摘要
利用实验生理生态学方法对Pleurochrysis carterae种群增殖过程中出现丝状体的环境诱因进行了研究,从营养胁迫、钙化抑制胁迫、低温胁迫以及外源α-酮戊二酸的影响等几个方面,探讨了环境因子对P.carterae细胞休眠的诱导作用。结果表明,氮营养盐水平在P.carterae形成丝状体过程中有重要的作用,氮缺乏和氮限制会明显诱导丝状体的早期大量形成,即细胞快速进入休眠期。磷缺乏和磷限制对颗石藻丝状体形成的短期诱导作用不显著。正常钙化的颗石藻在缺钙环境中钙壳逐渐脱落、细胞裸露、没有种群增殖、不形成丝状体。低温胁迫下,颗石藻细胞不分裂,但细胞维持游泳的钙化单细胞状态,不形成丝状体。外源α-酮戊二酸对颗石藻形成丝状体具有浓度相关的效应,小于1.2mmol/L的浓度抑制丝状体的早期发生;1.2mmol/L及以上浓度的α-酮戊二酸能诱导丝状体早期发生。
The life cycle of Pleurochrysis carterae （Prymnesiophyceae, Haptophyta） includes two cell phases with different morphologies. They are unicellular coccolith-bearing swimming cells and the resting cells, which form benthic non-calcified branched filamentous colonies. This dramatic change of cell morphology can be used as indicator to find the cause（s） that trigger the resting cells formation. In this paper, four environmental factors that have effects on the filamentous colonies were studied during the population growth of P. carterae. They are nitrogen and phosphate stress, calcification inhibition, low temperature, and extracellular α-ketoglutaric acid. The results show nitrogen has significant effects on the resting cell formation, deficiency or limitation supply of nitrogen triggered early formation of massive resting cells, whereas phosphate deficiency or limitation has no obvious impact. The calcium-deficiency condition induces gradual coccolith detachment from the calcified swimming cells, and the cells eventually become unicellular naked cells without the formation of filamentous colonies or population growth. Low temperature causes unicellular coccolith-bearing swimming cells unable to divide, resulting in no population growth nor filamentous colony formation. The addition of extracellular α-ketoglutaric acid has concentration dependent effects on the resting cell formations. The induction of filamentous occurrence was suppressed at concentration lower than 1.2 mmol/L. In contrast, α-ketoglutaric acid stimulates the formation of filamentous colony at concentration higher than 1.2 mmol/L.
出处
《海洋与湖沼》
CAS
CSCD
北大核心
2010年第6期834-841,共8页
Oceanologia Et Limnologia Sinica
基金
国家自然科学基金项目,40776064号
教育部长江学者和创新团队发展计划,IRT0734号
宁波科技计划项目:宁波市水产养殖种质资源库,2007A31004号
宁波大学王宽诚幸福基金项目资助
