模拟污水中氮、磷对水稻幼苗根系呼吸作用的影响

研究了模拟污水中不同浓度的Ｎ、Ｐ对水稻幼苗根系呼吸强度、细胞色素氧化酶、呼吸途径等的影响。结果表明，在总氮（ＮＴ）、总磷（ＰＴ）浓度分别小于４．２８ｍｍｏｌ／Ｌ、０．２ｍｍｏｌ／Ｌ时，呼吸速率、细胞色素氧化酶和呼吸商（ＲＱ）均随Ｎ、Ｐ浓度增大而增加，当超过这一浓度后，则随总氮总磷浓度上升而下降。总氮、总磷浓度分别小于４．２８ｍｍｏｌ／Ｌ、０．２ｍｍｏｌ／Ｌ时，磷酸戊糖途径（ＨＭＰ）随Ｎ、Ｐ浓度增加

EFFECTS OF NITROGEN AND PHOSPHORUS IN MIMIC WASTEWATER ON ROOT RESPIRATION OF RICE SEEDLINGS

The influences on respiratory intensity, cytochrome oxidase activity and respiratory pathway in roots of rice seedings were investigated under various concentrations of nitrogen and phosphorus in mimic wastewater, When the rice seedlings were treated by mimic wastewater containning lower N and P, the respiration rate, respiratory quotient and cytochrome oxidase activity increased in direct ratio with N and P concentrations, However,they decreased when N and P concentrations increased in mimic wastewater which were higher concentrations of N and P. The results showed the respiratory pathway had changed in rice roots, When N_T<4. 28 mmol/L,P_T<0. 2 mmol/L,HMP pathway weakened and EMP-TCAC strengthened with N and P increasing, whereas when N_T > 4. 28 mmol/L and P_T>0. 2 mmol/L,HMP pathway enhanced and EMP-TCAC declined in pace with N and P increasing. In addition, increased cyanide-resistant respiratory pathway and weakened cyanide-sensitive respiratory pathway were observed when N_T>2. 14 mmol/L and P_T>0. 1 mmol/L, There was a striking similarity in changing trend among respiratory intensity and EMP-TCAC pathway,cyanide-sensitive respiratory pathway,cytochrome oxidase activity in treated roots ,the similarity showed that N and P in mimic wastewater had affected respiratory intensity mainly by ways of affecting EMP-TCAC and cytochrome pathway which was sensitive to cyanide.