光照强度和磷浓度对寡枝刚毛藻生长的影响

在利用沉水植被对湖泊进行生态修复过程中,当营养盐有所降低,水体透明度增加有利于沉水植物生长时,丝状绿藻——刚毛藻会大量生长,从而影响生态修复效果.为了研究光照强度和磷浓度对寡枝刚毛藻(Cladophora oligoclona)生长的影响,本实验用含有不同磷浓度(0.005,0.02,0.1,0.6mg/L)的BBM培养基,在不同光照强度10,30,50μmol/(m2·s)]下培养寡枝刚毛藻16d.结果发现,在光照强度为10μmol/(m2·s),初始P浓度0.1mg/L以上时,刚毛藻鲜重增加(约0.05g),其余处理条件下,刚毛藻鲜重均减少,其中光强为50μmol/(m2·s),初始磷浓度为0.005mg/L时,刚毛藻鲜重减少量最大(约0.49g).叶绿素荧光参数Fv/Fm值的变化表现为光强越大,Fv/Fm的值越低.在光强为10μmol/(m2·s)时,Fv/Fm值在0.75左右.光强为50μmol/(m2·s)时,Fv/Fm值仅为0.3.在相同光强下,不同磷浓度对Fv/Fm值变化无显著影响.相对于磷浓度对刚毛藻生长的影响,光强对刚毛藻的生长影响更大,且高光强不利于刚毛藻的生长.

Effects of light intensity and phosphorus concentration on the growthof Cladophora oligoclona

In the process of ecological restoration using submerged vegetation, green filamentous algae Cladophora will be blooming with decreased nutrients and increased water transparency. To determine the effects of light intensity and phosphorus concentration on growth of C.oligoclona, the growth and photosynthetic activity of C. oligoclona cultured in BBM medium at different concentrations of phosphorus (0.005, 0.02, 0.1,0.6mg/L) and light intensities 10, 30, 50μmol/(m2·s)] for 16 days was examined. The results showed that at the light intensity of 10μmol/(m2·s), the fresh weight of C. oligoclona increased by about 0.05g at the phosphorus concentrations of 0.1mg/L or above. However, the fresh weight of C. oligoclona decreased under other conditions. The greatest fresh weight loss was observed (about 0.49g) at the highest light intensity of 50μmol/(m2·s) and the lowest phosphorus concentration of 0.005mg/L. Chlorophyll fluorescence parameters Fv/Fm values inversely related to light intensity, the value of Fv/Fm decreased as the light intensity increased. Fv/Fm value was 0.75 at 10μmol/(m2·s) whereas Fv/Fm value was only 0.3 at 50μmol/(m2·s). Under the same light intensity, the different concentrations of phosphorus had no significant effects on the Fv/Fm values. These data showed that light intensity exerted more effects on the growth of C. oligoclona than phosphorus concentration. However, higher light intensity was detrimental to the growth of C. oligoclona.