不同温度和接种密度下亚心形扁藻增殖的初步研究

A preliminary study on multiplication of Platymonas subcordiformis at different temperatures and inoculation densities

在自然变温和水浴恒温的条件下。用3种接种密度培养亚心形扁藻Platymonas subcordi- formis,以研究其增殖形式。结果表明,较高接种密度时,扁藻密度始终较高且较早进入平稳期;接种密度相同,恒温下较早进入平稳期。但就所能达到的最大密度而言,变温培养时更高;低密度接种的比生长速率最大,而中等接种密度下的比生长速率最稳定;培养时的比生长速率较高,且比较稳定;增殖模型所反映的和观测结果一致。随着接种密度增加,依赖于初始种群密度的参数a减少,环境容量增加而瞬时增殖速度下降。模型也反映出在相同接种密度条件下,变温培养的环境容量大于恒温培养;恒温时的微藻瞬时增长速度要大于变温时。就(N_t)/(N_0)而言,在变温下培养扁藻,各处理间的差异不具有统计学意义,而在恒温培养时各处理间的差异显著;低密度接种时,变温和恒温条件下的(N_t)/(N_0)具有显著差异,而在中密度接种和高密度接种时,两种温度条件下的(N_t)/(N_0)差异不显著。

At a natural fluctuant temperature and a constant temperature, and starting from three inoculation densities, the multiplication of Platymonas subcordiformis was studied. Higher inoculation densities always resulted in higher subsequent concentrations of the microalgae, and an earlier setting in of the steady growth phase. When the initial density was the same, the microalgae reached steady growth phase earlier at a constant temperature than it did at a fluctuant temperature, although the latter treatment reached a much higher maximum density. At the same temperature, lower inoculation density resulted in the fastest relative growth rate, and medium inoculation density correlated with the most stable relative growth rate. And the microalgae cultivated at a fluctuant temperature showed higher and more stable relative growth rate. The multiplication models developed correlated well with the observations. As the inoculation density increased, the initial-density dependent parameter a also decreased, along with the increase of environmental capacity and the decrease of instantaneous multiplication speed. These models also reflected that, when the initial density was the same, the microalgae cultivated at a fluctuant temperature had higher environmental capacity than that cultured at a constant temperature. Furthermore, the microalgae showed higher instantaneousgrowth rate at a constant temperature. The ratios of Nt/No were not statistically different among treatments at the fluctuant temperature, while there was significant difference between treatments at the constant temperature. When the initial density was low, the ratio of Nt/No was significantly different between the constant and fluctuant temperature treatments, while medium and higher initial densities did not result in significant differences between the treatments of the different temperature regimes.