铜绿微囊藻对香蒲叶片氮代谢相关酶活性的影响

Effects of Microcystis aeruginosa on enzyme activities related to nitrogen metabolism in Typha orientalis Presl. leaves

采用共培养的实验方法,通过追踪测定香蒲(Typha orientalis Presl.)叶片中NO-3、NH+4、TN、可溶性蛋白的含量及硝酸还原酶(NR)、谷氨酰胺合成酶(GS)、谷氨酸脱氢酶(GDH)活性,研究了不同初始密度铜绿微囊藻(Microcystis aeruginosa)对香蒲叶片内各种形态氮含量及氮代谢相关酶活性的影响。结果表明,铜绿微囊藻初始密度为1.0×104cells/m L时,香蒲叶片NR、GS和GDH活性增加,可溶性蛋白及TN含量也增加,说明低密度铜绿微囊藻对香蒲叶片的氮代谢具有促进作用,香蒲吸收同化氮能力增强;铜绿微囊藻初始密度为1.0×107cells/m L时,香蒲叶片NR及GS酶活性降低,而GDH活性增强,NO-3、NH+4含量增加,而可溶性蛋白及TN含量降低,表明高密度铜绿微囊藻对香蒲叶片的氮代谢具有抑制作用,香蒲吸收同化氮能力减弱。

The effect of different initial densities of Microcystis aeruginosa acted on the contents of various forms of nitrogen and the enzyme activities related to nitrogen metabolism in Typha orientalis Presl. leaves was e- valuated through co-cultivating with Microcystis aeruginosa and Typha orientalis Presl leaves by monitoring con- tents of NO3-, NHf, TN, soluble protein, and enzyme activities of nitrate reductase （NR）, glutamine syn- thetase （GS） and glutamate dehydrogenase （GDH）. Study results showed the enzyme activities of NR, GS and GDH increased and the same as the contents of TN and soluble protein in Typha orientalis Presl. leaves while the initial co-cultivated concentration of Microcystis aeruginosa was at 1.0 × 10^4 cells/mL. This result indicated that low density of Mierocystis aeruginosa had enhanced the capability of absorption and assimilation of nitrogen in Typha orientalis Presl. leaves. The enzyme activities of NR and GS decreased whereas activities of GDH in- creased in Typha orientalis Presl. leaves while the initial co-cultivated concentration of Microcystis aeruginosa was at 1.0 ×10^7 cells/mL. In addition, the contents of NO3- and NH4＋ increased whereas the contents of TN and sol- uble protein decreased during this incubation period. The result indicated that high density of Microcystis aerugi- nosa had inhibited the nitrogen metabolism in Typha orientalis Presl. leaves. Meanwhile, the capability of ab- sorption and assimilation of nitrogen was weaken in Typha orientalis Presl. leaves as well.