共查询到20条相似文献,搜索用时 15 毫秒
1.
A. R. Harris 《Journal of nematology》1983,15(3):405-409
Thirty-eight grapevine (Vitis spp.) rootstocks were screened in pots for resistance to the dagger nematode, Xiphinema index, from 1979 to 1981. Resistance ratings were based on visible root symptoms and on changes in the nematode populations over 16 months. Nineteen of the 23 Californian hybrid rootstocks tested were resistant, as were ''Harmony'','' ''Freedom,'' ''Schwarzmann,'' and ''3309.'' Two hybrids of V. rufotomentosa, ''171-52'' and ''176-9,'' were possibly immune to X. index. The rootstocks ''ARG 1,'' '' 110 R,'' ''1202,'' and ''1616,'' which are used commercially for phylloxera resistance were susceptible. 相似文献
2.
The signifiers, 'race', 'culture' or 'ethnicity' are utilized in the teenage pregnancy literature (1) to highlight 'differences' in adolescent sexual and reproductive behaviour and (2) as explanatory tools. When 'white' teenagers are the focus of research, psychological explanations are usually invoked, whereas for 'black' teenagers, explanations are socio-cultural in nature. In this article, we explore how, through a process of racialization, the psychomedical literature on teenage pregnancy in South Africa contributes to the entrenchment of 'race', 'culture' and 'ethnicity' as fixed, 'natural' signifiers. We utilize Derrida's notion of différance , together with Phoenix and Woollett's adaptation - 'normalized absence/pathologized presence' - to indicate how 'black' people are cast as the Other, the pathologized presence which relies on the normalized absent trace, 'whiteness', for definition. We analyse how the notions of 'tradition' and 'culture' are deployed to sanitize or disguise the underlying racializing project. 'Black' is exoticized and rendered strange and thus open to scrutiny, monitoring and intervention. 'Culture' and 'tradition' appeal to the myth of origin, thus providing pseudohistorical explanations which essentialize and naturalize racialized collectivities. 相似文献
3.
Pathogenicity tests of Pratylenchus brachyurus on selected greenhouse-grown soybean cultivars indicated the nematode reduced seed yield of ''Hood'' but not that of ''Custer'', ''Bragg'', ''Dyer'', or ''Pickett''. Root weights of all cultivars were reduced. Damage and numbers of nematodes within soybean roots growing at 13, 21, and 29 C were greater at higher temperatures. At 29 C, root pruning was prominent in ''Hood'' and ''Pickett'' but limited in ''Custer'' and ''Hill''. Root pruning was not observed at 13 C and only ''Pickett'' showed pruning at 21 C. Plant height and foliage weight were not affected. P. brachyurus had no effect on the emergence of ''Pickett'' or ''Bragg'' soybeans. Nematode counts from roots of ''Pickett'' at intervals after inoculation indicated that hatching of second generation second-stage larvae occurred about 15 days after egg laying. An average of 68% of the initial inoculum penetrated the roots within five days of inoculation, the highest observed was 81% in five days. Details of structural damage in penetrated tissues were studied in sectioned roots. In soybean roots infected by P. brachyurus and/or Rhizoctonia solani greater damage occurred with nematode and fungus combined than with either acting alone. 相似文献
4.
G. D. Griffin 《Journal of nematology》1980,12(4):287-293
Simultaneous inoculations of alfalfa with Meloidogyne hapla larvae and Ditylenchus dipsaci at 16, 20, 24, and 28 C did not depress penetration of either nematode in ''Nev Syn XX'' -a selection resistant to M. hapla and D. dipsaci, ''Vernal 298'' -a selection resistant to M. hapla and susceptible to D. dipsaci, ''Lahontan'' -a cultivar resistant to D. dipsaci and susceptible to M. hapla, and ''Ranger'' -a cultivar susceptible to both M. hapla and D, dipsaci. Infection with D. dipsaci depressed growth of susceptible ''Vernal 298'' and ''Ranger'' at all soil temperatures, except for ''Vernal 298'' at 16 C. Infection with M. hapla alone did not depress growth of any of the alfalfas. A combination of M. hapla and D. dipsaci resulted in a synergistic weight depression on ''Ranger'' at all soil temperatures. Inoculation of the four alfalfas with D. dipsaci 2, 4, 6, and 8 wk before inoculation with M. hapla at 16, 20, 24, and 28 C did not influence the resistance or susceptibility of ''Nev Syn XX,'' ''Lahontan,'' or ''Ranger.'' However, galling of ''Vernal 298'' by M. hapla was affected by soil temperature, plant age, and inoculation with D. dipsaci. 相似文献
5.
''Floratam'' and ''FX-313'' St. Augusfinegrasses (Stenotaphrum secundatum) were compared in a time-course experiment for host suitability and susceptibility to the lance nematode, Hoplolaimus galeatus. Nematode densities were determined in the soil and acid-fuchsin stained roots 42, 84, 126, 168, and 210 days after pots containing 230 cm³ of autoclaved native Margate fine sand/pot were infested with 104 ± 9 nematodes and maintained at 25 ± 2 C in the laboratory. ''FX-313'' was a more suitable host for H. galeatus. Numbers of H. galeatus reached a maximum at 210 days after inoculation, with 5,550 and 4,120 nematodes (adults plus juveniles)/pot for ''FX-313'' and ''Floratam,'' respectively. Root and shoot dry weights of both grasses were not affected by H. galeatus throughout the experiment. Three polyploid, 2n = 30 to 32 (''Floratam,'' ''FX-10,'' and ''Bitterblue'') and three diploid, 2n = 18 (''FX-313,'' ''Florida Common,'' and ''Seville'') S. secundatum genotypes were inoculated with H. galeatus (99 ± 9/pot) and compared with uninoculated controls 210 days after inoculation. St. Augustinegrass genotypes differed as hosts of H. galeatus. ''FX-313'' and ''Florida Common'' represented the high and low extremes, respectively, for nematode reproduction (9,750 and 5,490 nematodes/pot or 4,239 and 2,387 nematodes/100 cm³ of soil). However, differences in root and shoot growth were not detected 210 days after inoculation with H. galeatus. 相似文献
6.
城市公园是城市居民与自然生态系统互动的主要场所,为居民提供重要的生态系统服务。从景感生态角度和方法对城市公园文化服务进行评价,需要掌握大量居民个体对城市公园的感知、感受信息。随着现代信息技术和人们生活方式的发展,社交媒体成为大众获取信息、发布观点的主要方式之一。社交媒体数据具有数据易于获取、时间跨度长、数据量大等优势,同时,通过对社交媒体信息进一步进行文本提取与分析,还可以获取用户对特定活动场所更为具体的感知和感受,因此,社交媒体数据为城市公园景感评价提供了有价值的新的数据来源和手段。构建了基于社交媒体数据的城市公园景感评价框架和流程、评价指标以及信息提取方法,包括对获取数据进行预处理;构建感官感知及公园要素词库;通过情感分类,形成积极和消极情感文本,表征用户对文本关联景感要素的满意度;将各类情感文本分别进行要素及其对应感知感官的统计,以频率衡量景感要素对用户感知的重要性;在此基础上,基于重要性-绩效分析(IPA)方法构建了感知评价模型。最后,以北京玉渊潭公园为例,进行了实证研究。结果表明:视觉在居民对城市公园的感知体验中占据主导地位,触觉感知次之,听觉感知普遍不被重视,而嗅觉感知评价... 相似文献
7.
Four biotypes (pathotypes) of the citrus nematode, Tylenchulus semipenetrans, occurring in California, U.S.A. were differentiated on the basis of differences of infectivity on ''Homosassa'' sweet orange, ''Troyer'' citrange, ''Pomeroy'' and ''Rubidoux'' Poncirus trifoliata, ''Thompson Seedless'' grape, and ''Manzanillo'' olive. A method for differentiating biotypes of T. semipenetrans is described. Field observations indicate that biotypes of this nematode are very stable. The importance of using highly infective biotypes in the development and selection of satisfactory citrus-nematode-resistant rootstocks is emphasized. 相似文献
8.
9.
Eleven soybean [Glycine max (L.) Merr.] cultivars resistant to one or more plant-parasitic nematodes, and one resistant to the Mexican bean beetle (Epilachna varivestis Muls.), were tested for susceptibility to Hoplolaimus columbus. All cultivars were parasitized, but nematode reproduction varied. ''Pickett-71'' was the most susceptible host among the cultivars tested. ''Dyer'' and three ''P.I. cultivars'' were most tolerant when yield /plant and total yield were compared for fumigated and unfumigated plots, even though their yield potential was low. ''Hardee,'' ''Coker 4504,'' ''W-4,'' ''D71-9257,'' and ''ED-371'' appeared tolerant throughout the growing season and yielded well in unfumigated soil. Infection and reproduction of H. columbus in ''Forrest'' soybean roots were greater at 30 ± 1 C than at 20 or 25 ± 1 C. Plant height and root weight varied with the soil treatments. 相似文献
10.
The infectivity and development of two biotypes of citrus nematode (Tylenchulus semipenetrans) were compared on highly resistant Poncirus trifoliata selection ''Pomeroy,'' moderately susceptible ''Troyer'' citrange, and highly susceptible sweet orange selection ''Homosassa'' small seedlings in a glasshouse. Biotype-1 was more infective on the above hosts and developed faster on sweet orange and on ''Troyer'' citrange than Biotype-2. The differences in infectivity were interpreted to reflect differences in the ability of the nematodes to penetrate the epidermis and hypodermis and become established in host roots. Poncirus selections ''Pomeroy,'' ''Webber-Fawcett,'' and ''Rubidoux'' seedlings were highly resistant to the citrus nematode in California, but seedlings of ''Pomeroy'' and ''Rubidoux'' were only moderately resistant in Japan. These differences in degree of infection may indicate different biotypes of the nematode. Host range tests with California Biotype-1 indicate that it differs from those occurring in Israel. 相似文献
11.
Penetration, rate of development, and total population of Meloidogyne incognita in roots of susceptible ''Allgold'' and resistant ''Nemagold'' sweet potatoes increased with temperature 24-32 C. Rate of larval penetration in ''Allgold'' was significantly higher than in ''Nemagold'' after 48 hr of root exposure at 24, 28, and 32 C. At 24, 28, and 32 C (16 hr) day and 20 C (8 hr) night temperature the life cycle of M. incognita required 42, 32, and 28 days in ''Allgold'', and 44, 33, and 31 days in ''Nemagold''; mature females in the first generation were 40, 40, 40, and 10, 22, 20 respectively. The correlation between the length of time roots were allowed to grow in the soil prior to inoculation and number of larvae recovered from the roots after inoculation was positive for ''Allgold'' and negative for ''Nemagold''. Therefore, a root exudate repellent to M. incognita larvae is proposed as a hypothetical basis for resistance to M. incognita in sweet potatoes. 相似文献
12.
为挖掘并精准利用福建地方特色花生(Arachis hypogaea)资源,以‘赖坊’、‘衙口小琉球’、‘朱口小籽’、‘文亨红衣’、‘洋后’等5种地理标志花生为研究对象,描述生物学性状,比较分析其营养(脂肪酸、矿质元素、维生素E、甾醇和白藜芦醇等)差异。结果表明,供试花生外形特征和种皮颜色有明显的差异,主茎高或侧枝长与单株生产力均呈负相关;部分品种间的蛋白质、脂肪、可溶性糖、膳食纤维、脂肪酸、矿质元素和天然功能性成分含量差异显著(P<0.05),其中‘衙口小琉球’的蛋白质含量最高,‘朱口小籽’的脂肪、油亚比、维生素E、白藜芦醇含量最高,‘文亨红衣’的铁、植物甾醇含量最高。供试的5个花生品种均达到食用花生1级、油用花生3级标准,且地方特征明显,更适合直接食用。 相似文献
13.
Fares Alshammari Hamoud Fahad Alshammari Bandar Alsaedi Rafat Zreiq Fahad D Algahtan 《Bioinformation》2021,17(1):274
Patient protection has become one of the key elements of the quality of health care systems in Saudi Arabia. Medical errors that threaten patient safety are mediated by several factors including system risk factors. Hence, we used a self-structured questionnaire to assess and rank the system factors according to the perceptions of nurses working in the hospitals of the ministry of health in Hail, KSA. Eight out of twelve factors tested were perceived as threatening factors of the patient safety that are; ''Shortage of medical staff'', ''Poor design of the hospital structure'', ''Long working hours'', ''Overcrowding of patients'',''Poor coordination between hospital departments, ''Punitive and blaming environment, ''Lack of clinical practice standards'' and, ''Poor financial incentives''. Thus, considering the negative impact of the identified threatening system factors in this study on patient safety, urgent planning and managing appropriate corrective actions should be designed to improve patient safety issues. 相似文献
14.
15.
''Ascolano'' and ''Sevillano'' olive trees, Olea europaea L., were highly susceptible to Meloidogyne javanica (Trueb) Chitwood, and growth of their tops was decreased greatly in tests in a glasshouse. Roots of ''Manzanillo'' olive trees were galled moderately by M. javanica, and their tops weighed 6% less than those of noninoculated trees. ''Manzanillo'' olive is considered highly tolerant to M. javanica. ''Ascolano'' and ''Manzanillo'' olive trees were highly susceptible to M. incognita (Kofoid &White) Chitwood. Their roots were galled moderately to severely, and growth of their tops were decreased between 13% and 44%. ''Ascolano'' and ''Manzanillo'' olive trees were considered to be highly resistant to M. arenaria (Neal) Chitwood and M. hapla Chitwood since no galls or mature females were found on their roots three and one-half months after inoculation. 相似文献
16.
A. W. Johnson 《Journal of nematology》1970,2(1):36-41
The ring nematode (Criconemoides ornatus), stunt nematode (Tylenchorhynchus martini), and sting nematode (Belonolaimus Iongicaudatus) reproduced readily on six bermudagrasses (Common, ''U-3'', ''Tufcote'', ''Continental'', ''Tiffine'', and ''Tifdwarf''). Populations of a single nematode species influenced the population development of a second and third parasitic nematode species on a particular host plant. Activity of most nematodes adversely affected reproduction of other nematode species in mixed cultures. Generally, the number of fibrous roots produced by plants decreased as the number of nematode species in the treatments increased. Tifdwarf bermudagrass appeared to be more tolerant to C. ornatus and T. martini than other grasses tested. 相似文献
17.
Studies were conducted to examine under differing temperatures (12, 16, 20, 24, 28, and 32 C) the penetration anti development of Meloidogyne hapla in resistant lines ''298'' and ''Nev. Syn XX'', and susceptible ''Lahontan'' and ''Ranger'' hardy-type alfalfas. The results indicated that resistance to M. hapla was similar to that previously described for M. incognita in nonhardy alfalfa. Although initial penetration in resistant seedlings was similar to that of susceptible seedlings, nematode larvae failed to establish and develop in root tissues and nematode numbers subsequently declined. In susceptible seedlings, nematode development proceeded rapidly, and egg production began after 5 weeks. Temperature had little influence on the nematode development except to slow the response at the lower temperatures. Other studies were conducted to verify a previously reported immune (no penetration) reaction to M. hapla by the ''Vernal'' selection ''M-4''. When compared to the resistant (penetration without nematode development) Vernal selection ''M-9'' under differing temperatures (20, 24, 28, and 32 C), each selection was equally penetrated by M. hapla but at a lower level than in susceptible Ranger cuttings. Generally, no root galling was observed in either M-4 or M-9; however, very slight galling was found 35 days after inoculation on about 50% of these cuttings when grown at 32 C. 相似文献
18.
Phaseolin seed protein variability in a group of 8 wild and 77 cultivated common bean (Phaseolus vulgaris) accessions was determined using 1-dimensional SDS/ PAGE and 2-dimensional IEF-SDS/PAGE. Wild common bean accessions exhibited the 'CH' and 'B' patterns, previously undescribed among either wild or cultivated common beans. The cultivated genotypes showed (in decreasing frequency) the previously described 'S,' T,' and 'C phaseolin patterns as well as the new 'B' pattern similar to the pattern identified in a Colombian wild common bean accession. In the northeastern part of the Colombian bean-growing region, the cultivars exhibited almost exclusively an 'S' phaseolin type, while in the south-western part, the 'T' and 'C phaseolin cultivars were more frequent. Seed size analysis indicated that 'T' and 'C' phaseolin cultivars had larger seeds than 'S' and 'B' phaseolin cultivars. Our results suggest that Colombia is a meeting place for Andean and Middle American common bean germplasms, as well as a domestication center for the common bean. 相似文献
19.
Rates of reproduction of root-knot nematodes on corn varied with Meloidogyne species, with different populations of certain species, and with corn cultivars. M. arenaria, M. incognita and M. javanica reproduced at varying rates on all corn cultivars tested. None of the three selections of M. hapla reproduced on corn. Most of the Meloidogyne populations increased more rapidly on ''Coker'' and ''Pioneer'' hybrids than on ''McNair'' hybrids or on open-pollinated varieties or inbreds. Nematodes often reduced root growth, but the differences within given nematode-cultivar treatments were not usually significant. Root growth of ''Coker 911,'' which supported a high rate of reproduction, was affected less than ''Pioneer 309B'' which supported a low rate of nematode reproduction. 相似文献