Effects of delayed first feeding on growth and survival of rock bream Oplegnathus fasciatus larvae

The effects of the timing of first feeding (0, 1 and 2 days after yolk exhaustion) and starvation on the point-of-no-return (PNR), survival and growth of laboratory-reared rock bream larvae were studied under controlled conditions. Larvae began to feed exogenously at 3 days after hatching (dah) and reached PNR on 54 h after yolk exhaustion at 22 +/- 1.5 degrees C. Larvae growth was significantly affected by the time of first exogenous feeding. The growth of 0 day delayed first feeding larvae was obviously faster than those of the other delayed first feeding larvae (P<0.05) whether at 7 dab (SL=3.40 mm, SGR=5.7, CV=4.0) or at 15 dah (SL=4.85 mm, SGR=6.1, CV=8.2) with a more uniform size distribution. Survival of 0 day delayed first feeding larvae and I day delayed first feeding larvae was 13% and 8% at the end of experiment, respectively, while no larvae survived up to 7 dah for 2 days delayed first feeding larvae and unfed larvae. Food resulted in a progressive deterioration of the larval digestive system and atrophy of skeletal muscle fibre. The ratios of head length to SL (standard length), body height to SL and eye diameter to SL were the most sensitive morphometric indices to detect the effects of fasting on larval condition. Present results showed that the combination of morphological and morphometric variables could be used to evaluate the nutritional condition of rock bream larvae. In order to avoid the potential mortality and gain better development, survival and growth in industrial production, the rock bream larvae must establish successful first feeding within 2 days after yolk exhaustion. (C) 2008 Elsevier B.V. All rights reserved.

Effects of different light sources and illumination methods on growth and body color of shrimp Litopenaeus vannamei

Shrimps Litopenaeus vannamei with initial body weight of 2.108 +/- 0.036 g were sampled for specific growth rates (SGR) and body color measurements for 50 days under different light sources (incandescent lamp, IL; cool-white fluorescent lamp, FL; metal halide lamp, MHL; and control without lamp) and different illumination methods (illumination only in day, IOD, and illumination day and night, IDN). Body color of L. vannamei was measured according to the free astaxanthin concentration (FAC) of shrimp. The SGR, food intake (FI), feed conversion efficiency (FCE) and FAC of shrimps showed significant differences among the experimental treatment groups (P < 0.05). Maximum and minimum SGR occurred under IOD by MHL and IDN by FL, respectively (difference 56.34%). The FI of shrimp for the control group did not rank lowest among treatments, confirming that shrimp primarily use scent, not vision, to search for food. FI and FCE of shrimps were both the lowest among treatment groups under IDN by FL and growth was slow, thus FL is not a preferred light source for shrimp culture. Under IOD by MHL, shrimps had the highest FCE and the third highest FI among treatment groups ensuring rapid growth. FAC of shrimp were about 3.31 +/- 0.20 mg/kg. When under IOD by MHL and IDN by FL, FAC was significantly higher than the other treatments (P < 0.05). To summarize, when illuminated by MHL, L. vannamei had not only vivid body color due to high astaxanthin concentration but also rapid growth. Therefore, MHL is an appropriate indoor light source for shrimp super-intensive culture. SGR of shrimp was in significantly negative correlation to FAC of shrimp (P < 0.05). Thus, when FAC increased, SGR did not always follow, suggesting that the purpose of astaxanthin accumulation was not for growth promotion but for protection against intense light. (c) 2005 Elsevier B.V. All rights reserved.

Feeding and growth on bivalve biodeposits by the deposit feeder Stichopus japonicus Selenka (Echinodennata : Holothuroidea) co-cultured in lantern nets

Suspension aquaculture of filter-feeding bivalves has been developing rapidly in coastal waters in the world, especially in China. Previous studies have demonstrated that dense populations of filter-feeding bivalves in shallow water can produce a large amount of faeces and pseudofaeces (biodeposits) that may lead to negative impacts on the benthic environment. To determine whether the deposit feeder Stichopus (Apostichopus) japonicus Selenka can feed on bivalve biodeposits and whether the sea cucumber can be co-cultured with bivalves in suspended lantern nets, three experiments were conducted, two in tanks in the laboratory and one in the field. In a 3-month flow-through experiment, results showed that sea cucumbers grew well with specific growth rate (SGR) reaching 1.38% d(-1), when cultured in the bottom of tanks (10 m(3) water volume) where scallops were cultured in suspension in lantern nets. Moreover, results of another laboratory experiment demonstrated that sea cucumbers could survive well on bivalve biodeposits, with a feeding rate of 1.82 +/- 0.13 g dry biodeposits ind(-1) d(-1), absorption efficiency of organic matter in biodeposits of 17.2% +/- 5.5%, and average SGR of 1.60% d(-1). Our longer-term field experiments in two coastal bays (Sishili Bay and Jiaozhou Bay, northern China) showed that S. japonicus co-cultured with bivalves also grew well at growth rates (0.09-0.31 g wet weight ind(-1) d(-1)) depending on individual size. The results suggest that bivalve lantern nets can provide a good habitat for sea cucumbers; and the co-culture of bivalve molluscs with sea cucumbers may provide an additional valuable crop with no additional inputs. (c) 2006 Elsevier B.V. All rights reserved.

Metagentiana, a new genus of Gentianaceae

The evidence from cross morphology, floral anatomy, chromosomes, palynology, and embryology all indicates that sect. Stenogyne is discordant within the genus Gentiana and is as distinct from the other sections of Gentiana as are other genera, such as Tripterospermum and Crawfurdia. In light of these characters, sect. Stenogyne is removed from Gentiana and given generic rank as the new genus Metagentiana. It is more related to Tripterospermum and Crawfurdia than to Gentiana, though it is more primitive than the first two genera. Together with Tripterospermum and Crawfurdia the new genus forms a monophyletic group, which is the sister group to the genus Gentiana. Fourteen new combinations required at specific rank are proposed.

Two new names in Chinese Stellaria (Caryophyllaceae)

During preparation of the account of Stellaria L (Caryophyllaceae) for the Flora of China, Volume 6, it was noticed that two names are illegitimate later homonyms: Stellaria arenaria Maximowicz, non Linnaeus, and Stellaria pilosa Franchet, non Dulac. Therefore, the following ne names (nomina nova) are provided here: Stellaria arenarioides Shi L. Chen, Rabeler & Turland and Stellaria pilosoides Shi L. Chen, Rabeler & Turland.

Karyomorphology of Biebersteinia Stephan (Geraniaceae) and its systematic and taxonomic significance

The systematic and taxonomic position of Biebersteinia Stephan has long been in dispute. The present paper describes for the first time the karyomorphology of two species in Biebersteinia Stephan. Both species commonly showed the interphase nuclei of the simple chromocenter type and the mitotic prophase chromosomes of the interstitial type. The karyotype formulae of both B. heterostemon and B. odora were 2n=10=2m(2sec)+8sm(2sec), belonging to the 3A type of Stebbins' classification. The karyotype of this genus is recorded for the first time. The basic chromosome numbers of four of the five known species of Biebersteinia have been recorded as x=5. The combination of resting nuclei of the simple chromocenter type, mitotic prophase chromosomes of the interstitial type, two pairs of chromosomes with four obvious secondary constrictions at the mitotic prophase and metaphase stages, and the peculiar 3A karyotype in Biebersteinia can be regarded as the karymorphological marker of this genus. The karyomorphological data presented here do not support the traditional grouping of this genus in Geraniaceae. The unique karyomorphology of Biebersteinia justifies its familiar or ordinal status, which is congruent with embryological, anatomical, chemical and molecular data. The systematic position of Biebersteinia needs further study.

Embryology of Crawfurdia delavayi (Gentianaceae) and its systematic value

The embryological characters of Crawfurdia delavayi Frabnch. are described and the systematic relationships of Crawfurdia discussed. Anthers are tetrasporangiate. The development of anther walls conforms to the Dicotyledonous type. The tapetum is of single origin. The development of the tapetum with uninucleate cells is of the glandular type. The tapetal cells on the connective side show radial elongation or periclinal division and intrude into the anther locule. The epidermis of anther walls persists and its cells become pillar and fibrous, and the endothecium degenerates. The ovary is bicarpellary and unilocular. The placentation is typically parietal with 8 rows of anatropous ovules. The development of embryo sac is of the polygonum type. Before fertilization, two polar nuclei fuse into a secondary nucleus. Three antipodal cells persist. Flowers are protandrous. Fertilization is porogamous. The development of the endosperm is of the nuclear type. The embryogeny corresponds to the solanad type physalis II variation. The embryological data indicate that it is better to separate Crawfurdia from Gentiana as an independent genus.

苏里格气田苏6加密井区山1-盒8层段河流沉积体系分析

Sulige gas field is located in Northwest of Yi-Shan Slope of the Ordos Basin. The Shan 1 Member of the Shanxi Formation and He8 Member of the ShiHeZi Formation are not only objective strata of research but also main producing strata of the Sulige Field. From core and wireline log data of 32 wells in well Su6 area of Sulige field, no less than six lithofaice types can be recognised. They are Gm,Sl,Sh,Sm,Sp,Fl,Fm. Box-shaped, bell-shaped, funnel-shaped and line-segment-shaped log are typcial gamma-ray log characters and shapes. The Depositonal system of the Shan1-He8 strata in research area have five bounding-surface hierarchies and was composed of six architectural elements, CH, LS,FF（CH）,SB,LA,GB. The depositional model of Shan 1 was the type of a sandy meandering river with natural levee, abandoned channels and crevasse splay. Channel depth of this model maybe 7-12 m and the fullest-bank flow can reach 14 m high. Based on analysis of depositional causes, a sandy braided river model for the depositional system of He 8 can be erected. It consists of active main channels, active chute channels, sheet-like sand bars, abandoned main channels and abandoned chute channels. Channel depth of this model can be 3-4 m with 9 m of highest flow. Six gamma-ray log cross sections show that the connectivity of sandbodies through Shan 1 Member is lower than He 8. Influenced by occurrence of mudy and silty deposits, vertical connectivity of sandbodies through He 8 is not high.

喀斯特低热河谷石漠化区环境梯度的小气候效应——以贵州花江峡谷区小流域为例

对典型喀斯特石漠化小流域区4 种石漠化等级(潜在(L) 、轻度(SL) 、中度(M) 、强度(ST) ) 样地的小气候特征进行了监测,对比分析了它们的气温、相对湿度、光强分布和土壤温度、湿度分布状况和日变化动态。结果表明,各等级石漠化样地内光照强度、气温及其变动幅度的大小顺序为ST > M >SL > L ;土温和土壤湿度及其变动幅度为M > ST > SL > L ;大气相对湿度及其变动幅度为ST > M > SL> L 。强度石漠化样地内日平均相对湿度雨季仅76 % ,旱季只有51 % ,分别与潜在石漠化相差13 %和35 %;光照强度为潜在的4 倍以上;雨季气温高3 ℃;表土(5 cm) 土温最高相差1615 ℃;日均表土含水率低4197 %。随着石漠化程度的加深,退化生态系统的环境调蓄能力逐渐减弱。