Feeding,defaecation and absorption efficiency in the Cape rock lobster jasus lalandii     

《African Journal of Marine Science》2013,35(1):59-65

In order to estimate the absorption rate of carbon by the palinurid lobster Jasus lalandii, the net quantity of ingested carbon and gross carbon content of faeces must be known. Experimental animals were selected for consistent feeding and subsequently starved for 72 h. Ingested carbon was established by determining the carbon content of the prey mussel Choromytilus meridionalis under controlled aquarium conditions through five eating/defaecating cycles. The losses of particulate and dissolved organic carbon due to messy feeding were measured and amounted to 20,1 per cent of the food presented. Of the net carbon ingested, 20,5 per cent was voided as faeces, thereby giving a mean absorption efficiency of 79,5 per cent (n = 15, SD = 4,6%). J. lalandii, as a top carnivore in the inshore Benguela ecosystem, is therefore highly efficient in the utilization of ingested carbon. In animals of commercial size (≥ 89 mm carapace length), small variations in absorption efficiencies exhibited were neither dependent on body mass nor ingested mass, but may rather be attributed to scatter inherent in all biological systems.  相似文献   

Sexual reproduction in Sarcotragus spinosulus from two different shallow environments     

Mercurio Maria  Corriero Giuseppe  Gherardi Miriam  Baldacconi Rossella  Elda Gaino 《Marine Ecology》2013,34(4):394-408

The reproductive cycle of the demosponge Sarcotragus spinosulus from two different shallow environments (La Pierta and La Strea) of the Ionian coasts of Apulia (SE Italy) was studied from February 2006 to February 2007 in 20 tagged specimens. The sponge is viviparous. All the monitored specimens showed sexual reproduction, even if the process usually involved small portions of the sponge tissue. Most of the specimens showed hermaphroditism, with contemporaneous production of oocytes and spermatic cysts in the same reproductive season. Young oocytes occurred from June to September in specimens from La Pierta and from June to October in those from La Strea. Large mature eggs, measuring up to 200 μm, showed a peak in August to September, concomitant with the appearance of spermatic cysts, whose density values were about 100 times higher than those estimated for female elements. At La Pierta, embryos were present for 11 months, whereas at La Strea they were very scarce during the first 4 months of observation, with the results that there was a significant difference in the production of embryos between the two groups of sponges. Embryo development occurred in patches inside the choanosomal region. Cleavage started in September and led in June to a solid stereoblastula, which, only at La Pierta, produced parenchymella larva (371.3 + 31.3 μm on average) from June to July. In the specimens from La Strea, larvae were never observed. The slight differences in the reproductive cycle between the two groups of sponges may be explained in the light of the major variability of the environmental parameters which could have affected the specimens from La Strea negatively.  相似文献   

Estimation of size at first maturity in two South African coral species     

《African Journal of Marine Science》2013,35(4):513-516

The corals Acropora austera and Platygyra daedalea have been the subject of extensive reproductive and population genetic studies in the iSimangaliso Wetland Park (iSimangaliso), on the KwaZulu-Natal coast, eastern South Africa. Despite this, estimates of size at first maturity in these two species are lacking. This information could be used to provide a baseline to differentiate juveniles from adult sizes of corals, an important factor for assessing the condition of scleractinian communities in reefs. Here, we present the methods followed to provide such estimates for these two hard corals. Using generalised linear models and assuming knife-edge maturity (50% probability), it was estimated that A. austera from iSimangaliso matures at c. 15 cm mean colony diameter (MCD) (95% CI: 9.25–20.75 cm MCD) and P. daedalea matures at c. 7 cm MCD (95% CI: 4.55–8.39 cm MCD). These estimates were comparable to those for tropical species which is remarkable considering the high-latitude nature of the sampled reefs. It is expected that the findings from this study will assist in the assessment of reproduction, recruitment, survival and genetic variation in clonal organisms such as corals, and will provide a baseline to assess the effects of climate change on coral communities in the region.  相似文献   

北部湾墨西哥湾扇贝形态性状与闭壳肌质量的关系     

王辉  李艳红  刘进  朱晓闻  刘志刚 《广东海洋大学学报》2013,(3)

为寻找墨西哥湾扇贝中对其闭壳肌重量影响最显著的形态学特征,在整个扇贝的生长过程中,每一个月测一次壳高(mm)、壳宽(mm)、铰合线长(mm)、体质量(g)和闭壳肌质量(g),每一轮的样本采集量为60,通过通径分析研究这些形态学特征对闭壳肌质量的影响。结果显示,根据各形态学特征对闭壳肌质量的直接的、间接的、总路径的贡献,发现体质量的影响是最显著的(p<0.01),其他的形态学特征如壳高、壳宽和铰合线长对于闭壳肌生长既不限制也不促进。  相似文献   

海湾扇贝与紫扇贝生殖隔离研究     

张守都  张国范  李莉 《海洋科学》2012,36(8):9-14

对海湾扇贝(Argopecten irradians)和秘鲁紫扇贝(Argopecten purpuratus)进行了跨种间的杂交尝试,结果显示两个物种之间正向和反向均可受精和正常发育,没有发现合子前隔离,并且通过internal transcribed spacer 1(ITS1)标记验证了杂交的成功.至杂交子一代性成熟时通过对杂合子成熟性腺进行H.E.染色石蜡切片观察发现,雄性性腺明显退化且不能产生有活力的精子,雌性性腺发达且能形成外观正常卵子,但是却不能与亲本进行回交,即表现为典型的合子后隔离:杂种不育.  相似文献   

Single Nucleotide Polymorphism of FSHβ Gene Associated with Reproductive Traits in Japanese Flounder (Paralichthys olivaceus)     

Feng He  Haishen Wen  Dahui Yu  Jifang Li  Bao Shi  Caifang Chen  Jiaren Zhang  Guoxiong Jin  Xiaoyan Chen  Dan Shi  Yanping Yang 《中国海洋大学学报(英文版)》2010,9(4):395-398

Follicle stimulating hormone β (FSHβ) of Japanese flounder (Paralichthys olivaceus) plays a key role in the regulation of gonadal development.This study aimed to investigate molecular genetic characteristics of the FSHβ gene and elucidate the effects of single nucleotide polymorphisms (SNPs) of FSHβ on reproductive traits in Japanese flounder.We used polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) and sequencing of the FSHβ gene in 60 individuals.We identified only an SNP (T/C) in the coding region of exon3 of FSHβ.The SNP (T/C) did not lead to amino acid changes at the position 340 bp of FSHβ gene.Statistical analysis showed that the SNP was significantly associated with testosterone (T) level and gonadosomatic index (GSI) (P0.05).Individuals with genotype TC of the SNP had significantly higher serum T levels and GSI (P0.05) than that of genotype CC.Therefore, FSHβ gene could be a useful molecular marker in selection for prominent reproductive trait in Japanese Flounder.  相似文献   

有限灌溉对荒漠绿洲春玉米产量及产量性状的影响   总被引：1，自引：0，他引：1  

张恒嘉  赵文智 《中国沙漠》2010,30(4):891-895

对干旱环境下临泽荒漠绿洲春玉米进行了有限灌溉试验研究,旨在探究有限灌溉对绿洲玉米农田生产力的影响。结果表明,在所有处理中,全生育期灌水最少的处理MI1玉米籽粒产量比灌水量略高于它的处理MI2和灌水量较高的处理MI4增产25.7%和38.8%,但MI1与其他处理及对照间差异不显著。MI1处理全生育期灌水量最少,其产量不但未显著下降,反而高于灌水最多的对照CK。不同灌溉处理及对照间玉米穗粗、秃顶长、穗行数均不存在显著差异,但个别处理及对照间其他产量性状却存在差异,其中对照CK、处理MI5、MI1的穗长分别比处理MI4增加15.3%、13.6%和12.4%,对照CK和处理MI1、MI5的行粒数分别比MI4处理增加17.3%、13.9%和12.2%,对照CK的穗粒数分别比处理MI4、MI2和MI3增加19.3%、19.1%和14.5%,处理MI1的千粒重分别比MI4、MI5、CK增加26.9%、14.0%和14.0%。  相似文献   

Differences in Leaf Functional Traits Between Rhus typhina and Native Species          下载免费PDF全文

Congyan Wang  Jun Liu  Hongguang Xiao  Jiawei Zhou 《洁净——土壤、空气、水》2016,44(11):1591-1597

  相似文献   

红鳍东方鲀(Takifugu rubripes)耐低温性状和生长性状遗传参数评估     

赵海池  刘志峰  王新安  包玉龙  刘圣聪  杨明超  闫鹏飞  马爱军 《海洋与湖沼》2024,55(2):517-525

采用人工控温的方式, 对构建的31个F₁红鳍东方鲀(Takifugu rubripes)全同胞家系开展低温胁迫实验, 获得耐低温性状低温累计存活时间(CDH), 基于混合线性模型分别开展耐低温性状和生长性状遗传参数评估,对每一性状是否需要考虑共同环境效应所构建的两种模型进行似然比检验。结果显示, 经似然比检验, 最终选用模型A和模型BF进行耐低温和生长性状遗传评估; 耐低温性状CDH遗传力为(0.27±0.08),属于中等遗传力; 体重BW遗传力为(0.36±0.13), 属于中等遗传力, 体长BL遗传力为(0.14±0.06), 属于低等遗传力, 经检验, 遗传力估计值均达到极显著水平(P<0.01)。CDH和体重、体长的遗传相关分别为(-0.40±0.22)和(-0.44±0.24), 表型相关分别为(-0.09±0.06)和(-0.16± 0.05), 均为负相关; 体重和体长之间的遗传相关为(0.92±0.05), 表型相关为(0.80±0.02), 呈正相关且结果极显著(P<0.01)。研究结果表明, 红鳍东方鲀的耐低温性状和生长性状都具有较好的改良潜力, 考虑到两性状间存在负遗传相关, 在开展耐低温选育时, 对首先不同性状进行品系选育, 然后利用品系间杂交培育出耐高温、生长快的新品种。该项研究首次完成了红鳍东方鲀耐低温性状的遗传参数评估, 为制订红鳍东方鲀耐低温选育育种规划提供了理论依据。  相似文献   

Plant drought tolerance trait is the key parameter in improving the modeling of terrestrial transpiration in arid and semi-arid regions   总被引：1，自引：0，他引：1       下载免费PDF全文

Xintao Liu  Xingjie Lu  Shulei Zhang  Zhongwang Wei  Nan Wei  Shupeng Zhang  Hua Yuan  Wei Shangguan  Shaofeng Liu  Jianfeng Huang  Lu Li  Xiulan Ye  Jinxuan Zhou  Wenke Hu  Yongjiu Dai 《大气和海洋科学快报》2022,15(1):35-41

陆面过程蒸腾作用的模拟制约着天气,气候降水预测的精确度.近几十年来,为了更好地描述植被蒸腾的水力约束,陆面过程模式发展了基于植物性状的植物水力胁迫方案.然而,我们对于植物性状在蒸腾模拟中的地位仍然缺乏了解,植物性状对蒸腾的重要性仍需进一步量化.本研究利用Morris方法评估植物性状参数在通用陆面模式植物水力胁迫方案(CoLM-P₅₀HS)中的重要性,针对17种植物性状,筛选出最为重要的:耐旱性状(P₅₀),气孔性状,和光合作用性状.在12个FLUXNET站点中,参数的重要性由归一化敏感度来衡量.P₅₀的重要性随着降水的减少而增加,而气孔性状和光合作用性状的重要性则随着降水的减少而减少.在干旱或半干旱地区,P₅₀比气孔性状和光合作用性状更重要,这意味着当植物经常经历干旱时,水力安全策略比植物生长策略更关键.而耐旱性状的巨大变异性进一步暗示了多种植物水力安全策略的共存.忽视P₅₀的变异性可能会对陆面过程模式蒸腾作用的模拟造成严重误差.因此,为了更好地表示植物水力功能的变异性,需要增加对耐旱性状的观测并耦合到陆面模式中.  相似文献