米氏凯伦藻胞内多聚磷酸盐对环境磷变化的响应研究

RESPONSE OF INTRACELLULAR POLYPHOSPHATE IN KARENIA MIKIMOTOI TO THE VARIATION OF PHOSPHORUS IN THE ENVIRONMENT

米氏凯伦藻(Karenia mikimotoi)赤潮常发生在磷限制海域,且能长时间维持,可能具有独特的胞内磷储库利用能力和机制,但相关认识很少。因此,论文通过研究不同磷浓度对米氏凯伦藻的生长和生理特征的影响,重点分析了胞内多聚磷酸盐(polyP)对环境不同磷含量的响应变化,初步阐明胞内磷储库对米氏凯伦藻生长和维持的作用。结果表明,当环境磷匮乏时,米氏凯伦藻以0.15 d^(-1)的比生长速率维持生长,光合活性和生长能力与磷饱和时无显著差异,表明其可适应低磷环境。米氏凯伦藻胞内磷库可支持细胞分裂近2次。磷胁迫下,米氏凯伦藻胞内polyP被保留,直到磷限制时才被利用,表明polyP不是其优先利用且唯一的磷储库。研究结果从营养生理学角度为磷储库在米氏凯伦藻赤潮发生中的作用提供一定的科学解释。

Karenia mikimotoi blooms often occur in phosphorus(P)-limited sea areas and can last for a long time under P deficiency.To classify the major role of P pool during blooms,the growth and the physiological response of intracellular P pool,especially polyphosphate,in K.mikimotoi were examined under different P conditions.K.mikimotoi could sustain growth at a growth rate of 0.15 d^(-1) under P depleted environment and its photosynthetic activity and growth capability showed no difference with those in P-replete conditions,showing the ability of acclimation of K.mikimotoi to P deficiency.The particulate phosphorus content in the intracellular P pool could support cells to divide almost twice.Under a low-phosphate condition,intracellular polyphosphate was synthesized adequately,and did not decrease until cell growth was suppressed under P-limited condition,suggesting that polyphosphate was not a preferred utilized intracellular P pool nor the unique P pool.This study provided an insight for understanding P regulation in K.mikimotoi during its bloom from the perspective of nutritional physiology.