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排序方式: 共有190条查询结果,搜索用时 140 毫秒
91.
Summary Recent exploration work resulted in interesting new information for the checklist of Korean cultivated plants (Baik et al. 1986). 30 species could be additionally included. For another 36 species collections and/or observations are presented for the first time.
Ergänzende Notizen zur Liste der koreanischen Kulturpflanzen (1)
Zusammenfassung Im Ergebnis der weiteren Exploration konnten interessante neue Informationen für die Liste der koreanischen Kulturpflanzen (Baik et al. 1986) gewonnen werden. 30 Arten wurden neu aufgenommen. Für weitere 36 Arten liegen erstmals Sammlungen und/oder Beobachtungen vor.
(I)
(Baik et al. 1986). 30 . 36 / .相似文献
92.
Tran Van Do Akira Osawa Nguyen Toan Thang Nguyen Ba Van Bui Thanh Hang Cam Quoc Khanh Le Thi Thao Diep Xuan Tuan 《New Forests》2011,41(2):247-262
The population changes of early successional forest species, Wendlandia paniculata, Schima wallichii, Camellia tsaii, and Lithocarpus ducampii, were described and analyzed in a chronosequence of 1–30 year-old secondary forests representing regrowth after shifting
cultivation in northwestern Vietnam, utilizing 51 temporary plots for stem census. Another five temporary plots were used
for stem census in surrounding old-growth forest for comparison. In the first year after land abandonment, seedling stem density
(H < 2 m) was 65,800/ha, increasing to 161,200/ha by third year, then sharply decreasing to 2,500/ha in 21–30 year-old forests.
The sapling stratum (H ≥ 2 m and DBH < 5 cm) started to be recruited in the fifth year, increasing to reach a peak density of 4,530 stems/ha at
year ten, then decreased to 580 stems/ha at year 21–30. The tree stratum (DBH ≥ 5 cm) achieved the maximum density of 600
stems/ha at year ten. Meanwhile, the density of all strata in the old-growth forest was 2,980 stems/ha. Sprouts played an
important role, accounting for 34% at the first year then increased gradually to 73% at year 21–30. Total basal area attained
a peak at 5.43 m2/ha at year ten; it was 4.9 m2/ha in the old-growth forest. These four species played an important role in providing ecological services for recruitment
of other species during the first 10 years of fallow stand development, which increased to 35 species in 21–30 year-old secondary
forest. 相似文献
93.
Hiep Thi Nguyen Thanh Quang Dang-Nguyen Tamas Somfai Nguyen Thi Men Barbara Beck-Woerner Nguyen Viet Linh Bui Xuan Nguyen Junko Noguchi Hiroyuki Kaneko Kazuhiro Kikuchi 《Animal Science Journal》2021,92(1):e13650
Male pronucleus (MPN) formation is a very important physiological event during fertilization, which affects in vitro production of transferrable embryos. The aim of this study was to find out the correlation between the number of penetrated sperm and the occurrence of failure of MPN formation in porcine oocytes. In vitro matured porcine oocytes were fertilized in vitro with frozen epididymal sperm. Two different frozen sperm lots were tested in this study, which were different in terms of polyspermy rates. The numbers and the status of penetrated sperm in oocytes were evaluated 10 h after insemination. Under high polyspermy condition, the polyspermy rate was 83.5% with an average mean of 3.5 sperms per penetrated oocyte, whereas the percentage of polyspermy was 65.5% with an average mean of 2.4 sperms per penetrated oocyte under moderate polyspermic condition. Correlation analysis revealed a negative correlation between the number of penetrated sperm and their MPN formation percentage both in the sperm lot of high polyspermy (R = −0.560, p < 0.05) and in the sperm lot of moderate polyspermy (R = −0.405, p < 0.05) which suggests that penetration of excessive spermatozoa disables the oocyte cytoplasm to promote MPN formation. 相似文献
94.
V. Lebot † C. Herail T. Gunua J. Pardales M. Prana M. Thongjiem N. Viet 《Plant pathology》2003,52(3):303-313
Isozyme variation was studied in 94 isolates of Phytophthora colocasiae originating from Indonesia, Papua New Guinea, the Philippines, Thailand and Vietnam. Eight polymorphic enzyme systems (HK, PGM, PGI, Gluco, MDH, ICD, 6PDH, ME) revealed 52 isozyme patterns (zymotypes), each uniquely characterized by the presence or absence of 60 electromorphs. A core sample of 20 isolates was subsequently analysed with RAPD markers. Seven primers were used successfully and all profiles were reproducible. Clear bands were revealed and, in some cases, allowed differentiation between isolates exhibiting identical zymotypes. Results indicate that throughout this vast geographic region, taro leaf blight is caused by numerous and distinct strains that are genetically variable. Variation occurs within and between countries. The geographical distribution of zymotypes shows that none is common to two different countries. Although the differences in pathogenicity are not yet established, different P. colocasiae genotypes are likely to recombine and evolve rapidly as this species is heterothallic. From these results, a long-term breeding strategy is recommended for taro ( Colocasia esculenta ) based on recurrent selection using a wide genetic base composed of carefully selected parents from diverse geographic origins to maximize multigenic resistance in progenies. 相似文献
95.
Khukhuu A Lan DT Long PT Ueno A Li Y Luo Y Macedo AC Matsumoto K Inokuma H Kawazu S Igarashi I Xuan X Yokoyama N 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2011,73(5):701-705
Theileria orientalis is a benign bovine protozoan parasite that occasionally causes serious economic loss in the livestock industry. We report the findings of a molecular epidemiological survey of T. orientalis in 94 Vietnamese yellow cattle, 43 water buffaloes, 21 sheep, 21 goats and 85 blood-sucking ticks of cattle in the Thua Thien Hue province of Vietnam. The major piroplasm surface protein (MPSP) gene of T. orientalis was detected using polymerase chain reaction from 13 cattle (13.8%), 11 water buffaloes (25.6%), 1 sheep (4.8%) and 9 ticks (10.6%). Phylogenetic analysis using MPSP gene sequences showed the presence of seven genotypes, four previously categorized genotypes (Types 1, 3, 5 and 7) and three new genotypes (Types N-1, N-2 and N-3). 相似文献
96.
Dang QL Kim WK Nguyen CM Choi YH Choi GJ Jang KS Park MS Lim CH Luu NH Kim JC 《Journal of agricultural and food chemistry》2011,59(20):11160-11167
The methanol extract of Annona squamosa seeds was highly active against two phytoparasitic nematodes, Bursaphelenchus xylophilus and Meloidogyne incognita. It efficiently suppressed plant diseases, caused by Phytophthora infestans and Puccinia recondita. Ten annonaceous acetogenins (AAs) were isolated, and their chemical structures were identified by mass and nuclear magnetic resonance spectral data. Out of 10 substances, eight displayed strong in vitro nematicidal activity against B. xylophilus with LD(50) values ranging 0.006 to 0.048 μg/mL. Squamocin-G showed potent nematicidal activity against M. incognita. Squamocin, squamocin-G, and squamostatin-A also displayed potent in vitro and in vivo antifungal activities against P. infestans causing tomato late blight. In addition, squamostatin-A effectively controlled the development of wheat leaf rust caused by P. recondita. Our findings suggested that A. squamosa seeds and its bioactive AAs can be an alternative resource of a promising botanical nematicide and fungicide to control various plant diseases. 相似文献
97.
Binh Thanh Nguyen Vinh Ngoc Nguyen Tong Xuan Nguyen My Hoang Nguyen Hao Phu Dong Gai Dai Dinh Nghia Van Nguyen Tan-Viet Pham 《Soil Use and Management》2023,39(1):415-428
Although most studies have indicated that biochar can boost rice (Oryza sativa) growth, the material may also suppress it, depending on ratios of carbon (C) to nitrogen (N) and available N to available phosphorous (P). The current study sought to examine the impacts of biochar on rice growth and to identify underlying mechanisms. A pot experiment was conducted using two soils of high (3.05%) and low (0.54%) organic carbon (OC) content, mixed with 0, 1.5, 3, 6, and 12% biochar and planted with rice. Rice growth components, five rice tissue nutrients, and nine soil properties were measured. The results showed that the response of rice growth to biochar rates could be described using an exponential-growth function in high-OC soil but an inverted U-shaped curve in low-OC soil. In high-OC soil, the 12% biochar rate led to the greatest total biomass, increased by 47%, whereas in low-OC soil, the 3 and 6% rates exhibited the highest total biomass, increased by 44%, compared to the no-biochar added soils. Biochar elevated the C:N ratio from 11.5 to 39.1, with an optimal range of 20–30 corresponding to the highest rice growth. Biochar declined the ratio of NH4-N to Mehlich-1 P, causing N deficiency. In brief, high biochar rates may suppress rice growth when the soil C:N ratio exceeds 30. The applied biochar rate should be considered based on soil properties typically OC and N content to obtain the C:N ratio between 20 and 30 for optimal rice growth. 相似文献
98.
99.
Truong Trong Nghia Mathieu Wille Tran Cong Binh Hoang Phuoc Thanh Nguyen Van Danh & Patrick Sorgeloos 《Aquaculture Research》2007,38(14):1539-1553
A series of rearing trials in small 1 L cones and large tanks of 30–100 L were carried out to develop optimal rearing techniques for mud crab (Scylla paramamosain) larvae. Using water exchange (discontinuous partial water renewal or continuous treatment through biofiltration) and micro‐algae (Chlorella or Chaetoceros) supplementation (daily supplementation at 0.1–0.2 million cells mL−1 or maintenance at 1–2 millions cells mL−1), six different types of rearing systems were tried. The combination of a green‐water batch system for early stages and a recirculating system with micro‐algae supplementation for later stages resulted in the best overall performance of the crab larvae. No clear effects of crab stocking density (50–200 larvae L−1) and rotifer (30–60 rotifers mL−1) and Artemia density (10–20 L−1) were observed. A stocking density of 100–150 zoea 1 (Z1) L−1, combined with rotifer of 30–45 mL−1 for early stages and Artemia feeding at 10–15 nauplii mL−1 for Z3–Z5 seemed to produce the best performance of S. paramamosain larvae. Optimal rations for crab larvae should, however, be adjusted depending on the species, larval stage, larval status, prey size, rearing system and techniques. A practical feeding schedule could be to increase live food density from 30 to 45 rotifers mL−1 from Z1 to Z2 and increase the number of Artemia nauplii mL−1 from 10 to 15 from Z3 to Z5. Bacterial disease remains one of the key factors underlying the high mortality in the zoea stages. Further research to develop safe prophylactic treatments is therefore warranted. Combined with proper live food enrichment techniques, application of these findings has sustained a survival rate from Z1 to crab 1–2 stages in large rearing tanks of 10–15% (maximum 30%). 相似文献
100.
Nguyen Viet LINH Kazuhiro KIKUCHI Michiko NAKAI Fuminori TANIHARA Junko NOGUCHI Hiroyuki KANEKO Thanh Quang DANG-NGUYEN Nguyen Thi MEN Nguyen VAN HANH Tamas SOMFAI Bui Xuan NGUYEN Takashi NAGAI Noboru MANABE 《The Journal of reproduction and development》2013,59(6):549-556
Mitochondria are reported to be critical in in vitro maturation of
oocytes and subsequent embryo development after fertilization, but their contribution
for fertilization has not been investigated in detail. In the present study, we
investigate the contribution of mitochondria to fertilization using reconstructed
porcine oocytes by fusion of ooplasmic fragments produced by serial centrifugations
(centri-fusion). Firstly, we evaluated the characteristics of ooplasmic fragments.
Three types of fragments were obtained by centrifugation of porcine oocytes matured
in vitro for 46 h: brownish (B), transparent (T) and large (L)
fragments containing both B and T parts in a fragment. The production efficiencies of
these types of fragments were 71.7, 91.0 and 17.8 fragments/100 oocytes,
respectively. In experiments, L fragments were excluded because they contained both
brownish and transparent components that were apparently intermediate between B and T
fragments. Observations by confocal microscopy after staining with MitoTracker Red
CMXRos® and transmission electron microscopy revealed highly condensed
active mitochondria in B fragments in contrast to T fragments that contained only
sparse organelles. We reconstructed oocytes by fusion of a karyoplast and two
cytoplasts from B and T fragments (B and T oocytes, respectively). The B oocytes
showed higher sperm penetration (95.8%) and male pronuclear formation rates (94.2%)
by in vitro fertilization than T oocytes (66.7% and 50.0%,
respectively). These results suggest that the active mitochondria in oocytes may be
related to their ability for fertilization. 相似文献