汞脅迫對水葫蘆光合特性和生理生化特征的影響

王賽　王瑞瑩　錢蘭華　王利芬　朱培淼　王波

摘 要：當前我國水體汞污染日益嚴重，由于其易遷移性和毒性，嚴重威脅著生態(tài)環(huán)境和人類的健康，尋找對汞脅迫具有一定抗性的水生植物已經(jīng)刻不容緩。試驗采用溶液培養(yǎng)法研究不同質(zhì)量濃度的HgCl2（0，2.5，5.0，10.0，20.0，40.0 mg·L-1）對水葫蘆幼苗生長和發(fā)育的影響。結果表明，水葫蘆鮮質(zhì)量增長量、葉綠素含量、Pn值和SOD活性在低質(zhì)量濃度的HgCl2溶液中隨著汞質(zhì)量濃度的升高而增加，在質(zhì)量濃度為5 mg·L-1時達到最高點；但隨著HgCl2質(zhì)量濃度進一步增大，這些指標值反而持續(xù)下降。Pro和SP含量在HgCl2質(zhì)量濃度為10 mg·L-1時達到最高點，但當HgCl2質(zhì)量濃度達到20 mg·L-1時較對照顯著下降；而Gs，Ci，Tr值表現(xiàn)出先下降后上升的趨勢，但各處理間差異不顯著，其中，Ci，Tr值在HgCl2質(zhì)量濃度為5 mg·L-1時達到最低值，Gs在10 mg·L-1時達到最低值；MDA含量和POD活性則隨著HgCl2質(zhì)量濃度的升高而上升。水葫蘆對10 mg·L-1 以下的HgCl2脅迫具有較好的適應性，且可促進水葫蘆的生長；但高質(zhì)量濃度HgCl2對水葫蘆的生長則有抑制作用。研究結果可為水葫蘆對Hg2+脅迫的適應機制提供一定理論依據(jù)。

關鍵詞：水葫蘆；汞脅迫；葉綠素含量；光合特性；生理生化特征

中圖分類號：S555+.5 文獻標識碼：A DOI 編碼：10.3969/j.issn.1006-6500.2017.05.002

Abstract： The water mercury pollution has been seriously polluted in recently years in our country， because of its easy mobility and toxicity serious threat to the ecological environment and human health seriously， therefore to search for the hydrophyte with some resistance to mercury stress was extremely urgent. The aim of the study was to investigate the influence that HgCl2 under various concentrations（0， 2.5， 5.0 10.0， 20.0， 40 mg·L-1） on the growth and development of Eichhornia crassipes seedlings with hydroponics. The results indicated the FW increment， chlorophyll content， Pn value， SOD activities of Eichhornia crassipes increased first and then decreased with the increasing of HgCl2 stress. The highest value at 5 mg·L-1， but as HgCl2 concentration increased further， these indicators continued to decline inversely. Pro and SP reached to the highest point at the 10 mg·L-1 concentration， and they continued to decline at the concentration more than 20 mg·L-1 significantly. While Gs， Ci， Tr showed the opposite tendency compared with Pn. But it was not significant between difference HgCl2 stress. Ci， Tr reached to the highest point at the 5 mg·L-1 concentration， but Gs at 10 mg·L-1. The MAD content and POD activity significantly rose with the increasing of HgCl2 stress. The conclusion was that it was beneficial to Eichhornia crassipes when HgCl2 stress was below to 10 mg·L-1， meanwhile high concentration HgCl2 could be harmful to Eichhornia crassipes. The results of this research could provide a theoretical basis for exploring the adaptation mechanism of Eichhornia crassipes under HgCl2 stress.

Key words： Eichhornia crassipes； mercury stresses； chlorophyll content； photosynthetic characteristics； physiological and biochemical characteristics

水葫蘆（Eichhornia crassipes）為雨久花科、鳳眼蓮屬的一種漂浮性水生植物。已有研究表明，水葫蘆可以吸收污水中的重金屬、放射性污染物和有機污染物質(zhì)，并將其富集體內(nèi)，是一種良好的耐污染材料。由于汞污染制毒性強、易遷移和易轉(zhuǎn)化等特點，現(xiàn)已成為全球最關心的問題[1]。汞有單質(zhì)態(tài)、無機汞和有機汞3種形式。……