Abstract

This study examined the feasibility of using ultrasonic treatment to investigate the adhesion and growth of the green alga Scenedesmus acutus. The number of S. acutus cells in a colony ranged from one to eight, with a median of four. The percentages of 1- and 2-cell colonies increased with the duration of sonication. Although unaffected by a short-term (30 s) sonication, the ratio of colony formation of S. acutus on agar plates was significantly decreased by extended (60 s) sonication. Additionally, short-term sonication was effective in detaching adhered algal cells from the test tube wall without adversely affecting their growth, implying its potential usefulness in monitoring the growth of S. acutus. S. acutus cells adhered to the test tube wall within several hours, with the ratio of adhered cells reaching the maximum level (ca. 90 %) within 24 h. At 25°C, the cells usually adhered to the test tube wall rapidly including the conditions at which the growth of S. acutus was suppressed, such as a low nutrient concentration and weak irradiance. However, adhesion proceeded slowly at 15°C, implying that temperature is essential to regulating the adhesion of S. acutus.

中文摘要

本文檢驗超音波振盪對於研究急尖柵藻吸附力及生長情形之有效性。急尖柵藻的群體(colony)含有一到八個細胞，典型為四個。具一及二個細胞的群體比例隨著超音波振盪時間而增加，短暫地超音波振盪 (30秒) 並不會影響急尖柵藻群體在瓊脂平板 (agar plate) 的形成比率；但延長超音波振盪時間至60秒，其群體形成的比率就明顯降低。短時間超音波振盪有效地分離吸附的藻類細胞，而且不會影響細胞的生長，因此短時間的超音波振盪具有監控急尖柵藻細胞生長的潛力。急尖柵藻細胞在數小時內就會吸附於試管壁上，在24小時內，吸附細胞的比率約達百分之九十。25°C 培養的狀況下，急尖柵藻細胞吸附於管壁上的速度很高，即便在低濃度營養鹽及低光照等不利細胞生長的條件下亦然。然而在15°C 培養條件下，吸附速度變慢，這意味者溫度是調節急尖柵藻吸附能力的關鍵因子。

Keyword: Adhesion,culture experiments,growth,Scenedesmus acutus,ultrasonic treatment,吸附,培養實驗,生長,急尖柵藻,超音波振盪