温度对龙须菜“2007”生理生化特性的影响

The Effects of Temperature on the Physiological and Biochemical Characteristics of Strain “2007” of Gracilaria lemaneiformis

关键词:  龙须菜  相对生长速率  光合色素  硝酸还原酶  叶绿素荧光

Key words:  Gracilaria lemaneiformis  relative growth rate  photosynthetic pigments  nitrate reductase activity  chlorophyll fluorescence parameters

摘要:

[目的]龙须菜(Gracilaria lemaneiformis)"2007"新品系具有耐高温﹑生长快﹑琼胶含量高等特点,目前已经在中国南方海域进行栽培推广,研究温度对龙须菜"2007"生理生化特性的影响具有重要意义。[方法]测定在不同温度(15℃,20℃,25℃,30℃)培养条件下龙须菜"2007"新品系的相对生长速率(RGR)、光合色素含量﹑硝酸还原酶活性﹑叶绿素荧光参数等生理生化特性的变化。[结果]在15~25℃温度范围内,龙须菜的最大相对电子传递速率(rETR_max)无明显差异(P>0.05),但显著高于30℃时(P<0.05)。在15~30℃范围内,饱和光强(I_k)却随着温度的增加而显著的下降,两两存在显著性差异(P<0.05)。随着温度的递增,Q₁₀(反映硝酸还原活性与温度关系)显著下降(P<0.05),到达30℃高温时,Q₁₀已经下降到1.13,说明30℃高温对龙须菜"2007"的生理活性有一定的损伤,硝酸还原酶活性降低,光合作用的能力显著下降。[结论]最适合龙须菜"2007"生长的温度为20℃,此时,龙须菜"2007"RGR最大,叶绿素(Chl a)和藻胆蛋白的含量最高。

Abstract:

[Objective] Gracilaria lemaneiformis new strain "2007" has the features of high temperature resistance, rapid growth, high contents of agar, and so on.At present it has been cultured in southern of China.Thus, it is important to investigate the effects of temperature on the physiological and biochemical characteristics of strain "2007" of G.lemaneiformis.[Methods] The strain "2007" of G.lemaneiformis was cultivated at various temperatures of 15℃, 20℃, 25℃ and 30℃, and its responses to temperature were studied, including relative growth rate (RGR), contents of photosynthetic pigments, nitrate reductase activity, and chlorophyll fluorescence parameters.[Results] The maximum relative electron transfer rate (rETR_max) had no significant difference (P>0.05)between 15℃ and 25℃ but significantly higher than 30℃ (P<0.05).Being cultivated between 15℃ and 30℃, the saturation light (I_k) of strain "2007" of G.lemaneiformis markedly decreased with the increasing temperature, having significant difference between each other (P<0.05).The value of Q₁₀ gradually decreased with increasing temperature (P<0.05), and decreased to 1.13 at 30℃, indicating that the high temperature of 30℃ damaged the physiological activities of strain "2007" of G.lemaneiformis to a certain degree, inducing the decrease in nitrate reductase activity and lower capacity of photosynthesis.[Conclusion] The results showed that the suited growth temperature was 20℃.The relative growth rate, the contents of chlorophyll a, carotenoid and phycobiliprotein of strain "2007" of G.lemaneiformis were the highest cultured at 20℃.