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931.
Jennifer J. Weber Stephen G. Weller Ann K. Sakai Olga V. Tsyusko Travis C. Glenn César A. Domínguez Francisco E. Molina‐Freaner Juan Fornoni Mike Tran Nhu Nguyen Karen Nguyen Lien‐Khuong Tran Greg Joice Ellen Harding 《Evolution; international journal of organic evolution》2013,67(8):2309-2322
We investigated the role of morph‐based differences in the expression of inbreeding depression in loss of the mid‐styled morph from populations of tristylous Oxalis alpina. The extent of self‐compatibility (SC) of reproductive morphs, the degree of self‐fertilization, and the magnitude of inbreeding depression were investigated in three populations of O. alpina differing in their tristylous incompatibility relationships. All three populations exhibited significant inbreeding depression. In two populations with highly modified tristylous incompatibility, manifested as increased reciprocal compatibility between short‐ and long‐styled morphs, substantial SC and self‐fertilization of mid‐styled morphs were detected, and expected to result in expression of inbreeding depression in the progeny of mid‐styled morphs in the natural populations. In contrast, significant self‐fertility of the mid‐styled morph was absent from the population with typical tristylous incompatibility, and no self‐fertilization could be detected. Although self‐fertilization and expression of inbreeding depression should result in selection against the mid‐styled morph in the later stages of the transition from tristyly to distyly, in O. alpina selection against the mid‐styled morph in the early phases of the evolution of distyly is likely due to genic selection against mid‐alleles associated with modified tristylous incompatibility, rather than expression of inbreeding depression. 相似文献
932.
Erwan?SaouterEmail author Gert?van?Hoof Tom?C.?J.?Feijtel J.?William?Owens 《The International Journal of Life Cycle Assessment》2002,7(1):27-38
The environmental profile of laundry detergents at three time points (1988, 1992, and 1998) were compared on the basis of
two distinct, complementary approaches: Environmental Risk Assessment (ERA) and Life-Cycle Assessment (LCA). The results are
presented in this paper and its accompanying paper in this issue (Part I: Product Environmental Risk Assessment). Life-Cycle
Inventory (LCI) data from The Netherlands and Sweden were used for this retrospective analysis. The chosen time period studied
(1988 - 1998) spans significant, multiple formulation and process change in laundry detergents, including the introduction
of compact, then super-compact, granular detergents. Cradle-to-Gate LCAs based on 1 kg of finished product (from raw material
supply to packaged finished product leaving the suppliers site) revealed no significant differences between the products themselves,
as manufactured between 1988, 1992 and 1998. Cradle-to-Grave LCAs based on 1000 wash cycles (from raw material supply to disposal
of used product) indicated that the consumption of raw materials and energy, as well as environmental emissions (air, water
and solid waste), decreased after the introduction of compact detergents in 1988. The LCAs revealed that a number of category
indicator values decreased (for acidification, aquatic toxicity greenhouse effects, eutrophication, toxicity, ozone depletion
and smog). Furthermore, the results of the LCAs support the conclusion that the differences between The Netherlands and Sweden
are due to (1) differences in electrical generation between the countries, (2) differences in energy consumption during consumer
use, (3) differences in detergent dosage per wash and (4) differences in the wastewater treatment infrastructure. 相似文献
933.
台湾中部暗绿绣眼鸟的繁殖生物学 总被引:2,自引:0,他引:2
本研究将暗绿绣眼鸟 (Zosteropsjaponicasimplex)捕捉、套彩色环后释放 ,分别于 1999年和 2 0 0 1年 3~ 8月追踪监测 7对和 13对暗绿绣眼鸟的繁殖行为。总结此二年对 2 0对暗绿绣眼鸟的监测 ,其繁殖期始于 3月中旬 ,终止于 8月下旬。 1对最多可年产 5窝 ,但以 3~ 4窝为常见。初次筑巢所需时间平均为 10 4d ,筑第 2、3巢的时间依次减少 ;窝与窝之间的繁殖间隔视情况而定 ,如孵化或喂养失败 ,通常都在 1~ 2d内再筑巢 ,如繁殖育雏成功 ,平均相隔 7d再筑巢。 2年 6 3窝的窝卵数平均为 2 6 8± 0 71(n =6 3)枚 ;孵化期平均为 11±0 6 4 (n =4 7)d ;6 3窝孵化成功 4 7窝 ,孵化成功率为 74 6 % ;雏鸟离巢日龄平均为 10 5± 0 88(n =35 )d ;4 7窝雏鸟喂养成功 35窝 ,育雏成功率为 74 5 % ;6 3窝繁殖成功 35窝 ,繁殖成功率为 5 5 5 %。失败因素包括气候、动物掠食、人为破坏和其它不明原因 相似文献
934.
G. Wenzel F. Hoffmann E. Thomas 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1977,51(2):81-86
Summary Further progress of studies aimed at increasing production of androgenetic Secale cereale plants via the culture of anthers is described. Two culture media initially developed for rice and wheat anther culture have been shown to have pronounced influence on rye. It has been possible to increase the average percentages of responsive anthers (i.e. those producing embryoids or calluses) from 0.26% to 10% with a maximum in certain experiments of over 40 %. Of nearly 400 plants produced in 1976, 1/4 are green and can be grown further by transfer to potting compost; 3/4 are albino. Stable green haploid lines were present amongst the plants, and after vegetative propagation of the lines representative samples have been treated with colchicine resulting in diploid, triploid and tetraploid plants. The influence of the genetic background of the donor plants on the success rate of anther culture and on the percentage of albino formation is discussed. 相似文献
935.
Summary High variation in laying date and clutch size of the blue tit between a Mediterranean mixed habitat on the mainland, southern France, and a sclerophyllous habitat on the island of Corsica is hypothesized to be related to differences in the food supply. The diet of the nestlings and feeding frequencies were studied using camera nestboxes and electronic chronographs. Food items brought to the nestlings were much more diverse on Corsica than on the mainland, including many fewer caterpillars and a wider range of taxa. However, when expressed as a volume index, prey items were on average larger on Corsica than on the mainland. Feeding frequencies were significantly lower on Corsica. A good correlation was found in both habitats between laying date and the caterpillar peak date, although both the leafing development of oaks and the peak of abundance of caterpillars occurred 3 weeks later in the Corsican sclerophyllous trees than in the mainland deciduous ones. Differences in the feeding ecology of tits between the two habitats are discussed in the light of the evergreen habit, which means that only 30% of leaves are available for phyllophagous insects instead of 100% in deciduous trees. the combination of a late and low food supply in evergreen trees is the best explanation for the differences in breeding traits betwen the two populations. 相似文献
936.
Synopsis The autumnal diets of 23 fish species in 9 families from South Carolina blackwater streams were characterized by rank order statistics and analyzed by detrended correspondence analysis (DCA). DCA ordinations of fishes and their food items indicate two primary gradients. The first axis contrasts fine particle feeders and omnivores (Catostomidae, some cyprinids) eating algae, detritus, microcrustacea and bivalves, with predators(Anguilla, Esox, largeAmeiurus) on decapods and vertebrates. The second is a gradient from benthic feeders (percid darters,Noturus catfishes) with varied invertebrate diets, to taxa (Gambusia, some cyprinids and centrarchids) feeding at the surface. With increasing size, fishes shift to larger prey and increased surface feeding. Much of the trophic differentiation within the assemblage reflects diversification at generic and family levels. DCA is an effective method for summarizing trophic relations in diverse assemblages. 相似文献
937.
目的:研究江苏省结直肠癌发病与hMSH2基因IVS12(-6)T〉C多态及饮食习惯的相关性。方法:对江苏省金坛、泰兴和淮安地区近2年来新发结直肠癌患者共计108例以及配对180例健康体检者的饮食等生活习惯因素进行调查,提取外周血DNA,应用PCR-DHPLC和DNA序列分析的方法,采用病例对照研究结合现场收集的流行病学资料统计分hMSH2基因IVS12(-6)T〉C与结直肠癌发病的关系。结果:hMSH2基因IVS12(-6)T〉C在家族性结直肠癌患者中检出率较高,且与散发性结直肠癌病例之间差异有统计学意义(P〈0.05),在喜食油炸和腌渍食物组,hMSH2基因IVS12(-6)T〉CC突变与正常人群之间也存在明显的统计学差异(P〈0.05)。结论:hMSH2基因IVS12(-6)T〉C突变,通过遗传性和后天获得性等多重因素影响,使得该突变的携带者有更高的结直肠癌发病风险。 相似文献
938.
目的对广州地区西藏小型猪的繁殖性能和繁殖行为进行了观察研究。方法以广州地区雌雄西藏小型猪为研究对象,根据其繁殖卡的详细资料进行分类统计。结果雄性西藏小型猪阴茎首次伸出日龄为(39.50±2.63)d,此时体重为(3.26±0.87)kg;其射精日龄为(65.22±3.69)d,体重为(5.34±1.03)kg。雌性西藏小型猪初情日龄为(142±5.3)d,成年母猪发情周期为(20.35±0.72)d,发情持续期(4.2±0.31)d;其妊娠期约为114 d左右。初产雌性西藏小型猪产仔数为(2.30±0.82)头,2月龄断乳存活率为86.5%;而经产雌性西藏小型猪产仔数为(5.70±1.00)头,其2月龄断乳存活率为91.4%。哺乳期雌性西藏小型猪母性强,护仔行为强烈。结论广州地区西藏小型猪生长发育繁殖正常,产仔率和2月龄存活率等繁殖性能指标与原产地一致。 相似文献
939.
Peter R. Brown Nguyen Phu Tuan Grant R. Singleton Dao Thi Hue Phung Thi Hoa Phi Thi Thu Ha Tran Quang Tan Nguyen Van Tuat 《Population Ecology》2005,47(3):247-256
Rodent pests cause significant damage to lowland irrigated rice crops in the Red River Delta of northern Vietnam. Data from a 4-year study were examined to look at the population dynamics of the ricefield rat, Rattus argentiventer (representing 50% of captures), the lesser ricefield rat, Rattus losea (30% of captures), and the black rat, Rattus rattus complex (9% of captures) that inhabit the irrigated mixed-cropping system. We tested the hypothesis that these rodent species were breeding in response to the availability of high-quality food provided by crops rather than in response to rainfall. The abundance of rodents fluctuated annually, with a main peak following the spring rice crop, and a secondary peak following the summer rice crop. There was a strong relationship between the monthly abundance of rats and rainfall, but a weak relationship between monthly rates of increase and rainfall. There were distinct peaks in breeding activity during the reproductive stages of the rice crops suggesting that changes in crop stages were more important than rainfall in this seasonal, but irrigated agroecosystem. The modal litter size for R. argentiventer was 8 (mean of 8.67±0.20 SE, range 2–16), where the mode for R. losea, was 7 (mean of 7.32±0.15 SE, range 3–14). Management of these species needs to be conducted prior to the onset of the main breeding seasons. 相似文献
940.
Toadflaxes (Linaria Miller) represent the largest genus of the tribe Antirrhineae (formerly included in the Scrophulariaceae) of the Plantaginaceae
family. These taxa vary according to their ranges (narrow-regional–widespread), biological traits (duration, flower morphology,
breeding system) and ecological preferences. No comparative genetic studies have been performed up to the moment and the levels
and distribution of genetic diversity within this genus remain undocumented. We have conducted an allozyme study in 8 taxa
of Section Supinae. Five of them are narrow endemic, self-incompatible, insect-pollinated outcrossers that inhabit relatively unaltered habitats.
The other three taxa are widespread, small-flowered selfers that inhabit crops subjected to high levels of recurrent disturbance.
Linaria taxa showed moderate to high levels of genetic diversity. Parameters of genetic diversity were directly addressed to differences
in breeding systems. Mean number of alleles per locus, total genetic diversity and genetic diversity within populations were
higher among the outcrossers than among the selfers, (A
e = 2.28 vs. 1.23; H
T = 0.24 vs. 0.13; H
S = 93.99% vs. 54.2%) while genetic diversity among populations and population differentiation were lower for the outcrossers
than for the selfers (D
ST = 0.02% vs. 45.98%; G
ST = 0.03 vs. 0.52). Gene flow within and among populations produced a higher number of different genotypes (mean N
G = 16 for outcrossers vs. 5.4 for selfers) and migrants (mean N
m = 4.58 for outcrossers vs. 0.84 for selfers) that were attributed to an effective pollinator service in outcrossing populations.
Differences in the levels and distribution of the genetic diversity are discussed in relation to biological and autoecological
constraints of each group of taxa. 相似文献