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1.
RAPD (randomly amplified polymorphic DNA) markers were employed to characterize polymorphisms among 5 provenances of Acacia leucophloea and to detect genetic relatedness of the species with 6 other acacias (A. holosericea, A. auriculiformis, A. mangium, A. dealbata, A. ferruginea, and A. nilotica) widely grown in India. Of 194 markers scored for the provenances, 29.38% exhibited polymorphism. Also, 326 markers were generated among 7 species of Acacia, accounting for 55.82% of the polymorphisms. The fifteen 10-mer primers employed were capable of producing 1–8 polymorphic bands for the provenances, and 6–17 for all seven species of Acacia. The genetic similarity coefficient based on Jaccard’s coefficient revealed that provenances Thirumangalam and Dharmapuri were closely related. The dendrogram based on a sequential agglomerative hierarchical non-overlapping (SAHN) clustering analysis grouped 4 provenances of A. leucophloea (Dharapuram, Thirumangalam, Pudukottai and Dharmapuri) into one cluster and the other provenance, Sendurai, into a separate cluster. The genetic similarity matrix for 7 Acacia species showed that A. nilotica and A. dealbata were distantly related, while A. holosericea and A. ferruginea were very closely related. Cluster analysis grouped the species of Acacias into 3 major groups of which A. dealbata alone formed a separate group. The RAPD markers generated 36 provenance-specific markers and 162 species-specific markers that could have strong applications for species identification and tree breeding programs for A. leucophloea and for other Acacia species included in this study.  相似文献   

2.
The relationship between Xenorhabdus nematophilus and Photorhabdus luminescens, the bacterial symbionts of the entomopathogenic nematodes Steinernema carpocapsae and Heterorhabditis bacteriophora, against the diamondback moth, P. xylostella (L.), pupae showed the pathogenic capability of P. luminescens to be over that of X. nematophilus. They gave 60 and 40?% mortality with LC50 values of 5?×?104 and 5.5?×?105 cells/ml, respectively.The number of bacterial cells influences the rate of killing the pupae of P. xylostella and a direct correlation between mortality of the pupae, percentage of deformed adults and the spraying dose with significant differences were observed. An inverse correlation found between the no. of eggs laid/female, percentage of hatching, adult survival and the spraying dose. These bacterial effects have been attributed to different toxic bacterial enzymes which damage the haemocytes and inhibit activation of the humoral immune system of the insect.  相似文献   

3.
We investigated the effects of two commercial diatomaceous earth based insecticides (DE), Protect-It® and SilicoSec®, the nano-structured silica product AL06, developed by the section for Urban Plant Ecophysiology at Humboldt University Berlin, and the monoterpenoids, eugenol, and cinnamaldehyde on two stored product pests, Callosobruchus maculatus and Sitophilus oryzae. Protect-It® was more effective than SilicoSec® against C. maculatus while the reverse was true for S. oryzae. Generally C. maculatus was more sensitive towards DE and silica treatment than S. oryzae. Mortality rate of both pest species increased when DE’s were applied to food commodities previously treated with a monoterpenoid. In admixture experiments, the toxicity of SilicoSec® + cinnamaldehyde (LD50 = 42.73 ppm), SilicoSec® + eugenol (LD50 = 24.30 ppm), and Protect-It® + eugenol (LD50 = 2.60 ppm) was increased over DE alone against S. oryzae. Both substances showed a synergistic effect considering their co-toxicity coefficient relative to the LD50-value. In contrast, we could not find any synergistic effects in experiments with C. maculatus. Here only Protect-It® + cinnamaldehyde (LD50 = 20.84 ppm) showed an additive effect while all other combinations of monoterpenoid and DE indicated antagonistic effects. In addition to contact insecticidal effects both monoterpenoids showed a strong fumigant action. The presented results indicate that the natural product DE has great potential to replace synthetic pesticides commonly used in stored product pest management. Efficacy of DE can be improved by adding certain monoterpenoids against certain insect pests.  相似文献   

4.
Our previous studies have revealed that the ThCAP gene plays a vital role in transgenic Populus (P. davidiana × P. bolleana) in response to cold stress. However, the regulatory mechanism of ThCAP gene expression has been unclear. In this study, the 5′ flanking region of the ThCAP promoter (PThCAP) was cloned using a genome-walking method. By analyzing cis-acting regulatory elements of PThCAP, a DRE motif and MYC and MYB elements were found to be located in the promoter. To identify the regulatory elements that control the expression of the ThCAP gene promoter, a series of deletion derivatives of PThCAP, P1–P5, from the translation start code (?1538, ?1190, ?900, ?718 and ?375 bp), were fused to the GUS reporter gene, and then each deletion was stably introduced into Arabidopsis thaliana plants. Deletion analysis of the promoter suggested that only the P2 fragment had strong GUS expression in leaves and roots of A. thaliana exposed to low temperature stress. These results suggest that this 290-bp region (?1190 to ?900 bp), as an important part in PThCAP, was associated with cold tolerance of A. thaliana. Our results provide evidence for the regulatory mechanism of ThCAP gene involved in the response to cold stress, and that the gene is promising candidate gene for genetic improvement of crops.  相似文献   

5.
The naturally occurring Verticillium nonalfalfae shows promise for biocontrol of the highly invasive Tree of Heaven (Ailanthus altissima), but might also bear a risk for non-target tree species. In this study, we conducted inoculations on potted seedlings of A. altissima as well as on eight indigenous and two invasive tree species associated with Tree of Heaven in Austria. Although vascular discolourations developed in all inoculated tree species, V. nonalfalfae was reisolated from Ailanthus and eight of the ten non-target-species, whereas typical disease symptoms and mortality only occurred on A. altissima. Results confirmed high susceptibility (S) of A. altissima to V. nonalfalfae but indicated tolerance (T) of Acer campestre, Acer pseudoplatanus and Quercus robur, possible resistance (PR) of Fraxinus excelsior, Populus nigra, Tilia cordata, Ulmus laevis and Ulmus minor and resistance (R) of Fraxinus pennsylvanica and Robinia pseudoacacia to this potential biocontrol agent. Results from seedling inoculations were confirmed by cursory field observations in Ailanthus-inoculated forest stands, where admixed A. campestre, A. pseudoplatanus, F. excelsior, Populus alba, R. pseudoacacia and U. laevis canopy trees remained asymptomatic, while mortality was induced in Ailanthus.  相似文献   

6.
Information on population genetic structure and crop genetic diversity is important for genetically improving crop species and conserving threatened species. The PAL gene sequence is part of a multigene family that can be utilized to design DNA marker systems for genetic diversity and population structure investigation. In the current study, genetic diversity and population structure of 100 accessions of wild Pistacia species were investigated with 78 PAL markers. A protocol for using PAL sequences as DNA markers was developed. A total of 313 PAL loci were recognized, showing 100% polymorphism for PAL markers. The PAL markers produced relatively more observed and effective alleles in Pistacia falcata and Pistacia atlantica, with a higher Shannon’s information index and expected heterozygosity in P. atlantica, Pistacia vera and Pistacia mutica. Pairwise assessment of Nei’s genetic distance and genetic identity between populations revealed a close association between geographically isolated populations of Pistacia khinjuk and Pistacia chinensis. The accessions of wild Pistacia species had more genetic relationship among studied groups of species. Analysis of molecular variance indicated 19% among-population variation and 81% within-population variation for the PAL gene based DNA marker. Population structure analysis based on PAL revealed four groups with high genetic admixture among populations. The results establish PAL markers as a functional DNA marker system and provide important genetic information about accessions from wild populations of Pistacia species.  相似文献   

7.
Gardenia jasminoides and Rosa chinensis are economically important horticultural plants in China. Frankliniella occidentalis and Thrips hawaiiensis are serious coexisting pests that previously demonstrated opposite population trends on G. jasminoides and R. chinensis flowers. To further study the different performances between F. occidentalis and T. hawaiiensis, we investigated their population dynamics in the field (for 5 years) and their life history characteristics on the two flowers in the laboratory. In the field, the density of F. occidentalis was lower than that of T. hawaiiensis on G. jasminoides but was higher than that of T. hawaiiensis on R. chinensis. Under laboratory conditions, F. occidentalis showed significantly slower development, and lower survival and fecundity levels than T. hawaiiensis on G. jasminoides, but the opposite was true on R. chinensis. Significant differences in the net reproductive rate (R 0) between F. occidentalis and T. hawaiiensis were observed, with respective values of 38.66 ± 2.85 and 47.91 ± 2.70 on G. jasminoides, and 55.64 ± 2.15 and 32.45 ± 2.16 on R. chinensis. The intrinsic rates of increase (r m ) of F. occidentalis and T. hawaiiensis were 0.156 ± 0.008 and 0.198 ± 0.007, respectively, on G. jasminoides, and 0.172 ± 0.003 and 0.165 ± 0.002, respectively, on R. chinensis. Thus, the performances of both thrips with respect to population size in the laboratory were in accordance with those in the field, suggesting that the innate capacity for insect population increases may directly impact their population dynamics in fields. Thus, the population performance of different thrips species on flowers is species-dependent, which could be exploited in thrips control programs by breeding pest-resistant cultivars.  相似文献   

8.
Taxus chinensis and T. wallichiana in have been threatened in their distribution areas in recent decades because of their over-exploitation and reduction and destruction of native habitats. Determining the genetic diversity in populations of the two species will provide guidelines for their protection and preservation. Two hundred and fifteen trees from six populations of T. chinensis and 150 sampled trees of T. wallichiana were sampled. Six microsatellite primer pairs selected from 16 primer pairs were used to investigate genetic variation at the population and species levels. Five yielded polymorphic alleles, and among the 13 putative alleles amplified, 11 were polymorphic (accounting for 76.33 %).Shannon’s information index (I) and percentage of polymorphic bands (PPB) (I = 0.202 and PPB = 67.22 % for T. chinensis; I = 0.217 and PPB = 65.03 % for T. wallichiana). Both species had low levels of genetic diversity (mean H o = 0.107, H e = 0.121 for T. chinensis; H o = 0.095, H e = 0.109 for T. wallichiana). Genetic differentiation among populations was higher (F ST = 0.189) for T. chinensis and lower (0.156) for T. wallichiana, indicating limited gene flow (Nm) among populations for T. chinensis (0.68) and T. wallichiana (0.65). Variation among individuals of T. chinensis was 63.59 and 73.12 % for T. wallichiana. Thus, the threatened status of the two conifers is related to a lack of genetic diversity. All populations are isolated in small forest remnants. An ex situ conservation site should be established with a new population for these species that comprises all the genetic groups for the best chance to improve their fitness under environmental stresses.  相似文献   

9.
Biochemical changes associated with flowering in Bambusa arundinacea Linn and Bambusa nutans Wall. ex Munro were analyzed. Gregarious flowering was initiated in natural areas and plantations of B. arundinacea in late 2014 and reached full bloom in early 2015, whereas sporadic flowering recorded during 2014–2015 in vegetatively propagated plants of B. nutans. Leaf and nodal shoot samples from flowering culms/shoots and nonflowering culms/shoots were collected in February 2015 at the initiation of fruit filling, then analyzed and compared for soluble sugars, phenols and peroxidase activity. In both species sugars were higher in leaves of flowering culms/shoots and lower in nodal shoots of flowering culms/shoots compared to the nonflowering. Phenols were lower in leaves and nodal shoots of flowering B. arundinacea, but higher in leaves and decreases in nodal shoots of B. nutans. Peroxidase activity increases in leaves and nodal shoots of B. arundinacea after flowering but increases in nodal shoots and decreases in leaves of B. nutans.  相似文献   

10.
We studied leaf litter fall, decomposition and nutrient release patterns of Shorea robusta and Tectona grandis by using a litter bag technique to better understand the release pattern of nutrients to soil from leaf litter. Annual litterfall varied from 13.40 ± 2.56 t ha?1 a?1 for S. robusta to 11.03 ± 3.72 t ha?1 a?1 for T. grandis and the decay constant (k) of decomposed leaf litter was distinctly higher for T. grandis (2.70 ± 0.50 a?1) compared to S. robusta (2.41 ± 0.30 a?1). Biomass loss was positively correlated with the initial litter C, WSC, C/N and ash content in S. robusta and N, P and K concentration for T. grandis. Biomass was negatively correlated with lignin and L/N ratio for S. robusta and L, WSC, L/N and C/N ratio for T. grandis (P < 0.01). Nutrient use efficiency (NUE) and nutrient accumulation index (NAI) of S. robusta was higher than for T. grandis. The retranslocation of bioelements from senescent leaves ranked as P > N > K. Annual N, P and K input to soil through litterfall differed significantly between the two species in the following order: N>K>P. S. robusta was superior in terms of K and P return and T. grandis was superior in terms of N return. The two tree species showed a similar patterns of nutrient release (K > P > N) during decomposition of their leaf litter. Nutrients of N, K and P were the primary limiting nutrients returned to soil through litterfall with important roles in soil fertility and forest productivity.  相似文献   

11.
The large white butterfly, Pieris brassicae (L.), is an important pest of Indian mustard, Brassica juncea (L.) Czern., and inflicts heavy damage to all the above ground plant parts with strong yield reducing impacts. Farmers have few practical options other than to spray insecticides to protect their crop. In this study, an attempt was made during 2012–2013 and 2013–2014 crop seasons at Ludhiana, India, to evaluate Ethiopian mustard, Brassica carinata A. Braun as a trap crop to manage this pest as an alternate pest management strategy. B. carinata borders surrounding B. juncea were compared to chemically protected B. juncea and control (without B. carinata borders) plots for their effects on P. brassicae infestation and grain yield. Oviposition preference of adult butterflies was studied in a two-choice test in field cages, while the effect of two host plants on larval performance was studied under laboratory conditions under no choice conditions. B. juncea plots bordered with B. carinata harbored significantly lower larval population compared to control B. juncea plots during both the seasons. The grain yield in the bordered plots was also significantly higher than that from control plots and was statistically non-significant from that obtained in chemically protected plots. Female butterflies showed distinct oviposition preference for B. carinata over B. juncea and the larvae reared on B. carinata completed development in shorter period and grew bigger and heavier than those reared on B. juncea. Results indicated that B. carinata has potential to be used as trap crop to manage P. brassicae.  相似文献   

12.
Bioactivity of essential oils (EOs) from Monarda species has never been investigated on phytoparasitic nematodes. In this study, the EOs from two Italian ecotypes of Monarda didyma and M. fistulosa and their main compounds, carvacrol, γ-terpinene, o-cymene, and thymol, were evaluated for their in vitro activity on the infective stages of phytoparasitic nematodes Meloidogyne incognita and Pratylenchus vulnus, as well as on M. incognita egg hatch. Soil treatments with the two EOs were also investigated for their suppressiveness on M. incognita on tomato. Both EOs were strongly active on M. incognita juveniles, as a only 1.0 μL mL?1 LC50 value was evaluated after a 24-h exposure to both EOs, whereas a lower activity was recorded on P. vulnus (15.7 and 12.5 μL mL?1 LC50 values for M. didyma and M. fistulosa EOs, respectively). Among the EOs’ main compounds, carvacrol was highly active also at a short exposure in low concentrations, whereas γ-terpinene and thymol were much less active on both nematode species and o-cymene showed a discrete activity on P. vulnus only at the highest concentration. Hatch percent of M. incognita eggs treated with M. didyma and M. fistulosa EOs was always significantly lower than in water or in Tween 20 and Oxamyl solutions. In the experiment in soil, the multiplication of M. incognita and gall formation on tomato roots was significantly reduced by soil treatments with both EOs. The strong nematicidal activity of both Monarda EOs may suggest them as potential sources of new sustainable nematicidal products.  相似文献   

13.
The objective of this work was to evaluate the effect of different water deficiency and rehydration levels on the concentrations of osmoregulators in two plant species (Hymenaea courbaril and H. Stigonocarpa) in the Amazon. We adopted a 2 × 5 × 5 factorial system, referring to 2 species (H. courbaril and H. stigonocarpa) and 5 stages of hydration and rehydration. The five hydration and rehydration stages were established in: (1) Control treatment E0; (2) Plants with 13 days of stress after incubation—E13; (3) Plants with 26 days of stress E26; (4) The plants that were established after 26 days after incubation and rehydrated for two days (RD2); (5) rehydrated for two days (RD4). The plants that were established after 26 days after incubation and rehydrated for four days. The experiment totaled fifty young plants with five replicates. Biochemical measurements were performed at the beginning of the experiment (E0) at 13 (E13) and 26 (E26) days after the water stress, in which the plants were rehydrated, repeating the analyses after two (RD2) and four (RD4) days. Both species increased the sucrose concentration by 18%, with a decrease of 52% in starch content. The RD4 time presented the highest mean starch concentration (0.19 mmol g?1 of the residue for H. courbaril and 0.27 mmol g?1 of residue for H. stigonocarpa). Increased proline concentrations were recorded for controls until RD2 for both species. For glycine betaine, the highest increases in treatments E26 and RD2 were observed for the H. courbaril species. Our rehydration period was not sufficient for total recovery of pre-stress concentrations of all studied solutes.  相似文献   

14.
Expansins are cell-wall-loosening proteins that have multiple roles during plant development and stress-related processes. In this study, a novel expansin gene PwEXP2 was cloned by rapid amplification of cDNA ends based on the cDNA library of Picea wilsonii and EST fragment of PwEXP2. It was found that PwEXP2 coded 253 amino acids, and putative signal peptides exist at the N-terminal, followed by 8 cysteines, a HFD (His-Phe-Asp) conserved domain, and 4 tryptophan residues at the C-terminal. PwEXP2 was located in cytoplasm and nucleus when transformed in an onion epidermal cell. Quantitative real-time PCR assays showed that PwEXP2 was expressed in various tissues with a relatively high level in needles and low level in mature pollen. The expression level of PwEXP2 dramatically increased after seed germination. Gene expression profiles in abiotic stresses showed that PwEXP2 was induced by high temperature and osmotic stress but not involved in ABA-dependent signaling pathway. These results display the important roles of the PwEXP2 in plant development and multiple adversity stresses.  相似文献   

15.
Indonesia’s pulp and paper industry needs a large area of sustainably grown plantations to support its continued development. Acacia mangium has been the key species underpinning the pulp and paper industries in Sumatra, however increased disease pressure on A. mangium is expected to require large-scale conversion of Acacia plantations to Eucalyptus in the near future. The effect of such a large scale change in plantation species on soil moisture, for both tree production, and catchment hydrology is unknown. In this study we sought to characterize the impacts of plantation species (Acacia or Eucalyptus) and nitrogen management, on soil moisture, soil water depletion and depth to groundwater under stands of Acacia mangium and Eucalyptus pellita over the first 2–3 years after establishment. The study was conducted in experiments at four sites in Sumatra, Indonesia. Soil moisture and soil water depletion were not influenced by plantation species or fertilizer treatment. Soil moisture content and soil water depletion were strongly influenced by shallow groundwater at two of the four sites, however depth to groundwater did not influence stem growth. Results from the field trials cautiously suggest that large scale conversion of Acacia mangium to Eucalypt species in these regions is unlikely to result in increased moisture stress, nor is conversion of plantation species likely to lead to substantial differences in catchment hydrology. This study demonstrated the importance of conducting multi-site studies when investigating biophysical relationships in forest/plantation systems.  相似文献   

16.
The invasive stink bug Halyomorpha halys is established in many European and American agro-ecosystems, where it causes severe crop losses. Potential control measures might include enhancement of plant defences. When attacked by herbivorous insects that oviposit on it, the plant may respond by priming direct defences, which might affect the development of future brood. Halyomorpha halys attacks numerous plant species in the invaded areas. Here, we investigated whether Vicia faba plants challenged by H. halys females can impair the development of its offspring through the activation of induced direct defences. We measured the weight and dimension of nymphs that developed on oviposition-experienced plants after 7 and 17 days from hatching. Nymphs that developed on oviposition-experienced plants weighed less compared to those that developed either on control plants or on plants solely subjected to H. halys feeding, and third instars showed shorter dimensions (tibia length). In addition, when oviposition-experienced plants were attacked by nymphs, higher and more rapid expression of two jasmonic acid-dependent genes (cysteine proteinase inhibitor gene and NAI1) was detected, possibly due to a mechanism of priming. Increased expression of the salicylic acid-responsive PR1 gene was also detected in egg-experienced plants, although the response was delayed compared to JA-dependent genes. Our results suggest that V. faba plants recognize H. halys oviposition as a warning signal and pre-activate defences against future nymphal herbivory.  相似文献   

17.
Pea weevil (Bruchus pisorum) is a damaging insect pest affecting pea production worldwide. The aim of this study was to identify sources of resistance to pea weevil in a Pisum spp. germplasm in multi-environment field tests. Seed infestation and larval development were assessed in each environment and subjected to a heritability-adjusted genotype and genotype x environment biplot analysis. Results showed that seed infestation and larval development are independent traits. Accessions P669 (P. sativum ssp. elatius) and P656 (P. fulvum) showed a stable reduction in seed infestation across environments. Meanwhile, accessions P314 (P. sativum ssp. elatius) and P1 (P. abyssinicum) showed a stable reduction in larval development. The most promising accession was P665 (P. sativum ssp. syriacum) which showed resistance at both pod and seed levels. This study demonstrates the importance of environmental conditions for pea weevil infestation. Moreover, by submitting data to a CCA, the influence of climatic parameters over seed infestation and larval development has been elucidated.  相似文献   

18.
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19.
Biological and other alternative control methods were tested against the woolly beech aphid (Phyllaphis fagi). Field applications of mineral oil to the egg stage reduced initial aphid population by 75%, but only when the eggs were exposed to oil close to the time of hatching. Earlier oil treatments had no effect. Bioassays with the insect pathogenic fungus Lecanicillium lecanii (Verticillium lecanii) in the commercial formulation Vertalec® were conducted using different dosages, i.e. 1 × 106 ml?1 (recommended dosage) and 2 × 107 ml?1. Both nymphs and adults were susceptible to fungal infection at both dosages. The existence of a dense wax-covering in adult P. fagi had no protective effect against fungal infection. In bioassays where leaves were treated with the recommended dosage of Vertalec, there was no difference in mortality measured after 14 days between adult P. fagi with an intact wax-layer and adult P. fagi where the wax-layer had been removed. In semi-field trials with two L. lecanii treatments at the recommended dosage, the aphid population was reduced. There was no enhanced effect with the addition of an additive to the fungal suspension or from covering the plants with a polypropylene cover. The results reveal potential alternative control methods against P. fagi populations. However, adequate control with L. lecanii probably requires several treatments as opposed to the two that were tested in the present experiment. Furthermore, efficiency may depend on summer temperatures and humidity.  相似文献   

20.

Key message

Pinus sylvestris seedlings quickly expand their roots to deeper soil layers while Pseudotsuga menziesii concentrates its root system in the topsoil, thereby running the risk of desiccation during long dry spells, as indicated by lower survival after simulated summer drought.

Context

Pseudotsuga menziesii (Douglas-fir) is regarded as a promising species to maintain the productivity of Central European lowland forests given the projected increase of long dry spells.

Aims

Will the species be able to regenerate from seed and spread outside plantations in a drier temperate Europe?

Methods

We measured the relative growth rate, biomass allocation, root architecture, and phenotypic plasticity of Pseudotsuga menziesii seedlings sown in a common garden and grown under current precipitation and prolonged drought, respectively. The species’ competitive ability with respect to Pinus sylvestris L., the most drought-tolerant native conifer in Central Europe, was assessed during three growing seasons.

Results

Pinus sylvestris seedlings had higher relative growth rates than did Pseudotsuga menziesii seedlings, first in terms of aboveground biomass and later in terms of shoot height. This resulted in heavier and taller seedlings after three growing seasons under both moist and dry conditions. Shorter vertical roots corresponded with lower survival of Pseudotsuga menziesii seedlings under dry conditions.

Conclusion

Fast root proliferation allows Pinus sylvestris seedlings to reach deeper water pools that are less rapidly depleted during transient drought. By contrast, the shallow root system might put Pseudotsuga menziesii seedlings at the risk of desiccation during prolonged dry spells.
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