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长江口强壮箭虫和肥胖箭虫的丰度变化对环境变暖的响应   总被引:9,自引:0,他引:9  
李云  徐兆礼  高倩 《生态学报》2009,29(9):4773-4780
根据1959年和2002年在长江口28°00′~32°00′N,122°00′~123°30′E海域4个季节8个航次海洋调查资料,分析强壮箭虫(Sagitta crassa)和肥胖箭虫(Sagitta enflata)丰度的平面分布和季节变化特征,并结合同步的温度资料分析不同生态类群的强壮箭虫和肥胖箭虫对环境变暖的响应.结果表明:长江口水域春、夏、秋3季强壮箭虫平均丰度均小于1.00 ind/m3,出现率低,无集群性.1959年冬季平均丰度达3.24 ind/m3,出现率较高,有明显的集群性,而2002年冬季平均丰度锐减为0.001 ind/m3,几无分布.肥胖箭虫夏季平均丰度、出现率和集聚强度明显高于其它季节.2002年夏季平均丰度达16.06 ind/m3,较1959年增加3.71 ind/m3,且分布区明显扩大.可见,暖温种强壮箭虫和暖水种肥胖箭虫对长江口海域变暖的响应不同,可作为长江口海洋变暖长期变化的重要指示种.  相似文献   

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Keys for the identification of the presently known species of the genus Leptosagitta (fam. Sagittidae) are presented. Four new species of this genus found in shallow waters of Vostok Bay, Amursky Bay (Peter the Great Bay), and Kievka Bay (all of the Sea of Japan) are described in detail: L. kiyashkoi sp. n., L. latyshevi sp. n., L. magna sp. n., and L. pauca sp. n.  相似文献   

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Chloroplast DNA of seven species belonging toAnemone (sectt.Omalocarpus, Anemonidium, andAnemonanthea),Hepatica, andPulsatilla have been analyzed by restriction enzymes. According to the dendrogram constructed, the sections ofAnemone and the generaHepatica andPulsatilla seem to be evolutionary approximately equidistant to each others. This supports the concept that these groups should be treated on a similar taxonomic level, either as genera or subgenera.  相似文献   

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Summary The distribution and development of serotonin-and RFamide-like immunoreactivities in the nervous system of Chaetognatha, Paraspadella gotoi, were examined in whole-mount preparations. In adults, a single serotonin-like immunoreactive (5HTLI) neuron and numerous RFamide-like immunoreactive (RFaLI) neurons were found in the central nervous system. Based on the structure of the fins, hooks, and eyes, seven postembryonic developmental stages were recognized. The most obvious features of the stages are: stage 1, newly hatched young; stage 2, elongation of a continuous lateral tail fin; stage 3, separation of the lateral and tail fins; stage 4, appearance of hooks; stage 5, pigmentation of eyes, stage 6, attachment by tail adhesive fins; stage 7, prey capture. Stage 1 did not show any immunoreactivity. The 5HTLI neuron first appeared at stage 4 and its axonal pathway became similar to the adult at stage 6. On the other hand, the RFaLI neurons appeared at stage 3 in the ventral ganglion. Some of their somata disappeared at stage 5 and the neuronal architecture resembled the adult at stage 7 although the RFaLI neurons in the cerebral ganglion were complete at the juvenile stage.We are sad to announce that Dr. M. Yoshida died on 29 October 1988  相似文献   

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报道了中国黄枝衣科(Teloschistaceae)的一中国新记录属粉黄衣属(新拟)(Xanthomendoza)和一中国新记录种漫粉黄衣(新拟)(Xanthomendoza ulophyllodes)及石黄衣属(Xanthoria)的一新记录种裂芽黄衣(新拟)(Xanthoria calcicola)。对漫粉黄衣的ITS序列进行了测定和系统发育分析,并对相关类群的形态和分子数据进行了讨论。对2新记录种的形态特征、生境与分布进行了详细描述,并提供了形态特征图。  相似文献   

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采用常规压片技术对分布于横断山区菊科(Compositae)风毛菊属(Saussurea DC.)的6种植物进行染色体数目和核型分析。结果表明:尖苞雪莲(S.polycolea var.acutisquama)核型公式为:2n=2x=32=20m+12sm,属2B型;球花雪莲核(S.globosa)型公式为:2n=2x=34=16m+18sm,属2B型;重齿风毛菊(S.katochaete)核型公式为:2n=2x=32=8m+18sm+6st,属3B型;柱茎风毛菊(S.columnaris)核型公式为:2n=2x=32=24m+8sm,属2B型;禾叶风毛菊(S.graminea)核型公式为:2n=2x=28=8m+18sm+2st,属3B型;长毛风毛菊(S.hieracioides)核型公式为:2n=2x=32=12m+16sm+4st,属2B型。6个种染色体中均未发现随体。其中尖苞雪莲和柱茎风毛菊染色体为首次报道。  相似文献   

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A lineage of benthic chaetognaths has developed limb-like appendages on the caudal part of the body, resulting from a local modification of the lateral fins, which are folds of the epidermis and have a role in balance when swimming. The most complex are those of Paraspadella gotoi which are used as props with the tip of the tail, allowing an elaborated mating behaviour comprising different movements: complete erection of the body, swings and jumps, astonishing for so simple-bodied animals. In the tail, the epidermis and the connective tissue, together with the longitudinal musculature, are involved in this innovation. All the components of the fins, i.e. connective tissue, fin rays and multilayered epidermic cells are conserved, but their function has changed. The movements of appendages are adjusted by one pair of small appendicular muscles localised in the body wall, while posture movements of the body are allowed by four longitudinal bundles of raising muscle. These two new muscles have successively appeared in the evolutive series previously described in Paraspadella. They have definitely arisen from the secondary muscle: the two lateral bundles for the former, and the two dorsal and two ventral ones for the latter. All are supercontracting muscles, a muscle kind also observed in the other benthic genus Spadella, but unknown in planktonic and benthoplanktonic chaetognaths.  相似文献   

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Chromosome C-band patterns have been studied in 34 populations of the Australian annualBulbine group, which comprises 4x (2n = 26, 28), 8x (2n = 52, 54) and 12x (2n = 78) populations. The 2n = 26B. semibarbata populations have a simple, low heterochromatin pattern with very minor polytypic variation. The 2n = 28 populations, corresponding morphologically to a group given separate status asB. alata, are similar in pattern but exhibit pronounced enhancement of telomeric and, more particularly, centromeric dot bands. NOR heterochromatin and satellites are difficult to identify inB. alata but appear to occur in different positions from the 26-chromosome karyotype. Eastern Australian 8 x patterns are consistent with a proposed hybrid ancestry,B. semibarbata ×B. alata. Annual and perennial C-band profiles in the AustralianBulbine are discussed briefly in relation to the additive and transformation models of heterochromatin evolution and to the possible adaptive significance of variation in heterochromatin content.Cytoevolution in the AustralianBulbine 2; for part 1 see Pl. Syst. Evol.157, 201–217.  相似文献   

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C-banding studies support earlier evidence thatB. bulbosa, as a previously circumscribed, is heterogeneous, consisting of three distinct entities: (1) theB. bulbosa complex (B. bulbosa s. str.) at 4x (2n = 24), 8x (2n = 48) and 12x (2n = 72) ploidy levels, (2) the rock lily and (3) the Kroombit population (both 2n = 46). Each of these three main groups has a distinctive banding profile, though centromeric and telomeric dot bands, variably expressed, are common to all. In theB. bulbosa complex, substantial heterochromatin development, apart from bands associated with the NORs on chromosomes 1 L, 2 S and 3 L, occurs only at the terminal regions of the short arms of the large and middlesized acrocentric chromosomes, with considerable polymorphic and polytypic variation in the number and size of the heterochromatic blocks, especially at the 4x level. Queensland 8xB. bulbosa populations differ in having terminal heterochromatin, probably associated with NORs, on 11 S and 12 S, and in having some strong interstitial bands. The differences appear to correlate with attributes relating to flower morphology, and may have systematic significance. The karyotypes of rock lily and Kroombit are somewhat similar but the former has a characteristic C-band profile with multiple interstitial bands on chromosomes 1–5 and 7–9, whereas the latter has only one interstitial band on chromosome 9.First contribution of a series on cytoevolution in the AustralianBulbine. Two introductory papers in Austral. J. Bot.34 (2)  相似文献   

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