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1.
Changes in percentage organic carbon content were assessed during the first five weeks of growth of Uniculm barley (Hordeum vulgare) and Brussels sprouts (Brassica oleracea) plants grown in controlled-environment conditions at two constant temperatures, 16° and 22°C. Foliage (leaf laminae), stem, and root material was assayed in both species, together with leaf sheaths of barley and cotyledon laminae of Brussels sprouts. In barley, there was a decline in percentage organic carbon content with increasing foliage age in plants grown at 22°C, but in sheath material there was no significant change at either temperature. Root material showed a decline in percentage carbon content at both growth temperatures, whereas stems showed the opposite trend. Similar results were found in Brussels sprouts, with an overall decline in percentage carbon content in foliage at 22°C and a rise in stem material at both growth temperatures. However, roots showed no significant change in percentage carbon content over the experimental period. The results demonstrate that percentage organic carbon content may change during plant growth. 相似文献
2.
Cruciferous vegetables have cancer preventive effects which may be due to reduction of oxidative DNA damage. We investigated the effect of an aqueous extract of cooked Brussels sprouts on formation of 7-hydro-8-oxo-2′-deoxyguanosine (8-oxodG) in calf thymus DNA in vitro. Damage was induced by a Fenton reaction, UVC (254 nm), UVA (365 nm), sunlamp light, and methylene blue with visible light.The extract inhibited 8-oxodG formation in all systems except visible light with methylene blue. The IC50 values were 6–20 μg/ml corresponding to the extract of 5–20 g of Brussels sprouts distributed in a volume of 50 L. The protective effect in the Fenton reaction was unaffected by addition of EDTA. After HPLC separation fractions were identified with similar DNA protective effects. Sinigrin, a glucosinolate abundant in Brussels sprouts, co-eluted with the most effective fraction and had DNA protective effects. In comparison with other antioxidants the patterns of effect of the extract in the five damage systems were more similar to that of sodium azide than to those of dimethylsulfoxide and vitamin C.Constituents of Brussels sprouts can protect DNA by direct scavenging, e.g. hydroxyl radical and other oxidants, without prooxidant effects at concentrations potentially achievable by modest intake of the vegetable. 相似文献
3.
Combined effects of patch size and plant nutritional quality on local densities of insect herbivores
Tibor Bukovinszky Rieta Gols Andre Kamp Filipe de Oliveira-Domingues Peter A. Hambäck Yde Jongema T. Martijn Bezemer Marcel Dicke Nicole M. van Dam Jeffrey A. Harvey 《Basic and Applied Ecology》2010,11(5):396-405
Plant–insect interactions occur in spatially heterogeneous habitats. Understanding how such interactions shape density distributions of herbivores requires knowledge on how variation in plant traits (e.g. nutritional quality) affects herbivore abundance through, for example, affecting movement rates and aggregation behaviour. We studied the effects of plant patch size and herbivore-induced differences in plant nutritional quality on local densities of insect herbivores for two Brassica oleracea cultivars, i.e. white cabbage and Brussels sprouts. Early season herbivory as a treatment resulted in measurable differences in glucosinolate concentrations in both cultivars throughout the season. Herbivore induction and patch size both influenced community composition of herbivores in both cultivars, but the effects differed between species. Flea beetles (Phyllotreta spp.) were more abundant in large than in small patches, and this patch response was more pronounced on white cabbage than on Brussels sprouts. Herbivore-induction increased densities in all patches. Thrips tabaci was also more abundant in large patches and densities of this species were higher on Brussels sprouts than on white cabbage. Thrips densities were lower on induced than on control plants of both cultivars and this negative effect of induction tended to be more pronounced in large than in small patches. Densities of the cabbage moth (Mamestra brassicae) were lower on Brussels sprouts than on white cabbage and lower on herbivore-induced than on uninduced plants, with no effect of patch size. No clear effects of patch size and induction were found for aphids. This study shows that constitutive and herbivore-induced differences in plant traits interact with patch responses of insect herbivores. 相似文献
4.
JUDITH G. SMITH 《The Annals of applied biology》1976,83(1):15-29
The most abundant natural enemies of aphids on Brussels sprout crops were Syrphidae, different species being attracted differentially to weedy or weed-free plots according to whether they were more host-plant-orientated (e.g. Melanostoma spp., Platycheirus spp.) and thus affected directly by the background, or more aphid-orientated (e.g. Syrphus balteatus) and so less affected by background than by aphid numbers. Oviposition by Melanostoma spp. was usually much greater in weedy sprout crops than on sprouts in bare soil, and their eggs were also very abundant on weeds. Eggs of other syrphid species were scarcer on weeds. In contrast to Melanostoma, Platycheirus spp. usually oviposted preferentially on sprouts growing in bare soil. Oviposition by S. balteatus was in response to aphid abundance and thus tended to become greater on sprouts in bare soil. Notably more adults of non-aphido-phagous Syrphidae were caught over weedy than over non-weedy Brussels sprout plants. Anthocoris nemorum nymphs and adults were very common on sprout plants and weeds in the weedy crop but were scarce on sprouts in bare soil; A. nemorum oviposited on white and yellow charlock (Raphanus raphanistrum and Sinapis arvensis) occasionally. Parasitism of Brevicoryne brassicae by Diaeretiella rapae appeared to be related to aphid numbers and was only indirectly influenced by the crop background. Field experiments with green and brown cloth backgrounds showed that some syrphids were attracted to green; A. nemorum was relatively scarce over both artificial backgrounds. It is concluded that decreased natural enemy action is partly responsible for the initially greater abundance of B. brassicae in a weed-free crop of Brussels sprouts than in a weedy crop. 相似文献
5.
FOTEINI G. PASHALIDOU MARTINUS E. HUIGENS MARCEL DICKE NINA E. FATOUROS 《Ecological Entomology》2010,35(6):748-753
1. Female parasitoids have evolved various foraging strategies in order to find suitable hosts. Egg parasitoids have been shown to exploit plant cues induced by the deposition of host eggs. 2. The tiny wasp Trichogramma brassicae uses oviposition‐induced cues from Brussels sprouts to locate eggs of the cabbage white butterflies Pieris brassicae and Pieris rapae that differ in their egg‐laying behaviour. These plant cues are elicited by male‐derived anti‐aphrodisiac pheromones in the accessory reproductive gland (ARG) secretions of mated female butterflies. However, the closely related generalist species Trichogramma evanescens does not respond to Brussels sprout cues induced by the deposition of P. brassicae egg clutches. 3. Here we showed in two‐choice bioassays that T. evanescens wasps respond to Brussels sprout cues induced by (i) the deposition of single eggs by P. rapae, and (ii) the application of ARG secretions from either mated P. rapae females, or from virgin female butterflies in combination with P. rapae's anti‐aphrodisiac compound indole. The wasps only associatively learned to respond to Brussels sprout cues after applying indole alone by linking those cues with the presence of P. rapae eggs. 4. Our results indicate that Trichogramma wasps more commonly exploit oviposition‐induced plant cues to locate their host eggs. Generalist wasps show less specificity in their response than specialists and employ associative learning. 相似文献
6.
Consequences of constitutive and induced variation in plant nutritional quality for immune defence of a herbivore against parasitism 总被引:1,自引:0,他引:1
Tibor Bukovinszky Erik H. Poelman Rieta Gols Georgios Prekatsakis Louise E. M. Vet Jeffrey A. Harvey Marcel Dicke 《Oecologia》2009,160(2):299-308
The mechanisms through which trophic interactions between species are indirectly mediated by distant members in a food web
have received increasing attention in the field of ecology of multitrophic interactions. Scarcely studied aspects include
the effects of varying plant chemistry on herbivore immune defences against parasitoids. We investigated the effects of constitutive
and herbivore-induced variation in the nutritional quality of wild and cultivated populations of cabbage (Brassica oleracea) on the ability of small cabbage white Pieris rapae (Lepidoptera, Pieridae) larvae to encapsulate eggs of the parasitoid Cotesia glomerata (Hymenoptera, Braconidae). Average encapsulation rates in caterpillars parasitised as first instars were low and did not
differ among plant populations, with caterpillar weight positively correlating with the rates of encapsulation. When caterpillars
were parasitised as second instar larvae, encapsulation of eggs increased. Caterpillars were larger on the cultivated Brussels
sprouts plants and exhibited higher levels of encapsulation compared with caterpillars on plants of either of the wild cabbage
populations. Observed differences in encapsulation rates between plant populations could not be explained exclusively by differences
in host growth on the different Brassica populations. Previous herbivore damage resulted in a reduction in the larval weight of subsequent herbivores with a concomitant
reduction in encapsulation responses on both Brussels sprouts and wild cabbage plants. To our knowledge this is the first
study demonstrating that constitutive and herbivore-induced changes in plant chemistry act in concert, affecting the immune
response of herbivores to parasitism. We argue that plant-mediated immune responses of herbivores may be important in the
evaluation of fitness costs and benefits of herbivore diet on the third trophic level. 相似文献
7.
Mahboubeh Kafil Saeed Boroomand Nasab Hadi Moazed Amit Bhatnagar 《International journal of phytoremediation》2019,21(2):92-100
A field experiment was conducted to understand the potential of vetiver grass (Vetiveria zizanioides) in heavy metal uptake from the soil and wastewater. Four main irrigation treatments including T1 (treated industrial wastewater), T2 (1:1 ratio of municipal:industrial wastewater), T3 (treated municipal wastewater) and T4 (fresh water) were applied. Moreover, the effect of arbuscular mycorrhizal fungus (AMF), Glomus mosseae, on plant growth and heavy metal concentration was evaluated. Three main criteria including bioconcentration factor (BCF), translocation factor (TF) and heavy metal uptake were applied to assess the potential of vetiver grass in accumulation and translocation of heavy metals to aerial parts. The highest concentration of heavy metals was found in plant and soil irrigated with T1 treatment followed by T2, T3 and the lowest concentrations were found in T4 treatment. Irrigation with treated municipal wastewater led to a significant increase in plant biomass and heavy metal uptake compared to other treatments. In T1 treatment (industrial wastewater), vetiver grass caused a significant decrease in Zn, Fe, Cu, Cd and Pb concentrations in soil as compared to no-plant treatment (without planting vetiver grass). Therefore, vetiver grass, irrigated with treated industrial wastewater, is a promising method for the development of urban and industrial green space. 相似文献
8.
Influence of crop background on aphids and other phytophagous insects on Brussels sprouts 总被引:1,自引:0,他引:1
JUDITH G. SMITH 《The Annals of applied biology》1976,83(1):1-13
More Brevicoryne brassicae and other alate aphids were caught in yellow water-traps in a weed-free crop of Brussels sprouts than in a crop with a weedy background. More B. brassicae colonized Brussels sprout plants in bare soil than in weeds; very few alatae were attracted to cruciferous weeds in the crop. Results in 1 yr suggest that initially larger populations on the weed-free sprouts became smaller than populations on the weedy sprouts because the larger aphid population attracted more natural enemies. Aleyrodes brassicae and certain Lepidoptera were also more abundant on sprout plants in bare soil than on sprouts surrounded by weeds; more adult A. brassicae were caught in water traps over the bare soil. More A. brassicae were present on sprout plants surrounded by a green than by a brown cloth background but the differences were not significant (P < 0–05). Numbers of B. brassicae on sprout plants with green and brown backgrounds varied greatly and did not differ significantly. In field cages, B. brassicae alatae were more attracted to potted sprout plants surrounded by bare soil than to ones surrounded by rings of living or cut grass or by artificial green rings. This effect was greater with small than with large sprout plants surrounded by grass rings. The maintenance of a limited weed cover is considered potentially useful in integrated control of some brassica pests. 相似文献
9.
Maaike Bruinsma Sarah van Broekhoven Erik H. Poelman Maarten A. Posthumus Martin J. Müller Joop J. A. van Loon Marcel Dicke 《Oecologia》2010,162(2):393-404
Herbivore-induced plant defences influence the behaviour of insects associated with the plant. For biting–chewing herbivores
the octadecanoid signal-transduction pathway has been suggested to play a key role in induced plant defence. To test this
hypothesis in our plant—herbivore—parasitoid tritrophic system, we used phenidone, an inhibitor of the enzyme lipoxygenase
(LOX), that catalyses the initial step in the octadecanoid pathway. Phenidone treatment of Brussels sprouts plants reduced
the accumulation of internal signalling compounds in the octadecanoid pathway downstream of the step catalysed by LOX, i.e.
12-oxo-phytodienoic acid (OPDA) and jasmonic acid. The attraction of Cotesia glomerata parasitoids to host-infested plants was significantly reduced by phenidone treatment. The three herbivores investigated,
i.e. the specialists Plutella xylostella, Pieris brassicae and Pieris rapae, showed different oviposition preferences for intact and infested plants, and for two species their preference for either
intact or infested plants was shown to be LOX dependent. Our results show that phenidone inhibits the LOX-dependent defence
response of the plant and that this inhibition can influence the behaviour of members of the associated insect community. 相似文献
10.
《Journal of Plant Interactions》2013,8(1):200-211
The effect of treated municipal wastewater on the roots and the leaves of turnip was studied to compare the 50% and 100% wastewater of 34 ml/d Sewage Treatment Plant (STP) with different doses of potassic fertilizers. Turnip (Brassica rapa) was used as a test plant. A pot experiment was conducted, using a factorial randomized block design to investigate the growth and translocation of heavy metals to the leaves and the roots of turnip. The concentration of heavy metal in wastewater used for irrigation was within the limits. However, the concentration in the plant parts showed a significant rise due to continuous use of wastewater. The concentration of heavy metals in leaves and roots was at excessive levels at 40 and 55 days after sowing (DAS), while at 70 DAS, metal concentration was comparatively low. The range of heavy metals in wastewater irrigated plants was Cd = 1–16.3, Ni = 0–136, Fe = 263–1197, Cu = 0–18, Mn = 37–125, and Zn = 42–141 mg/kg. Concentration of heavy metals in plants was found in the order of Fe>Zn>Ni>Mn>Cu>Cd. 相似文献
11.
Assessing risks and benefits of floral supplements in conservation biological control 总被引:1,自引:0,他引:1
Karin Winkler Felix L. Wäckers Aad J. Termorshuizen Joop C. van Lenteren 《BioControl》2010,55(6):719-727
The use of flowering field margins is often proposed as a method to support biological control in agro-ecosystems. In addition
to beneficial insects, many herbivores depend on floral food as well. The indiscriminate use of flowering species in field
margins can therefore lead to higher pest numbers. Based on results from field observations and laboratory experiments we
assessed risks as well as benefits associated with the provision of nectar plants in field margins, using Brussels sprouts
as a model system. Results show that Brussels sprouts bordered by nectar plants suitable for the cabbage white Pieris rapae L., suffered higher infestation levels by this herbivore. In contrast, nectar plants providing accessible nectar for the
diamondback moth Plutella xylostella L., did not raise densities of P. xylostella larvae in the Brassica crop. Margins with Anethum graveolens L., selected on the basis of its suitability as nectar plant for parasitoids, significantly increased the number of adult Diadegma semiclausum Hellén in the crop. This didn’t translate into enhanced parasitism rates, as parasitism of P. xylostella by D. semiclausum exceeded 65 % in all treatments, irrespective of the plants in the field margin. Our findings emphasize the importance of
taking a multitrophic approach when choosing flowering field margin plants for biocontrol or other ecosystem services. 相似文献
12.
【背景】随着工业化的发展,重金属污染逐渐成为主要的环境污染之一。微生物修复去除重金属污染成为近些年来新兴的修复方法,筛选开发具有良好修复功能的微生物菌株具有重要的现实意义。【目的】筛选具有促进植物生长作用的重金属修复菌株,为生物修复和植物促生等综合开发利用提供微生物资源。【方法】利用选择性培养基从淤泥中筛选重金属铅的抗性菌株,根据形态学观察、生理生化鉴定和16S rRNA基因序列分析对菌株进行分离鉴定,通过单因素分析不同培养条件对菌株生长的影响;采用原子吸收光谱法、比色法及平板对峙法等对菌株的重金属铅吸附率、无机磷溶解能力、吲哚乙酸(indole-3-acetic acid,IAA)分泌及拮抗镰刀菌效果等进行分析。【结果】从污染严重的塘泥中筛选到一株对重金属铅有较好吸附率的菌株,在150 mg/L Pb2+浓度下,对Pb2+的吸附率达90%以上;初步鉴定该菌株为蜡样芽孢杆菌,命名为SEM-15;菌株还具有较好的溶解无机磷、分泌IAA及拮抗镰刀菌的能力;菌株生长适应性强,可以在pH 10.0的强碱性环境下生长,该菌株具有很好的重金属铅污染修复及促生防病的应用潜力。【结论】菌株SEM-15是一株具有植物促生作用的重金属铅吸附菌株,在重金属污染土壤联合植物修复的应用中可能具有较好的开发价值。 相似文献
13.
The physiological response of plants to different irrigation frequencies may affect plant growth and water use efficiency (WUE; defined as shoot biomass/cumulative irrigation). Glasshouse‐grown, containerized Pelargonium × hortorum BullsEye plants were irrigated either daily at 100% of plant evapotranspiration (ET) (well‐watered; WW), or at 50% ET applied either daily [frequent deficit irrigation (FDI)] or cumulatively every 4 days [infrequent deficit irrigation (IDI)], for 24 days. Both FDI and IDI applied the same irrigation volume. Xylem sap was collected from the leaves, and stomatal conductance (gs) and leaf water potential (Ψleaf) measured every 2 days. As soil moisture decreased, gs decreased similarly under both FDI and IDI throughout the experiment. Ψleaf was maintained under IDI and increased under FDI. Leaf xylem abscisic acid (ABA) concentrations ([X‐ABA]leaf) increased as soil moisture decreased under both IDI and FDI, and was strongly correlated with decreased gs, but [X‐ABA]leaf was attenuated under FDI throughout the experiment (at the same level of soil moisture as IDI plants). These physiological changes corresponded with differences in plant production. Both FDI and IDI decreased growth compared with WW plants, and by the end of the experiment, FDI plants also had a greater shoot fresh weight (18%) than IDI plants. Although both IDI and FDI had higher WUE than WW plants during the first 10 days of the experiment (when biomass did not differ between treatments), the deficit irrigation treatments had lower WUE than WW plants in the latter stages when growth was limited. Thus, ABA‐induced stomatal closure may not always translate to increased WUE (at the whole plant level) if vegetative growth shows a similar sensitivity to soil drying, and growers must adapt their irrigation scheduling according to crop requirements. 相似文献
14.
Minirhizotron observations of roots of leeks and Brussels sprouts grown in the Wageningen Rhizolab were used to study the dynamics of root length. Day of appearance and the time of decay were assessed for individual root segments visible on the minirhizotron surface.A Brussels sprouts crop produced much more root length than leeks, but the average longevity of these roots was about half that of leek roots.To investigate whether root colour or UV fluorescence could be used as a quantitative index of root functionality or root age, changes in root colour (on a scale of greys) over time were measured with interactive image analysis. In both crops a gradual change towards black was found with ageing. Measurements of the intensity of the UV fluorescence showed that leek roots fluoresced more than Brussels sprouts roots. Over time, UV fluorescence decreased in Brussels sprouts roots but increased in leek roots. It is concluded that UV fluorescence cannot be used as a universal indicator of root age or root functionality, but in some plant species it may be used to separate (transparent) roots from the background with image analysis techniques. 相似文献
15.
D. J. OCKENDON 《The Annals of applied biology》1985,107(1):101-104
Embryo yields from anther culture were determined for seven F1 hybrid genotypes of Brussels sprouts, one of which was known to be highly responsive. At least 1400 anthers were cultured for each genotype and the genotypes were tested in two groups. Although the results were variable, the genotypes were provisionally grouped as follows: two were highly responsive (with up to 180 and 376 embryos per 100 anthers cultured), one was moderately responsive (with up to 53 embryos) and four were virtually non-responsive. The possible genetic basis for the difference in responsiveness is discussed, together with the implications of the results for the utilisation of anther culture in Brussels sprouts breeding. 相似文献
16.
Roots in the Wageningen Rhizolab are observed using two methods: (i) non-destructively, using horizontal, glass minirhizotrons at intervals of 14 days between observations; (ii) with destructive sampling using augers on three dates in the season. This paper reports changes with depth and time in root numbers per unit interface area of the minirhizotron tube (number of intersections) of four crop species (wheat, Brussels sprouts, leek and potato). The number of root intersections of Brussels sprouts, wheat and potato declined with depth at any time, whereas leek showed a different pattern because maximum root growth was observed at a depth of 10–20 cm. Root density generally decreased in the following order: Brussels sprouts, wheat, potato and leek. Plots of root length densities, Lrv(cm. cm-3), obtained by auger sampling, versus the number of intersections showed considerable variation in slope with species, time in the season and year, implying that a single, universal equation to convert minirhizotron observations into volumetric root densities does not exist. Causes of variation in the slopes are discussed. It is concluded that limited auger sampling combined with minirhizotron observations yield adequate quantitative estimates of relevant root properties. 相似文献
17.
Falling aphids enhance impact of biological control by parasitoids on partially aphid-resistant plant varieties 总被引:1,自引:0,他引:1
Cage experiments, in which the population increase of Metopolophium dirhodum was measured either in the absence or presence of the parasitoid Aphidius rhopalosiphi, showed reductions of peak populations in the presence of the parasitoid of 30% on the susceptible wheat cultivar Armada, but of 57% on the partially resistant Rapier. On both cultivars, aphid population curves in the presence and absence of the parasitoid diverged before the first mummies were formed. The number of aphids leaving plants was measured, and was found to increase in the presence of the parasitoid, particularly with Rapier (almost double). Most aphids (about 75%) which left plants fell, and a smaller proportion regained plants when parasitoids were present than when they were absent. A field experiment with Brevicoryne brassicae and natural predation on Brussels sprouts also showed an increase in aphids leaving a less susceptible compared with a more susceptible cultivar. 相似文献
18.
【目的】探究土壤中四环素残留对土培黄豆芽的生长发育、根际微生物及营养品质的影响,为正确评估抗生素残留对蔬菜种植业的影响及制定土壤-蔬菜系统中抗生素污染防控策略提供理论基础。【方法】模拟土壤中不同四环素残留水平(0、25、50mg/kg),采用高效液相色谱(high performance liquid chromatography,HPLC)方法测定黄豆芽中的四环素残留量、理化方法测定黄豆芽的营养品质、高通量技术测定根际微生物群落。【结果】黄豆芽中四环素累积量随土壤中四环素残留量的增加而增加,累积量分布表现为根>下胚轴>子叶;四环素残留显著抑制黄豆芽的根和下胚轴的发育及其生物量、维生素C含量和抗氧化性,但增加了纤维素含量。在这些指标中维生素C含量的变化最显著,在黄豆芽生长第5天,25mg/kg和50mg/kg四环素残留组中,黄豆芽中维生素C含量较对照组分别降低41.35%和49.80%;此外,四环素残留显著影响黄豆芽根际微生物群落结构,尤其是与氮循环相关的属。其中,明显增加了不动杆菌属(Acinetobacter)和栖热菌属(Thermus)的相对丰度,减少了假黄色单胞菌属(Pseudoxanthomonas)和氢嗜菌属(Hydrogenophaga)的相对丰度。【结论】土壤中的四环素残留显著影响黄豆芽的生长发育、根际微生物群落结构以及维生素C等重要营养品质指标。 相似文献
19.
A maternal influence on the conditioning to plant cues of Aphidius colemani Viereck, parasitizing the aphid Myzus persicae Sulzer 总被引:1,自引:0,他引:1
Abstract. The offspring of parasitoids, Aphidius colemani Viereck, reared on Brussels sprouts and emerging from Myzus persicae Sulzer on a fully defined artificial diet, show no preferences in a four-way olfactometer, either for the odour of the diet, the odour of Brussels sprouts, or the odour of two other crucifers (cabbage and Chinese cabbage). A similar lack of odour preferences is shown when the host aphids are exposed for parasitization (for 48 h) on cabbage, Chinese cabbage or wheat. However, if parasitization occurs on Brussels sprouts, a weak but statistically highly significant response to Brussels sprout odour is observed. Although as many as 30–35% of the parasitoids show no response to any odour, another 35% respond positively to the odour of Brussels sprout compared with responses to the odours of cabbage, Chinese cabbage or wheat of only approximately 10%. An analagous result is obtained when the parent parasitoids are reared on cabbage. In this case, significant positive responses of their offspring to cabbage odour occur only if the 48-h parasitization has occurred also on cabbage. However, with parasitoids from Brussels sprouts parasitizing the aphids for 48 h also on Brussels sprouts, the offspring subsequently emerging from pupae excised from the mummies show no preference for Brussels sprout odour. Thus, although the Brussels sprout cue had been experienced early in the development of the parasitoids, they only become conditioned to it when emerging from the mummy. Both male and female parasitoids respond very similarly in all experiments. It is proposed that the chemical cue (probably glucosinolates in these experiments) is most likely in the silk surrounding the parasitoid pupa, and that the mother may leave the chemical in or around the egg at oviposition, inducing chemical defences in her offspring to the secondary plant compounds that the offspring are likely to encounter. 相似文献
20.
为减少油松定植后的死亡率,在控制成本的基础上促进油松良好生长,该研究采用裂区实验设计方法,选取三个灌溉水平与三个园林废弃物有机肥施用量进行比较试验,通过测定油松树高、胸径、叶绿素及叶片养分含量指标探究灌溉和施用有机肥对油松林木生长的影响。结果表明:灌溉可以显著提高油松在胸径、树高、生理等方面的生长指标,树高和胸径在中水灌溉(A2)下的促进效果甚至高于高水灌溉(A3);试验处理1 a后,施肥对油松的生长影响显著,但三个施肥水平间的差异不显著;灌溉与施用有机肥之间不存在显著交互作用。综上可知,施肥和灌溉对油松的生长会产生显著的促进作用,从施肥和灌溉的效果并综合资源利用效率的角度考虑,少量施用有机肥,并以80 L·(10天·株·次)-1的灌水量在生长季(4月—9月)进行滴灌是较为经济、有效的油松生态林管护措施。 相似文献