不同富营养化程度水体对枫杨幼苗的生长及抗氧化酶的影响

为探讨水体富营养化对枫杨(Pterocarya stenoptera)的胁迫作用,通过水培试验,研究一年生枫杨幼苗在总氮和总磷分别为2 mg·L~(-1)和0.4 mg·L~(-1)(轻度,记为C1);20 mg·L~(-1)和8 mg·L~(-1)(中轻度,记为C2);40 mg·L~(-1)和15 mg·L~(-1)(中度,记为C3);80 mg·L~(-1)和25 mg·L~(-1)(重度,记为C4)的模拟富营养化水体中的生长状况、根茎叶中TN、TP的含量,以及枫杨叶片中SOD和POD的活性。结果表明,富营养化水体处理的枫杨的株高、基径、生物量的值均大于对照处理的值;随着氮磷浓度的增加,枫杨幼苗叶中的TN和TP浓度均呈上升的趋势,且处理间差异显著(P0.05),而根和茎的氮磷浓度则呈现先上升后下降的趋势,C3处理中最大,分别为(根:16.49 g·kg~(-1),2.18 g·kg~(-1);茎:11.14 g·kg~(-1),1.27 g·kg~(-1))。不同氮磷水平处理的枫杨叶片中的SOD和POD活性存在一定的差异,其中C4处理的叶片SOD活性显著低于C1,C2和C3处理(P0.05),而POD的活性则表现为C3处理最高,达5214g·U~(-1),显著高于C1和C4处理(P0.05)。研究结果有利于了解枫杨在不同富营养化程度水体的生长状况,为深入探究枫杨在富营养化水体中的去污机理提供参考。

Effects of water with different eutrophication levels on seedling growth and activities of antioxidant enzymes of Pterocarya stenoptera

The study aimed to explore the stress of water eutrophication on Pterocarya stenoptera. The water cultivation experiment was conducted to study the biomass, TN and TP contents in roots, stems and leaves, and the activity of SOD and POD in leaves of one-year seedlings of P. stenoptera, which were grown in simulated eutrophic water with TN and TP of 2 mg·L^-1 and 0.4 mg·L^-1 (mild, denoted as C1); 20 and 8 mg·L^-1 (medium mild, denoted as C2); 40 and 15 mg·L^-1 (moderate, denoted as C3); 80 and 25 mg·L^-1 (severe, denoted as C4). The results showed that the height, stem base diameter, biomass of P. stenoptera grown in different eutrophic levels treatments were bigger than those grown in the control treatment.With the increase of eutrophic levels, the concentrations of TN and TP in P. stenoptera leaves were increased significantly among the different treatments (P<0.05). However, the concentrations of nitrogen and phosphorus in roots and stems changed different with those in leaves, they were increased to the maximum at C3 treatment, and the nitrogen and phosphorus were 16.49 and 2.18 g·kg^-1 for root, 11.14 and 1.27 g·kg^-1 for stem. For C4 treatment, nitrogen and phosphorus were significantly decreased compared with those in C3 treatment (P<0.05). The activities of SOD and POD were different among the different eutrophic levels treatments. The SOD activity of leaves in C4 treatment was significantly lower than that in C1, C2 and C3. The activity of POD was the highest in C3 treatment, reaching 5 214 g·U^-1, which was significantly higher than that in C1 and C4 treatments (P<0.05). This study revealed the growth of P. stenoptera in different eutrophication levels, and it can be a reference for deeply exploring the decontamination mechanism of P. stenoptera in eutrophic water.