122,816 research outputs found
The Douglas-Fir Genome Sequence Reveals Specialization of the Photosynthetic Apparatus in Pinaceae.
A reference genome sequence for Pseudotsuga menziesii var. menziesii (Mirb.) Franco (Coastal Douglas-fir) is reported, thus providing a reference sequence for a third genus of the family Pinaceae. The contiguity and quality of the genome assembly far exceeds that of other conifer reference genome sequences (contig N50 = 44,136 bp and scaffold N50 = 340,704 bp). Incremental improvements in sequencing and assembly technologies are in part responsible for the higher quality reference genome, but it may also be due to a slightly lower exact repeat content in Douglas-fir vs. pine and spruce. Comparative genome annotation with angiosperm species reveals gene-family expansion and contraction in Douglas-fir and other conifers which may account for some of the major morphological and physiological differences between the two major plant groups. Notable differences in the size of the NDH-complex gene family and genes underlying the functional basis of shade tolerance/intolerance were observed. This reference genome sequence not only provides an important resource for Douglas-fir breeders and geneticists but also sheds additional light on the evolutionary processes that have led to the divergence of modern angiosperms from the more ancient gymnosperms
The development of spectro-signature indicators of root disease on large forest areas Annual progress report
Visible and near infrared spectrometric tests of selected black and white film-filter combinations for descriminating between healthy and diseased Douglas fir tree
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Biological control of conifer seed damage by the deer mouse (Peromyscus maniculatus)
This paper describes the development of a biological technique that successfully controls conifer seed damage by the deer mouse. Eleven experiments have been conducted on three study areas at the University of British Columbia Research Forest, Maple Ridge, B.C. Populations of deer mice have been monitored in all experiments with data from 56,000 trap nights. The technique involves a mixture of conifer seed (Douglas fir) with sunflower seed and oats which is uniformly distributed on logged areas in the late winter-early spring. Survival of conifer seed with these alternate foods was excellent, compared with control Douglas fir by itself, for an 8-week period during this time of year. Populations of seed-eating birds and chipmunks are not present on clearcut areas from late October to early April. In addition, deer mice are at their lowest density during the spring. Thus, the use of alternate foods with Douglas fir seed in a direct-seeding operation at the appropriate time of year will result in successful regeneration of cutover forest lands
Identification of varieties and gene flow in Douglasfir exemplified in artificially established stands in Germany
Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] is an economicallyvaluable non-native tree species in Germany and is considered verypromising in view of global climate change. Therefore, the genetic characterization of Douglas-fir populations and seed stands in Germany is essential.We studied coastal and interior Douglas-fir varieties, both presentin Germany, by using eleven isoenzyme and four microsatellite loci. Byanalyzing eight reference populations of known origin we were able toidentify the two varieties on the population level using Bayesian and distance based methods. Seven populations present in Bavaria were then successfully assigned to one of the two varieties. Within varieties we found stronger grouping within the interior variety than within the coastal one. Despite lower differences within coastal Douglas-fir we have first indications for the origin of two populations. For two Bavarian populations, natural regeneration was included and genetic data revealed no significant genetic difference between adults and offspring. The parentage analysis for one of the studied stands revealed that a large proportion of adults took part in the reproduction, but some trees were more successful than othersin transferring their genes to the next generation. Our study was ableto improve variety identification of Douglas-fir using isoenzyme markers and nuclear microsatellites and study reproductive patterns, both are important issues for the management of Douglas-fir stands in Bavaria
Ecology - As I See It
Dr. Jane Claire Dirks-Edmunds summarizes her research experiences on Saddleback Mountain in Oregon. Several handwritten corrections are included. Dirks-Edmunds began studying the area in 1933 with her advisor at Linfield College, Dr. James A. Macnab. In 1940, the research site was logged and her study switched from detailing an existing Douglas fir community to tracking its regrowth.
Dr. Dirks-Edmunds graduated from Linfield College in 1937; she returned to teach in the Biology department at Linfield from 1941-1974
Tolerance of Plant Monoterpenes and Diterpene Acids by Four Species of Lymantriidae (Lepidoptera) Exhibiting a Range of Feeding Specificities
Lymantriidae (Lepidoptera) is a family of leaf-feeding insects that includes some of the most damaging forest pests worldwide. Species within this family vary widely in feeding specificity. We evaluated the ability of four species, Douglas fir tussock moth (Orgyia pseudotsugata McDunnough), nun moth (Lymantria monacha L. ), rusty tussock moth (Orgyia antiqua (L.)), and white- marked tussock moth (Orgyia leucostigma (J. E. Smith)), to contend with one of the most ubiquitous and effective groups of plant defense compounds, terpenoids. We selected these species to provide a range of feeding specificities on conifer hosts, from obligate to occasional. We evaluated the effects of three monoterpenes (bornyl acetate, limonene, and myrcene) and two diterpene acids (isopimaric acid and neoabietic acid) on larval performance. Although these four species differ in their feeding ranges, utilization of conifers as hosts, and other life history processes, each shows a relatively high tolerance for conifer terpenes. The mean relative growth rates, relative consumption rates, and development times were not affected by these monoterpenes and diterpene acids when administered at concentrations present in the foliage of conifers in which they are most abundant. The most likely explanation seems to be metabolism, as a) no limonene or myrcene were recovered from frass or larvae, and b) borneol, an apparent metabolite of bornyl acetate, was recovered from frass of Douglas fir tussock moth, rusty tussock moth, and white-marked tussock moth, and from tissues of Douglas fir tussock moth and white-marked tussock moth
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