Photosynthesis,Transpiration, and Water Use Efficiency of Vegetative and Reproductive Shoots of Grassland Species from North-Eastern China

The differences in net photosynthetic rate (P _N), transpiration rate (E), and water use efficiency (WUE) between the vegetative and reproductive shoots of three native grass species from the grassland of northeastern China [grey-green and yellow green populations of Leymus chinensis (Trin.) Tzvel., Puccinellia tenuiflora (Griseb) Scrib & Merr, Puccinellia chinampoensis Ohwi] were compared. The two type shoots experienced similar habitats, but differed in leaf life-span and leaf area. The leaf P _N and WUE for the vegetative shoots were significantly higher than those for the reproductive shoots in the grasses, while their E were remarked lower in the dry season. Relative lower leaf P _N and WUE for the reproductive shoots of grassland grasses may explain the facts of lower seed production and the subordinate role of seed in the grassland renewal in north-eastern China.     

Long-term retention of surgically implanted radio transmitters in pikeperch

Radio-tagged pikeperch Stizostedion lucioperca (55–74 cm L _T) were recaptured in a reservoir by anglers 52–55 months after tagging. A total of four fish were recaptured during the summer of 2001. These recaptures are remarkable because of the long period between tagging and recapture and because only one (of 15 potential) tagged pikeperch had been caught in the long period since tagging.     

Midsummer heat wave effects on lacustrine plankton: Variation of assemblage structure and fatty acid composition

The effects of the 2003 European heat wave on a freshwater plankton assemblage and its fatty acid (FA) composition were investigated. Composition and FA profiles of four size categories of planktonic organisms collected in 2003 were compared to those of the colder year 2002.     

Cardiovascular and respiratory responses associated with limb autotomy in the blue crab, Callinectes sapidus

Cardiovascular and respiratory variables were recorded in the blue crab, Callinectes sapidus, during injury and subsequent autotomy of a chela. Cardiac function and haemolymph flow rates were measured using a pulsed-Doppler flowmeter. Oxygen uptake was recorded using an intermittent flow respirometry system. Crabs reacted to the loss of a chela with a rapid increase in heart rate, which was sustained for 2 h. Stroke volume of the heart also increased after the chela was autotomized. A combined increase in heart rate and stroke volume led to an increase in cardiac output, which was maintained for an hour after the loss of a chela. There was also differential haemolymph perfusion of various structures. There was no change in perfusion of the anterolateral arteries or posterior and anterior aortae, during injury of the chela or subsequent autotomy. Haemolymph flow rates did increase significantly through the sternal artery during injury and immediately following autotomy of the chela. This was at the expense of blood flow to the digestive gland: a sustained decrease in haemolymph flow through the hepatic arteries occurred for 3 h following autotomy. Fine-scale cardiac changes associated with the act of autotomy included a bradycardia and/or associated cardiac pausing before the chela was shed, followed by a subsequent increase in cardiac parameters. Changes in the cardiovascular physiology were paralleled by an increase in oxygen uptake, which was driven by an increased ventilation of the branchial chambers. Although limb loss is a major event, it appears that only acute changes in physiology occur. These may benefit the individual, allowing rapid escape following autotomy with a subsequent return to normal activity.     

Effect of organic and conventional farming on soil bacterial diversity of pecan tree (Carya illinoensis K. Kosh) orchard across two phenological stages

We described the bacterial diversity of walnut grove soils under organic and conventional farming. The bacterial communities of rhizospheric and nonrhizospheric soils of pecan tree (Carya illinoensis K. Koch) were compared considering two phenological stages (sprouting and ripening). Sixteen operational taxonomic units (OTUs) were identified significantly more abundant according to the plant development, only one according to the farming condition, and none according to the soil origin. The OTUs specificaly abundant according to plant development included Actinobateria (2) and Betaproteobacteria (1) related OTUs more abundant at the sprouting stage, while at the fruit ripening (FR) stage the more abundant OTUs were related to Actinobacteria (6), Alphaproteobacteria (6), and unclassified Bacteria (1). The Gaiellaceae OTU18 (Actinobacteria) was more abundant under conventional farming. Thus, our study revealed that the plant development stage was the main factor shaping the bacterial community structure, while less influence was noticed for the farming condition. The bacterial communities exhibited specific metabolic capacities, a large range of carbon sources being used at the FR stage. The identified OTUs specifically more abundant represent indicators providing useful information on soil condition, potential tools for the management of soil bacterial communities.     

A physiological analogy of the niche for projecting the potential distribution of plants

Aim  To develop a physiologically based model of the plant niche for use in species distribution modelling. Location  Europe. Methods  We link the Thornley transport resistance (TTR) model with functions which describe how the TTR’s model parameters are influenced by abiotic environmental factors. The TTR model considers how carbon and nutrient uptake, and the allocation of these assimilates, influence growth. We use indirect statistical methods to estimate the model parameters from a high resolution data set on tree distribution for 22 European tree species. Results  We infer, from distribution data and abiotic forcing data, the physiological niche dimensions of 22 European tree species. We found that the model fits were reasonable (AUC: 0.79–0.964). The projected distributions were characterized by a false positive rate of 0.19 and a false negative rate 0.12. The fitted models are used to generate projections of the environmental factors that limit the range boundaries of the study species. Main conclusions  We show that physiological models can be used to derive physiological niche dimensions from species distribution data. Future work should focus on including prior information on physiological rates into the parameter estimation process. Application of the TTR model to species distribution modelling suggests new avenues for establishing explicit links between distribution and physiology, and for generating hypotheses about how ecophysiological processes influence the distribution of plants.     

Trace element transfer from alginate dressings to wounds

ABSTRACT

A method has been developed for impregnating alginate-based wound dressings with trace elements required for wound healing and for quantifying the transfer from these dressing to wound fluid (for which a substitute—blood serum—was used in these experiments). Under ideal conditions, up to 85% can be carried across from the tow to the wound fluid.     

Effects of the timing of applications on the incompatibility of three fungicides and one isolate of the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin (Deuteromycotina)

Abstract: The effect of timing of application on the incompatibility of three fungicides (metalaxyl, mancozeb, copper oxide) and isolate MK2001 of the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin was assessed in vitro . Isolate MK 2001 at 1 × 10⁷ conidia/ml concentration was highly pathogenous to adults of Lygus lineolaris (Hemiptera) (84% mortality at day 4 post-treatment). The fungicides at the manufacturer recommended rate (1X) were strongly fungistatic and inhibited the fungal isolate radial growth on Sabouraud dextrose agar (SDA). Mancozeb, metalaxyl and copper oxide exhibited insecticidal activity of 24, 40 and 48% respectively, on L. lineolaris adults. It is clear that application of the fungal isolate MK2001 2–4 days before applying fungicides metalaxyl, mancozeb or copper oxide synergized the insecticidal effect of the isolate. On the contrary, application of metalaxyl, mancozeb, copper oxide 2–4 days before applying isolate MK2001 antagonized the insecticidal effect. The simultaneous use of each fungicide (metalaxyl, mancozeb or copper oxide) and the isolate gave lesser insect mortality. This study revealed that although some fungicides are incompatible for use alongside fungal isolates, the proper evaluation of their time of use could be beneficial in biological control or IPM programmes. Furthermore, the application of B. bassiana isolate MK2001 followed by fungicide application could synergize insecticidal activity.     

Zinc,copper, selenium,and glutathione peroxidase in blood of 11-yr-old dunedin,New Zealand children

Blood was obtained from 564 11-yr-old children who had participated since birth in a multidisciplinary health and development study. Serum zinc concentration did not differ between the boys and the girls (mean±SD: 91=17 μg/100 mL,n=453). Five-6% of serum zinc values were low; although there was a weak correlation with height, none of the boys with low values were below the 10th percentile for height for this group. Serum copper concentration (112±24 μg/100 mL,n=454) was unrelated to sex, height, weight, body mass index, socioeconomic status (SES), or iron status. Blood selenium concentration (49±10 ng/mL,n=564) was lower than previously reported for Dunedin children; it was higher in children in the lower SES categories. The data represent normal values for healthy, 11-yr-old NZ children.