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排序方式: 共有162条查询结果,搜索用时 171 毫秒
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Frauke Kleemann Maximilian von Fragstein Barbara Vornam Annika Müller Christoph Leuschner Andrea Holzschuh Teja Tscharntke Reiner Finkeldey Andrea Polle 《European Journal of Forest Research》2011,130(5):707-716
Knowledge on phenological, morphometric, and phytochemical variation of local progenies of European aspen (Populus tremula, L.) is limited. The goal of this study was to characterize variation in growth and ecologically important leaf properties
in aspen full-sib families in relation to interacting organisms (mycorrhiza, endophytes, and insects) and to determine whether
these interactions were affected by soil application of a systemic fungicide. In local progenies, within-family variation
of neutral molecular genetic markers (nuclear microsatellites) was higher than between families. Significant variation in
growth, production of phenolic defensive compounds and other phytochemical leaf traits was found between families. Phenolic
compounds showed clear negative correlation with generalist herbivores, but did not result in negative trade-off with biomass
production. Differences in mycorrhizal colonization were not found among full-sib families and application of a systemic fungicide
suppressed neither mycorrhizal colonization nor infestation with insects. However, a strong suppression of endophytes occurred,
whose long-term consequences may require attention when fungicides are used in agroforestry plantations. 相似文献
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Zusammenfassung Zunächst werden die bisher bekannten Ringfasziationen in drei Gruppen eingeteilt, nämlich den Normal-Typus, auch Kanal- oderOenothera-Typus genannt, zu welchem der überwiegende Teil der Ringfasziationen gehört, der Trichter- oderPisum-Typus und schließlich der Röhren- oderPrimula-Typus. Ringfasziationen werden stets durch Invaginationen gebildet. Es werden Angaben zur Morphologie und vor allem zur Anatomie der röhrigen Fasziation vonPrimula malacoides gemacht. Der innere Leitbündelring hat keine Verbindung zum äußeren Leitbündelring und zum Wurzelsystem; beiPrimula hat das innere System jedoch Verbindung mit der Tracheidenplatte im Boden der Röhren.
The types of ring-fasciation and tube-fasciation inPrimula
Summary At first the ring fasciation as hitherto known are divided in three groups, namely the normal type, named also the channal- orOenothera-type, to which belong the prevailing parts of such fasciations, the funnal- orPisum-type and finally the tupe- orPrimula-type. Ring fasciations are always formed by invagination. It becomes some statements on morphology and above all on anatomy ofPrimula malacoides. The inner ring of leading elements has no joining to the outer ring of leading elements of the root system; inPrimula the inner ring however has joining with the plate of tracheids in the bottom of the tube.
Primula
: , Oenothera, ; Pisum , , Primula. . , , Primula malacoides. , , Primula相似文献
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The course of events from taking a food into the mouth to the perception of the food's flavor involves many steps, from dilution with saliva, mastication, and transportation of the compounds to the olfactory epithelium to transformation into signals that go to the brain. In addition, there are also the effects of the food's structure and properties. In this study, a proton-transfer-reaction mass spectrometer (PTR-MS) was used to investigate how four pectin-containing systems with different structures and strengths affected the release of aroma compounds in a model mouth and in the nose of an assessor. Both the model mouth and the in-nose measurements showed that the strength and structure of pectin-containing systems are important with regard to the quantity of aroma compounds that are released. Mastication and saliva were also shown to have a large influence on how much of the aroma compound is released from the mouth to the nose. 相似文献
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Wilhelmson A Laitila A Vilpola A Olkku J Kotaviita E Fagerstedt K Home S 《Journal of agricultural and food chemistry》2006,54(2):409-416
The steep water is generally aerated in industrial barley malting. However, it is questionable whether oxygen actually reaches the embryo, which remains entrapped under the husk, testa, and pericarp until chitting occurs. The aim of our study was to investigate whether barley embryos experience oxygen deficiency during steeping, and whether various steeping conditions affect the oxygen deficiency. Alcohol dehydrogenase Adh2 was induced in all steeping conditions studied. Therefore, oxygen deficiency occurred regardless of the steeping conditions. However, steeping conditions affected the rate of recovery from oxygen deficiency, germination rate, and onset of alpha-amylase production. When barley was subjected to oxygen deficiency by applying N(2) gas during steeping, the timing of the treatment determined its effects. The importance of aeration increased as the process proceeded. Oxygen deprivation at the beginning of the process had little effect on malt quality. Therefore, the timing of aeration is important in the optimization of germination during the steeping stage of malting. 相似文献
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Rosén LA Östman EM Shewry PR Ward JL Andersson AA Piironen V Lampi AM Rakszegi M Bedö Z Björck IM 《Journal of agricultural and food chemistry》2011,59(22):12139-12148
Rye products typically induce low insulin responses and appear to facilitate glucose regulation. The objective of this study was to investigate differences in postprandial glucose, insulin, and satiety responses between breads made from five rye varieties. Breads made from whole grain rye (Amilo, Rekrut, Dankowski Zlote, Nikita, and Haute Loire Pop) or a white wheat bread (WWB) were tested in a randomized cross-over design in 14 healthy subjects (50 g available starch). Metabolic responses were also related to the composition of dietary fiber and bioactive compounds in the breads and to the rate of in vitro starch hydrolysis. The Amilo and Rekrut rye breads induced significantly lower insulin indices (II) than WWB. Low early postprandial glucose and insulin responses (tAUC 0-60 min) were related to higher amounts of caffeic, ferulic, sinapic, and vanillic acids in the rye breads, indicating that the phenolic acids in rye may influence glycemic regulation. All rye breads induced significantly higher subjective feelings of fullness compared to WWB. A low II was related to a higher feeling of fullness and a lower desire to eat in the late postprandial phase (180 min). The data indicate that some rye varieties may be more insulin-saving than others, possibly due to differences in dietary fiber, rate of starch hydrolysis, and bioactive components such as phenolic acids. 相似文献
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Density‐dependent processes have repeatedly been shown to have a central role in salmonid population dynamics, but are often assumed to be negligible for populations at low abundances relative to historical records. Density dependence has been observed in overall spring/summer Snake River Chinook salmon Oncorhynchus tshawytscha production, but it is not clear how patterns observed at the aggregate level relate to individual populations within the basin. We used a Bayesian hierarchical modelling approach to explore the degree of density dependence in juvenile production for nine Idaho populations. Our results indicate that density dependence is ubiquitous, although its strength varies between populations. We also investigated the processes driving the population‐level pattern and found density‐dependent growth and mortality present for both common life‐history strategies, but no evidence of density‐dependent movement. Overwinter mortality, spatial clustering of redds and limited resource availability were identified as potentially important limiting factors contributing to density dependence. The ubiquity of density dependence for these threatened populations is alarming as stability at present low abundance levels suggests recovery may be difficult without major changes. We conclude that density dependence at the population level is common and must be considered in demographic analysis and management. 相似文献
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