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211.
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皱纹盘鲍三倍体生长的初步研究 总被引:13,自引:0,他引:13
将用低温休克法和细胞松弛素B诱导法,获得的皱纹盘鲍(Haliotis discus hannai Ino)三倍体诱导群与二倍体的个体,在室内同样条件下饲育,对其生长情况进行了比较,结果表明:(1)三倍体与二倍体的当年稚鲍在壳长和体重的增长上无明显差异。(2)三倍体与二倍体的2龄鲍,在第二年前期生长无明显差异,但从第二年后期开始,三倍体的壳长、体重增长逐渐优于二倍体。(3)统计学分析表明,三倍体与二倍体的3龄鲍在体重、软体部和足肌的增长方面,存在着明显差异。(4)在室内饲育19个月的鲍,三倍体诱导群的壳长比二倍体大10.2%,体重比二倍体大20.1%,足肌湿重比二倍体大17.6%。 相似文献
213.
Dissolved titanium distributions in the Mid-Atlantic Bight 总被引:1,自引:0,他引:1
Although titanium is abundant in Earth's crust, its sources and distribution in the ocean are poorly understood. To elucidate its behavior, distributions of dissolved (< 0.2 μm) Ti were determined in surface waters and vertical profiles from the Mid-Atlantic Bight (MAB). Concentrations of Ti decreased from 390 pM at the Delaware Bay mouth to < 100 pM across the Delaware continental shelf. In vertical profiles, small increases in bottom waters suggest a possible flux of Ti from shelf sediments, consistent with previous reports of pore water enrichments of dissolved Ti in MAB sediments. Concentrations in surface waters of the outer shelf and slope ranged between 30 and 140 pM, with most values below 90 pM. Concentrations in a 1000 m vertical profile in the eastern Gulf Stream ranged between 110 and 280 pM, and showed a variable distribution attributed to the mixing of water masses in the outer MAB. A simple model of Ti sources to the MAB suggests that atmospheric deposition of dissolved Ti is comparable to net riverine contributions and therefore must be considered in applications of Ti as a tracer of oceanographic processes. 相似文献
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The atomic force microscopy (AFM) is a recently developed, bench-top instrument that can image the surface structures of biological
specimens at high resolution with simultaneous measurement of their size. This paper describes the application of AFM to marine
bacteria. Both natural and cultured bacteria were retained on a filter or placed on glass, washed, air-dried and observed
by AFM. The instrumental condition, the choice of suitable filter, effect of fixation and filtration, comparison with epifluorescent
microscopic (EFM) count, and the size and shape of bacterial cells were investigated. An Isopore filter was best for concentration
and subsequent observation because of its surface flatness. Cross section images showed that both rod and coccoid cells were
flattened, the former usually having a two-humped shape. Bacterial cells were differentiated from non-living particles based
on their cross section shape and size. Bacterial counts by AFM and EFM showed good agreement. Although size measurement is
easily done by the instrument, AFM tends to overestimate the size of microspheres. More work is thus needed on the size measurement
of living organisms. Because AFM easily provides images of natural bacterial cells at high magnification, it can be used as
a new tool to study the fine structures of marine bacteria.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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