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Rhopalium development in Aurelia aurita ephyrae   总被引:3,自引:0,他引:3  
Rhopalia of developing ephyrae were examined using the SEM and TEM at 24 h intervals following strobilation induction. Kinocilia are shorter in the ephyra stage than in polyps. A few ephyra-type kinocilia are found in rhopalia as early as 24 h after induction, before a distinct rhopalium is seen. By 72 h, the shorter kinocilia predominate and are almost as numerous as in ephyrae (120 h). Many of the kinocilia are associated with mechanoreceptor cells (MR) found in the rhopalia. These MR cells are compared to those reported for medusae. Although newly released ephyrae lack a touch plate, the MR cells in their rhopalia along with the statocyst and neuromuscular system apparently enable these organisms to detect and respond to gravity.  相似文献
2.
Life cycle of Phacellophora camtschatica (Cnidaria: Scyphozoa)   总被引:1,自引:0,他引:1  
Abstract. Gelatinous zooplankton play important roles in marine ecosystems and at times can have significant impacts on human activities. Many scyphozoans have enigmatic life cycles and the specific habitat for benthic life history stages is unknown. This is especially true for many of the large surface-cruising scyphomedusae of the northeast Pacific Ocean. Phacellophora camtschatica belongs to the family Ulmaridae and is known to have scyphistomae in the life history. However, the life cycle of P. camtschatica has not been formally described. Here the life cycle of members of P. camtschatica is described based on laboratory observations and compared with early life history stages in the scyphomedusa Aurelia labiata .  相似文献
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王雷  彭赛君  董志军 《生态学报》2021,41(4):1634-1644
海洋酸化和重金属污染作为全球性海洋环境问题,均影响海洋生物的生存和生态系统的健康。海月水母是近岸海域常见的胶质性浮游动物,其生长发育和种群数量易受到海洋环境变化的影响。研究海月水母碟状幼体对海洋酸化(pH 8.1和pH 7.6)和Cu2+(0、10 μg/L和25 μg/L)胁迫的生理响应,从氧化应激酶和酸碱平衡相关酶活性、呼吸、运动和生长等方面探究海洋酸化和铜污染对海月水母碟状幼体的综合影响。研究发现,经过16 d的暴露期后Cu2+对海月水母碟状幼体产生较强的毒性效应,抑制Ca2+-ATP酶和过氧化氢酶活性,造成超氧化物歧化酶活性和呼吸代谢速率异常升高、收缩频率降低、生长速度减慢。正常pH,25 μg/L铜暴露处理的超氧化物歧化酶活性和呼吸率最高,收缩频率和伞部直径最小。随着铜暴露浓度的增加,海洋酸化可以缓解Cu2+对海月水母呼吸率和生长的影响,但对Ca2+-ATP酶和过氧化氢酶活性具有协同抑制作用。确定了海洋酸化和Cu2+对海月水母的不同生理影响,这种差异影响可能会导致未来海洋生物多样性和生态系统的改变。  相似文献
4.
以巴布亚硝水母(Mastigias papua)为研究对象,观察了水螅体无性生殖产生类浮浪幼虫胞芽、类浮浪幼虫胞芽变态发育为水螅体、水螅体横裂产生碟状体以及碟状体发育为水母体的过程和形态变化。25 ℃时类浮浪幼虫胞芽经过93 h后变态发育为水螅体。换用带有虫黄藻的天然海水并将培养温度从25 ℃升至27 ℃后,水螅体开始横裂,萼部触手环下方产生缢痕。水螅体横裂开始47 h后,缢痕更加明显,其上方部分发育为碟状幼体,后期碟状体搏动越来越频繁,最后释放。释放后的碟状体在实验室培养条件下21 d后可发育为水母幼体。巴布亚硝水母虽然只有产生类浮浪幼虫胞芽一种无性生殖方式,但繁殖速度较快,27 ℃时1个水螅体平均1 d可产生1.7个类浮浪幼虫胞芽,类浮浪幼虫胞芽可在3或4 d的短时间内附着变态。  相似文献
5.
The continuous changes in the number of newly established polyps of Aurelia aurita (L.) on settling plates under natural conditions were observed from August 1998 to September 1999 in Tokyo Bay, Japan. A sharp decline in survivorship of newly settled polyps was observed within the first few days, however, survivorship of polyps settled in October increased by budding up to 399% after two months. The number of discs in each strobila varied from 1 to 6, however, most of the strobilae formed single discs. The percentage ratios of the total number of ephyrae to the initial number of polyps on settling plates were generally lower than 10%, but the highest ratio of 594.4% was estimated for the polyps settled in October. It is considered that most of the liberated ephyrae originate from the polyps settled in October in Tokyo Bay. This study suggests that the occurrence of ripe medusae with planula larvae throughout the year contributes to the success of settlement and growth of the polyp stage in Tokyo Bay.  相似文献
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