细基江蓠繁枝变型对水体硝态氮变化的生理响应

Physiological responses of Gracilaria tenuistipitata under different levels of NO_3^-N

通过静态模拟实验,比较研究了6个硝态氮(NO3--N)摩尔浓度水平(0,10,20,40,60,80μmol/L)下培养的细基江蓠繁枝变型(Gracilariatenuistipitatavar.liuiZhangetXia)的丙二醛(MDA)、游离脯氨酸含量以及硝酸还原酶(NR)、超氧化物酶歧化酶(SOD)、过氧化物酶(POD)活性的变化。结果表明,随着水体NO3--N摩尔浓度的逐渐增加,细基江蓠繁枝变型NR、SOD和POD的活性均呈现先增加后下降的显著变化(P<0.05),膜脂过氧化产物MDA含量随水体NO3--N摩尔浓度的变化则呈相反的趋势(P<0.05);游离脯氨酸含量则与水体NO3--N摩尔浓度呈正相关(r=0.9161)。综合分析结果认为,单独以硝态氮为氮源时,20μmol/L的供氮水平能使细基江蓠繁枝变型处于相对最佳的生理状态。

With static experiments, this paper investigated the malondiadehyde（MDA） and proline contents, and the nitrate reductase （NR）, superoxide dismutase（SOD） and peroxidase（POD） activities of Gracilaria tenuistipitata var.liui Zhang et Xia cultured in different levels of NO3^-N （0, 10, 20, 40, 60, 80μmol/L） of water. The results showed that the NR, SOD, and POD activities increased firstly and then decreased gradually with the increase of NO3^-N concentration of water（P〈0.05）,but the MDA content decreased firstly and then increased gradually with the increase of it（P〈0.05）. The proline contents were positively correlated with NO3^-N concentration of water （r=0.9161）. A conclusion could be made that 20μmol/L NO3^-N was able to maintain an excellent physiological condition of Gracilaria tenuistipitata when NO3^-N is an only one nitrogen source.