Optics and Photonics Society of Iran

Light is an important factor for the growth of plant cells, including microalgal cells. Therefore, any changes in light intensity and the way of exposure on these cells can play an important role in changing the rate of growth or even internal compounds. The main objective of this work is to investigate how variation in the period of intermittent exposure (photoperiod) on microalgal samples affects the cell growth or its internal composition. We have tried to gain the optimum exposure photoperiod. The results show that, for the identical time period of 12 hours exposure at 24 hours and 6 different intermittent intervals, microalgal cells growth increases by shortening the time period. In the following, we examined the rotational motion of these cells during ten days period of growth and also the effects of optical trapping on cells rotational movement.