scholarly journals Seasonal availability of inoculum of the Heterobasidion root disease pathogen in central Wisconsin

2016 ◽  
Vol 46 (8) ◽  
pp. 1076-1080 ◽  
Author(s):  
Glen R. Stanosz ◽  
Denise R. Smith ◽  
Jennifer Juzwik
Keyword(s):  
Late Summer ◽  
Root Disease ◽  
Growing Seasons ◽  
Seasonal Factors ◽  
Winter Temperatures ◽  
Spore Trapping ◽  
Root Grafts ◽  
Root Contact ◽  
Heterobasidion Irregulare

After deposition of airborne basidiospores, the root disease pathogen Heterobasidion irregulare Garbelotto and Otrosina infects fresh conifer stumps and spreads through root grafts or by root contact to adjacent trees. Infection can be prevented, however, by borate application. Because the need for stump protection depends on inoculum availability, spore trapping was conducted (usually biweekly) from September 2009 through December 2011 in three infested plantations of predominantly red pine (Pinus resinosa Aiton) in central Wisconsin. A semiselective medium in Petri plates was exposed for 1 h in daylight at each of four locations in each plantation. After 7–10 days incubation at 20 °C, plates were examined and presence and abundance of colonies of the Spiniger asexual stage were recorded. Heterobasidion irregulare was detected on most dates during the two growing seasons, but colonies were most abundant during late summer, fall, and early winter. Relatively fewer colonies developed on medium exposed during periods of coldest winter temperatures, but colonies of the pathogen did develop frequently on medium exposed at ≤ 5 °C and occasionally on medium exposed at ≤ 0 °C. Biologically based guidelines for stump treatment require additional studies of seasonal factors influencing inoculum availability, in situ spore germination, infection, and establishment of the pathogen.

Mechanisms of intertree transmission of Ceratocystiswageneri in young Douglas-fir

1986 ◽  
Vol 16 (6) ◽  
pp. 1250-1254 ◽  
Author(s):  
P. F. Hessburg ◽  
E. M. Hansen
Keyword(s):  
Microscopic Examination ◽  
Fine Roots ◽  
Douglas Fir ◽  
Root Disease ◽  
Limited Growth ◽  
Successful Transmission ◽  
Root Grafts ◽  
Root Contact ◽  
Root Feeding ◽  
Graft Transmission

Root-feeding insects are known to vector black-stain root disease in Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco). Intertree spread through root grafts and limited growth through soil is demonstrated as well. In potted seedling experiments, contact between roots of inoculated and healthy seedlings was either allowed or prevented. Transmission occurred in both treatments but was significantly more frequent (P = 0.01) when intertree root contact was allowed. In the root-contact treatment, 67% of the receptor seedlings died as a result of successful transmission. In the noncontact treatment, 35% of the receptor seedlings died. Evidence points to wounds on fine roots as principal infection courts. Root graft transmission of C. wageneri was verified through field excavation and microscopic examination of 23 root grafts from three widely separated sites.

Seasonal Photosynthesis and Partitioning of Nonstructural Carbohydrates in Leafy Spurge (Euphorbia esula)

Weed Science ◽  
2007 ◽  
Vol 55 (4) ◽  
pp. 346-351 ◽  
Author(s):  
Russ W. Gesch ◽  
Debra Palmquist ◽  
James V. Anderson
Keyword(s):  
Late Summer ◽  
Leafy Spurge ◽  
Adventitious Bud ◽  
Adventitious Buds ◽  
Continuous Increase ◽  
Carbohydrate Partitioning ◽  
Growing Seasons ◽  
Autumn Leaf ◽  
Carbohydrate Status ◽  
New Strategies

Previous evidence indicates that changes in well-defined phases of dormancy in underground adventitious buds of leafy spurge in late summer and autumn are regulated by complex sensing and signaling pathways involving aboveground sugar signals. However, little information exists concerning seasonal photosynthesis and carbohydrate partitioning of leafy spurge, although such information would help to elucidate the involvement of sugar in controlling bud dormancy. An outdoor study was conducted over two growing seasons to determine and model seasonal patterns of photosynthesis and aboveground carbohydrate partitioning and their relationship to underground adventitious bud carbohydrate status. Photosynthesis and total nonstructural carbohydrate (TNC) content of aboveground tissues was greatest during vegetative growth. Photosynthesis gradually declined over the growing season, whereas TNC decreased sharply during flowering, followed by a gradual decline between midsummer and autumn. Leaf starch increased dramatically to midsummer before declining sharply throughout late summer and early autumn, whereas sucrose content responded inversely, indicating a mobilization of starch reserves and export of sugars to overwintering belowground sink tissues. Because newly formed underground adventitious buds showed a continuous increase in TNC from midsummer through autumn, export of sugars from aboveground tissues likely contributed to the increase in TNC. These results may facilitate new strategies for biological control of leafy spurge.

scholarly journals Concentrations, ratios, and sinking fluxes of major bioelements at Ocean Station Papa

Elem Sci Anth ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Montserrat Roca-Martí ◽  
Claudia R. Benitez-Nelson ◽  
Blaire P. Umhau ◽  
Abigale M. Wyatt ◽  
Samantha J. Clevenger ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Late Summer ◽  
Euphotic Zone ◽  
Particulate Phosphorus ◽  
Particulate Nitrogen ◽  
Sinking Particles ◽  
Ocean Station Papa ◽  
Particle Size Classes

Fluxes of major bioelements associated with sinking particles were quantified in late summer 2018 as part of the EXport Processes in the Ocean from RemoTe Sensing (EXPORTS) field campaign near Ocean Station Papa in the subarctic northeast Pacific. The thorium-234 method was used in conjunction with size-fractionated (1–5, 5–51, and >51 μm) concentrations of particulate nitrogen (PN), total particulate phosphorus (TPP), biogenic silica (bSi), and particulate inorganic carbon (PIC) collected using large volume filtration via in situ pumps. We build upon recent work quantifying POC fluxes during EXPORTS. Similar remineralization length scales were observed for both POC and PN across all particle size classes from depths of 50–500 m. Unlike bSi and PIC, the soft tissue–associated POC, PN, and TPP fluxes strongly attenuated from 50 m to the base of the euphotic zone (approximately 120 m). Cruise-average thorium-234-derived fluxes (mmol m–2 d–1) at 120 m were 1.7 ± 0.6 for POC, 0.22 ± 0.07 for PN, 0.019 ± 0.007 for TPP, 0.69 ± 0.26 for bSi, and 0.055 ± 0.022 for PIC. These bioelement fluxes were similar to previous observations at this site, with the exception of PIC, which was 1 to 2 orders of magnitude lower. Transfer efficiencies within the upper twilight zone (flux 220 m/flux 120 m) were highest for PIC (84%) and bSi (79%), followed by POC (61%), PN (58%), and TPP (49%). These differences indicate preferential remineralization of TPP relative to POC or PN and larger losses of soft tissue relative to biominerals in sinking particles below the euphotic zone. Comprehensive characterization of the particulate bioelement fluxes obtained here will support future efforts linking phytoplankton community composition and food-web dynamics to the composition, magnitude, and attenuation of material that sinks to deeper waters.

Planting Date Affects Survival and Height Growth of Hybrid Poplar

1986 ◽  
Vol 62 (3) ◽  
pp. 164-169 ◽  
Author(s):  
Edward A. Hansen
Keyword(s):  
Hybrid Poplar ◽  
Late Summer ◽  
Growing Season ◽  
Climatic Conditions ◽  
Planting Date ◽  
Planting Dates ◽  
Soil Frost ◽  
Growing Seasons ◽  
Poplar Cuttings ◽  
Energy Plantations

In this study I investigated the effects of planting date for soaked versus unsoaked cuttings of two hybrid poplar clones under irrigated versus unirrigated and weedy versus weed-free conditions. Cuttings were planted each year for 4 years. Survival at the end of the first growing season was generally greater than 90% for all planting dates. At the end of the second growing season survival for trees planted before July 16 was again generally more than 90%. However, cuttings planted from July 30 through August 27 showed a major decline in survival and survival of fall planted cuttings ranged from 6 to 90%. Mortality of late summer- or fall-planted cuttings occurred prior to the beginning of the second growing season and was attributed to frost heaving. The tallest trees were not those planted at the earliest possible dates (April in Rhinelander). Instead, the tallest trees at the end of the first and second growing seasons were those planted in early- and mid-May. This optimum planting period was the same regardless of clone, soaking, irrigation, or weed treatment. Actual optimum planting date would change with location and local climatic conditions. Some climatic indices may prove more universal in predicting when to plant. Although tentative, it appears that for best growth, unrooted hybrid poplar cuttings should be planted in soil warmer than 10 °C. Trees do not grow as well if planted immediately after soil frost leaves the ground. Key words: Energy plantations, plantation establishment, woody biomass, intensive culture, Populus.

Diurnal gross photosynthetic patterns and potential seasonal CO2 assimilation in Cladonia stellaris and Cladonia rangiferina

1983 ◽  
Vol 61 (3) ◽  
pp. 642-655 ◽  
Author(s):  
Thomas J. Moser ◽  
Thomas H. Nash III ◽  
Steven O. Link
Keyword(s):  
Photosynthetic Activity ◽  
Growing Season ◽  
Early Morning ◽  
Co2 Assimilation ◽  
Atmospheric Moisture ◽  
Growing Seasons ◽  
Late Evening ◽  
Summer Rain ◽  
Cladonia Rangiferina

The daily, in situ gross photosynthetic patterns of Cladonia stellaris (Opiz.) Pouz. & Vězda. and Cladonia rangiferina (L.) Wigg. were monitored during portions of the 1977, 1978, and 1979 growing seasons at Anaktuvuk Pass, Alaska. Photosynthetic activity in both species closely paralleled atmospheric moisture status, where peak photosynthetic rates were attained during or following sporadic summer rain. In addition, thallus absorption of moisture during extended periods of high atmospheric water vapor content gave rise to short periods of minimal photosynthetic activity. During late evening and early morning hours moistened thalli exhibited minimal or no photosynthetic activity, coinciding with consistent attenuation in solar radiation during these periods. Photosynthetic activity was not homogeneous throughout the thallus. The greatest activity occurred in the apical regions and decreased progressively into the basal regions. The apical 10-mm regions of C. stellaris and C. rangiferina thalli accounted for approximately 50% of their photosynthetic capabilities. The potential gross CO2 assimilation of the apical 10-mm regions over 72 days of the 1978 growing season was estimated at approximately 35 g CO2∙m−2 and 16 g CO2∙m−2 for C. stellaris and C. rangiferina, respectively.

Surface burning in a mature stand of Pinus resinosa and Pinus strobus in Michigan: effects on understory vegetation

2001 ◽  
Vol 10 (1) ◽  
pp. 91 ◽  
Author(s):  
David D. Neumann ◽  
Donald I. Dickmann
Keyword(s):  
Late Summer ◽  
Pinus Resinosa ◽  
Red Pine ◽  
Phytolacca Americana ◽  
Vegetative Cover ◽  
White Pine ◽  
Periodic Surface ◽  
Surface Fires ◽  
Growing Seasons ◽  
Surface Burning

Beginning in 1991, periodic surface fires (frontal fire intensities <200 kW m–1) were introduced into a mixed red pine (Pinus resinosa Ait.) and white pine (P. strobus L.) plantation (dbh 16–60 cm). Replicated plots of 0.4–0.5 ha were either burned three times at biennial intervals (early May of 1991, 1993, and 1995), burned once (early May 1991), or not burned. Measurements were conducted during the 1994 and 1995 growing seasons. The pine overstory was largely unaffected by the fires. The understory on unburned plots contained 16 111 large seedlings (>1 m, ≤ 1.9 cm dbh) and 3944 saplings (2.0–5.9 cm dbh) per ha, consisting of 23 woody angiosperm taxa. Plots burned once contained 60% of the large seedlings, 7% of the saplings, and 6 fewer taxa than unburned plots. No large seedlings and few saplings were found in plots burned biennially. Cover of low (<1 m) woody and herbaceous vegetation in plots burned once or three times was twice that of unburned plots, even in the growing season immediately following the May 1995 re-burn. Recovery of low vegetative cover in the re-burned plots was rapid, exceeding that in once-burned or unburned plots by late summer following the burn. Species richness of low vegetation was 20–25% higher in burned than unburned plots, except in the year immediately following reburning. Taxa dominating this site following burning were Sassafras albidum (Nutt.) Nees, Rubus spp., Phytolacca americana L., and Dryopteris spinulosa (O.F. MÜll.) Watt. Restoration of low-intensity surface fires to ecosystems dominated by mature red pine or white pine is feasible, but major changes in understory structure and composition will occur.

Seasonal changes in forage nutritive value of common weeds encountered in Missouri pastures

2019 ◽  
Vol 34 (2) ◽  
pp. 164-171
Author(s):  
Gatlin Bunton ◽  
Zach Trower ◽  
Craig Roberts ◽  
Kevin W. Bradley
Keyword(s):  
Tall Fescue ◽  
Crude Protein ◽  
Nutritive Value ◽  
Late Summer ◽  
Growing Season ◽  
Quality Parameter ◽  
Neutral Detergent Fiber ◽  
Weed Species ◽  
Growing Seasons

AbstractDuring the 2015, 2016, and 2017 growing seasons, weed and weed-free mixed tall fescue and legume forage samples were harvested from 29 pastures throughout Missouri for investigation of the nutritive value of 20 common pasture weed species throughout the season. At certain times during the growing season, many broadleaf weed species had greater nutritive values for a given quality parameter as compared with the available weed-free, mixed tall fescue and legume forage harvested from the same location. There were no significant differences in crude protein concentration between the weed-free forage and many weeds throughout the growing season. However, crude protein content of common burdock, common cocklebur, common ragweed, dandelion, horsenettle, and lanceleaf ragweed was greater than that of the corresponding forage sample at multiple collection periods. The digestible neutral detergent fiber (dNDF) content of all broadleaf weeds except lanceleaf ragweed was significantly lower than that of the weed-free forage at all collection periods. Conversely, large crabgrass had significantly greater digestible neutral detergent fiber levels than did the mixed tall fescue forage at all sampling dates. Dandelion and spiny amaranth had greater in vitro true digestibility (IVTD) content than did the forage for the entire growing season. Three perennial weeds—horsenettle, vervains, and late boneset—did not differ in IVTD levels as compared with the mixed tall fescue and legume forage at any collection date. For most summer annual weeds, the trend was toward greater digestibility earlier in the season, with a gradual decline and often lower IVTD by the late summer or early fall. The results of this study will enable producers to make more informed management decisions about the potential benefit or detriment a weed may provide to the overall nutritive value of the pasture system.

scholarly journals Exploring the Potential of Satellite Solar-Induced Fluorescence to Constrain Global Transpiration Estimates

2019 ◽  
Vol 11 (4) ◽  
pp. 413 ◽  
Author(s):  
Brianna Pagán ◽  
Wouter Maes ◽  
Pierre Gentine ◽  
Brecht Martens ◽  
Diego Miralles
Keyword(s):  
Eddy Covariance ◽  
Land Surface ◽  
Radiant Energy ◽  
Energy System ◽  
Plant Responses ◽  
Natural Ecosystem ◽  
Growing Seasons ◽  
Phenological Changes ◽  
Opening And Closing

The opening and closing of plant stomata regulates the global water, carbon and energy cycles. Biophysical feedbacks on climate are highly dependent on transpiration, which is mediated by vegetation phenology and plant responses to stress conditions. Here, we explore the potential of satellite observations of solar-induced chlorophyll fluorescence (SIF)—normalized by photosynthetically-active radiation (PAR)—to diagnose the ratio of transpiration to potential evaporation (‘transpiration efficiency’, τ). This potential is validated at 25 eddy-covariance sites from seven biomes worldwide. The skill of the state-of-the-art land surface models (LSMs) from the eartH2Observe project to estimate τ is also contrasted against eddy-covariance data. Despite its relatively coarse (0.5°) resolution, SIF/PAR estimates, based on data from the Global Ozone Monitoring Experiment 2 (GOME-2) and the Clouds and Earth’s Radiant Energy System (CERES), correlate to the in situ τ significantly (average inter-site correlation of 0.59), with higher correlations during growing seasons (0.64) compared to decaying periods (0.53). In addition, the skill to diagnose the variability of in situ τ demonstrated by all LSMs is on average lower, indicating the potential of SIF data to constrain the formulations of transpiration in global models via, e.g., data assimilation. Overall, SIF/PAR estimates successfully capture the effect of phenological changes and environmental stress on natural ecosystem transpiration, adequately reflecting the timing of this variability without complex parameterizations.

scholarly journals Influence of a Municipal Solid Waste Landfill on the Surrounding Environment: Landfill Vegetation as a Potential Risk of Allergenic Pollen

2019 ◽  
Vol 16 (24) ◽  
pp. 5064 ◽  
Author(s):  
Magdalena Daria Vaverková ◽  
Dana Adamcová ◽  
Jan Winkler ◽  
Eugeniusz Koda ◽  
Jana Červenková ◽  
...  
Keyword(s):  
Plant Species ◽  
Low Cost ◽  
Late Summer ◽  
Cost Effective ◽  
Early Spring ◽  
Early Summer ◽  
Allergenic Pollen ◽  
Grass Species ◽  
Vegetation Monitoring ◽  
Growing Seasons

When the landfill use comes to end, important subsequent steps include aftercare, safety assurance, and ecological regeneration. Landfill revegetation is cost-effective and eco-friendly approach in the management of landfill areas, which serves the purpose of stabilization and provides a pleasant landscape. There are various vegetation types that can be planted, yet grass species are often used for low-cost reasons. Plants can be important sources of air pollution, particularly by grass pollen. The main goal of our study was to identify plant species that produce allergenic pollen. Long-term vegetation monitoring took place on three sites in the growing seasons of years 2008–2018. Studied objects were landfills located in the Czech Republic. The vegetation was assessed using a floristic survey of identified plant species. Plant species that produced allergens were recorded. During the monitoring, 298 plant species were determined. Plant species with allergenic pollen have a considerable share in the landfill vegetation. Thus, landfills are potential sources of various kinds of allergenic pollen. Moreover, our results indicated that there are three periods of pollen production: early spring, late spring, and early summer; late summer; and autumn. The second period is typical for the production of highly allergenic pollen by grasses. Most detected plant species with allergenic pollen are common for all monitored sites, which demonstrates that the vegetation of landfills is a significant source of allergenic pollen.

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