Nondestructive Age Estimation of Mountain Big Sagebrush (Artemisia tridentata ssp. vaseyana) Using Morphological Characteristics

Current methods for determining plant age of shrub species require destructive sampling and annual growth ring analysis on the primary stem. Although individual plant ages can frequently be determined in this manner, the method is time consuming and of limited value for plants that have lost stem wood from stem splitting and rot. Nondestructive methods for estimating big sagebrush (Artemisia tridentata Nutt.) plant age would be useful in assessing stand age structure and population dynamics at variable spatial scales. The purpose of this study was to test a suite of traits for potential use in estimating mountain big sagebrush (Artemisia tridentata ssp. vaseyana [Rydb.] Beetle) age. We evaluated traits including plant height, crown area, subcanopy litter depth, percent crown mortality, bark furrow depth, bark fiber length, circumference and diameter of plant basal stem, and circumference of secondary and tertiary branches. We measured and harvested basal cross-sections from 163 plants of varying sizes from five locations in central and south-central Utah. Plant age was determined from annual growth rings. Linear regression analyses revealed that stem diameter (r² = 0.507 P < 0.0001) was the most highly correlated variable with plant age across all sites, followed by stem circumference (r² = 0.474 P < 0.0001), secondary branch circumference (r² = 0.360, P < 0.0001), tertiary branch circumference (r² = 0.405, P < 0.0001), and bark fiber length (r² = 0.373, P < 0.0001). Results support previous findings that stem girth has value for estimating mountain big sagebrush plant age and that this trait is a better indicator of age than any other tested traits. Although the relationship between stem diameter and plant age was significant, substantial stem size variability associated with plants of the same approximate age indicates that the method is most appropriate when precise age estimates are not required. This technique was developed specifically for mountain big sagebrush, but it is expected that it can be adapted for other sagebrush taxa.     

Structure-specific detection of plant cuticle bound residues of chlorothalonil by ELISA

Monoclonal antibodies (mAb) against the main photo-addition products of chlorothalonil with olefinic compounds of plant cuticles were produced. An indirect competitive enzyme-linked immunosorbent assay (ELISA) was developed for the detection of free and bound chlorothalonil and its derivatives. For the characterization of the binding properties of the mAb, derivatives of chlorothalonil (simulating structures of cuticle bound residues) were synthesized. The cross-reactivities of these products were determined by ELISA. The test system was employed to detect bound residues of chlorothalonil in enzymatically isolated tomato cuticles, which had been spiked with methanolic solutions of the compound, irradiated by simulated sunlight and extracted. The use of isolated cuticles allows work to be carried out with authentic material without disturbance by metabolic processes. © 1999 Society of Chemical Industry     

Holzbiologische Untersuchungen über den Einfluß von Auftausalz auf Hamburger Straßenbäume

Zusammenfassung Aus dem Stadtgebiet von Hamburg wurden 341 Stra?enb?ume der GattungenAcer, Aesculus, Betula, Fraxinus, Platanus, Quercus, Robinia, Sorbus undTilia hinsichtlich ihrer Empfindlichkeit gegenüber Streusalz untersucht. Als Untersuchungsmethoden dienten Jahrring-analyse sowie Histometrie und energiedispersive R?ntgen-Mikroanalyse. Auf Standorten mit hohem Bodensalzgehalt zeigten die meisten B?ume seit Mitte der 60er Jahre Zuwachsrückg?nge von über 50%, was zu einer Verringerung der wasserleitenden Querschnittsfl?che in den St?mmen und vermutlich zu den Blattnekrosen in der Krone führte. Alle an streusalzbelasteten Stra?en lebenden Ahornb?ume, Linden und Ro?kastanien zeigten eine starke Vitalit?tsminderung. Lediglich die Eichen und Robinien lassen keine streusalzbedingten Wachstums?nderungen erkennen. Zur Erholung der gesch?digten B?ume sowie zur Sicherung der toleranten Baumarten müssen eine weitere Salzzufuhr verhindert und die bereits angereicherten Salzmengen aus dem Kreislauf Boden-Baum-Boden entfernt werden.

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Wood-biological investigations on the influence of deicing salt on roadside trees in Hamburg

Summary From the urban area of Hamburg, 341 roadside trees of the generaAcer, Aesculus, Betula, Fraxinus, Platanus, Quercus, Robinia, Sorbus andTilia have been investigated concerning their sensitivity to deicing salt. The methods used were tree-ring analysis, histometrical studies, and X-ray microanalysis. Since the middle of the Sixties the radial growth of most tress decreased more than 50% on all sites with a high salt content in the soil, leading to a reduction of the water-conducting area in the stems. The necrosis of the leaves is presumably a result of this situation. All maples, horsechestnuts, and limes growing along roads affected by deicing salt showed a highly decreased vitality. Only oak and black locust do not exhibit any saltinfluenced growth responses. For the recovery of the injured trees as well as for safeguarding the more tolerant tree species a further salt transport to the roots must be prevented, and the amount of salt already accumulated must be removed from the soil-tree-soil cycle.

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Wir danken Dr.H. Meyer-Spasche, Ordinariat für Bodenkunde der Universit?t Hamburg, für die Bereitstellung der bodenchemischen Standortsdaten, Prof. Dr.N. Parameswaran für die energiedispersive R?ntgen-Mikroanalyse sowie Frau Dipl.-HolzwirtS. Wrobel und FrauF. Quiehl für ihre Mithilfe bei der Laborauswertung. Die Arbeit wurde von der Beh?rde für Bezirksangelegenheiten, Naturschutz und Umweltgestaltung (BBNU) der Freien und Hansestadt Hamburg finanziell unterstützt. Die Baubeh?rde stellte Informationen über die Intensit?t der Streusalzanwendung zur Verfügung.     

Crop coefficients for winter wheat in a sub-humid climate regime

Estimations of evapotranspiration (ET) from natural surfaces are used in a large number of applications such as agricultural water management and water resources planning. Lack of reliable, cheap and easy-to-use instruments, associated with the chaotic and varying nature of the meteorological and plant physiological factors influencing ET cause these estimations to be based on calculated values rather than the measured ones. The two-step approach where ET from a reference crop is calculated and multiplied by empirical crop coefficients to obtain ET from a crop has gained wide acceptance. Daily coefficients for a winter wheat crop growing under standard conditions, i.e. not short of water and growing under optimal agronomic conditions, were estimated for a cold sub-humid climate regime. One of the two methods used to estimate ET from a reference crop required net radiation (R_n) as input. Two sets of coefficients were used for calculating R_n. Weather data from a meteorological station was used to estimate R_n and ET from the reference crop. The winter wheat ET was measured using an eddy covariance system during the main parts of the growing seasons 2004 and 2005. The meteorological data and field measurements were quality controlled and discarded from the analysis if flagged for errors. Daily values of ET from the reference crop and winter wheat calculated from hourly values were used to calculate the crop coefficients. Average daily crop coefficients were in the 1.1–1.15 range during mid-season with standard deviations ranging from 0.13 to 0.23 for both years. These values exceed values used in some sub-humid climate regime studies, but agree well with values from the international literature.     

Evaluation of a new qPCR test to identify the organisms causing high total bacterial count in bulk tank milk

Milk quality in bulk tank milk(BTM)is measured by flow cytometry technology as total bacterial count(TBC)and somatic cell count(SCC).To investigate SCC problems,culture or PCR can be used to identify mastitis causing bacteria,e.g.,Mastit 4,a commercially available qPCR test.TBC in BTM can be investigated further using culture-based methods such as standard plate count,laboratory pasteurization count,coliform count,and spore counts.To our knowledge,no qPCR addressing the bacteria involved in TBC has been commercially introduced.The aim of this study is to evaluate a recently introduced 3-h qPCR test,TBC 4.The TBC 4 qPCR detects four target groups,Pseudomonas,Streptococci,Enterobacteriacea/Enterococcus,and Bacillus/Clostridia.These target groups relate to problems on the farm such as cooling,mastitis,environment,and silage.We will continue with new research to compare the TBC 4 qPCR test with traditional culture.For this study,BTM samples from different TBC intervals were selected based on Bacto Count results found at routine payment investigation at Eurofins laboratory(Vejen,Denmark).These samples were analyzed using TBC 4 qPCR assay within 24 h.In total,346 BTM samples were divided into six different intervals of colony forming units(CFU).For all four targets in each of the different intervals of CFU,the percent of positive samples,the average C_t-value,the percent of positive samples with C_t30 and C_t25 were calculated.For Pseudomonas,Streptococci,and Enterobacteriacea/Enterococcus,the number of positive samples with lower C_t-values(high bacteria content)correlated with the CFU mL~(–1).We found Enterobacteriacea/Enterococcus,Pseudomonas,and Streptococci in high number of bacteria(C_t25)in 25,19 and 56%of samples with CFU mL~(–1) between 50 001–100 000 and 53,44,and 39%in samples with CFU mL~(–1)100 000.The TBC 4 qPCR test showed to be a strong and fast tool for farmers,advisors and service technicians to address problems with high TBC and ensuring the delivery of good quality milk to the dairy.     

Estimating soil C loss potentials from the C to N ratio

Thirty-seven arable soil samples (0–20 cm depth) ranging in clay content from 4 to 40% and in C to N ratio from 8 to 20 were incubated at ?100 hPa and 20 °C for 238 days. The CO₂-C evolved during days 105–147 and days 0–238 was related to the soil C to N ratio by a power function. We hypothesized the existence of a threshold value for the soil C to N ratio below which CO₂-C evolution remains constant. A soil C to N threshold value of 9.7 was estimated for both incubation periods and the function predicted that the CO₂-C evolution was halved when the soil C to N ratio approached 14. Data obtained by Springob and Kirchmann [Springob, G., Kirchmann, H., 2002. C-rich sandy Ap horizons of specific historical land-use contain large fractions of refractory organic matter. Soil Biology & Biochemistry 34, 1571–1581.] showed a similar relationship, but with a C to N threshold value of 10.8. We suggest that the relationship established between the C to N ratio of a soil and its CO₂-C loss during incubation represents a simple but useful measure for predicting soil C loss potentials on a more general level.     

Synaptic changes in layer 2/3 underlying map plasticity of developing barrel cortex

The functional and anatomical rearrangements of cortical sensory maps accompanying changes in experience are not well understood. We examined in vivo and in vitro how the sensory map and underlying synaptic connectivity of the developing rat barrel cortex are altered when the sensory input to the cortex is partially deprived. In the nondeprived cortex, both the sensory responses and synaptic connectivity between columns were strengthened through an increase in the synaptic connection probability between L2/3 pyramids in adjacent columns. This was accompanied by a selective growth of L2/3pyramid axonal arbors between spared columns. In contrast, deprived and nondeprived cortical columns became weakly connected in their L2/3 pyramid connections.     

Salmon gill poxvirus disease in Atlantic salmon fry as recognized by improved immunohistochemistry also demonstrates infected cells in non‐respiratory epithelial cells

Gill diseases cause serious losses in farming of Atlantic salmon and the number of agents involved increases. Salmon gill poxvirus (SGPV) and the gill disease in causes where SGPV apparently was the only disease‐causing agent were initially characterized. Recently, it was further shown that SGPV can be a common denominator in widely different multifactorial gill diseases. Here, we present the challenge of diagnosing gill disease with SGPV in salmon fry of 0,3–5 grams. Apoptosis of gill lamellar epithelial cells and hemophagocytosis was also observed in fry similar to findings in smolts and grow‐out fish. Using our newly developed immunohistochemistry method, we further demonstrate that some of the apoptotic epithelial cells covering the oral cavity were positive for SGPV. Thus, SGPV is not restricted to respiratory epithelium alone and may infect the fish at very early life stages. Furthermore, as the cases examined here are from Norway, Faroe Island and Scotland, we show that SGPV is more widespread than previously reported.     

The use of shellfish for eutrophication control

Effects of excess loading of nutrients to the marine environment can be mitigated by mussel cultures, basically through nutrient removal from the marine environment when shellfish are harvested. Shellfish farming also provide other goods and services to the marine environment primarily through the impact on water transparency caused by shellfish filtration. There is an increasing awareness of the mitigation potential in mussel culture in relation to eutrophication, but so far practical examples of culture on full scale devoted to mitigation are few. Further, impact of mussel farming on nutrient cycling, e.g. in the sediments below the culture units, has raised concerns. In this review, we clarify concepts in relation to nutrient mitigation and discuss goods and services delivered by mussel mitigation cultures and their impact on an ecosystem scale based primarily on results from studies in heavily eutrofied estuaries. A multi-criteria approach for site selection is presented based on experiences from Danish waters, and economic aspects of mitigation cultures are analysed in relation to use of the produced mitigation mussels. Future perspectives for extractive cultures are discussed in relation to source of excess nutrients.     

Tropical spiny lobster (Panulirus ornatus) farming in Vietnam – bioeconomics and perceived constraints to development

This paper presents bioeconomic data on lobster farming in Vietnam, and perceived constraints to the development of the industry. The farms were found to be profitable, with an average benefit cost ratio of 1.44 and an average net revenue of 262 million VND year^?1 (or just under US$15 000 year^?1). Investment in the enterprise is high compared with other enterprises in the region. However, disease has the potential to devastate lobster crops and there is little information available to lobster farmers about disease prevention and management. Hence, the lobster enterprise is a high‐risk high‐return industry. The predominant perceived constraints to the development of lobster operations include water quality and temperature issues, insufficient access to credit, good‐quality affordable feed and accurate information about technology improvements in lobster farming. It seems that improving the livelihood of lobster farmers in Vietnam is dependent on reducing their dependence on wild stocks for seed and feed, improving access to credit and improving technical and market information flows. Such improvements are likely to lead to higher profitability, given high export demand and hence sustained high prices for their lobster product.