Response of low-molecular-weight organic acids inmangrove root exudates to exposure of polycyclic aromatic hydrocarbons
Response of low-molecular-weight organic acids inmangrove root exudates to exposure of polycyclic aromatic hydrocarbons
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DOI：
10.1007/s11356-017-8845-4
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发表时间：
2017-05-01
影响因子：
5.8
通讯作者：
Yan, Chongling
中科院分区：
文献类型：
--
作者：
Jiang, Shan;Xie, Feng;Yan, Chongling
低分子量有机酸（LMWOAs）是根系分泌物的重要组成部分。它们在沉积物中多环芳烃（PAHs）的降解中起着关键作用，因为它们影响PAHs的生物有效性和降解菌的定殖。研究了红树林（桐花树和秋茄）根系分泌物在菲和芘溶液中暴露7 d和40 d后的LMWOAs变化。处理7 d后，两种红树林根系分泌物总量和6种LMWOA含量均增加。最大的增加是在草酸中发现的，即，测定的LMWOAs中的主要成分。再加上LMWOA分泌速率的增强，根系代谢强度，脱氢酶活性，增加。相比之下，暴露40天后，总LMWOAs的渗出率显着下降，在多环芳烃污染组相比，对照，表明多环芳烃的负面影响，由于其毒性的根系代谢和活动。草酸的下降幅度也最大，这表明与草酸有关的生物反应在PAH胁迫下是脆弱的。
Low-molecular-weight organic acids (LMWOAs) represent an important component of root exudates. They play a pivotal role in the degradation of polycyclic aromatic hydrocarbons (PAHs) in sediments as they influence PAH bioavailability and degrader colonization. This study examined variations of LMWOAs in mangrove root exudates (Aegiceras corniculatum and Kandelia obovata) after exposure in phenanthrene and pyrene solution for 7 and 40 days, respectively. After 7 days of treatment, total root exudates and six types of LMWOA in root exudates from both mangrove species were enhanced. The largest increase was found in oxalic acid, i.e., the dominant component in determined LMWOAs. Coupled with the enhancement in LMWOA exudation rates, root metabolism intensities, measured as the dehydrogenase activity, increased. In contrast, after 40 days of exposure, the exudation rate of total LMWOAs had dropped markedly in PAHcontaminated groups compared to the control, indicating that PAHs negatively impacted root metabolism and activities due to their toxicity. The largest decrease was also found in oxalic acid, suggesting that the biological reactions related with oxalic acid are vulnerable under PAH stresses.