环境及营养条件对稀脉浮萍和紫背浮萍氮磷含量的影响

以稀脉浮萍和紫背浮萍为对象,对在不同光照、温度和培养液氮磷浓度等条件下生长的生物量氮和磷含量的系统分析,研究了环境营养条件对氮和磷含量的影响.结果表明紫背浮萍和稀脉浮萍氮含量主要受培养液中氮浓度和温度的影响,低氮浓度和低温均可导致氮含量降低,氮浓度超过3mg·L^-1,温度高于25℃时氮含量基本保持稳定;光照强度变化对这2种浮萍的氮含量基本没有影响.紫背浮萍和稀脉浮萍磷含量会受培养液中磷浓度、温度和光照的影响.低温和低光照可导致磷含量降低,温度超过25℃,光照高于8000lx时2种浮萍磷含量则基本保持稳定;这2种浮萍的磷含量均随培养液中磷浓度增加而增加直至达到饱和,它们之间的关系可以用Monod方程来描述,其中紫背浮萍饱和磷含量高于稀脉浮萍.

Effect of Environment and Nutrient Factors on the Content of Nitrogen and Phosphorus in Two Duckweeds Species: Spirodela polyrrhiza and Lemna aequinoctialis

Effects of temperature, light density, nitrogen level and phosphorus level of medium to the content of two species Spirodela polyrrhiza and Lemna aequinoctialis were researched. The results showed that the content of nitrogen in two species kept constant when the concentration of nitrogen was higher than 3 mg\5L^-1 and temperature higher than 25.It decreased under lower concentrations of nitrogen and lower temperature. Photon flux density had no effect on it. But weak photon flux density and low temperature led to reduce the content of phosphorus of duckweed. The content of phosphorus in two duckweed species kept constant when photon flux density was higher than 8 000 lx and temperature higher than 25. The relationship between the content of phosphorus and concentrations of phosphorus in medium could be described by Monod model. The saturated phosphorus content of Spirodela polyrrhiza was higher than Lemna aequinoctialis.