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31.
Sébastien Boquel Marie‐Andrée Giguère Catherine Clark Upeksha Nanayakkara Jianhua Zhang Yvan Pelletier 《Entomologia Experimentalis et Applicata》2013,148(1):48-55
Seed potato crops are currently sprayed weekly with mineral oil to prevent transmission of the Potato virus Y (PVY; Potyviridae: Potyvirus), one of the most prevalent and important non‐persistent viruses affecting potato production. In spite of its wide usage as inhibitor of virus transmission, the mode of action for mineral oil is poorly known. The objective of this study was to quantify the effect of dosage and time from application of mineral oil on the inhibition of PVY acquisition. The bird cherry‐oat aphid, Rhopalosiphum padi (L.) (Hemiptera: Aphididae), known as vector of PVY, was used in all the experiments. The results indicated that mineral oil efficiently decreased PVY acquisition by 75 and 70% 1 day after application of 5 and 10 l ha?1, respectively. The inhibition effect decreased with time from application; mineral oil inhibits acquisition for less than 4 days at 5 l ha?1 and between 8 and 12 days at 10 l ha?1. As mineral oil was detected in the body of fewer aphids when they fed on plants 1 day after oil application, a change in the aphid probing behaviour on mineral oil‐treated plants was deduced. These results support the hypothesis that mineral oil physically inhibits the binding of the virus at the tip of the stylets. 相似文献
32.
GERALDINE D. RYAN LISA EMILJANOWICZ SIMONE A. HÄRRI JONATHAN A. NEWMAN 《Ecological Entomology》2014,39(3):309-315
1. Elevated CO2 can alter plant physiology and morphology, and these changes are expected to impact diet quality for insect herbivores. While the plastic responses of insect herbivores have been well studied, less is known about the propensity of insects to adapt to such changes. Genetic variation in insect responses to elevated CO2 and genetic interactions between insects and their host plants may exist and provide the necessary raw material for adaptation. 2. We used clonal lines of Rhopalosiphum padi (L.) aphids to examine genotype‐specific responses to elevated CO2. We used the host plant Schedonorus arundinaceus (tall fescue; Schreb), which is capable of asexual reproduction, to investigate host plant genotype‐specific effects and possible host plant‐by‐insect genotype interactions. The abundance and density of three R. padi genotypes on three tall fescue genotypes under three concentrations of CO2 (ambient, 700, and 1000 ppm) in a controlled greenhouse environment were examined. 3. Aphid abundance decreased in the 700 ppm CO2 concentration, but increased in the 1000 ppm concentration relative to ambient. The effect of CO2 on aphid density was dependent on host plant genotype; the density of aphids in high CO2 decreased for two plant genotypes but was unchanged in one. No interaction between aphid genotype and elevated CO2 was found, nor did we find significant genotype‐by‐genotype interactions. 4. This study suggests that the density of R. padi aphids feeding on tall fescue may decrease under elevated CO2 for some plant genotypes. The likely impact of genotype‐specific responses on future changes in the genetic structure of plant and insect populations is discussed. 相似文献
33.
W. L. Yee 《Journal of Applied Entomology》2012,136(7):549-560
The brown sugar flotation and hot water methods are accepted procedures for detecting larval western cherry fruit fly, Rhagoletis indifferens Curran, in sweet cherry [Prunus avium (L.) L.] and could be included in a systems approach, a combination of all steps involved in cherry production, for showing the absence of larvae in fruit. The methods require crushing cherries and then submerging them in brown sugar solution or hot water to extract the larvae. Larvae are visually detected when they float to the surface of the brown sugar solution or sink in the hot water. The objective of this study was to test the efficacy of these two methods. Both methods detected at least one larva in all 288 moderately to heavily infested cherry samples. The brown sugar flotation and hot water methods detected 89.6–94.7% and 83.0–85.9% of total larvae, respectively, from cherry samples on each of three dates. Significantly higher percentages of 1st instars were detected using the brown sugar than hot water method on two dates, of 3rd instars on one date and of total larvae on two dates. Percent detection of 3rd instars was higher than that of 1st instars using both methods. For both methods, greater percentages of split whole cherries with seeds and non‐split cherries had larvae than split whole cherries with no seeds and halved cherries. Results show that both methods were equally efficacious in detecting the presence of R. indifferens larvae in cherry samples, but brown sugar flotation was more efficacious than the hot water method in detecting a higher percentage of total larvae present and could be integrated into a systems approach for R. indifferens. 相似文献
34.
A micrografting technique for use on shoots derived by shoot-tip culture is described. Autografts of Prunus domestica cv. Hauszwetsche as well as heterografts of several sour cherry cultivars ( Prunus cerasus L. cvs Schattenmorelle, Weiroot 158, Köröser) were established. Successful graft formation in vitro was confirmed by translation of 86 Rb+ from the stock root into growing scion tissues. A mechanically strong graft union was formed during the course of a 3-week subculture of micrografts in a liquid medium without the addition of growth regulators. In the case of graft rejection, 86 Rb+ was mainly attracted to new developing shoots from lateral meristems of the stock plant. Histological examination of the graft union revealed callus formation, cytodifferentiation and xylogenesis leading to the formation of vascular connections. Stem elongation after micrografting was related to vigour of the stock and scion genotypes. Early stem elongation could be used as a criterion for preselection of growth vigour in graft combinations. Micrografts were transferred to soil and grown in the greenhouse. 相似文献
35.
Grafting symptomless scions, derived from petunia asteroid mosaic virus (PeAMV)-infected trees, to healthy rootstocks resulted in only 3.3% infection in the resulting trees. Up to 90% of seeds from infected sweet cherries contained high quantities of PeAMV, but the virus was not transmitted to the seedlings apparently because of low virus content in the embryo and loss of infectivity during seed maturation and storage. Replanting healthy cherry trees cv. Sam, grafted to different rootstocks, into contaminated soils resulted in new infections. Eight of 13 trees on rootstocks derived from Prunus avium (F 12/1 and cv. Sam on its own roots) were infected with PeAMV within a period of four years but only one of 16 trees on Weiroot-rootstocks (selections from Prunus cerasus) became infected. The detection of PeAMV in naturally contaminated soil samples by the bait plant procedure, using Nicotiana clevelandii, was superior to testing soil eluates by enzyme-linked immunosorbent assay (ELISA) and immuno electron microscopy (IEM). Wild plants may contribute to virus propagation and maintenance of virus contamination of the soil as 25 of 310 samples from 712 herbaceous plants growing in the vicinity of infected trees contained PeAMV; the contaminated samples represented 12 species. The perpetuation of PeAMV by infected scion wood is probably of minor significance, and infection via the soil probably represents the most important means of spread of viral twig necrosis in northern Bavaria. 相似文献
36.
Vitrification of shoots of Prunus avium L. L. was induced and expressed in a four week in vitro multiplication cycle simply by replacing agar by gelrite. The first vitrification symptoms were visible from the 7th day on. Enzymatic antioxidants were compared weekly in crude extract of normal (on agar) and vitrifying (on gelrite) shoots. The activity of superoxide dismutase was higher in vitrifying shoots. The other enzymes (gaîacol-peroxidase, catalase, ascorbate peroxidase, mono- and dehydro-ascorbate reductases, glutathione reductase) had lower activities. Increased superoxide dismutase activity might mean hydrogen peroxide accumulation and decreased activities of the other enzymes, deficiency in its detoxification. The question therefore is raised whether the hyperhydric morphological abnormalities result from the accumulation of toxic oxygen forms. Vitrification is often considered as a morphological response to several stresses. Contrary to most plants which adapt themselves to stresses by increasing all the above defence enzymes, in vitro shoots under vitrifying conditions appear unable to react in a similar manner.Abbreviations Apx
ascorbate peroxidase
- Gpx
gaîacol peroxidase
- CAT
catalase
- H2O2
hydrogen peroxide
- SOD
superoxide dismutase
- MDHAR
monodehydroascorbate reductase
- DHAR
dehydroascorbate reductase
- GR
glutathione reductase
- MS
Murashige and Skoog (1962)
- IBA
indolebutyric acid
- BAP
benzyladenine
- GA3
gibberellic acid 相似文献
37.
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39.
好气与淹水条件下水稻土各粒级团聚体有机碳矿化量 总被引:9,自引:0,他引:9
采用室内恒温培养法观测了好气和淹水处理下水稻土不同粒级团聚体中有机碳矿化的动态变化.结果表明:两种处理下,各粒级团聚体中有机碳矿化量都表现为培养前期快速下降,培养后期保持相对稳定的趋势.不同粒级团聚体之间有机碳矿化速率存在明显差异,在整个培养过程中,均以1~2 mm粒级团聚体最高,以<0.053 mm粒级团聚体最低.统计分析表明,不同粒级团聚体中有机碳矿化量变化与有机碳和微生物生物量碳含量呈显著线性相关.好气和淹水处理下对土壤总有机碳累计矿化量贡献最大的是0.25~1 mm粒级团聚体,分别达41.77%和34.11%;好气处理下贡献最小的是0.053 mm粒级团聚体,淹水处理下贡献最小的是1~2 mm粒级团聚体,分别仅为7.8%和6.6%. 相似文献
40.
甜樱桃(Prunus avium L.)品种S基因型鉴定 总被引:10,自引:0,他引:10
根据蔷薇科S-RNase基因(S基因)高度保守区C2和RC4区设计一对特异引物PruC2和PruC4R,对甜樱桃品种的基因组DNA进行S基因特异PCR扩增。克隆S基因的扩增片段,核酸序列在GenBank上搜索,确定了4种S基因的核酸序列和大小。结果表明,在琼脂糖凝胶上位置相同的扩增带其核酸序列相同,是同一种S基因。4种S基因扩增片段的大小分别是:S1为677bp,S3为762bp,S4为945bp,S6为456bp。参试的自交不亲和品种的S基因型分别是:红灯、红艳、早红宝石和先锋相同,为S1S3;抉择、红丰和那翁相同,为S3S4;大紫为S1S6;长把红为S1S4;养老为S2S6;自交亲和品种外引7号和斯太拉为S3S4。 相似文献