Days In Mid-summer Research Articles

Trichomes affect grapevine leaf optical properties and thermoregulation

In the context of climate change, the optical properties of grapevine leaves have been used in imaging technologies to screen grapevine phenotypes tolerant to water deficit and heat waves in field conditions. Image-based plant phenotyping is challenging because the adaxial and the abaxial sides of the leaf present different morphology. This study investigated the effect of trichomes of the abaxial epidermis on the spectral responses in the two grapevine leaf sides. It was also examined the effect of pubescence on leaf thermoregulation, either during water deficiency or not. For this study, 99 Vitis spp. genotypes were categorised for their prostrate trichome density between main veins on the abaxial side of the leaves (using the descriptor OIV 084). In the first week of 2022, August, reflectance spectra from 400 to 700 nm and color indexes CIELAB and RGB were recorded in five leaves (both abaxial and adaxial sides) per genotype. During three days in midsummer, crop water stress index (CWSI) was also determined in each genotype. The abaxial leaf side was more reflective than the adaxial one in all visible color bands. Values of CIELAB (except for component a*) and RGB were higher for the abaxial leaf side than the adaxial one. The different spectral and color responses between leaf sides positively correlated with the descriptor OIV 084. Trichomes, which mainly occur on the abaxial side in grapevine, significantly contribute to the different optical properties between the two leaf sides. Correlation between OIV 084 and CWSI values was significantly positive (p < 0.05) only when vines were under drought, indicating that trichomes rise leaf temperature by probably reducing evaporative cooling under dry conditions. Therefore, pubescence could be a promising trait to consider when selecting varieties for drought tolerance.

Allotments in the Future: Building Resilience to Climate Change through Improved Site Design and Efficient Water Practices

In recent years, there has been a resurgence in the popularity of allotments and home- grown food in the UK. This interest is likely to increase as people become more aware of the health benefits of spending time outdoors. Climate projections for the UK indicate that over the next 20 years, winters will become warmer and wetter, and the summers hotter and drier. Most UK allotments and community gardens are a collection of individual plots whose holders are free to manage them as they wish, within site rules. The efficacy of individual efforts to collect and store rainwater is often limited as most allotment sites were laid out when water practices were a secondary consideration. Our research, which included visiting allotment sites and reviewing growing practices, suggests that grouping plots and sharing water facilities could enable plot holders to store sufficient water to meet anticipated demand for thirty rain-free days in midsummer. This combined with growing practices that improve soil moisture capacity and water use efficiency will provide effective mitigation against climate change.

Climatic Analysis of Ozone Data from the Konza Prairie Biological Station Sensor

A controversy involving human health issues and burning to maintain grassland health in the Flint Hills prompted this study. Available ground-level ozone and corresponding weather data for dates from April to October for the eleven-year period from 2002 to 2012 were subjected to statistical and synoptic climatic analysis. High ozone levels in the Flint Hills occurred during the presence of warm, dry air masses early in the warm season and more humid warm days in mid-summer. Synoptic analysis of ozone exceedance days in April documents the importance of surface high pressure to the east of the Flint Hills and weak southerly winds.

Salvinia molesta D.S. Mitch.

<i>Salvinia molesta</i> D.S. Mitch.

Treatment performance assessment and hydrological characterization of an arctic tundra wetland receiving primary treated municipal wastewater

Currently, tundra wetlands are used to treat municipal wastewater in many Arctic communities, typically following primary treatment from a wastewater stabilization pond. Inclusion of tundra wetlands as part of the municipal wastewater treatment strategy for the Canadian Arctic is an option to meet upcoming federal Wastewater Systems Effluent Regulations (WSER). Water quality improvement has been demonstrated in tundra wastewater treatment wetlands; however, the mechanisms responsible for this observed treatment are not well understood. In this study, we conducted a detailed physical, hydraulic, and biogeochemical analysis of a tundra wetland receiving primary treated municipal wastewater in Coral Harbour, Nunavut. The primary objective was to gain a better understanding of the processes which contribute to water quality improvement within these types of environmental systems. Data were collected during four study periods throughout the treatment season, between mid-June 2011 and early-September 2012. Study results illustrated seasonal variability in the treatment performance and hydraulic characteristics of the wetland. Hydraulic residence times (HRTs) as short as 11h were observed during the spring freshet, and as long as 14 days in mid-summer. Short HRTs in the spring freshet suggested the observed reduction of wastewater constituents was primarily by dilution from watershed contributions. Biogeochemical data showed seasonal increases in pH and DO, which were driven by algae growth, which corresponded to increases in TSS, and decreases in E. coli and nitrogen species. During the entire treatment season, the wetland effluent met the WSER, which does not currently include Nunavut, Canada. Contaminant concentration reductions were variable over the treatment season with the minimum reductions observed during the spring freshet (92.5% of BOD5, 3.7 log of E. coli, 95.4% of TSS, 77.3% of TN, 73.7% of TAN, 46.2% of NH3–N, and 78.9% of TP). Requisites for the responsible use of a wetland for wastewater treatment in an arctic setting should include the characterization of hydrological setting to quantify how external hydrologic inputs will influence treatment performance.

4th Young Investigator Workshop

The present issue of Chemical Monthly is dedicated to the work of young researchers participating in the 4th Young Investigator Workshop (YIW) which took place in August 2012 at Vienna University of Technology (http://investi gator.ias.tuwien.ac.at/). This novel symposium series was launched in 2009 by the Organic Division of the European Association for Chemical and Molecular Sciences (EuChEMS) as a meeting of the most promising researchers in Europe at the beginning of their independent career. Participants are nominated by the chemical societies of their respective countries, initially solely from EuChEMS member states. The series gained recognition rapidly among young researchers due to the unique setup: young scientists are free to network among themselves in an informal environment, sharing their most recent breakthrough results. These unique experiences made YIW become a regular event within the Organic Division of EuChEMS. Due to the success of past workshops, executives within the division decided to open up the meeting beyond European borders. For the first time, young researchers from Asia and North and South America joined a handpicked selection of aspiring young team leaders from Europe, making YIW4Vienna the largest meeting in this series to date. A total of 38 delegates from 23 countries celebrated a firework display of organic chemistry during several hot days in mid-summer in Vienna. It was this substantially increased audience together with the extremely high scientific quality of the presentations which resulted in a significantly increased visibility of this event. Ultimately, the attention of Springer was stirred to support the event as major sponsor and prompted this publisher to dedicate a special issue of this journal to the next generation of researchers in organic chemistry. We are sure you will enjoy reading this issue covering some of the exciting research presented at the workshop from many different areas of organic chemistry. You should also memorize the names of the corresponding authors of the articles, since they will be amongst the researchers leaving significant footprints within the field in the forthcoming years.

Evaluation of measurement accuracy and comparison of two new and three traditional net radiometers

Net radiation ( R n ) is the sum of the radiant energy at the Earth's surface and is a major component of the surface energy balance. However, R n is difficult to measure accurately, and multiple instruments are available to measure it. Two new instruments (Hukseflux Thermal Sensors B.V., model NR01; Kipp & Zonen B.V., model CNR 2) have been released within the past two years. We compared these models, two less-expensive older models (Kipp & Zonen B.V., model NR-Lite; Radiation and Energy Balance Systems, Inc., model Q*7.1), and a more expensive older model (Kipp & Zonen B.V., model CNR 1) over a uniform turfgrass surface for 33 days in mid-summer. Three replicates of each radiometer were included in the study (except for the CNR 1). The instruments that independently measure the four components of R n (models CNR 1 and NR01) were typically the most accurate. Incoming shortwave measurements from the four component instruments were compared to a reference pyranometer, and outgoing longwave measurements were compared to infrared measurements of surface temperature. The differences from the reference pyranometer and surface temperature measurements were typically 2% or less. There was a difference of approximately 5% in incoming longwave measurements between these two radiometer models. This is likely due to differences in calibration approaches, which are discussed. This emphasizes the need for standardization of longwave calibration methods and establishment of a world reference for longwave radiation. The instruments that do not separate shortwave and longwave radiation into component measurements (net all-wave radiometers, models NR-Lite and Q*7.1) were generally the least accurate, and had offsetting day and night differences that reduced daily total R n differences relative to the reference. The CNR 2 measures net shortwave and net longwave, and is an intermediate between a four component instrument and a net all-wave instrument. The R n measurement accuracy of the CNR 2 typically fell between that of the two groups. Differences among radiometers tended to be larger at night than during the day, indicating higher variability in longwave measurements. An inversion (flip) test in the field showed the NR-Lites and Q*7.1s had well matched detectors, however two of the three replicate CNR 2s had mismatch errors greater than 5%. This becomes important for measurements over non-vegetated surfaces. The data presented here should be helpful in selecting the most cost effective instrument for a given application.

Impact of dicyandiamide application on nitrous oxide emissions from urine patches in northern Victoria, Australia

Animal production systems in Australia are a significant contributor to nitrous oxide (N2O) emissions from soil, with the Australian Greenhouse Gas Inventory attributing ~25% of the N2O emissions from agricultural soils to animal production. Recent studies in New Zealand using dicyandiamide (DCD) in association with the application of urine to pastoral soil have reported reductions in N2O emission of up to 78% and reduced nitrate leaching of up to 45%. As such, the application of DCD to grazed pastures offers potential to reduce emissions resulting directly from animal production. This study was conducted on a border-check irrigated perennial pasture used for dairy production in northern Victoria. Automated enclosure chambers were linked to a fourier transformed infrared spectrometer to determine N2O emissions. The three treatments were a control, dairy cow urine (1000 kg N/ha) and dairy cow urine (1000 kg N/ha) with DCD included (10 kg/ha). The treatments were applied in mid-spring (15 September 2005) and again in mid-summer (25 January 2006) to a new area of pasture with N2O emissions measured for 120 and 70 days, respectively. Soil temperature and soil water content were monitored continuously. Soil inorganic-N was measured (0–100 mm) every 7 to 14 days for up to 120 days. Application of DCD reduced N2O emissions from a urine patch by 47% when applied in mid-spring and 27% when applied in mid-summer. The impact of the application of DCD on emissions from single urine patches lasted for ~50 days in mid-spring and 25 days in mid-summer. These reductions are lower than those reported in New Zealand studies and are likely to be related to soil conditions, principally temperature. The surface application of DCD has potential to reduce emissions from urine patches in northern Victoria; however, the effects are likely to be short-lived given the soil temperatures and high clay content typical of many Australian soils. More research is required to examine emission reduction options that are cost effective for animal production systems.

An investigation of the effect of initial milk yield level on the response to sward height and concentrate supplementation in grazing dairy cows

The increase of milk yield potential of dairy cows raises a number of questions relating to their management at pasture where the intake potential might be limiting. The interaction of initial milk yield (IMY), sward availability (SH) and level of concentrate supplementation (CI) is largely unknown.Two experiments of 42 and 24 days in spring and midsummer were carried out with 45 and 27 Holstein Friesian cows respectively. In spring, five IMY groups (range 16.9 to 35.5 kg/day) and in midsummer three IMY groups (range 22.2 to 31.8 kg/day) were used. In both periods, three compressed sward height(3 to 5, 5 to 7 and 7 to 9 cm) and three CI (0, 3 and 6 kg/day, with 160 g CP/kg DM, 12.8 MJ ME/kg DM) were used. The grazing area consisted of 7.9 ha of perennial ryegrass which was set stocked. The herbage intake (HDMI) was estimated indirectly from individual cow performance. Grazing time (GT) was recorded for each cow on 24 hour observations. Multiple regression analyses were carried out relating the dependent variables herbage intake, grazing behaviour and milk production to the independent variables (IMY, SH, CI).

An investigation of the effect of initial milk yield level on the response to sward height and concentrate supplementation in grazing dairy cows

The increase of milk yield potential of dairy cows raises a number of questions relating to their management at pasture where the intake potential might be limiting. The interaction of initial milk yield (IMY), sward availability (SH) and level of concentrate supplementation (CI) is largely unknown.Two experiments of 42 and 24 days in spring and midsummer were carried out with 45 and 27 Holstein Friesian cows respectively. In spring, five IMY groups (range 16.9 to 35.5 kg/day) and in midsummer three IMY groups (range 22.2 to 31.8 kg/day) were used. In both periods, three compressed sward height(3 to 5, 5 to 7 and 7 to 9 cm) and three CI (0, 3 and 6 kg/day, with 160 g CP/kg DM, 12.8 MJ ME/kg DM) were used. The grazing area consisted of 7.9 ha of perennial ryegrass which was set stocked. The herbage intake (HDMI) was estimated indirectly from individual cow performance. Grazing time (GT) was recorded for each cow on 24 hour observations. Multiple regression analyses were carried out relating the dependent variables herbage intake, grazing behaviour and milk production to the independent variables (IMY, SH, CI).

Body mass variation in semidomesticated reindeer

The between-years and within-year variation in mass of semidomesticated reindeer calves and females was studied in four herds in Finnish Lapland. Mass data covered 11–23 years. In two of the herds the intensity of supplemental feeding in mid and late winter increased throughout the sampling period, whilst in two other herds the amount of food available per capita fell drastically as a result of increased density (about 1–4 individuals/km2). Calf mass increased in both supplementally fed herds and female mass in one of them. In herds on natural ranges female mass was density dependent. Both calf mass (three herds) and female mass (one herd) correlated negatively with the number of warm days in midsummer, most likely because of severe insect harassment. The sum of snow depth during the two or three preceding winters influenced body mass inversely in one herd and positively in another herd, where snow depth probably increased the availability of arboreal lichens. The detrimental effect of warm midsummers disappeared with intensification of supplemental feeding and the resultant improvement of female condition in winter. Within-year coefficients of variation (CV) correlated negatively with mean mass for calves in all four herds and for females in one herd. For calves (two herds) and for females (one herd) CV correlated positively with the number of warm days in midsummer. We suggest that late-born calves, and females who lost body reserves in winter, were most sensitive to insect harassment.

Water extraction and fruit expansion by kiwifruit

Abstract The behaviour of 4-year-old kiwifruit (Actinidia deliciosa (A. Chev.) C. F. Liang & A. R. Ferguson) vines growing in a Springbank soil within the Kerikeri Irrigation Scheme was monitored over the 1982–83 season. Water stress was induced in two vines by withholding irrigation and preventing rainfall recharge. Fruit volume expansion appeared strongly linked to the hydraulic status of the vines and could be described by a simple model whereby fruit either expand at the maximum rate shown on well-watered vines, or not at all if water is limiting. Volume losses resulting from fruit softening after extreme water stress were quickly recovered upon the reapplication of irrigation and could be ignored for modelling the influence of water stress on harvest yields. In the absence of rainfall or irrigation, the readily available moisture in this soil is capable of maintaining unrestricted fruit volume expansion for 10 days in mid summer. This result is extrapolated to other soils within the Irrigation Scheme...

Field Biology and Host Range of the Green Broomweed Looper, Narraga fimetaria (Lepidoptera: Geometridae), in Central Texas1

Narraga fimetaria (Grote and Robinson) is the most common insect consuming the foliage of annual broomweed in central Texas. Broomweed and snakeweed are its only hosts. We reared larvae in the laboratory and collected them in the field on two annuals, Amphiachyris dracunculoides (DC.) Nutt. (common broomweed) and Gutierrezia texana (DC.) T.&G. (Texas broomweed), and two perennials, G. sarothrae (Pursh) Britt. and Rusby (broom snakeweed) and G. microcephala (DC.) Gray (threadleaf snakeweed). Four generations occurred in the field, and a generation required 31 to 33 days in midsummer. Adults from overwintering pupae emerged during April and May, and larvae were present on broomweed plants throughout the season until November. The highest population peaks in the field were only 0.37 and 0.61 larvae per plant in August and September, which caused no noticeable damage to the plants. Major parasites of larvae were Websteriana costalis (Coquillett) (Diptera: Tachinidae), Tetrasphaeropyx n. sp. (Hymenoptera: Braconidae), and Euplectrus comstockii Howard (Hymenoptera: Eulophidae).

Thermal biology of the common garter snake Thamnophis sirtalis (L.) : I. Temporal variation, environmental effects and sex differences.

This paper describes the thermal biology of the common garter snake, Thamnophis sirtalis, a diurnal, viviparous colubrid. The body temperatures of snakes caught in the field are cooler and more variable early and late in the day, and early and late in the active season. On sunny days in midsummer, females average about 1 C° warmer than males. The frequency distribution of body tempratures for females is skewed to the left, whereas that for males is nearly symmetrical. Under cloudy skies, body temperatures are lower and more variable than under sunny skies, and the difference between males and females disappears. This and related considerations suggest to us that males are less determined, or less precise, thermoregulators than are females. Air and ground-surface temperatures, and snout-vent length, are poor predictors of body temperature. In contrast with other studies, we found no indication that the body temperatures of gravid and nongravid females differ either in mean or variance. We discuss our conclusions in light of previous studies and identify in the latter, analytical shortcomings which we believe hinder interpretation and synthesis.

Life History of Tricholyga bombycis (Diptera: Tachinidae), a Parasite of Bombyx mori(Lepidoptera: Bombicidae)

Tricholyga bombycis was collected from the field and reared in the laboratory. The egg, larvae, pupae, and adults are described. Macrotype eggs, laid mostly on the intersegmental regions of the silkworm, Bombyx mori, averaged ca. 2 in each host. Hatching occurred in 2–3 days. The parasite larva entered and fed inside the host larva for 5–6 days. The 3rd instars emerged through the integument of the host and pupated within 6–8 h. Adults emerged 10 days later, although in winter the period was extended to 14 days. Thus a generation required ca. 18 days in mid-summer and ca. 22 days in winter. The sex ratio of reared adults was 1:1.

Sunlight and viability of cereal rust uredospores

Uredospores (urediniospores) of Puccinia striiformis West., P. graminis Pers. f.sp. tritici Eriks. & Henn. and P. recondita Rob. & Desm. f.sp. tritici Eriks. & Henn. were exposed to sunlight on cooled supporting surfaces at ground level, while control spores were held in shade at similar temperatures. Spores in shade remained highly germinable for the duration of the exposures. About 20 h exposure to sunlight on relatively clear days in midsummer in England reduced germinability of P. graminis uredospores to 10% whilst 6–10 h caused a similar reduction in germinability of uredospores of P. striiformis. Sparse data for P. recondita indicate its uredospores to be about two-thirds as resistant as those of P. graminis. Exposure for a complete day in relatively sunny conditions reduced the germinability of P. striiformis uredospores to less than 0·1%. Experiments with short-wave cut-off filters suggested that solar energy in wavelengths close to 300 nm was only partly responsible for inactivation; wavelengths within the 315–400 nm band were also involved. It is concluded that the detrimental effect of solar radiation on longdistance uredospore dispersal, although variable, is likely to be significant on certain occasions, particularly for P. striiformis.

Life History of Winthemia manducae (Diptera: Tachinidae), a Parasite of the Tobacco Hornworm1

Winthemia manducae Sabrosky & DeLoach was collected from all tobacco-growing areas of North Carolina but only as far south as Florence, S. C. It was reared from pupae of Manduca sexta (Johannson) and M. quinquemaculata (Haworth). The egg and larva are described. Macrotype eggs were laid on the integument of large last-stadial host larvae, in numbers from 1 to 125 but averaged about 8 per host. Eggs noramlly did not hatch until the host prepupa molted in its cell in the soil, at which time the parasitic larvae entered the host pupa before its integument hardened. The egg stage usually lasted about 7 days, but little hatching occurred unless the host pupated. Multiple parasitism involving Apanteles congregatus (Say) prevented the egg from hatching because A. congregatus killed the host before it pupated. The larvae of W. manducae fed inside the host pupa for 7 days then left the host and pupated within 2 days, largely in the upper 3 inches of the soil. Pupation was greatly delayed, probably by bacterial action, when full-grown larvae were confined with the dead host. Adults emerged 16 days later, the males emerging first. Females began ovipositing in 4 days. Thus a generation required about 37 days in midsummer. The sex ratio of reared adults was 1:1, but males were not found in the field with the females. Larvae required 233 and pupae 500 day-degrees for development above the lower threshold of 8.3°C. A threshold between 18 and 24°C was detected below which pupation of mature larvae was greatly delayed. Only full-grown larvae were observed to overwinter and these were tolerant to experimental exposure to subfreezing temperatures. The egg appeared to be the stage most susceptible to submersion and the pupa the stage most susceptible to high temperature under field conditions.