多环芳烃胁迫对菜心生长及生理特性的影响

Effects of polycyclic aromatic hydrocarbons stress on growth and physiological characteristics of Brassica parachinensis

【目的】明确多环芳烃(PAHs)胁迫对菜心Brassica parachinensis生长的影响,探讨PAHs胁迫对菜心的生理毒性。【方法】采用萘(Nap)、菲(Phe)、荧蒽(Flt)、苯并芘(BaP)和茚并芘(InP)5种PAHs混合溶液施入土壤胁迫菜心,在移栽定植后第10、17和24天分析菜心叶片丙二醛(MDA)、H_2O_2和脯氨酸(Pro)含量以及抗氧化酶活性的变化,观察测定定植后第24天菜心的生长情况。【结果】PAHs胁迫下菜心株高增加,以10.0 mg·kg^(-1)处理的株高最高;0.4和0.8 mg·kg^(-1)处理对菜心的茎粗影响不大,对提高单株鲜质量和根鲜质量有一定的促进作用,2.0、5.0和10.0 mg·kg^(-1)处理不同程度地降低了菜心的茎粗、单株鲜质量和根鲜质量;PAHs胁迫下,菜心叶片中MDA、H_2O_2和Pro含量随着胁迫时间的延长和PAHs含量的增大而升高。超氧化物歧化酶(SOD)活性随着胁迫浓度的增大而增强;过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性随着PAHs含量的增大呈先升高后下降的趋势。【结论】低含量PAHs胁迫对菜心的生长影响不大,高含量PAHs胁迫抑制菜心的正常生长,表现为茎径变小、单株鲜质量和根鲜质量降低且开花提前。PAHs胁迫下,H_2O_2和膜脂过氧化产物MDA含量提高,对菜心产生不利的效应,可以通过提高脯氨酸含量和抗氧化酶活性来缓解。

【Objective】To determine the effects of polycyclic aromatic hydrocarbons(PAHs)stress on the growth of Chinese flowering cabbage(Brassica parachinensis),and explore the physiological toxicity of PAHs.【Method】The PAHs solution mixing naphthalene,phenanthrene,fluoranthene,benzopyrene and indenopyrene was applied to soil to stress the growth of B.parachinensis.The changes of malondialdehyde(MDA),H2O2 and proline contents and antioxidase activites in leaves of B.parachinensis were analyzed on the 10th,17th,and 24th day after planting,and the growth was measured on the 24th day after planting.【Result】The plant height of B.parachinensis was increased by PAHs treatments,and it was highest under 10.0 mg·kg–1 PAHs treatment.The treatments of 0.4 and 0.8 mg·kg–1 PAHs had little effects on stem diameter of B.parachinensis,but had some promotions on individual plant fresh weight and root fresh weight.The stem diameter,individual plant fresh weight and root fresh weight of B.parachinensis were decreased by 2.0,5.0 and 10.0 mg·kg–1 PAHs treatments for different degrees.The contents of MDA,H2O2 and proline in leaves of B.parachinensis increased with the stress time and PAHs content increasing.With the PAHs content increasing,the activity of superoxide dismutase(SOD)increased,and the activities of peroxidase(POD),catalase(CAT)and ascorbic acid peroxidase(APX)increased firstly and then decreased.【Conclusion】Stress from low content of PAHs has little effect on the growth of B.parachinensis,while stress from high content of PAHs can inhibit plant normal growth as it decreases stem diameter,individual plant fresh weight and root fresh weight and also causes earlier blooming.B.parachinensis could alleviate the disadvantageous effects from increasing contents of H2O2 and MDA under PAHs stress by increasing proline content and antioxidant enzyme activities.