The soil seed bank of the threatened plant <Emphasis Type="Italic">Magnolia stellata</Emphasis> is subordinate to the emergence of current-year seedlings     

Hiromitsu Kisanuki  Hisae Oguro  Arisa Nakai  Suzuki Setsuko  Naoyuki Nishimura  Nobuhiro Tomaru 《Journal of Forest Research》2008,13(2):143-146

We studied seed bank formation of the threatened star magnolia, Magnolia stellata, to examine the early stage of regeneration. Forty-five seedling plots (2 × 2 m), each including a soil-sampling quadrat (40 × 40 cm), were established randomly under or around the crowns of mature M. stellata trees. Seeds of M. stellata were collected from each quadrat to a depth of 5 cm. Only four seeds of M. stellata were found (0.56 seeds/m²) and all were located under mature crowns. Current-year seedlings were abundant in water channels, on moss, or under mature crowns, suggesting that the seeds may require wet soil conditions for germination. Magnolia stellata seeds show considerable germination below the crowns of mature trees in the year following masting, while some seeds remain dormant in the soil. Considering the soil seed bank and the current-year seedling bank of M. stellata, a frequent supply of seed is essential for the regeneration of this species. Thus, it is important to maintain mature trees in addition to promoting seed production.  相似文献   

Asexual fungus <Emphasis Type="Italic">Verticillium dahliae</Emphasis> is potentially heterothallic     

Toshiyuki Usami  Mizuho Itoh  Yoshimiki Amemiya 《Journal of General Plant Pathology》2009,75(6):422-427

Verticillium dahliae, a soilborne plant pathogen, causes wilt disease in many important crops. We reported previously that the mating type gene MAT1-2-1 is spread to isolates of this asexual fungus. However, we did not determine whether V. dahliae is homothallic or heterothallic because the opposite mating type gene, MAT1-1-1, had not been identified. In the present study, we identified the MAT1-1-1 gene from an isolate lacking MAT1-2-1 and the mating type idiomorphs of V. dahliae. Each isolate we tested contained either the MAT1-1 or MAT1-2 idiomorph, indicating that the asexual fungus V. dahliae is potentially heterothallic.  相似文献   

Clearance of the challenge organisms from the upper respiratory tract of chickens injected with an inactivated Haemophilus paragallinarum vaccine     

K Kume  A Sawata  T Nakai 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1984,46(6):843-850

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Duration of the complement-fixation antibodies induced in pigs and guinea pigs by Haemophilus pleuropneumoniae vaccine     

T Nakai  A Sawata  K Kume 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1985,47(3):503-506

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Intranasal inoculation of chickens with encapsulated or nonencapsulated variants of Haemophilus paragallinarum: electron microscopic evaluation of the nasal mucosa   总被引：2，自引：0，他引：2  

A Sawata  T Nakai  K Kume  H Yoshikawa  T Yoshikawa 《American journal of veterinary research》1985,46(11):2346-2353

Chickens were inoculated intranasally with encapsulated or nonencapsulated strains of Haemophilus paragallinarum. The nasal mucosa of the chickens were examined, using scanning and transmission electron microscopy. In chickens given the encapsulated variant, marked loss of cilia and microvilli, infiltration of leukocytes, and deposition of a mucopurulent substance were seen on the surface of the nasal mucosa; the number of microvillous cells were markedly increased, and infiltration of mast cells into the lamina propria of the mucous membrane was observed. Numerous encapsulated organisms were found near cilia and on microvillous cells, and the capsule surrounding the organisms appeared to mediate attachment of the organisms to the cilia. In contrast, the nasal mucosa of the chickens given the nonencapsulated variants changed little morphologically. A few nonencapsulated organisms were found near cilia. Colonization of the nasal mucosa by encapsulated organisms probably was essential to induce the morphologic changes seen in the nasal mucosa.  相似文献   

Generation of PDX‐1 mutant porcine blastocysts by introducing CRISPR/Cas9‐system into porcine zygotes via electroporation     

Fuminori Tanihara  Maki Hirata  Nhien T. Nguyen  Quynh A. Le  Takayuki Hirano  Tatsuya Takemoto  Michiko Nakai  Dai‐ichiro Fuchimoto  Takeshige Otoi 《Animal Science Journal》2019,90(1):55-61

Recently, we established the GEEP (“gene editing by electroporation of Cas9 protein”) method, in which the CRISPR/Cas9 system, consisting of a Cas9 protein and single guide RNA (sgRNA), is introduced into pig zygotes by electroporation and thus induces highly efficient targeted gene disruption. In this study, we examined the effects of sgRNA on the blastocyst formation of porcine embryos and evaluated their genome‐editing efficiency. To produce an animal model for diabetes, we targeted PDX‐1 (pancreas duodenum homeobox 1), a gene that is crucial for pancreas development during the fetal period and whose monoallelic disruption impairs insulin secretion. First, Cas9 protein with different sgRNAs that targeted distinct sites in the PDX‐1 exon 1 was introduced into in vitro‐fertilized zygotes by the GEEP method. Of the six sgRNAs tested, three sgRNAs (sgRNA1, 2, and 3) successfully modified PDX‐1 gene. The blastocyst formation rate of zygotes edited with sgRNA3 was significantly (p < 0.05) lower than that of control zygotes without the electroporation treatment. Our study indicates that the GEEP method can be successfully used to generate PDX‐1 mutant blastocysts, but the development and the efficiency of editing the genome of zygotes may be affected by the sgRNA used for CRISPR/Cas9 system.  相似文献   

Dynamic properties of three types of wood-based composites     

Yingcheng Hu  Tetsuya Nakao  Takahisa Nakai  Jiyou Gu  Fenghu Wang 《Journal of Wood Science》2005,51(1):7-12

This study used a vibration test method to show that grain angles of face veneer have substantial effects on sound velocities and dynamic Youngs moduli of three types of wood-based composites. The sound velocity at 0° grain angle of face veneer was the highest, and it decreased with increasing grain angle in the range of 0° to 90°. This tendency was similar to that for dynamic Youngs modulus. The relationship between the grain angle of face veneer and the sound velocity of three types of wood-based composites can be expressed in the form of Hankinsons equation or a second-order parabolic equation. This study also showed that the application of orthotropic elasticity theory was valid for the three types of wood-based composites. The relationship between the grain angle of the face veneer and the Youngs modulus of three types of wood-based composites can be expressed in the form of the Jenkin equation, Hankinsons equation, or a second-order parabolic equation. Rule of mixture can also be used to predict the Youngs modulus of wood-based composite from the Youngs moduli of the two elements.Part of this study was presented at the 53rd Annual Meeting of the Japan Wood Research Society, Fukuoka, Japan, March 2003 and the 15th Annual Meeting of Chugoku Shikoku Branch of the Japan Wood Research Society, Higashi-Hiroshima, Japan, September 2003  相似文献   

Temporal water deficit and wood formation in Cryptomeria japonica     

Abe H  Nakai T  Utsumi Y  Kagawa A 《Tree physiology》2003,23(12):859-863

Cell behavior in the cambium and developing xylem of 3-year-old Japanese cedar (Cryptomeria japonica D. Don.) trees, during and after an 11-day suspension of irrigation, was analyzed. Leaf xylem pressure potential and tangential strain of the stem surface were monitored throughout the experiment. Anatomical features and numbers of developing tracheids and cambial cells were observed in four trees, sampled on Days 0, 4, 8 and 11 after irrigation was suspended. Daytime xylem pressure potential decreased to -1.9 MPa on Day 7 and remained the same until irrigation was resumed on Day 11. The transverse dimensions of the tracheids, which began to form secondary walls, began to decrease on Day 4. The number of cells in the cambial zone and cell expansion zone decreased abruptly on Day 8. Tangentially aligned developing tracheids with collapsed cell walls were observed in samples harvested on Days 8 and 11. Secondary wall formation was recognized in these tracheids. After the resumption of irrigation, xylem pressure potential recovered rapidly to the same value as before the suspension of irrigation. Tangential strain increased within 30 min after the resumption of irrigation, and continued to increase until the onset of light the next day. Eighteen days after the resumption of irrigation, anatomical features of cells in the cambium and cell-expansion zone were similar to those observed before suspension of irrigation.  相似文献   

Characterization of Components of Partial Resistance, Rps2, and Root Resistance to Phytophthora sojae in Soybean     

Mideros S  Nita M  Dorrance AE 《Phytopathology》2007,97(5):655-662

ABSTRACT Phytophthora root and stem rot of soybeans caused by Phytophthora sojae is a serious limitation to soybean production in the United States. Partial resistance to P. sojae in soybeans is effective against all the races of the pathogen and is a form of incomplete resistance in which the level of colonization of the root is reduced following inoculation. Other forms of incomplete resistance include the single dominant gene Rps2 and Ripley's root resistance, which are both race-specific. To differentiate partial resistance from the other types of incomplete resistance, the components lesion length, numbers of oospores, and infection frequency were measured in eight soybean genotypes inoculated with two P. sojae isolates. The Rps2 and root-resistant genotypes had significantly lower oospore production and infection frequency compared with the partially resistant genotype Conrad, while the root-resistant genotype also had significantly smaller lesion lengths. However, the high levels of partial resistance in Jack were indistinguishable from Rps2 in L76-1988, based on the evaluation of these components. Root resistance in Ripley and Rps2 in L76-1988 had similar responses for all components measured in this study. Partial resistance expressed in Conrad, Williams, Jack, and General was comprised of various components that interact for defense against P. sojae in the roots, and different levels of each component were found in each of the genotypes. However, forms of incomplete resistance expressed via single genes in Ripley and Rps2 in L76-1988, could not be distinguished from high levels of partial resistance based on lesion length, oospore production, and infection frequency.  相似文献   

Involvement of two different types of Verticillium dahliae in lettuce wilt in Ibaraki Prefecture, Japan   总被引：1，自引：0，他引：1  

Toshiyuki Usami  Mizuho Itoh  Satomi Morii  Takuya Miyamoto  Masato Kaneda  Takashi Ogawara  Yoshimiki Amemiya 《Journal of General Plant Pathology》2012,78(5):348-352

Although wilt diseases of various plants by Verticillium dahliae occur worldwide, Verticillium wilt of lettuce is relatively new and rare. In 2009, this disease appeared suddenly in commercial fields in Ibaraki Prefecture, Japan. To investigate the cause of the disease, we characterized each lettuce isolate for pathogenicity, mating types, and genetic characteristics and found two types of V. dahliae. A population that included at least two types of V. dahliae was the putative infection source of the disease. Effective management systems against V. dahliae isolates of different races and having different host ranges are necessary.  相似文献