高产油突变藻株Desmodesmus sp．D90G．19的光合作用特征

The photosynthetic characteristics of a Desmodesmus sp. mutant D90G-19 with improved lipid productivity

Desmodesmus sp．S-1藻株经重离子诱变后得到的-株突变体D90G．19，较其野生型的油脂产率提高了20．6％；同时对野生型和突变株的光合放氧速率，色素组成和叶绿素荧光动力学进行了分析。与野生型相比，突变体D90G-19的光合作用有如下特点：1．D90G．19的光饱和点为500gmol／（m2·s），无论是在强光还是在弱光下，D90G-19的光合作用效率都显著高于其野生型；2．突变体D90G．19对高温的适应性比野生型强：3．在弱碱性条件下，D90G-19的光合效率的提升较之野生型更为显著。培养D90G-19的最佳光照强度应在250～400μmol／（m2·s）之间，最适温度在25～30℃，培养液pH值则以弱碱性为宜（7〈pH≤8）。叶绿素荧光动力学数据表明，突变体D90G-19的光合作用系统在强光下的损伤程度小于野生型，能够耐受更高的光强胁迫。

After induced by heavy-ion beam, a mutant of Desmodesmus sp., D90G-19 was obtained, which had a lipid productivity 20.6% higher than the wild type. The photosynthetic characteristics of mutant D90G-19 was characterized by analysis of photosynthetic oxygen evolution rate, chlorophyll concentration and chlorophyll fluo- rescence. Compared to the wild type, the D90G-19 had a higher photosynthetic efficiency regardless of high or low light intensity, the D90G-19 had a higher temperature tolerance and the D90G-19 had a more significant increase in photosynthetic efficiency under weak base condition. The optimum light intensity, temperature and pH for D90G-19 were 250-400 μmol/（m2-s）, 25-30℃ and 7〈pH≤8 respectively. The photo saturation point of D90G-19 was about 500 μmol/（m2.s）, and the Y（NO） suggested that the damage of photosynthesis system II in D90G-19 was less than that in wild type when they were exposed to high intensity light.