽  
N Availability ◽  
Populus Balsamifera ◽  
Floodplain Soil ◽  
Balsam Poplar ◽  
River Floodplains

The transition from alder (Alnus tenuifolia) to balsam poplar (Populus balsamifera) is a critical turning point in primary succession on river floodplains in interior Alaska. Associated with the change in plant species are large changes in N cycling. N-fixation and nitrification decrease and the system becomes N-limited, with NH4+ dominating the inorganic N pool. Balsam poplar leaves contain large quantities of tannins and low molecular weight phenolic compounds. We evaluated the effect of these compounds on microbial respiration and N cycling in laboratory assays on soils from an alder-dominated site. Plant compounds were purified and applied to silica gel as an inert carrier. Both tannins and phenolics caused net N-immobilization over a 30-day assay. However, tannins inhibited respiration while phenolics stimulated it. There were no specific effects on nitrification. Thus, tannins acted as a general microbial inhibitor, while phenolics acted as a growth substrate. By inhibiting mineralization while stimulating immobilization, poplar secondary compounds may reduce soil N-availability during the transition betwen alder and poplar stages in succession. Keywords: respiration, mineralization, tannins, secondary chemicals, succession, plant–microbe interactions.

scholarly journals Foliar Penetration of Picloram and 2,4-D in Aspen and Balsam Poplar

Weed Science ◽  
1970 ◽  
Vol 18 (1) ◽  
pp. 57-63 ◽  
Author(s):  
M. P. Sharma ◽  
W. H. Vanden Born
Keyword(s):  
Relative Humidity ◽  
Populus Tremuloides ◽  
High Relative Humidity ◽  
Populus Balsamifera ◽  
Cuticular Waxes ◽  
Adaxial Surface ◽  
Balsam Poplar ◽  
Detached Leaves ◽  
Young Leaves ◽  
Dichlorophenoxy Acetic Acid

Added surfactant (Atlox 210) at 1% (v/v) and high relative humidity enhanced the penetration of both 4-amino-3,5,6-trichloropicolinic acid (picloram) and (2,4-dichlorophenoxy)acetic acid (2,4-D) into detached leaves of aspen poplar (Populus tremuloides Michx.). The influence of added surfactant was greater for picloram and the dimethylamine of 2,4-D than for the ethyl or butoxyethanol ester of 2,4-D. Penetration of picloram and the dimethylamine of 2,4-D occurred more readily from the abaxial than from adaxial surfaces of leaves. The ethyl ester of 2,4-D penetrated equally readily from both leaf surfaces. Penetration of picloram and the dimethylamine of 2,4-D from the adaxial surface of leaves occurred readily in young leaves in early June. There was an increase in penetration in early July followed by a decrease in August and September to a level equal to or less than that in June. Penetration from the abaxial surface of leaves was nearly equal in June and July, but there was a gradual decrease in August and September. An increase in temperature from 10 to 25.5 or to 40.5 C resulted in a sharp increase in penetration of both picloram and 2,4-D under both low and high relative humidity. Autoradiographic evidence showed that movement of picloram within the leaf also was much more extensive at the higher temperatures. Partial removal of cuticular waxes from the adaxial surface of leaves with chloroform resulted in up to four-fold increases in penetration of picloram and 2,4-D. Differences in penetration rate of picloram between leaves of aspen poplar and balsam poplar (Populus balsamifera L.) did not account for reported differences in susceptibility between these two species.

scholarly journals Contemporary range position predicts the range‐wide pattern of genetic diversity in balsam poplar ( Populus balsamifera L.)

2020 ◽  
Vol 47 (6) ◽  
pp. 1246-1257 ◽  
Author(s):  
Andrew V. Gougherty ◽  
Vikram E. Chhatre ◽  
Stephen R. Keller ◽  
Matthew C. Fitzpatrick
Keyword(s):  
Genetic Diversity ◽  
Populus Balsamifera ◽  
Balsam Poplar

scholarly journals Roles of Gβγ in membrane recruitment and activation of p110γ/p101 phosphoinositide 3-kinase γ

2002 ◽  
Vol 160 (1) ◽  
pp. 89-99 ◽  
Author(s):  
Carsten Brock ◽  
Michael Schaefer ◽  
H. Peter Reusch ◽  
Cornelia Czupalla ◽  
Manuela Michalke ◽  
...  
Keyword(s):  
G Protein ◽  
Living Cells ◽  
Membrane Lipid ◽  
Cellular Functions ◽  
Direct Stimulation ◽  
Membrane Recruitment ◽  
Ph Domains ◽  
Phosphoinositide 3 Kinase ◽  
Stimulation Of

Receptor-regulated class I phosphoinositide 3-kinases (PI3K) phosphorylate the membrane lipid phosphatidylinositol (PtdIns)-4,5-P2 to PtdIns-3,4,5-P3. This, in turn, recruits and activates cytosolic effectors with PtdIns-3,4,5-P3–binding pleckstrin homology (PH) domains, thereby controlling important cellular functions such as proliferation, survival, or chemotaxis. The class IB p110γ/p101 PI3Kγ is activated by Gβγ on stimulation of G protein–coupled receptors. It is currently unknown whether in living cells Gβγ acts as a membrane anchor or an allosteric activator of PI3Kγ, and which role its noncatalytic p101 subunit plays in its activation by Gβγ. Using GFP-tagged PI3Kγ subunits expressed in HEK cells, we show that Gβγ recruits the enzyme from the cytosol to the membrane by interaction with its p101 subunit. Accordingly, p101 was found to be required for G protein–mediated activation of PI3Kγ in living cells, as assessed by use of GFP-tagged PtdIns-3,4,5-P3–binding PH domains. Furthermore, membrane-targeted p110γ displayed basal enzymatic activity, but was further stimulated by Gβγ, even in the absence of p101. Therefore, we conclude that in vivo, Gβγ activates PI3Kγ by a mechanism assigning specific roles for both PI3Kγ subunits, i.e., membrane recruitment is mediated via the noncatalytic p101 subunit, and direct stimulation of Gβγ with p110γ contributes to activation of PI3Kγ.

scholarly journals Hormones and Heterosis in Hybrid Balsam Poplar (Populus balsamifera L.)

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 143 ◽  
Author(s):  
Yue Hu ◽  
Barb Thomas
Keyword(s):  
Growth Performance ◽  
Growth Traits ◽  
Block Design ◽  
Field Trials ◽  
Stem Volume ◽  
Hybrid Vigour ◽  
Populus Balsamifera ◽  
Balsam Poplar ◽  
Significant Difference ◽  
Cross Type

Balsam poplar (Populus balsamifera L.) is a transcontinental tree species in North America, making it an ideal species to study intra-specific hybrid vigour as a tool for increasing genetic gain in growth. We tested the hypothesis that intra-specific breeding of disparate populations of balsam poplar would lead to the expression of hybrid vigour and we determined the role of endogenous hormones linked to ecophysiological and growth performance. In September 2009, three field trials were established in Canada (two in Alberta (AB), i.e., Fields AB1 and AB2, and one in Quebec (QC), i.e., Field QC1) in conjunction with Alberta-Pacific Forest Industries Inc. and the Ministry of Forests, Wildlife and Parks, Quebec. Five male parents from each province as well as five female parents from QC and four female parents from AB were used for breeding intra-regional and inter-regional crosses. Based on a significant difference at year six for height and diameter, from the AB1 and AB2 field trials, the AB × QC cross-type was selected for further study. Cuttings from the AB × QC cross-type were grown in a randomized complete block design under near-optimal greenhouse conditions. Families were identified as slow- or fast-growing, and the relationship between hormone levels and growth performance of the genotypes within the families were examined. In late June, after 34 days of growth, internode tissue samples collected from each progeny were analyzed for gibberellic acids, indole-3-acetic acid, and abscisic acid content. Stem volume of two-month-old rooted cuttings, grown under optimal greenhouse conditions, was positively and significantly correlated with the photosynthetic rate, greenhouse growth, and stem volume of 8-year-old field-grown trees (Fields AB1 values: r = 0.629 and p = 0.012; AB2 values: r = 0.619 and p = 0.014, and QC1 values: r = 0.588 and p = 0.021, respectively). We determined that disparate and native populations of balsam poplar can be bred to produce superior progeny with enhanced stem growth traits.

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