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151.
PETE SMITH STEPHEN J. CHAPMAN† W. ANDY SCOTT‡ HELAINA I. J. BLACK† MARTIN WATTENBACH RONNIE MILNE§ COLIN D. CAMPBELL† ALLAN LILLY† NICK OSTLE‡ PETER E. LEVY§ DAVID G. LUMSDON† PETER MILLARD† WILLIE TOWERS† SÖNKE ZAEHLE¶ JO U. SMITH 《Global Change Biology》2007,13(12):2605-2609
We present results from modelling studies, which suggest that, at most, only about 10–20% of recently observed soil carbon losses in England and Wales could possibly be attributable to climate warming. Further, we present reasons why the actual losses of SOC from organic soils in England and Wales might be lower than those reported. 相似文献
152.
Responses to olfactory and visual cues by over-wintered and summer generations of the pollen beetle, Meligethes aeneus 总被引:1,自引:0,他引:1
Abstract. Behavioural responses to odours of oilseed rape in bud and flower stage and to green and yellow colours are studied for the two main phenological stages of pollen beetles, Meligethes aeneus , a major pest of oilseed rape, Brassica napus . Over-wintered individuals oviposit in buds of oilseed rape. Adults of the new generation (i.e. the summer generation) feed on flowers of different plant species before over wintering. In olfactometer experiments, the over-wintered beetles display a higher preference for odour of oilseed rape at the bud stage compared with the summer generation, both with and without colour stimuli. Flower odours are preferred in combination with yellow colour. Colour stimuli presented alone do not affect the behaviour. The summer generation beetles respond to both bud and flower odour. Adding colour stimuli changes the summer generations preference towards yellow and flower odour. 相似文献
153.
DspA/E is a pathogenicity factor of Erwinia amylovora that is translocated into the plant cell cytoplasm through an Hrp type III secretion system. Transient expression of dspA/E in Nicotiana benthamiana or yeast induced cell death, as it does in N. tabacum and apple as described previously. DspA/E-induced cell death in N. benthamiana was not inhibited by coexpression of AvrPtoB of Pseudomonas syringae pv. tomato , which inhibits programmed cell death (PCD) induced by several other elicitors in plants. Silencing of NbSGT1 , the expression of which is required for PCD mediated by several resistance proteins of plants, prevented DspA/E-induced cell death in N. benthamiana. However, silencing of NbRAR1 , or two MAP kinase kinase genes, which are required for PCD associated with many resistance genes in plants, did not prevent cell death induced by DspA/E. Silencing of NbSGT1 also compromised non-host resistance against E. amylovora . E. amylovora grew rapidly within the first 24 h after infiltration in N. benthamiana , and DspA/E was required for this early rapid growth. However, bacterial cell numbers decreased after 24 h in TRV-vector-transformed plants, whereas a dspA/E mutant strain grew to high populations in NbSGT1 -silenced plants. Our results indicate that DspA/E enhances virulence of E. amylovora in N. benthamiana, but the bacteria are then recognized by the plant, resulting in PCD and death of bacterial cells or restriction of bacterial cell growth. 相似文献
154.
THE CONTROL OF GERMINATION IN STACHYS ALPINA (L.) 总被引:1,自引:1,他引:0
155.
THE New Zealand obese (NZO) mouse is characterized by genetically determined obesity, accompanied by insulin resistance, glucose intolerance and hyperinsulinaemia1–4. The pattern of insulin release in response to stimuli has not been described. In the experiments reported here, a marked functional abnormality of the islets of Langerhans in vivo was observed, with no response of plasma insulin to glucose, glucagon and tolbutamide but a greatly exaggerated response to arginine. This observation of a selective defect of islet function not only has important implications concerning the normal physiology of insulin release but may also aid in understanding the evolution of the abnormalities of islet cell function in human diabetes5. 相似文献
156.
SV40 virus DNA transcribes differently in vitro from in vivo. In a series of parallel experiments, the in vitro and in vivo single-stranded DNAs are shown to differ in structure. 相似文献
157.
Methods and Equipment for the Study of the Incorporation of Phosphorus by Intact Barley Plants in Experiments of Short Duration 总被引:9,自引:0,他引:9
Paper partition chromatography has been used for the separationof organic phosphorus compounds extracted from roots after shortperiods of absorption of radioactive phosphorus by whole barleyplants. Methods of extraction, fractionation, and identification ofthe compounds are described. Equipment has been designed to record rapidly the activity alongthe length of the chromatograms. Salient features are congruencebetween chromatograms and record, high sensitivity and provisionfor automatic change of sensitivity. 相似文献
158.
Radioactive starch, glucose and fructose have been preparedfrom tobacco leaves after assimilation of C14O2. The apparatusused for photosynthesis consisted of a shallow Perspex leafchamber connected to a closed gas system, in which C14O2 wasgenerated from BaC14O2. Six leaves, area 14 to 18 sq. dm. whenexposed to bright sunlight with an initial CO2 concentrationof 8 to 10 per cent., assimilated 3.35 g. of C14O2 in 8 to 10hours. At least 80 per cent. of the C14O2 supplied appearedin the leaves as starch and sugar and over 80 per cent. of theradioactivity was accounted for in these carbohydrates. Thespecific activity per m. atom of carbon of the isolated productswas 85 to 90 per cent. of that of the C14O2. Small amounts ofradioactive carbon were also incorporated in the leaf proteinand in the celluose, hemicellulose and polyuronides. 相似文献
159.
160.
1. Birds are considered to be the primary selective agents for warning colouration in butterflies, and select for aposematic mimicry by learning to avoid brightly coloured prey after unpleasant experiences. It has long been thought that bright colouration plays an important role in promoting the avoidance of distasteful prey by birds. 2. The hypothesis that warning colouration facilitates memorability and promotes predator avoidance was tested by means of a field experiment using distasteful model butterflies. Artificial butterflies with a Heliconius colour pattern unknown to local birds were generated using bird vision models, either coloured or achromatic, and hung in tree branches in a tropical forest. Two sequential trials were conducted at each site to test avoidance by naïve and experienced predators. 3. There was a significant reduction in predation in the second trial. Also, coloured models were attacked less than achromatic models. Specifically, coloured butterflies were attacked significantly less in the second trial, but there was no significant decrease in predation on achromatic models. 4. The present results imply an important role for colour in enhancing aversion of aposematic butterflies. It has also been demonstrated that previous experience of distasteful prey can lead to enhanced avoidance in subsequent trials, supporting mimicry theory. 相似文献