Response Of Different Vegetables Seedlings Stressed In Different Concentration Polycyclic Aromatic Hydrocarbons

Polycyclic Aromatic Hydrocarbons(PAHs)is a kind of toxic POPs that carcinogenic,teratogenic and mutagenic effects and widely distributed in the air,soil and water.The PAHs in nature could change the distribution in the atmosphere,water,soil,organisms and other systems through complex physical migration,chemical and biological transformation reactions.The research objects were fruit vegetables(Cucumis sativus L.),leafy vegetables(Brassica campestris L.ssp.chinensis var.utilis Tsen et Lee),root vegetables(Raphanus sativus L.)cultivated widely which composed by 0.3,0.6,0.9 mg·L-1 PAHs.Which did not add PAHs as the comparison group in order to study the effects of 16 kind of PAHs on the growth index and the physiologica index of vegetables seedling.It aimed to create the foundation to further explore the characteristics of different vegetables absorbed and enriched PAHs.The following results were obtained:1.Effects of polycyclic aromatic hydrocarbons on growth index of vegetables seedlings.The leaf width,fresh weight and dry weight of the compared Cusumis sativus L.seedling were significantly higher than that of each PAHs concentration treatment,but each PAHs concentration treatment had no significant difference.Under 0.3 mg·L-1 PAHs concentration treatment,the leaf width and fresh weight of Cucumis sativus L.seedling reached the minimum,but they increased with the increase of PAHs concentration treatment.The dry weight of Cucumis sativus L.seedling was decreased with the increase of PAHs concentration treatment.The leaf width and dry weight of Brassica campestris L.ssp.chinensis var.utilisTsen et Lee and Raphanus sativus L.seedlings had no significant difference.The fresh weight of Brassica campestris L.ssp.chinensis var.utilis Tsen et Lee and Raphanus sativus L.seedlings reached the minimum under 0.9 mg·L-1 PAHs concentration treatment.While the fresh weight of Brassica campestris L.ssp.chinensis var.utilis Tsen et Lee seedling reached the maximum under the comparison,the fresh weight of Raphanus sativus L.seedlings reached the maximum under 0.6 mg·L-1 PAHs concentration treatment.2.The chlorophyll,MDA,vitamin C content and antioxidant enzyme activity of three kind of vegetables seedlings were different.The CAT activity of Cucumis sativus L.seedling,the vitamin C content and the POD activity of Brassica campestris L.ssp.chinensis var.utilis Tsen et Lee seedling,the chlorophyll b content,the SOD and CAT activity of Raphanus sativus L.seedlings reached the minimum under 0.3 mg L-1 PAHs concentration treatment.Under 0.6 mg·L-1 PAHs concentration treatment,the POD activity of Cucumis sativus L.seedling and the MDA content of Raphanus sativus L.seedlings reached the minimum.The SOD activity of Cucumis sativus L.seedling and the POD activity of Raphanus sativus L.seedlings reached the minimum.The chlorophyll synthesis and photosynthesis of Cucumis sativus L.and Brassica campestris L.ssp.chinensis var.utilis Tsen et Lee leaves,the vitamin C content of Cucumis sativus L.and Raphanus sativus L.seedlings enhanced with the increase of PAHs concentration treatment.The MDA content of Cucumis sativus and Brassica campestris L.ssp.chinensis var.utilis Tsen et Lee seedlings increased with the increase of PAHs concentration treatment,and they were reached the maximum under 0.9 mg·L-1 PAHs concentration treatment.3.There were some similarities and differences in the absorption of PAHs in different vegetables seedlings.Under 0.6mg·L-1 and 0.9mg L-1 PAHs concentration treatment,the absorption of high ring PAHs in 3 kind of vegetables seedlings were higher than comparison,9.79%,51.48%,61.90%and 21.78%,86.89%,81.78%respectively.The total PAHs content of Cucumis sativus L.and Raphanus sativus L.seedlings increased with the increase of PAHs concentration treatment.Under 0.6mg·L-1 and 0.9mg·L-1 PAHs concentration treatment,the total PAHs content of Brassica campestris L.ssp.chinensis var.utilis Tsen et Lee seedlings had significantly different from comparison.Under 0.6mg·L-1 and 0.9mg·L-1 PAHs concentration treatment,the total PAHs content of 3 kind of vegetables seedlings followed the order of Brassica campestris L.ssp.chinensis var.utilis Tsen et Lee>Raphanus sativus L.>Cucumis sativus L.