Effects of aphids and moth caterpillars on epiphytic microorganisms in canopies of forest trees

2000 ◽  
Vol 30 (4) ◽  
pp. 631-638 ◽  
Author(s):  
Bernhard Stadler ◽  
Thomas Müller
Keyword(s):  
Population Dynamics ◽  
Functional Groups ◽  
Filamentous Fungi ◽  
Growing Season ◽  
Aphid Species ◽  
Growth Media ◽  
Forest Trees ◽  
Epiphytic Microorganisms ◽  
Colony Forming Units ◽  
Different Types

Different types of herbivores were investigated for their effects on microorganisms in the phyllosphere of forest trees during the growing season. Aphids on spruce, beech, and oak produced honeydew, which was readily consumed by microorganisms and resulted in two to three orders of magnitude higher densities (colony forming units) of bacteria, yeasts, and filamentous fungi on leaves of infested trees. The amounts of honeydew excreted by different aphid species and their mode of excretion (large droplets, tiny droplets scattered over leaves, production of wax wool) affected the degree to which honeydew could be processed by epiphytic microorganisms. All groups of microorganisms appeared to be energy limited. These results were consistent for different growth media offered to the microorganisms. Leaf-feeding moth caterpillars also positively affected the growth of microorganisms on leaves of beech and oak. The effects were more pronounced for bacteria and yeasts especially on oak. Thus, different functional groups of herbivores positively affected the growth of microorganisms in the phyllosphere of trees. It is suggested that the population dynamics of herbivores and their feeding characteristics are important features, which should be considered when the population dynamics of microorganisms in the canopies of trees is studied.

Population dynamics of endophytic bacteria in field-grown sweet corn and cotton

1995 ◽  
Vol 41 (10) ◽  
pp. 895-901 ◽  
Author(s):  
John A. McInroy ◽  
Joseph W. Kloepper
Keyword(s):  
Population Dynamics ◽  
Endophytic Bacteria ◽  
Sweet Corn ◽  
Seedling Emergence ◽  
Growing Season ◽  
Culturable Bacteria ◽  
Relative Contribution ◽  
Fundamental Information ◽  
Colony Forming Units ◽  
The Mean

Investigations were designed to gain fundamental information on the microbial ecology of endophytic bacteria in model dicotyledonous and monocotyledonous hosts. Population dynamics of indigenous endophytic bacteria in cotton (Gossypium hirsutum L. 'DES119') and sweet corn (Zea mays L. 'Silver Queen') stems and roots were studied in a 2-year field trial by quantifying culturable bacteria at intervals during the season on three media: R2A, medium SC, and tryptic soy agar. Population dynamics of endophytic bacteria inside cotton petioles and bolls were also determined in 1 year. Endophytes were recovered from sweet corn roots and stems at seedling emergence at mean population densities of 4 log (colony-forming units per gram fresh weight (cfu/g-fw)) for both seasons, and were present throughout most of the growing season at populations ranging from 4 to 6 log(cfu/g-fw) in 1990 and 4 to 7 log(cfu/g-fw) in 1991. Endophytic bacteria were also present at emergence in cotton roots and stems in 1991 but were not detected until 2 days after emergence in 1990. Endophytic populations in cotton roots ranged from 4 to 6 log(cfu/g-fw) for most of the growing season in 1990 and 1991, while populations in cotton stems fluctuated between 3 and 7 log(cfu/g-fw) during both seasons. In cotton petioles, mean populations generally ranged from 1 to 4 log(cfu/g-fw), while no endophytic bacteria were recovered from bolls (minimum detectable limit = 1.30 log(cfu/g-fw)). The relative contribution of seeds and soil as sources of endophytic bacteria recovered from inside plants was assessed using surface-disinfested seed in a potting mix or on water–agar. With sweet corn, the mean endophytic bacterial population in seedlings grown on water agar was below 2 log(cfu/g-fw), while with cotton the mean was 5 log(cfu/g-fw) 6 days after germination. Internal populations resulting from surface-disinfested seed planted in nonsterile potting mix were 6 log(cfu/g-fw) at 6 days after planting with corn but only 2 log(cfu/g-fw) with cotton. These results indicate that endophytic bacteria are natural inhabitants of internal regions of roots and stems and that the endophytes may arise from both seeds and soils.Key words: cotton, sweet corn, endophytes, colonization.

Respon Padi Gogo Terhadap Residu Pupuk Organik

Agrotek ◽  
2018 ◽  
Vol 3 (2) ◽  
Author(s):  
Baso Daeng
Keyword(s):  
Environmental Sustainability ◽  
Upland Rice ◽  
Organic Fertilizer ◽  
Growing Season ◽  
Chicken Manure ◽  
Good Effect ◽  
Best Response ◽  
Different Types ◽  
Main Plot ◽  
Plot Design

<em>The rate of conversion of paddy fields and irrigation water crisis suggest to consider the development of upland rice.� Empowerment of organic-based dryland done to increase rice, as well as environmental sustainability efforts.� The purpose of this experiment was to determine the effect of organic fertilizer residue to upland rice in the second growing season.� Experiments using a split-split plot design.� The main plot consisted of a dosage of 50% and 100% organic fertilizer in the first growing season.� Sub plot consisted of chicken manure (20 tons ha<sup>-1</sup>), <span style="text-decoration: underline;">Centrosema</span>� <span style="text-decoration: underline;">pubescens</span> (4.3 tons ha<sup>-1</sup>) + chicken manure (10 tons ha<sup>-1</sup>), and <span style="text-decoration: underline;">Thitonia</span> <span style="text-decoration: underline;">diversifolia</span> (4.3 tons ha<sup>-1</sup>) + chicken manure (10 tons ha<sup>-1</sup>).� Sub-sub plot consist of Danau Gaung and Batu Tegi varieties.� The different types of fertilizer had no effect on plant productivity.� The addition of <span style="text-decoration: underline;">Thitonia</span> <span style="text-decoration: underline;">diversifolia</span> gave a good effect on some growth variable and its resistance due pathogen attack.� Batu Tegi varieties are varieties that give the best response from an organic fertilizer.� Interaction between dosage, type of fertilizer, and varieties do not provide areal impact.</em>

Effects of crop sequence and rainfall on population dynamics of Fusarium solani f.sp. phaseoli in soil

1992 ◽  
Vol 70 (10) ◽  
pp. 2005-2008 ◽  
Author(s):  
Robert Hall ◽  
Lana Gay Phillips
Keyword(s):  
Population Dynamics ◽  
Phaseolus Vulgaris ◽  
Population Density ◽  
Fusarium Solani ◽  
Population Densities ◽  
Total Rainfall ◽  
Colony Forming Units ◽  
Bean Crop ◽  
Previous Summer ◽  
Crop Sequence

Evidence is presented that population dynamics of Fusarium solani f.sp. phaseoli in soil depend on the effects of crop sequence and rainfall on parasitic activities of the pathogen. In a rotation trial started in 1978 and conducted over 14 years, population densities (colony-forming units/g) of the fungus in soil remained below 50 in treatments (fallow, repeated corn, repeated soybean) where the preferred host plant (common bean, Phaseolus vulgaris) was not grown. Where bean was grown every 3rd year or every year, population densities reached 475 and 660, respectively, by 1984. Thereafter, population densities of the fungus fluctuated widely from year to year in both rotation and repeated bean treatments. In the rotation treatment, peaks in population density of the pathogen coincided with the years of bean production. In repeated bean plots between 1985 and 1991, population density of the fungus in June was significantly correlated (r = 0.77, p = 0.04) with total rainfall received during the previous summer (June–August). It is postulated that higher rainfall during the growing season of the bean crop stimulated root growth and root infection, leading to the accumulation of higher levels of potential inoculum in infected tissue and the release of higher levels of inoculum into the soil by the following June. Key words: Fusarium solani f.sp. phaseoli, bean, Phaseolus vulgaris, rainfall, crop rotation.

Summary

2013 ◽  
Author(s):  
André M. de Roos ◽  
Lennart Persson
Keyword(s):  
Population Dynamics ◽  
Life History ◽  
General Framework ◽  
Community Effects ◽  
Present Volume ◽  
Ontogenetic Niche Shifts ◽  
Niche Shifts ◽  
Different Types ◽  
Emergent Community ◽  
Ontogenetic Niche

This chapter provides a summary of the topics covered by the present volume. The summary serves the purpose of clearly showing how different chapters fit together in a general framework with respect to model approaches as well as results obtained. Reading this summary chapter will show readers the different types of community modules that will be analyzed as well as provide a clear impression of the results and insights that presented in this book. Topics discussed include biomass overcompensation, ontogenetic (a)symmetry in energetics, emergent community effects of biomass overcompensation, ontogenetic niche shifts in consumer life history, ontogenetic niche shifts in predator life history, competition between consumers with and without ontogenetic niche shifts, and ontogenetic (a)symmetry in energetics and population dynamics.

scholarly journals Forest Ecology beyond the Growing Season: Surveys of Fallen Leaves & Learning about Ecological Interactions

2020 ◽  
Vol 82 (4) ◽  
pp. 241-246
Author(s):  
Evan Lampert
Keyword(s):  
Forest Ecology ◽  
Mechanical Damage ◽  
Growing Season ◽  
Literacy Skills ◽  
Quantitative Literacy ◽  
Ecological Interactions ◽  
Analysis Techniques ◽  
Animal Activity ◽  
Different Types ◽  
Fallen Leaves

Forests are excellent “outdoor classrooms” for active learning in ecology and evolution; however, in many areas trees have no leaves or visible animal activity for much of the year. Fallen leaves may preserve evidence of interactions such as herbivory and infectious diseases, although these can be difficult to differentiate from mechanical damage and decomposition in older fallen leaves. I developed an exercise in which students collect fallen leaves and observe several different types of damage to the leaves. I provide images and descriptions of different types of damage and practices to differentiate them. In addition, I provide a list of questions that can be answered by collecting fallen leaves and observations of damage. My students gained valuable quantitative literacy skills by entering data into an online worksheet and performing various calculations and data analysis techniques. This exercise provides many benefits and can be an engaging addition to a high school's or college's outdoor curriculum outside of the growing season.

scholarly journals Understanding medical civil-military relationships within the humanitarian-development-peace ‘triple nexus’: a typology to enable effective discourse

2020 ◽  
pp. jramc-2019-001382 ◽  
Author(s):  
Simon Horne ◽  
S Boland
Keyword(s):  
Functional Groups ◽  
Future Study ◽  
Relative Stability ◽  
Visual Representation ◽  
Geographical Area ◽  
Common Language ◽  
Different Types ◽  
Foreign Policies ◽  
Military Activity ◽  
Hearts And Minds

The interface between humanitarianism, development and peacebuilding is increasingly congested. Western foreign policies have shifted towards pro-active stabilisation agendae and so Civil-Military Relationships (CMRel) will inevitably be more frequent. Debate is hampered by lack of a common language or clear, mutually understood operational contexts to define such relationships. Often it may be easier to simply assume that military co-operation attempts are solely to ‘win hearts and minds’, rather than attempt to navigate the morass of different acronyms. In healthcare, such relationships are common and more complex - partly as health is seen as both an easy entry point for diplomacy and so is a priority for militaries, and because health is so critical to apolitical humanitarian responses. This paper identifies the characteristics of commonly described kinds of CMRel, and then derives a typology that describe them in functional groups as they apply to healthcare-related contexts (although it is likely to be far more widely applicable). Three broad classifications are described, and then mapped against 6 axes; the underlying military and civilian motivations, the level of the engagement (strategic to tactical), the relative stability of the geographical area, and finally the alignment between the civilian and military interests. A visual representation shows where different types may co-exist, and where they are likely to be more problematic. The model predicts two key areas where friction is likely; tactical interactions in highly unstable areas and in lower threat areas where independent military activity may undermine ongoing civilian programmes. The former is well described, supporting the typology. The latter is not and represents an ideal area for future study. In short, we describe an in-depth typology mapping the Civil-Military space in humanitarian and development contexts with a focus on healthcare, defining operational spaces and the identifying of areas of synergy and friction.

scholarly journals Plant growth under suboptimal water conditions: early responses and methods to study them

2020 ◽  
Vol 71 (5) ◽  
pp. 1706-1722 ◽  
Author(s):  
Marieke Dubois ◽  
Dirk Inzé
Keyword(s):  
Plant Growth ◽  
Osmotic Stress ◽  
Stress Responses ◽  
Soil Drought ◽  
Growth Media ◽  
Plant Responses ◽  
Short Term ◽  
Environmental Constraint ◽  
Early Stress ◽  
Different Types

Abstract Drought stress forms a major environmental constraint during the life cycle of plants, often decreasing plant yield and in extreme cases threatening survival. The molecular and physiological responses induced by drought have been the topic of extensive research during the past decades. Because soil-based approaches to studying drought responses are often challenging due to low throughput and insufficient control of the conditions, osmotic stress assays in plates were developed to mimic drought. Addition of compounds such as polyethylene glycol, mannitol, sorbitol, or NaCl to controlled growth media has become increasingly popular since it offers the advantage of accurate control of stress level and onset. These osmotic stress assays enabled the discovery of very early stress responses, occurring within seconds or minutes following osmotic stress exposure. In this review, we construct a detailed timeline of early responses to osmotic stress, with a focus on how they initiate plant growth arrest. We further discuss the specific responses triggered by different types and severities of osmotic stress. Finally, we compare short-term plant responses under osmotic stress versus in-soil drought and discuss the advantages, disadvantages, and future of these plate-based proxies for drought.

scholarly journals Lightning Damage Facilitates Beetle Colonization of Tropical Trees

2020 ◽  
Author(s):  
Brady P Parlato ◽  
Evan M Gora ◽  
Stephen P Yanoviak
Keyword(s):  
Population Dynamics ◽  
Tropical Forest ◽  
Forest Ecosystems ◽  
Tropical Trees ◽  
Pine Forests ◽  
Forest Trees ◽  
Beetle Population ◽  
Tree Diameter ◽  
Crown Dieback ◽  
The Relationship

Abstract Lightning is a common agent of disturbance in many forest ecosystems. Lightning-damaged trees are a potentially important resource for beetles, but most evidence for this association is limited to temperate pine forests. Here, we evaluated the relationship between lightning damage and beetle colonization of tropical trees. We recorded the number of beetle holes on the trunks of trees from 10 strike sites (n = 173 lightning-damaged trees) and 10 matching control sites (n = 137 control trees) in Panama. The trunks of lightning-struck trees had 370% more beetle holes than control trees. The abundance of beetle holes increased with increasing total crown dieback among both control and lightning-damaged trees, and with larger tree diameter among lightning-struck trees. Beetle holes also were more abundant in trunk sections of lightning-damaged trees located directly below a damaged section of the crown. The results of this study suggest that lightning damage facilitates beetle colonization in tropical forest trees and provide a basis for investigations of the effects of lightning-caused disturbance on beetle population dynamics and assemblage structure.

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