温度升高对高光强环境下蛋白核小球藻(Chlolorella pyrenoidosa)光能利用和生长的阻抑效应

The temperature elevation suppresses the light energy utilization and growth of Chlolorella pyrenoidosa under high light intensity conditions

以蛋白核小球藻(Cholorella pyrenoidosa)为实验材料,研究了温度变化对不同光照水平下蛋白核小球藻的光能利用和生长的影响,以明确光照强度对微藻的光能利用和生长的影响是否因温度不同而发生变化。实验中共设置了3个光照强度水平(50,150,300μmol.m-2.s-1)和2个温度水平(15℃,25℃)。实验结果表明,不同光照水平下小球藻叶绿素荧光的非光化学淬灭(NPQ)大小与温度有关,光照强度为150,300μmol.m-2.s-1时,温度升高使小球藻叶绿素荧光NPQ提高,并且光照强度越高小球藻叶绿素荧光NPQ增大越多,50μmol.m-2.s-1光照强度下温度升高对叶绿素荧光NPQ没有影响。实验发现,25℃培养温度下小球藻的光合电子传递速率(ETR)随光照强度增高而上升的速率要低于15℃时小球藻ETR上升的速率;随着光照强度增高,温度升高使小球藻ETR降低程度增大。实验结果还表明,15℃时小球藻培养液叶绿素a浓度随光照强度升高而增高,300μmol.m-2.s-1培养光强下具有最高的叶绿素a浓度。但在25℃时,光照强度升高叶绿素a浓度并不一定增高,300μmol.m-2.s-1光照强度下的叶绿素a浓度比150μmol.m-2.s-1光照强度下要低。本研究表明,温度升高增大了高光照水平下蛋白核小球藻对光能的热耗散,使光照增强对小球藻生长的促进作用减弱。由于温度升高对小球藻光能利用和生长的阻抑作用,小球藻生长的适宜光照水平因温度升高而降低。

In the experiment, we investigatd the effects of temperature Cholorella pyrenoidosa Chick. growing under different light intensity influence of light intensity on light energy utilization and growth levels （50,150,300μmol·m^-2s^-1 ） and two temperature levels found that the non-photochemical quenching light intensity conditions was influenced by alteration on light energy utilization and growth of conditions, and aimed to ascertain whether the of phytoplankton is affected by temperature. Three light （15℃ ,25℃ ） were included in the experiment. It was （NPQ） of chlorophyll fluorescence of C. temperature. At light intensities of 150 pyrenoidosa cultivated under different and 300 μmol·m^-2s^-1, temperature elevation led to an increase of NPQ, and the higher the light level, the larger increase in NPQ of C. pyrenoidosa. At light intensity of 50μmol·m^-2s^-1, however, temperature elevation did not affect NPQ of C. pyrenoidosa. As regards photosynthetic electron tranport rate of C. pyrenoidosa, it was revealed that the increase of electron tranport rate with light intensity at 25℃ was lower than that at temperature of 15℃. Moreover, the suppression effect of temperature elevation on the electron transport rate of C. pyrenoidosa increased with light intensity significantly. As far as the growth of C. pyrenoidosa is concerned, it was shown in the experiment that at temperature of 15℃, the chlorophyll a concentration of C. pyrenoidosa culture solution rised gradually with light intensity, and the highest chlorophyll a concentration of the solution was reached at 3001μmol·m^-2s^-1 However, when the temperature was 25℃, chlorophyll a concentration of C. pyrenoidosa solution did not increase with light intensity, the c hyll a concentration of C. pyrenoidosa solution cultivated at 3001μmol·m^-2s^-1 was lower than that of C. pyrenoidosa at 150μmol·m^-2s^-1. Our research clearly demonstrated that temperature elevation enhanced the dissipation of absorbed light energy as heat of C. pyrenoidosa exposed to high light intensity conditions, and therefore reduced the positive effects of light intensity augmentation on the growth of C. pyrenoidosa. The optimal light levels for growth of C. pyrenoidosa was lowered at higher temperature due to the suppression effect of temperature elevation on light energy utilization and growth.