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91.
E. Y. Y. LO 《Journal of evolutionary biology》2010,23(10):2249-2261
Natural hybridization is of marked importance from global to local biological diversity. In mangroves, species ranges overlap extensively with one another and species share a long overlap of flowering time. Although hybridization has been suggested, patterns of hybridization and the evolutionary potential of hybrids are not yet fully understood. This study provides molecular evidence for the parental origins and status of hybrids in the dominant mangrove genus Rhizophora based on comparisons of chloroplast and nuclear phylogenies and estimations of genetic relatedness and structure from inter‐simple sequence repeat (ISSR) markers. Phylogenetic analyses indicate that almost all species can act as maternal parents to hybrids and that hybridization can be bidirectional. Bayesian analyses indicate that hybrids are simple F1s, and no trace of backcrossing was detected within populations. Hybridization, for the most part, occurs almost only locally and dispersal of hybrid individuals is limited beyond the hybrid sites. 相似文献
92.
JOSÉ JAVIER PEGUERO‐PINA JAUME FLEXAS JERONI GALMÉS ÜLO NIINEMETS DOMINGO SANCHO‐KNAPIK GONZALO BARREDO DIDO VILLARROYA EUSTAQUIO GIL‐PELEGRÍN 《Plant, cell & environment》2012,35(12):2121-2129
Abies alba and Abies pinsapo are closely related species with the same ribulose 1·5‐bisphosphate carboxylase/oxygenase (Rubisco) large subunit (rbcL) but contrasting hydraulic traits and mesophyll structure occurring in the Iberian Peninsula under contrasting conditions. As photosynthesis and hydraulic capacities often co‐scale, we hypothesize that these species differ in mesophyll conductance to CO2 (gm). gm and key anatomical traits were measured in both species. Drought‐adapted population of A. pinsapo has higher photosynthesis than the more mesic population of A. alba, in agreement with its higher hydraulic capacity. However, A. alba exhibits the largest stomatal conductance (gs), and so water use efficiency (WUE) is much higher in A. pinsapo. The differences in photosynthesis were explained by differences in gm, indicating a correlation between hydraulic capacity and gm. We report a case where gm is the main factor limiting photosynthesis in one species (A. alba) when compared with the other one (A. pinsapo). The results also highlight the discrepancy between gm estimates based on anatomical measurements and those based on gas exchange methods, probably due to the very large resistance exerted by cell walls and the stroma in both species. Thus, the cell wall and chloroplast properties in relation to CO2 diffusion constitute a near‐future research priority. 相似文献
93.
自发性高血压大鼠中枢血管紧张素Ⅱ的变化对中枢肾上腺素和去甲肾上腺素含量的影响 总被引:1,自引:0,他引:1
自发性高血压大鼠中枢肾上腺能递质含量异常,然其原因仍不清楚。本工作发现:12周龄易卒中型自发性高血压大鼠(SHRSP)脑桥,下丘脑后部、尾核中去甲肾上腺素(NE)含量及延髓、下丘脑前部,下丘脑后部中肾上腺素(E)含量均高于同龄 Wista Kyoto 大鼠(WKY),SHRSP 中枢 AⅡ含量亦明显高于同龄 WKY;向8周龄 SHRSP 和 WKY 侧脑室慢性灌注巯甲丙脯氨酸,不仅降低动脉血压及各脑区AⅡ含量,亦使中枢 NE 及 E 水平下降,但巯甲丙脯氨酸对 SHRSP 的影响远较对 WKY 明显。结果提示:SHRSP 中枢肾上腺能递质含量增加可能与 SHRSP 中枢 AⅡ量含量升高以及 SHRSP 中枢 AⅡ对中枢肾上腺能递质的促释放调节机制明显易化有关。 相似文献
94.
95.
在离体脑片上测定了24个家兔外膝体中继细胞的被动膜特性。它们的静息电位为-62.7±4.1mV(SD);膜输入阻抗为30.4±11.2MΩ。运用Rall的线性电缆模型,计算出这些神经元树突的电紧张长度(L)为0.79±0.13;电压衰减因数(H)为回.33±0.11。说明家兔外膝体中继细胞是电学紧密的,树突远端的电位可扩散到胞体,幅度仅衰减25%左右。 相似文献
96.
We report measurements of hydraulic conductivity of Vitis oinifera,Oleo europaea and Populus deltoides 1-year-old twigs. Singleserial internodes were tested for the volume flow rate whichwas related to: (a) the xylem tissue cross-sectional area, (b)the vessel lumina cross-sectional area and (c) the leaf surfacearea supplied by a given stem section. From this, whole xylemhydraulic conductivity (Lx), vessel lumina hydraulic conductivity(Lxv) and leaf specific conductivity (LSC) were calculated.All the three parameters turned out to be linearly related toeach other. This is kcause: (a) the leaf surface area (A1) waslinearly related to xylem cross-sectional area (Ax and (b) theratio of the vessel lumina cross-sectional area (Axv) to xylemcross-sectional area (Ax) was approximately constant along thetwigs. Moreover, the hydraulic conductivity of twig segmentswhere buds grow most actively (distal internodes in V. viniferaand proximal ones in O. europaea) was much lower than in therest of the twigs. A possible role played by these constrictedtwig regions is discussed. Key words: Changes, Hydraulic conductivity, Stem 相似文献
97.
The first set of six polymorphic microsatellites was isolated from a partial genomic DNA library of an important marine food fish Gnathanodon specious, and was characterized in 28 unrelated individuals. The allele number ranged from three to 12 with an average of seven/locus; average expected heterozygosity was 0.57 ranging from 0.10 to 0.87, whereas the observed heterozygosity ranged from 0.11 to 0.96 (average: 0.57). All six markers conform to Hardy–Weinberg and linkage equilibria. These markers will be useful for accessing genetic population structure of wild populations and for selective breeding program in fish farms. 相似文献
98.
The plant-to-plant distribution of carrot fly damage was studied on carrots and parsnips in field and microplot experiments. The observed data were well-fitted by the relationship In (–In q) = In L+ constant, where q is the proportion of undamaged roots and L is the number of larval mines in a sample and is proportional to the number of associated larvae, N. Hence, if N1 and N2 are the numbers of larvae at two levels of infestation on one occasion, the relative numbers present, N2:N1 are estimated by In q2: In q1 In this way the relative efficiencies of insecticide treatments can be determined within an experiment from only q1 and q2 and compared between occasions. A nomogram relating q1, q2 and treatment efficiency is provided. The method can also probably be used to compare the relative susceptibilities of host-plant cultivars to carrot fly attack. Guidance is given on the sample sizes needed to estimate q within 95% confidence limits and constraints on the application of the method are stated. An appropriate statistical procedure for analysing data sets on carrot fly infestations is by analysis of deviance and an example is given in an Appendix. The principles described can probably be adapted to other crop/pest problems. 相似文献
99.
尖叶木樨榄作砧木嫁接油橄榄的研究 总被引:1,自引:0,他引:1
本文就云南、四川两省采用尖叶木樨榄(Olea ferrugineaRoyle.)作砧木嫁接油橄榄(Olea europaea L.)二十余年的试验观察,报道尖叶木樨榄在我国的分布及其生物学特性,系统总结尖叶木樨榄作砧木对油橄榄生长发育及开花结实的影响。试验结果表明:尖叶木樨榄作砧木具有种子出苗率高,嫁接繁殖容易,提早油橄榄开花结实年龄,增强油橄榄对酸性红壤的适应性,增强油橄榄对干旱环境和对某些病害的抗性等优点。此砧木已在我国西南部油橄榄适生区应用于生产性栽培。 相似文献
100.
本文报告了血浆亮脑啡肽样物质(LEK)的放射免疫测定法。用 TG-ECDI-LEK 背部皮内多点免疫家兔,获得高特异性的抗 LEK 血清,最小检出量5pg,多种肽类及吗啡、纳洛酮对此均无明显干扰。血浆迅速酸化及抑肽酶等能有效防止脑啡肽(EK)的降解。血浆 EK 可被 XAD-2树脂吸附和用水合甲醇洗脱。本法测定人血浆 LEK 为127.9±5.4pg/ml(m±S.E.M,n=61).作者观察到胰岛素低血糖休克后血浆 LEK 增加,嗜铬细胞瘤患者血 LEK 增加,提示肾上腺體质可能是它的来源之一。 相似文献