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101.
Plant root development is strongly affected by nutrient availability. Despite the importance of structure and function of roots in nutrient acquisition,statistical modeling approaches to evaluate dynamic and temporal modulations of root system architecture in response to nutrient availability have remained as widely open and exploratory areas in root biology. In this study,we developed a statistical modeling approach to investigate modulations of root system architecture in response to nitrogen availability. Mathematical models were designed for quantitative assessment of root growth and root branching phenotypes and their dynamic relationships based on hierarchical con figuration of primary and lateral roots formulating the fishbone-shaped root system architecture in Arabidopsis thaliana. Time-series datasets reporting dynamic changes in root developmental traits on different nitrate or ammonium concentrations were generated for statistical analyses. Regression analyses unraveled key parameters associated with:(i) inhibition of primary root growth under nitrogen limitation or on ammonium;(ii) rapid progression of lateral root emergence in response to ammonium; and(iii) inhibition of lateral root elongation in the presence of excess nitrate or ammonium. This study provides a statistical framework for interpreting dynamic modulation of root system architecture,supported by metaanalysis of datasets displaying morphological responses of roots to diverse nitrogen supplies. 相似文献
102.
The existence of mast fruiting has not been well documented in the Neotropics. The occurrence of a mast fruiting episode in the population of the tree Peltogyne purpurea in the Osa Peninsula of Costa Rica is described. In February and March of 2000 most of the trees of this species produced a large fruit crop, compared with 1995-1999, when the number of fruit producing trees was very low or zero and those that did bear fruit, did so at a low intensity. In contrast, the fruit crop of 2000 was massive, all trees examined produced fruits and the intensity of fruiting was maximal. There is not enough information on the event for a hypothesis to be formed because the climatic or biological cues that triggered this sporadic flowering are unknown and there is no meteorological data available for this area. Populations with this mode of reproduction may experience local extinction bacause of logging operations. 相似文献
103.
Wnt/β‐Catenin Signaling Activates Expression of the Bone‐Related Transcription Factor RUNX2 in Select Human Osteosarcoma Cell Types 下载免费PDF全文
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Loyola LA Bórquez J Morales G Araya J González J Neira I Sagua H San-Martín A 《Phytochemistry》2001,56(2):177-180
Diterpenoids with trichomonicidal activity were isolated from the aerial parts of Azorella yareta Hauman. One was 13beta-hydroxyazorellane, together with the known constituents mulinolic acid, mulin-11,13-dien-20-oic acid, azorellanol and 13alpha-hydroxyazorellane. Their structures were determined by spectroscopic and chemical methods. 相似文献
106.
Sources of (co)variation in alternative siring routes available to male great tits (Parus major) 下载免费PDF全文
Yimen G. Araya‐Ajoy Sylvia Kuhn Kimberley J. Mathot Alexia Mouchet Ariane Mutzel Marion Nicolaus Jan J. Wijmenga Bart Kempenaers Niels J. Dingemanse 《Evolution; international journal of organic evolution》2016,70(10):2308-2321
Males of socially monogamous species can increase their siring success via within‐pair and extra‐pair fertilizations. In this study, we focused on the different sources of (co)variation between these siring routes, and asked how each contributes to total siring success. We quantified the fertilization routes to siring success, as well as behaviors that have been hypothesized to affect siring success, over a five‐year period for a wild population of great tits Parus major. We considered siring success and its fertilization routes as “interactive phenotypes” arising from phenotypic contributions of both members of the social pair. We show that siring success is strongly affected by the fecundity of the social (female) partner. We also demonstrate that a strong positive correlation between extra‐pair fertilization success and paternity loss likely constrains the evolution of these two routes. Moreover, we show that more explorative and aggressive males had less extra‐pair fertilizations, whereas more explorative females laid larger clutches. This study thus demonstrates that (co)variation in siring routes is caused by multiple factors not necessarily related to characteristics of males. We thereby highlight the importance of acknowledging the multilevel structure of male fertilization routes when studying the evolution of male mating strategies. 相似文献
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J Villanueva G León H Molina V Molina A Araya M Krauskopf 《Biochemistry international》1983,7(4):405-413
Previtellogenic oocytes of the fish Cyprinus carpio contain 42S nucleoprotein particles that are composed of two proteins of molecular weights 48,500 and 39,300 (molar ratio 2:1), tRNA and 5S RNA (molar ratio 3:1). The tRNA population embodied in the 42S particle contains all amino acid acceptor species but their distribution differs from that found in tRNA from mature oocytes. 相似文献
109.
Kiyoto Maekawa Masahiro Kon Kunio Araya Tadao Matsumoto 《Journal of molecular evolution》2001,53(6):651-659
Molecular phylogenetic relationships among 25 species of the wood-feeding cockroach belonging to the genus Salganea St?l (Panesthiinae; Blaberidae) in Southeast Asia were analyzed based on the DNA sequence of the complete mitochondrial cytochrome
oxidase II (COII) gene. Most basal relationships among species of Salganea are poorly resolved by both neighbor-joining and nonweighted parsimony analyses, suggesting the possibility of a hard polytomy
due to a rapid and potentially simultaneous radiation early in the history of the genus. For more apical relationships, however,
some interesting phylogenetic relationships were recognized. The monophyly of the two species groups, morio and foveolata, the former of which is distributed mainly in the Sunda lands (containing the Malay Peninsula, Sumatra, Java, and Borneo),
whereas the latter is Sulawesi endemic, was strongly supported. Based on the inferred phylogenetic patterns and recent palaeogeographic
scenario for Southeast Asia, it is suggested that a radiation of Salganea species occurred in Southeast Asia presumably in the early Tertiary, and several barriers against dispersal and gene flow,
such as the formation of straits or high mountains, have arisen from the middle Tertiary.
Received: 4 April 2001 / Accepted: 20 April 2001 相似文献
110.