稀土元素 La 和 Ce 对小球藻生长的影响

本文以普通小球藻（Chlorella vulgaris）作为受试藻种，研究了硝酸镧和硝酸铈对其生长的影响，旨在探讨稀土化合物用于小球藻培养的方法和效果。具体实验包括：在藻类培养基中添加不同浓度的稀土硝酸盐，定时取样测定培养物光密度，绘制生长曲线并计算比生长速率（μ），测定细胞密度最大时的干物质含量、叶绿素含量、类胡萝卜素含量以及可溶性糖含量。通过实验得出：10-3~10-6 mM的稀土元素在培养早期能够促进小球藻的细胞增殖，但随着培养时间延长促进作用减弱，比生长速率与对照组的差异逐渐缩小；10-3 mM La可将叶绿素a和b的含量分别提高24.46%和28.51%，10-4mM的Ce可将其分别提高50.76%和38.92%；此外，10-3mM La或Ce可分别将胞内可溶性糖含量提高13.83%和34.88%。上述研究表明：在藻类培养基中添加一定浓度的La或Ce，可以加快小球藻细 胞的早期增殖速度，缩短获得最大生物量的培养时间，同时还可提高叶绿素、类胡萝卜素以及可溶性糖的含量，但是两种稀土元素的效应浓度范围略有差异。

Effect of Lanthanum and Cerium on Growth and Physiological Properties of Chlorella vuigaris

In order to study the biological effects of La and Ce on Chlorella vulgaris, growth curve was plotted, and the biomass, contents of chlorophyll a and b, carotenoid and soluble sugar were tested. The results showed that La and Ce at 10-3~10-6 mM stimulated algae cell proliferation at early stage, and their growth promoting effect weakened as time was increased. Compared with blank control, the contents of chlorophyll a and b increased by 24.46% and 28.51%, respectively, when cultured with La at 10-3 mM while they were raised by 50.76% and 38.92%, respectively, with Ce at 10-4 mM. In addition, 10-3 mM La and Ce could increase the soluble sugar content by 13.38% or 34.88%, respectively.. In conclusion, certain amounts of La or Ce could efficiently promote the algae cell growth at early stage, shorten the lag stage, and increase the contents of chlorophyll and soluble sugar.