海洋硅藻三角褐指藻经黑暗与UV辐射后的补偿生长(英文)

Compensatory growth in marine diatom Phaeodactylum tricornutum(Bacillariophyceae)after darkness and UV radiation

补偿生长是生物体对环境变化的一种适应性反应,主要指生物体遭受到不良环境胁迫后其生长及生理机能受到制约,但当不良环境胁迫解除后,生物体的生长能力会得到不同程度的恢复,表现出相对未受不良环境胁迫生物体超常生长的现象。迄今为止,补偿生长研究的对象主要集中在水生动物、反刍动物和高等植物上,而针对体积微小的海洋浮游植物的研究非常有限。海洋微藻是海洋生态系统最主要的初级生产者,在自然界物质和能量流动中扮演着至关重要的角色;同时,它们可以广泛应用在水产养殖、食品加工、医药保健、环境保护和生物制能等各种行业,具有非常好地开发利用前景。本文利用海洋硅藻三角褐指藻为试验材料,设置黑暗胁迫和UV辐射胁迫处理,着重测定微藻在恢复生长时期的藻生物量,叶绿素a含量和蛋白质含量等指标,探讨经黑暗与UV辐射胁迫后三角褐指藻的补偿生长现象。结果显示,无论是先经正常光照处理还是2d黑暗处理,UV辐射0.1min和0.8min的微藻生物量都明显高于不经UV辐射胁迫的微藻生物量;此外,经过不同程度的黑暗与UV辐射处理后,微藻在恢复生长期的叶绿素a和蛋白质含量在某些特定生长时期中明显高于对照组的叶绿素a和蛋白质含量。结果表明,三角褐指藻对外界环境变化具有适应能力,一旦不良环境胁迫被解除,微藻会表现出一定的补偿生长效应。我们的研究结果不但拓展和丰富了目前补偿生长的研究对象范围,而且还能为当前赤潮的形成、预测和防治提供一个新的研究思路,为有益经济微藻的高效率培养与利用提供理论指导。

Compensatory growth, which is refers to the exceptionally fast growth of individuals following a period of reduced growth resulting from suboptimal conditions, has been intensively studied in a wide range of ruminant animals, aquatic animals and higher plants. Up to now, however, there has been little information available on the compensatory growth in marine phytoplankton, the first primary producers in the marine environments and a natural resource containing a high content of bioactive compounds with many industrial applications, mainly because of their microscopic size and methodology limitation. In the present study, the compensatory growth of marine diatom Phaeodactylum tricornutum was investigated after algal cells were exposed to different conditions of darkness and UV radiation by determining cell biomass, chlorophyll a content and protein content in the recovery stage. Our results indicated that the cell biomass of marine Phaeoclactylum tricornutum microalga recovered from 0.1 min and 0.8 min radiation was comparatively higher than that without UV radiation through out the experiments, no matter in normal light treatment or 2-day darkness treatment. Besides, returning back to standardized growth condition after algal cells subjected to darkness treatment and UV radiation also tended to have a compensatory effect on the content of chlorophyll a and protein on some days. The results have provided the first demonstration that marine phytoplankton Phaeodactylum tricornutum which previously encountered various stresses of darkness and UV radiation showed compensatory growth if the stresses were relieved, and that the magnitude and duration of compensatory growth would depend on the variations of darkness and UV radiation from which the cells had formerly suffered. These findings could not only contribute to an expanding data concerning the compensatory growth of plant species, but also provide theoretical and technological base for predicting of red tides or for commercial culture of marine microalgae.