Selection Of Chemical Regulation Agents For Algal Growth And Studies On Their Mechanisms

Two chemicals, 2, 4-dichlorophenoxyacetic acid and glucose, which can promote the algae growth have been selected from six regulation agents; the growth speed and the concentration of the chlorophyll a of four algae have been tested. The main study area covers: 1) selecting the chemicals which can facilitate the growth of the Chlorella very obviously; 2) checking the effects of methanol on the Chlorella and the effects of different concentration of 2,4-D and glucose on the growth and chlorophyll a content of Chlorella pyrenoidosa, Scenedesmus obliquus, Nitzschia stagnorum and Microcystis aeruginosa. The purpose is to select the chemical regulation agents which can pronouncedly promote the growth of algae and check the influence on M. aeruginosa; thus to provide references to the culture of the algae in large scale.The experimental algae are cultured in a climate-control chamber with a temperature range of 25-27℃, a humidity of 80%, a ratio of the light to dark is 12h:12h, and a light intensity is about 30001x; the flasks have been rotated routinely for 3 times everyday, and changed the place randomly. The results are as follows:1. At a given range of concentration, 2, 4-D and glucose can promote or repress the algal growth and their effects will be changed with the concentration of 2, 4-D and the species of algae.2. The optimal effective concentrations of 2, 4-D on the growth of C. pyrenoidosa, S. obliquus Kutz, N. stagnorum and M. aeruginosa are 0.25mg/L, 0.50mg/L, 0.50mg/L and 0.50mg/L respectively, and those on the increment of chlorophyll a content is 0.50mg/L, 1.0mg/L, 0.25mg/L and 0.50mg/L respectively.3. The optimal effective concentrations of glucose on the growth of C. pyrenoidosa, S.obliquus and M. aeruginosa are 0.1g/L, 0.1g/L and 0.25g/L respectively, and those on the promotion of chlorophyll a content are 0.1g/L, 0.1g/L and 0.25g/L respectively.4. Over-dosage of 2, 4-D and glucose can repress the growth of alga, and any usage of glucose will repress the growth of N. stagnorum.