不同光照下梅尼小环藻对昼夜温差变化的生理响应

Physiological response of Cyclotella meneghiniana to diurnal temperature difference under different light conditions

为探讨硅藻在不同环境中对昼夜温差变化的响应机制,以梅尼小环藻为代表,研究了在高光照与低光照两种条件下,3种不同昼夜温差对梅尼小环藻生物量、光合活性、营养盐吸收利用的影响。试验结果表明:在5~10℃范围内,昼夜温差的减小能促进梅尼小环藻细胞密度与叶绿素a的增长,使其比生长速率增加;在高光照下,各组梅尼小环藻的最大量子产量(F_(v)/F_(m))差异显著,降幅范围为36.3%~65.2%(P<0.05),而低光照下各组F_(v)/F_(m)的组间差异不显著(P>0.05);此外,随着温差减小,培养基中PO_(4)^(3-)-P的净减小值越大;不同处理组梅尼小环藻对硅的亲和力也表现出差异:高光照下,5℃温差组的硅亲和力最高,其半饱和常数(K_(m))为1.755 ng/L,而低光照下,恒温组的亲和力最高,其K_(m)为4.673 ng/L;不同光照条件下,梅尼小环藻的生理习性对昼夜温差的响应不同,但总体上一定范围内昼夜温差减小有利于梅尼小环藻的生长繁殖。

To explore the response mechanism of diatom to diurnal temperature difference in different environments,Cyclotella meneghiniana was selected to investigate the effects of diurnal temperature difference on its biomass,photosynthetic activity,and nutrient absorption under high and low light conditions.The results showed that in the range of 5℃to 10℃,the decrease of diurnal temperature difference can promote the growth of cell density and chlorophyll a and make the specific growth rate increasing.Under high light condition,the maximum quantum yield(F_(v)/F_(m))was significantly different(P<0.05)between groups,and the decrease ranged from 36.3%to 65.2%.But under low light condition,there was no significant difference in F_(v)/F_(m)(P>0.05)between groups.In addition,with the decrease of diurnal temperature difference,the net decrease of PO_(4)^(3-)-P concentration in the culture medium increased.The affinity of Cyclotella meneghiniana to silicon varied in different groups.Under high light condition,the affinity of group with 5℃diurnal temperature difference was the highest,and the half saturation constant(K_(m))was 1.755 ng/L.However,under low light condition,the affinity of group with constant temperature was the highest,and the K_(m) was 4.673 ng/L.Under different light conditions,the response of physiological habits of Cyclotella meneghiniana to diurnal temperature difference is different.But in general,the decrease of diurnal temperature difference in a certain range is conducive to the growth and reproduction of Cyclotella meneghiniana.