STUDIES IN FOREST PATHOLOGY: XI. DECAY IN BLACK COTTONWOOD IN THE MIDDLE FRASER REGION, BRITISH COLUMBIA

1953 ◽  
Vol 31 (5) ◽  
pp. 675-692 ◽  
Author(s):  
G. P. Thomas ◽  
D. G. Podmore
Keyword(s):  
Early Stage ◽  
Populus Trichocarpa ◽  
Significant Loss ◽  
Tree Age ◽  
Relative Importance ◽  
Average Volume ◽  
Black Cottonwood ◽  
Infected Tree ◽  
High Incidence ◽  
Low Probability

A study of decay of black cotton wood, Populus trichocarpa Torr. and Gray, revealed that, although 70 species of fungi caused decay, only six caused significant loss in living trees and that two of these, Polyporus delectans Peck and Pholiota destruens (Brand.) Quél., caused 92% of this loss. The sporophores and associated decays of certain of the fungi are described and their relative importance is indicated. Data on the relation of decay to tree age showed that, despite a high incidence of infection, the average volume of decay per infected tree was low. In general, decay proved important only to the recovery of specialty products such as plywood. A significant reduction of strength was found to occur in wood containing an early stage of decay caused by P. destruens. The practicability of segregating trees having a high or low probability of being decayed was demonstrated through the use of decay indicators.

scholarly journals A peroxisomal β-oxidative pathway contributes to the formation of C6–C1 aromatic volatiles in poplar

2021 ◽  
Author(s):  
Nathalie D Lackus ◽  
Axel Schmidt ◽  
Jonathan Gershenzon ◽  
Tobias G Köllner
Keyword(s):  
Cinnamic Acid ◽  
Aromatic Compounds ◽  
Populus Trichocarpa ◽  
Alternative Pathway ◽  
Gene Families ◽  
Defense Responses ◽  
In Planta ◽  
Black Cottonwood ◽  
Oxidative Pathway

AbstractBenzenoids (C6–C1 aromatic compounds) play important roles in plant defense and are often produced upon herbivory. Black cottonwood (Populus trichocarpa) produces a variety of volatile and nonvolatile benzenoids involved in various defense responses. However, their biosynthesis in poplar is mainly unresolved. We showed feeding of the poplar leaf beetle (Chrysomela populi) on P. trichocarpa leaves led to increased emission of the benzenoid volatiles benzaldehyde, benzylalcohol, and benzyl benzoate. The accumulation of salicinoids, a group of nonvolatile phenolic defense glycosides composed in part of benzenoid units, was hardly affected by beetle herbivory. In planta labeling experiments revealed that volatile and nonvolatile poplar benzenoids are produced from cinnamic acid (C6–C3). The biosynthesis of C6–C1 aromatic compounds from cinnamic acid has been described in petunia (Petunia hybrida) flowers where the pathway includes a peroxisomal-localized chain shortening sequence, involving cinnamate-CoA ligase (CNL), cinnamoyl-CoA hydratase/dehydrogenase (CHD), and 3-ketoacyl-CoA thiolase (KAT). Sequence and phylogenetic analysis enabled the identification of small CNL, CHD, and KAT gene families in P. trichocarpa. Heterologous expression of the candidate genes in Escherichia coli and characterization of purified proteins in vitro revealed enzymatic activities similar to those described in petunia flowers. RNA interference-mediated knockdown of the CNL subfamily in gray poplar (Populus x canescens) resulted in decreased emission of C6–C1 aromatic volatiles upon herbivory, while constitutively accumulating salicinoids were not affected. This indicates the peroxisomal β-oxidative pathway participates in the formation of volatile benzenoids. The chain shortening steps for salicinoids, however, likely employ an alternative pathway.

Reproductive Failure in Populations of the Dog-Whelk, Nucella Lapillus, Caused by Imposex Induced by Tributyltin from Antifouling Paints

1986 ◽  
Vol 66 (4) ◽  
pp. 767-777 ◽  
Author(s):  
P. E. Gibbs ◽  
G. W. Bryan
Keyword(s):  
Vas Deferens ◽  
Early Stage ◽  
Premature Death ◽  
Intermediate Stage ◽  
Reproductive Failure ◽  
Nucella Lapillus ◽  
Egg Capsules ◽  
Male Characters ◽  
High Incidence ◽  
Declining Populations

The development of male characters, notably a penis and a vas deferens, on the female (the phenomenon of ‘imposex’) of the dog-whelk, Nucella lapillus, is described. Three stages are recognized: an ‘early’ stage involving the formation of a vas deferens and a small penis, an ‘intermediate’ stage characterized by the enlargement of the female penis to a size approaching that of the male and a ‘late’ stage during which the female opening (vulva) is occluded by overgrowth of vas deferens tissue. This blockage of the pallial oviduct prevents the release of egg capsules and renders the female sterile. The extent and cause of such reproductive failure is evident from the high incidence of females containing aborted capsules in declining populations close to sources of tributyltin (TBT) contamination. These same populations comprise fewer females than expected and it would appear that the accumulation of aborted capsules within the pallial oviduct eventually causes the premature death of the female.

Organ culture with black cottonwood: morphogenetic response of female catkin primordia

1972 ◽  
Vol 50 (7) ◽  
pp. 1627-1631 ◽  
Author(s):  
K. S. Bawa ◽  
R. F. Stettler
Keyword(s):  
Organ Culture ◽  
Vegetative Growth ◽  
Callus Formation ◽  
Populus Trichocarpa ◽  
General Tendency ◽  
Black Cottonwood ◽  
Axillary Shoots ◽  
Female Sex ◽  
Female Catkin

Female catkin primordia of black cottonwood (Populus trichocarpa T. & G. ex Hook.) were cultured for 70 days on a modified Murashige and Skoog's (1962) medium in vitro. Explants 2–3 mm long, and with bud scales removed, gave the best results, many of them developing floral structures characteristic of the female sex. There was a general tendency to callus formation with increasing age of the culture, occasionally followed by a reversal to vegetative growth. Catkin primordia raised on Wolter's medium without auxin or kinetin, but with 6-benzylaminopurine, and at 250 ft-c for a 16-h photoperiod, proliferated axillary shoots in loco of pistils.

HYPOTONIC CEREBRAL PALSY IN MENTAL DEFECTIVES

PEDIATRICS ◽  
1952 ◽  
Vol 9 (2) ◽  
pp. 204-211
Author(s):  
HERMAN YANNET ◽  
FRANK HORTON
Keyword(s):  
Cerebral Palsy ◽  
Mental Deficiency ◽  
Relative Importance ◽  
Pathologic Process ◽  
High Incidence ◽  
Convulsive Disorders ◽  
Mental Defectives ◽  
Clinical Pictures ◽  
Mental Defect

The relative importance of the hypotonic type of cerebral palsy among the mentally defective is stressed. This type of cerebral palsy manifests itself in either of three clinical pictures with some overlapping, namely, atonic, ataxic and athetoid. The etiology is variable in each of these groups and may be effective in either the prenatal, paranatal or postnatal periods. The severity of the mental defect, the high incidence of convulsive disorders, and the tendency toward microcephaly point towards the widespread nature of the pathologic process regardless of etiology. The syndrome of atonic diplegia, as herein described, is probably invariably associated with the more severe degrees of mental deficiency.

Frequency of enforcement is more important than the severity of punishment in reducing violation behaviors

2021 ◽  
Vol 118 (42) ◽  
pp. e2108507118
Author(s):  
Kinneret Teodorescu ◽  
Ori Plonsky ◽  
Shahar Ayal ◽  
Rachel Barkan
Keyword(s):  
High Probability ◽  
Real Life ◽  
Expected Value ◽  
Relative Importance ◽  
Decisions From Experience ◽  
High Severity ◽  
Low Probability ◽  
Violation Rate ◽  
Severity Of Punishment ◽  
Enforcement Policies

External enforcement policies aimed to reduce violations differ on two key components: the probability of inspection and the severity of the punishment. Different lines of research offer different insights regarding the relative importance of each component. In four studies, students and Prolific crowdsourcing participants (Ntotal = 816) repeatedly faced temptations to commit violations under two enforcement policies. Controlling for expected value, we found that a policy combining a high probability of inspection with a low severity of fines (HILS) was more effective than an economically equivalent policy that combined a low probability of inspection with a high severity of fines (LIHS). The advantage of prioritizing inspection frequency over punishment severity (HILS over LIHS) was greater for participants who, in the absence of enforcement, started out with a higher violation rate. Consistent with studies of decisions from experience, frequent enforcement with small fines was more effective than rare severe fines even when we announced the severity of the fine in advance to boost deterrence. In addition, in line with the phenomenon of underweighting of rare events, the effect was stronger when the probability of inspection was rarer (as in most real-life inspection probabilities) and was eliminated under moderate inspection probabilities. We thus recommend that policymakers looking to effectively reduce recurring violations among noncriminal populations should consider increasing inspection rates rather than punishment severity.

Ecotypic mode of regional differentiation caused by restricted gene migration: a case in black cottonwood (Populus trichocarpa) along the Pacific Northwest coast

2009 ◽  
Vol 39 (3) ◽  
pp. 519-525 ◽  
Author(s):  
Chang-Yi Xie ◽  
Cheng C. Ying ◽  
Alvin D. Yanchuk ◽  
Diane L. Holowachuk
Keyword(s):  
Genetic Differentiation ◽  
Pacific Northwest ◽  
Populus Trichocarpa ◽  
Common Garden ◽  
Northern Region ◽  
Regional Differentiation ◽  
Black Cottonwood ◽  
Gene Migration ◽  
Geographic Patterns ◽  
Leaf Flushing

Genetic differentiation of black cottonwood ( Populus balsamifera subsp. trichocarpa (Torr. & A. Gray ex Hook) Brayshaw) across a “no-cottonwood” belt on the coast of central British Columbia (BC), Canada, was examined using data on 3 year height, severity of infection by Valsa sordida Nitschke and Melampsora occidentalis H. Jacks., and abnormality of leaf flushing. The data were collected in a common-garden test consisting of 180 provenances of 36 drainages ranging from northern BC to Oregon, USA. The results demonstrated an ecotypic mode, north–south regional differentiation. Valsa sordida and M. occidentalis infected 41% and 89%, respectively, of the trees from the northern region, while 66% showed flushing abnormality. In contrast, only 1% and 27% of their southern counterparts were infected by the same diseases, and 1% had abnormal flushing. Trees from the northern region averaged 87% shorter than those from the south. Regional differentiation accounted for the highest amount of variation observed in all traits, with 60% in 3 year height, 34% in V. sordida, 76% in M. occidentalis, and 50% in abnormal leaf flushing. Regression analysis revealed geographic patterns that essentially reflected regional differentiation along the no-cottonwood belt. The species’ distribution biography, ecological characteristics, and life history suggest that restricted gene migration was the main factor responsible for the observed geographic patterns of genetic differentiation.

scholarly journals Preemergence Control of Black Cottonwood in Nursery Containers

2009 ◽  
Vol 27 (1) ◽  
pp. 51-55
Author(s):  
James E. Altland
Keyword(s):  
Populus Trichocarpa ◽  
Effective Control ◽  
Black Cottonwood ◽  
Cottonwood Trees ◽  
Preemergence Herbicides

Abstract Two experiments were conducted to evaluate preemergence herbicides for control of black cottonwood (Populus trichocarpa) in nursery containers. In 2006, granular preemergence herbicides were applied to recently filled, weed-free containers in May just prior to seed release from mature cottonwood trees. Flumioxazin provided the most effective cottonwood control, although control with isoxaben + trifluralin, oxyfluorfen + oryzalin, and pendimethalin was also effective. In 2007, containers were filled February 15, and herbicides were applied to separate groups of containers on February 22, March 14, April 16, and May 15. Containers were over-seeded with cottonwood for a 2-week period starting on May 16. Control with most herbicides improved as the date of application neared the date of seeding. Flumioxazin provided the most effective control throughout the experiment, but control from it also improved as the date of application neared the time of seeding.

Simulating Succession of Riparian Spruce Forests and White-Tailed Deer Carrying Capacity in Northwestern Montana

1987 ◽  
Vol 2 (3) ◽  
pp. 80-83 ◽  
Author(s):  
Kurt J. Jenkins ◽  
R. Gerald Wright
Keyword(s):  
Carrying Capacity ◽  
River Flow ◽  
Populus Trichocarpa ◽  
Timber Harvesting ◽  
Resource Monitoring ◽  
Black Cottonwood ◽  
Winter Range ◽  
Erosion Rates ◽  
The North ◽  
North Fork

Abstract Rates of succession were determined during the period 1945-80 in six floodplain plant communities along the North Fork of the Flathead River, Montana. A succession model was developed to forecast the long-range effects of land-use change on the carrying capacity of white-tailed deer winter range. The areas occupied by mature spruce (Picea englemannii x glauca hybrid) and spruce-black cottonwood (Populus trichocarpa) forests on the floodplain were relatively constant between 1945-1980. Early seral types were more variable due to short-term variations in river flow. Successional modelling demonstrated the effects of two timber harvesting strategies on white-tailed deer populations. Simulated populations declined following two timber harvesting schedules, but recovered after cessation of harvest. An additional application of the model showed the potential effects of increased erosion rates on deer populations and demonstrated the versatility of land succession models for resource monitoring. West. J. Appl. For. 2(3):80-83, July 1987

scholarly journals Structural covariance and cortical reorganisation in schizophrenia: a MRI-based morphometric study

2018 ◽  
Vol 49 (3) ◽  
pp. 412-420 ◽  
Author(s):  
Lena Palaniyappan ◽  
Olha Hodgson ◽  
Vijender Balain ◽  
Sarina Iwabuchi ◽  
Penny Gowland ◽  
...  
Keyword(s):  
Grey Matter ◽  
Early Stage ◽  
Brain Regions ◽  
Significant Loss ◽  
Anterior Cingulate ◽  
Morphometric Study ◽  
Grey Matter Volume ◽  
Structural Covariance ◽  
Matter Volume ◽  
Functional Defect

AbstractBackgroundIn patients with schizophrenia, distributed abnormalities are observed in grey matter volume. A recent hypothesis posits that these distributed changes are indicative of a plastic reorganisation process occurring in response to a functional defect in neuronal information transmission. We investigated the structural covariance across various brain regions in early-stage schizophrenia to determine if indeed the observed patterns of volumetric loss conform to a coordinated pattern of structural reorganisation.MethodsStructural magnetic resonance imaging scans were obtained from 40 healthy adults and 41 age, gender and parental socioeconomic status matched patients with schizophrenia. Volumes of grey matter tissue were estimated at the regional level across 90 atlas-based parcellations. Group-level structural covariance was studied using a graph theoretical framework.ResultsPatients had distributed reduction in grey matter volume, with high degree of localised covariance (clustering) compared with controls. Patients with schizophrenia had reduced centrality of anterior cingulate and insula but increased centrality of the fusiform cortex, compared with controls. Simulating targeted removal of highly central nodes resulted in significant loss of the overall covariance patterns in patients compared with controls.ConclusionRegional volumetric deficits in schizophrenia are not a result of random, mutually independent processes. Our observations support the occurrence of a spatially interconnected reorganisation with the systematic de-escalation of conventional ‘hub’ regions. This raises the question of whether the morphological architecture in schizophrenia is primed for compensatory functions, albeit with a high risk of inefficiency.

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