Size and shape of Carex meyeriana tussocks in an alpine wetland, northern Sichuan Province, China

1992 ◽  
Vol 70 (11) ◽  
pp. 2310-2312 ◽  
Author(s):  
Shiro Tsuyuzaki ◽  
Tatsuichi Tsujii
Keyword(s):  
Key Words ◽  
Morphological Characteristics ◽  
Basal Area ◽  
Sichuan Province ◽  
Alpine Wetland ◽  
Development Patterns ◽  
Size And Shape ◽  
Potentilla Anserina ◽  
Carex Meyeriana ◽  
Key Words Alpine

To determine the morphological characteristics of Carex meyeriana tussocks, surveys were conducted in a large alpine-grassy marshland (3430 m elevation) in northern Sichuan Province, China. While tussocks did not exceed 26 cm in height, the basal area of tussocks continually expanded. Mature tussocks sometimes resulted in aggregation of tussocks. Carex meyeriana rarely developed long horizontal rhizomes and produced shoot rhizomes that led to the development of bell-shaped tussocks as a result of basal shoot (tiller) development patterns. Equisetum limosum invaded and grew in immature tussocks, while Potentilla anserina and Chamaesium paradoxum invaded the tussock summits. From the sequence of those cohabitants, the upper parts of tussocks were gradually invaded with various species. Key words: alpine wetland, Carex meyeriana, China, cohabitant, morphology, tussock.

AEC Glacier alpine bluegrass

2002 ◽  
Vol 82 (1) ◽  
pp. 95-98 ◽  
Author(s):  
B. A. Darroch ◽  
S. N. Acharya ◽  
J. Woosaree
Keyword(s):  
Key Words ◽  
Seed Production ◽  
Rapid Growth ◽  
Cultivar Description ◽  
High Elevations ◽  
Key Words Alpine

AEC Glacier alpine bluegrass, Poa alpina L., is a reclamation cultivar developed for use in reclaiming and revegetating disturbed sites at high elevations. It is the second alpine bluegrass cultivar released by the Alberta Environmental Centre, Vegreville, AB. This cultivar is expected to complement a prior release, AEC Blueridge alpine bluegrass. AEC Glacier is adapted to high elevations where it is capable of rapid growth and seed production. Key words: Alpine bluegrass, Poa alpina, cultivar description, reclamation

scholarly journals First Report of Clubroot on Capsella bursa-pastoris Caused by Plasmodiophora brassicae in Sichuan Province of China

Plant Disease ◽  
2014 ◽  
Vol 98 (5) ◽  
pp. 687-687 ◽  
Author(s):  
L. Ren ◽  
X. P. Fang ◽  
C. C. Sun ◽  
K. R. Chen ◽  
F. Liu ◽  
...  
Keyword(s):  
Plasmodiophora Brassicae ◽  
Tap Water ◽  
Disease Incidence ◽  
Morphological Characteristics ◽  
Pcr Amplification ◽  
Sichuan Province ◽  
Clubroot Disease ◽  
Cruciferous Vegetable ◽  
First Report ◽  
Resting Spores

Shepherd's purse (Capsella bursa-pastoris (L.) Medicus) is an edible and wild medicinal plant widely distributed in China. This plant has been cultivated in Shanghai, China, since the end of the 19th century. Infection of C. bursa-pastoris by Plasmodiophora brassicae, the causal agent of clubroot disease on Brassica spp. has been reported in Korea (2), but is not known to occur in China. In February of 2011, stunted and wilted shepherd's purse (SP) plants were observed in a field planted to oilseed rapes (B. napus) in Sichuan Province of China. Symptomatic SP plants also exhibited root galls. Disease incidence was 6.2% and 100% for SP and B. napus, respectively. Root galls on diseased SP plants were collected for pathogen identification. Many resting spores were observed when the root galls were examined under a light microscope. The resting spores were circular in shape, measuring 2.0 to 3.1 μm in diameter (average 2.6 μm). PCR amplification was conducted to confirm the pathogen. DNA was extracted from root galls and healthy roots (control) of SP. Two primers, TC2F (5′-AAACAACGAGTCAGCTTGAATGCTAGTGTG-3′) and TC2R (5′-CTTTAGTTGTGTTTCGGCTAGGATGGTTCG-3′) were used to detect P. brassicae (1). No PCR amplifications were observed with the control DNA as template. A fragment of the expected size (approximately 520 bp) was obtained when DNA was amplified from diseased roots of SP. These results suggest that the pathogen in the galled roots of SP is P. brassicae. Pathogenicity of P. brassicae in SP was tested on plants of both SP and Chinese cabbage (CC) (B. campestris ssp. pekinensis). A resting spore suspension prepared from naturally infected SP roots was mixed with a sterilized soil in two plastic pots, resulting in a final concentration of 5 × 106 spores/g soil. Soil treated with the same volume of sterile water was used as a control. Seeds of SP and CC were pre-germinated on moist filter paper for 2 days (20°C) and seeded into the infested and control pots, one seed per pot for planted for CC and four seeds per pot for SP. The pots were placed in a chamber at 15 to 25°C under 12 h light and 12 h dark. Plants in each pot were uprooted after 4 weeks and the roots of each plant were washed under tap water and rated for clubroot disease. No disease symptoms were observed in the control treatments of SP or CC. Plants of both species showed symptoms of clubroot, with the disease incidence of 62.5% and 100% on SP and CC, respectively. The pathogen was isolated from diseased roots of each plant and confirmed as P. brassicae based on morphological characteristics and PCR detection. To our knowledge, this is the first report of clubroot disease on C. bursa-pastoris in Sichuan Province of China. This finding suggests that it may be necessary to manage C. bursa-pastoris in cruciferous vegetable (cabbage, turnip) and oilseed rape production fields. References: (1) T. Cao et al. Plant Dis. 91:80, 2007. (2) W. G. Kim et al. Microbiology 39:233, 2011.

Relationships between Ligustrum sinense Invasion, Biodiversity, and Development in a Mixed Bottomland Forest

2013 ◽  
Vol 6 (1) ◽  
pp. 175-186 ◽  
Author(s):  
Justin L. Hart ◽  
Brittany N. Holmes
Keyword(s):  
Plant Species ◽  
Woody Plant ◽  
Basal Area ◽  
Active Management ◽  
Ligustrum Sinense ◽  
Development Patterns ◽  
Woody Plant Species ◽  
Spearman's Rho ◽  
Spearman’S Rho ◽  
Bottomland Forest

AbstractInvasion of closed canopy forests by shade-tolerant alien plants has the potential to modify species composition, stand structure, ecosystem function, and long-term forest development patterns. Ligustrum sinense is a shade-tolerant alien shrub that has invaded bottomland forests throughout the southeastern United States. This species has received comparatively little attention in the literature despite its potential to drastically alter invaded sites. The overarching goal of our study was to document the relationships between Ligustrum sinense invasion and woody plant biodiversity and development patterns in an intact southeastern U.S. bottomland forest. The forest was dominated by Quercus nigra and Liquidambar styraciflua. Ligustrum sinense ranked fifth in basal area contribution, occurred in 97% of our plots, and represented 95% of all understory stems. Spearman's rho for dominance (based on basal area of stems > 5 cm diameter at breast height [dbh]) of L. sinense and woody plant species richness for each plot revealed a significant negative relationship (rs = −0.69, P < 0.01). A similar relationship was revealed between L. sinense density and woody plant species diversity (rs = −0.78, P < 0.01) and evenness (rs = −0.82, P < 0.01). Spearman's rho for L. sinense density and native understory stem density (individuals ≥ 1 m height, < 5 cm dbh) also revealed a significant negative association (rs = −0.48, P < 0.01). Under the current disturbance regime and without active management, we projected the forest would shift to support a stronger component of L. sinense and that structure would transition from tree to shrub dominance for sites within the forest.

Isolation of Frankia from nodules of Trevoa trinervis: ultrastructural characterization

1992 ◽  
Vol 38 (3) ◽  
pp. 174-180 ◽  
Author(s):  
Alicia Carrasco ◽  
Jaime Schwencke ◽  
Margarita Caru
Keyword(s):  
Electron Microscopy ◽  
Key Words ◽  
Double Layer ◽  
Root Nodules ◽  
Morphological Characteristics ◽  
Cortical Cells ◽  
Ultrastructural Characterization ◽  
Layer Technique

Root nodules obtained from Trevoa trinervis and its actinomycete Frankia were studied by electron microscopy. The microsymbiont was found in the cortical cells and it exhibits the typical actinomycetal structures: septate hyphae and symbiotic vesicles. Using the double-layer technique, two Frankia strains were isolated from the nodules. In vitro these strains exhibit morphological characteristics considered specific to the genus Frankia, i.e., hyphae, Frankia vesicles, and polymorphic sporangia. Key words: Frankia, actinomycetes, Trevoa.

Permeability of compacted granular materials

1984 ◽  
Vol 21 (4) ◽  
pp. 726-729 ◽  
Author(s):  
T. C. Kenney ◽  
D. Lau ◽  
G. I. Ofoegbu
Keyword(s):  
Grain Size ◽  
Laminar Flow ◽  
Key Words ◽  
Granular Materials ◽  
Size And Shape ◽  
Grain Size And Shape

Permeability tests were performed on materials of differing grain size and shape of gradation. It was found that permeability was primarily dependent on [Formula: see text] and was practically independent of the shape of gradation for the range of materials tested. Key words: permeability, tests, laminar flow, sand, gravel, particle gradation.

CHEMICAL PROPERTIES AND CLASSIFICATION OF ORGANIC HORIZONS FROM SELECTED SOILS IN BRITISH COLUMBIA

1987 ◽  
Vol 67 (2) ◽  
pp. 383-394 ◽  
Author(s):  
L. E. LOWE ◽  
A. M. SCAGEL ◽  
K. KLINKA
Keyword(s):  
British Columbia ◽  
Correlation Analysis ◽  
Key Words ◽  
Chemical Properties ◽  
Morphological Characteristics ◽  
Soil Classification ◽  
Canonical Variates Analysis ◽  
Organic Horizons ◽  
Canonical Variates

In order to assess the extent to which chemical properties of organic horizons support their differentiation on the basis of morphological characteristics, as used in the Canadian System of Soil Classification (CSSC), a total of 265 samples of organic horizons (including L, F, H, Of, Om and Oh) were analyzed for 26 chemical properties (organic and inorganic). One-way analysis of variance, correlation analysis and tests of normality were used to select variables for canonical variates analysis (CVA). The results of CVA indicated that the six types of horizon could be distinguished by a combination of chemical properties, and that the grouped upland (L-F-H) horizons could be distinguished from the grouped wetland (Of-Om-Oh) horizons. The results provided support for the present usage in the CSSC, based on field morphology. It was concluded that there remained a need to improve definitions, to review designations, and to develop quantitative diagnostic criteria for organic horizons. Some problems in the classification of organic horizons are discussed, particularly in relation to a hierarchical system. Key words: Organic horizons, horizon classification, British Columbia, chemical properties

scholarly journals Characterization, Phylogenetic Analyses, and Pathogenicity of Colletotrichum Species on Morus alba in Sichuan Province, China

Plant Disease ◽  
2019 ◽  
Vol 103 (10) ◽  
pp. 2624-2633 ◽  
Author(s):  
Longhai Xue ◽  
Lei Zhang ◽  
Xiao Xiang Yang ◽  
Xiaoqin Huang ◽  
Wenxian Wu ◽  
...  
Keyword(s):  
Dna Analysis ◽  
Phylogenetic Analyses ◽  
Morphological Characteristics ◽  
Sichuan Province ◽  
Morus Alba ◽  
Brown Spot ◽  
Colletotrichum Species ◽  
Fungal Isolates ◽  
Brown Spot Disease ◽  
Necrotic Spots

Brown spot disease caused by Colletotrichum species was found on leaves of mulberry (Morus alba L.) in Dujiangyan, Sichuan Province, China. Fungal isolates from leaf lesions were identified as six Colletotrichum species based on morphological characteristics and DNA analysis of the combined sequences ITS, GAPDH, ACT, CHS-1, TUB2, and GS. These included Colletotrichum fioriniae, C. fructicola, C. cliviae, C. karstii, C. kahawae subsp. ciggaro, and C. brevisporum. Results showed that the most important causal agent of mulberry anthracnose was C. fioriniae, causing typical brown necrotic spots or streaks, followed by C. brevisporum, C. karstii, and C. kahawae subsp. ciggaro, whereas the two other species (C. fructicola and C. cliviae) showed no pathogenicity to mulberry. This study is the first report of these species associated with mulberry in China.

scholarly journals Etiology and Symptoms of Maize Leaf Spot Caused by Bipolaris spp. in Sichuan, China

Pathogens ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 229 ◽  
Author(s):  
Xiaofang Sun ◽  
Xiaobo Qi ◽  
Wei Wang ◽  
Xuan Liu ◽  
Henan Zhao ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Plant Pathogens ◽  
Morphological Characteristics ◽  
Disease Diagnosis ◽  
Sichuan Province ◽  
Population Diversity ◽  
Seedling Blight ◽  
Maize Leaf ◽  
Linear Lesions ◽  
Wide Range

Many species of the genus Bipolaris are important plant pathogens and often cause leaf spot, root rot, and seedling blight in an extremely wide range of hosts around the world. In recent years, maize leaf spot caused by Bipolaris species has frequently occurred with complex symptoms and is becoming increasingly serious in Sichuan Province of China. To investigate the population diversity of Bipolaris spp. and their corresponding symptoms in maize, 747 samples of maize leaf spot were collected from 132 sampling sites in 19 administrative districts of Sichuan Province from 2011 to 2018. Based on morphological characteristics, pathogenicity testing, and phylogenetic analysis of the rDNA internal transcribed spacer (ITS) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) genes, a total of 1186 Bipolaris isolates were identified as B. maydis, B. zeicola, B. cynodontis, B. oryzae, B. setariae, and B. saccharicola, among which B. maydis and B. zeicola were the dominant pathogenic species, accounting for 57.34% and 42.07% of the isolates, respectively. We found that B. zeicola isolates were mainly distributed in high altitude and cool mountainous areas, while B. maydis was more widely distributed in Sichuan Province. The typical symptoms caused by the Bipolaris species were clearly distinct in maize. The typical symptoms caused by B. maydis were elongated strip lesions, or fusiform, elliptical lesions, and those caused by B. zeicola were narrow linear lesions. Herein, B. saccharicola was first reported on maize and caused subrotund lesions. This study provides useful information for disease diagnosis and management for Bipolaris leaf spot in maize.

Development and growth of even-aged stands of Douglas-fir and grand fir

1986 ◽  
Vol 16 (2) ◽  
pp. 367-372 ◽  
Author(s):  
Bruce C. Larson
Keyword(s):  
Growth Rates ◽  
Volume Growth ◽  
Basal Area ◽  
Douglas Fir ◽  
Stem Volume ◽  
Mixed Stands ◽  
Site Class ◽  
Development Patterns ◽  
Western Washington ◽  
Eastern Washington

Stand development patterns and growth rates of even-aged mixed stands of Douglas-fir (Pseudotsugamensiesii Mirb. Franco) and grand fir (Abiesgrandis Dougl. Lindl.) were investigated by stand reconstruction in eastern Washington. Although Douglas-fir dominated the stands early, grand fir of the same age eventually overtook the tallest Douglas-firs. Dominant trees of both species were found to have highly variable taper form (based on basal area to height ratios), although a linear relationship existed in other crown classes. Stem volume growth rates were determined by reconstructing past diameters and heights and were found comparable to site class IV Douglas-fir in western Washington. Intensive management, especially planting and thinning, could improve upon the observed mean annual increments of 800 board feet per acre at 80 years of age.

scholarly journals Regeneration of aspen following partial and strip understory protection harvest in boreal mixedwood forests

2009 ◽  
Vol 85 (4) ◽  
pp. 631-638 ◽  
Author(s):  
Alison D Lennie ◽  
Simon M Landhäusser ◽  
Victor J Lieffers ◽  
Derek Sidders
Keyword(s):  
Forest Management ◽  
Key Words ◽  
Populus Tremuloides ◽  
Picea Glauca ◽  
Basal Area ◽  
White Spruce ◽  
Mixedwood Forests ◽  
Partial Harvest ◽  
Second Year

Trembling aspen regeneration was studied in 2 types of partial harvest systems designed to harvest mature aspen but protect immature spruce and encourage natural aspen regeneration. Two partial harvest systems, where the residual aspen was either left in strips or was dispersed uniformly, were compared to traditional clearcuts. After the first and second year since harvest, aspen sucker density and growth was similar between the 2 partial harvests, but was much lower than in the clearcuts. However, in the partial cuts the regeneration density was very much dependent on the location relative to residual trees. The density of regeneration was inversely related to the basal area of residual aspen; however, sucker height was inversely related to the basal area of the residual spruce. Although there were adequate numbers of suckers after partial harvest, their viability and contribution to the long-term productivity of these mixedwood stands is not clear. Key words: silvicultural systems, forest management, residual canopy, white spruce, Populus tremuloides, Picea glauca, traffic

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