淡水浮游硅藻光适应（Light adaption）策略研究

Diatom blooms outbreak at a high frequencies and a large areas. Since the middle route of the south to North Water Diversion Project began to deliver water, the contradiction between water discharge and water storage became more prominent. Diatom bloom control is badly in need of excellent resolution. Previous study reveals that light stress can affect the efficiency and rate of photosynthesis directly and further inhibits the growth of algae. It is need to satisfy two preconditions to achieve the purpose of diatom bloom control through light control: (1) there are significant habitat differences in the light adaptation of diatoms; (2) the responses to light stress of diatoms have limitations. This project takes physiological and molecular biological methods to study light-adaptation of diatom in the same species and other dominant species from high-light and low-light ecosystem, further to identify the reason for light-adaptation differences. In light stress experiment, we attempt to explore the delay effect for growth decrease of diatom, the duration of the physiological regulation, the content change of D1 protein and the possibility of light recovery, in order to determine the limitation of physiological regulation of diatoms response to light stress. The study will help to reveal the light adaptation differences between different habitats and diatom and physiological regulation mechanism of diatoms response to light stress, and provide a theoretical basis and data support to control diatom bloom through water diversion control.

汉江硅藻水华发生频率和暴发面积不断增加，调水工程阻碍上游泄水控水华，水华防控急需新思路。前期研究发现光胁迫可通过直接影响光合作用效率和速率抑制藻类生长，达到高效的控藻效果。要通过控光达到控藻的目的，须满足以下两个前提：（1）硅藻的光适应特性具有明显的生境差异；（2）硅藻应对光胁迫的生理调节具有局限性。本项目采用生理学和分子生物学等方法，分离汉江高光和低光生境中相同种类和其他优势硅藻种类进行生长实验，比较其光适应特性，探明硅藻光适应特性差异是种类差异决定还是生境差异塑造。进行光胁迫实验，探究硅藻生理调节持续时间和对光合活性下降的推迟作用，以及光系统Ⅱ中D1蛋白含量变化和光恢复的可能性，以确定光胁迫下硅藻生理调节的局限性。本项目将有助于揭示硅藻光适应特性和光胁迫生理调节机制，为通过局部调水、调沙达到控藻目的提供理论基础和数据支撑。

项目针对枯水季节水库蓄水与开闸放水控藻的矛盾突出等控制硅藻水华的技术瓶颈，设计结合当地水利设施和水华硅藻光适应特性进行光控制的策略。本项目通过分离光强差异显著的两种生境中的硅藻优势种和相同种类的硅藻进行生长实验，结合对以往研究数据的整理分析结果，明确了硅藻光适应特性差异由原生境光照条件差异决定，而非藻类种类差异决定。通过光胁迫实验，明确了硅藻可以利用生理调节来应对高光或低光胁迫，但仅能持续较短时间。最后，通过野外调查，明确了藻类的光适应及其光合活性的变化趋势可以通过快速检测来判断。本项目探明了硅藻光适应特性差异的产生原因和硅藻应对光胁迫进行生理调节的局限性，建立了野外快速检测模式，为通过光控制措施控制硅藻水华提供了理论依据。在短时间内通过调用较少水量达到高效抑制硅藻生长的目的，可以为控制硅藻水华提供新的思路。