Hemiparasite – host plant interactions and the impact of herbivory: a field experiment

Botany ◽  
2011 ◽  
Vol 89 (8) ◽  
pp. 537-544 ◽  
Author(s):  
Mickayla D. Van Hoveln ◽  
Bethany A. Evans ◽  
Victoria A. Borowicz
Keyword(s):  
Host Size ◽  
Schizachyrium Scoparium ◽  
Plant Interactions ◽  
Compensatory Response ◽  
Host Growth ◽  
Subsequent Flowering ◽  
Shoot Mass ◽  
The Impact ◽  
Early Late ◽  
Pedicularis Canadensis

Schizachyrium scoparium Michx. (Nash) growing naturally with varying numbers of the perennial hemiparasite Pedicularis canadensis L. were randomly assigned to one of four clipping treatments (none, early, late, early and late) to determine how parasitism and herbivory affect the grass and whether herbivory of the host indirectly affects hemiparasite growth. Any clipping eliminated subsequent flowering by S. scoparium in year 1 and reduced the number of plants that flowered in year 2, when no clipping occurred. Only hosts clipped early exhibited depressed growth after one summer. The following year plants that had been clipped twice the previous year produced the least shoot mass, and plants that were never clipped produced the most. Hemiparasite load was negatively associated with host shoot mass, especially in year 1, but did not alter the host’s compensatory response to clipping. The effects of host size and host clipping on the nearest hemiparasite were determined in year 1. Pedicularis canadensis shoot mass declined with host size if the host was clipped late, but increased with host size when clipping occurred once early in the season. Although the impact of hemiparasites and clipping on host growth are independent, clipping can alter the value of the host for parasites.

The Role of Viruses in the Phytobiome

2018 ◽  
Vol 5 (1) ◽  
pp. 93-111 ◽  
Author(s):  
James E. Schoelz ◽  
Lucy R. Stewart
Keyword(s):  
Soil Bacteria ◽  
Plant Viruses ◽  
Plant Health ◽  
Plant Interactions ◽  
Current Information ◽  
Virus Interactions ◽  
The Impact ◽  
Review Current

Viruses are an important but sequence-diverse and often understudied component of the phytobiome. We succinctly review current information on how plant viruses directly affect plant health and physiology and consequently have the capacity to modulate plant interactions with their biotic and abiotic environments. Virus interactions with other biota in the phytobiome, including arthropods, fungi, and nematodes, may also impact plant health. For example, viruses interact with and modulate the interface between plants and insects. This has been extensively studied for insect-vectored plant viruses, some of which also infect their vectors. Other viruses have been shown to alter the impacts of plant-interacting phytopathogenic and nonpathogenic fungi and bacteria. Viruses that infect nematodes have also recently been discovered, but the impact of these and phage infecting soil bacteria on plant health remain largely unexplored.

Host plant interactions between wheat germplasm source and wheat stem sawfly Cephus cinctus Norton (Hymenoptera: Cephidae) I. Commercial cultivars

2013 ◽  
Vol 93 (4) ◽  
pp. 607-617 ◽  
Author(s):  
B. L. Beres ◽  
H. A. Cárcamo ◽  
J. R. Byers ◽  
F. R. Clarke ◽  
C. J. Pozniak ◽  
...  
Keyword(s):  
Host Plant ◽  
Insect Pest ◽  
Economic Losses ◽  
Plant Interactions ◽  
Wheat Stem Sawfly ◽  
Cephus Cinctus ◽  
Wheat Germplasm ◽  
Commercial Cultivars ◽  
Solid Stem ◽  
The Impact

Beres, B. L., Cárcamo, H. A., Byers, J. R., Clarke, F. R., Pozniak, C. J., Basu, S. K. and DePauw, R. M. 2013. Host plant interactions between wheat germplasm source and wheat stem sawfly Cephus cinctus Norton (Hymenoptera: Cephidae) I. Commercial cultivars. Can. J. Plant Sci. 93: 607–617. The wheat stem sawfly (WSS) Cephus cinctus Norton (Hymenoptera: Cephidae) is an economically destructive insect pest of wheat in the northern Great Plains. A significant resurgence of the insect pest in the southern prairies of Canada caused substantial economic losses from 1999 through 2007. Solid-stem cultivar selection is critical to the management of WSS but adoption of the use of these cultivars was low, which compounded losses at harvest. A study was conducted from 2001 to 2003 in southern Alberta and Saskatchewan, Canada (1) to establish the range of susceptibility of hollow- and solid-stem varieties representing the major spring wheat classes and (2) to determine the impact of host plant on WSS population dynamics. The solid-stem varieties were generally superior at reducing damage and fitness response of WSS. However, in addition to the durum cultivars AC Navigator and AC Avonlea, the variety McKenzie, which was considered hollow, provided improved efficacy over other hollow-stem cultivars. Our study suggests solid-stem cultivars are highly effective but prone to inconsistent performance and should therefore be integrated into a holistic strategy for WSS that includes agronomics and biocontrol. A companion paper will report on the response of cultivars with novel sources of germplasm.

scholarly journals purL gene expression affects biofilm formation and symbiotic persistence of Photorhabdus temperata in the nematode Heterorhabditis bacteriophora

Microbiology ◽  
2011 ◽  
Vol 157 (9) ◽  
pp. 2595-2603 ◽  
Author(s):  
Ruisheng An ◽  
Parwinder S. Grewal
Keyword(s):  
Gene Expression ◽  
Metabolic Pathway ◽  
Biofilm Formation ◽  
Heterorhabditis Bacteriophora ◽  
Bacterial Biofilm ◽  
Infective Juvenile ◽  
Plant Interactions ◽  
Symbiotic Interaction ◽  
The Impact ◽  
Photorhabdus Temperata

Extensive studies of the well-known legume and rhizobium symbiosis model system suggest that the purine metabolic pathway plays a key role in microbe–plant interactions, although the exact mechanism is unknown. Here, we report the impact of a key purine metabolic gene, purL, on the symbiotic interaction between the bacterium Photorhabdus temperata and its nematode partner Heterorhabditis bacteriophora. Real-time PCR assays showed that the purL gene was upregulated in P. temperata in the nematode infective juvenile compared with artificial media. Mutation of the purL gene by in-frame deletion dramatically decreased the capacity of the bacterium to persist in infective juveniles and its ability to form biofilm in vitro. It was further demonstrated that purL gene expression was positively related to bacterial biofilm formation and the symbiotic persistence of the bacterium in nematode infective juveniles. A ΔpurL mutant lost the ability to support infective juvenile formation in the media which weakly supported biofilm formation, suggesting that a critical level of biofilm formation is required by the bacteria to support infective juvenile formation and thus establish their partnership. In addition, the defects in both biofilm formation and symbiotic ability due to the disruption of the purL gene could be partially restored by the addition of 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR), an intermediate of the purine biosynthesis pathway. Overall, these data indicate that the purine metabolic pathway is important in microbe–animal symbioses, and that it may influence symbiotic interactions at the level of biofilm formation.

The Impact of Two-Stage Highly Interesting Questions on Completion Rates and Data Quality in Online Marketing Research

2012 ◽  
Vol 54 (2) ◽  
pp. 241-260 ◽  
Author(s):  
Jared M. Hansen ◽  
Scott M. Smith
Keyword(s):  
Data Quality ◽  
Response Bias ◽  
Marketing Research ◽  
Online Marketing ◽  
Completion Rates ◽  
Sample Representativeness ◽  
Online Marketing Research ◽  
The Impact ◽  
Early Late ◽  
Late Wave

Increasing both survey completion rates and data quality remains an important topic for fields as diverse as sociology, marketing, medicine and history. Thousands of studies have made response quality their central topic of examination, but their focus has largely been to measure response bias through the comparison of early–late wave responses. In this study, an innovative online field experiment tests a two-staged highly interesting question to produce an 8% better survey completion rate and to change sample representativeness by 12% over a usual one-stage highly interesting question appearing at the beginning of the questionnaire. In addition to these substantive findings, a distributional and probability analysis is developed that further refines methods for identifying the extent of non-response bias.

Abundance/host size relationship in a fish trematode community

1992 ◽  
Vol 66 (3) ◽  
pp. 187-192 ◽  
Author(s):  
A. Saad-Fares ◽  
C. Combes
Keyword(s):  
Interspecific Competition ◽  
Digestive Tract ◽  
Host Species ◽  
Size Class ◽  
Host Size ◽  
Trematode Species ◽  
High Threshold ◽  
East Mediterranean ◽  
Host Growth ◽  
Single Host

ABSTRACTThe abundance of six species of trematodes: Aphanurus stossichi, Bacciger israelensis, Diphterostomum israelense, Plagioporus idoneus, Lepocreadium album and L. pegorchis, parasitic in the digestive tract of marine teleostei (Sparidae) collected near Jounieh (east Mediterranean), was analysed as a function of the host-size. In two parasite/host systems, infections were observed from the lowest size classes of the sample, with a clear tendency to an increase of abundance in older fish. In four others, parasites appear only above a rather high threshold class, young individuals never being infected. In the last three parasite/host systems, host invasion may occur early or late, but infection decreases above a well defined size class, old fishes rarely or never being infected. A given trematode species. when parasitizing several host species, shows similar abundance/host size relationships, e.g. P. idoneus in Diplodus vulgaris and Oblada melanura. When more than one species of trematode infects a single host species, curves can be markedly distinct; for instance, L. pegorchis was collected from Pagellus erythrinus below 15 cm. whereas D. israelense parasitized the same fish approximately above the same size. There is no evidence that such a replacement of one trematode by another in the course of host growth is a result of interspecific competition.

scholarly journals Timing and Duration of Supplemental Lighting during the Seedling Stage Influence Quality and Flowering in Petunia and Pansy

HortScience ◽  
2010 ◽  
Vol 45 (9) ◽  
pp. 1332-1337 ◽  
Author(s):  
Wook Oh ◽  
Erik S. Runkle ◽  
Ryan M. Warner
Keyword(s):  
Dry Mass ◽  
Seedling Stage ◽  
Photon Flux ◽  
Flower Bud ◽  
Bedding Plants ◽  
Daily Light Integral ◽  
Number Of Leaves ◽  
Supplemental Lighting ◽  
Subsequent Flowering ◽  
The Impact

Increasing the photosynthetic daily light integral (DLI) during the seedling stage promotes seedling growth and flowering in many bedding plants. Our objective was to determine the impact of increased DLI for different periods during the seedling stage on young plant quality and subsequent growth and development. Seeds of petunia (Petunia ×hybrida Vilm.-Andr. ‘Madness Red’) and pansy (Viola ×wittrockiana Gams. ‘Delta Premium Yellow’) were sown into 288-cell plug trays and placed under a 16-h photoperiod provided by sunlight plus 90 μmol·m−2·s−1 [supplemental lighting (SL)] or 3 μmol·m−2·s−1 [photoperiodic lighting (PL)] from high-pressure sodium lamps when the ambient greenhouse photosynthetic photon flux was less than 400 μmol·m−2·s−1 from 0600 to 2200 hr. Plants were grown at 20 °C under PL or SL for the entire seedling stage or were exposed to SL for one-third or two-thirds of the seedling stage. Seedlings were then transplanted into 10-cm pots and grown until flowering with SL at 20 °C. Shoot dry mass of transplants increased linearly with increasing DLI provided to seedlings in petunia (y = −4.75 + 1.86x, R2 = 0.76) and pansy (y = −3.94 + 3.47x, R2 = 0.78) in which y = dry mass (g) and x = DLI (mol·m−2·d−1). SL during the last two-thirds or the entire plug stage increased shoot dry mass and the number of leaves in both species compared with SL during the earlier stage or PL. SL during the last two-thirds or the entire plug stage accelerated flowering, but plants had a lower shoot dry mass and flower bud number at first flowering compared with that in SL during the first third or two-thirds or that in PL. Therefore, SL generally had greater effects on transplant quality and subsequent flowering when provided later in the plug stage than if provided earlier in production.

scholarly journals Pruning from spheroidal to cubic canopy induced aphid outbreak by altering the plant performance in Box tree

2020 ◽  
Author(s):  
Anqun Chen ◽  
Yinzhan Liu ◽  
Xiaolin Liu ◽  
Juan Xuan ◽  
Chunlian Qiao ◽  
...  
Keyword(s):  
Structural Equation ◽  
Field Experiments ◽  
Plant Morphology ◽  
Dry Mass ◽  
Plant Performance ◽  
Plant Interactions ◽  
Mass Content ◽  
Leaf Dry Mass ◽  
The Impact ◽  
Aphid Abundance

Abstract Backgrounds: Plant-animal interactions comprise the fundamental relationships of ecological research, and are sensitive to environmental change. However, The effects of pruning on animal-plant interactions have rarely been studied. Methods: We conducted field experiments to examine the impact of artificially-pruned shapes (e.g. cubic and spheroidal canopy) on the performance of the Box tree and the resulting aphid abundance at three sites; on a university campus, at a road green belt, and in a residential area. The differences of aphid abundance and plant morphology were determined with ANOVAs and paired-sample tests. Relationships between the investigated parameters were detected with simple regression and structural equation modelResult: Abundance was higher in plants with a cubic canopy than with a spheroidal canopy. Plants with a cubic canopy had lower leaf dry mass content and inflorescence numbers, but greater fresh twig length than the plants with a spheroidal canopy. The aphid abundance was negatively correlated with the leaf dry mass content and inflorescence numbers, and positively correlated with the fresh twig length. Conclusion: Our findings have proven that pruning shape can significantly affect the abundance of herbivores on the pruned plants. The results can provide data support for human actives can alter plant performance, and thereby to change insect preference.

Starvation-induced Changes in Memory Sensitization, Habituation and Psychosomatic Responses

2019 ◽  
pp. 1-7
Author(s):  
O. N. Ilochi ◽  
T. A. Kolawole ◽  
B. O. Oluwatayo ◽  
A. N. Chuemere
Keyword(s):  
Compensatory Response ◽  
Motor Responses ◽  
Memory Processes ◽  
Global Challenge ◽  
Stress Markers ◽  
Elevated Plus Maze Test ◽  
Feed Deprivation ◽  
Calcium Magnesium ◽  
Induced Changes ◽  
The Impact

Starvation is a global challenge. Nutritional status of an organism may influence its psychosocial behavior and other nervous system processes like motor responses and its ability to learn and memorize.  This study determined the impact of starvation-induced stress on memory sensitization, habituation and psychosomatic responses in an experimental animal design. 25 wistar rats were randomly sampled and grouped into 1-control, 2- feed after 6 hours deprivation, 3-feed after12 hours deprivation, 4-feed after 18 hours deprivation and 5-feed after 24 hours deprivation. Behavioral tests carried out included the multiple maze tests and elevated plus maze test. Grip strength test was performed to determine neuromuscular response and endurance in all groups. Biochemical investigation of brain stress markers was done on the last day of the study. There was a significant (P≤0.05) enhancement in memory processes and anxiolytic behavior after 6 hours feed deprivation. An increase in antioxidants after 6 hours feed deprivation was suspected to be a compensatory response. A progressive decrease in memory facilitation, anxiolytic behavior and muscular strength was reported after 12, 18 and 24 hours feed deprivation. The increase in habituation and decrease in psychosomatic response was observed and appreciated as the duration of feed deprivation was increased. This study provided evidence about a possible link between memory processes and stress-related alterations in calcium, magnesium and nitric oxide. Starvation may impair learning, memory and motor responses, but this tendency is dependent on the extent of feed deprivation and nutrient depletion.

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