Nemat Alla Mamdouh M, Hassan Nemat M
Department of Botany, Faculty of Science, Damietta University, Damietta, Egypt.
Heliyon. 2020 Oct 7;6(10):e05172. doi: 10.1016/j.heliyon.2020.e05172. eCollection 2020 Oct.
The present study aimed at alleviating the impacts of alachlor (Ala) or atrazine (Atr) on maize growth by seed-dressing with naphthalic anhydride (NA, 0.4% w/w by seed weight). The dressed and undressed seeds were germinated for 10 days and treated with Ala or Atr at 3.2 or 1.8 kg ha, respectively, then the herbicide residues were determined in shoots one day after treatment. Atr residues were higher than Ala and remained in the same level for the 2 day then retracted consistently up to 12 days. Meanwhile, GSH and GST were significantly induced while growth parameters were reduced; the effect of Atr was higher than Ala. Nonetheless, ABA, phenolics and anthocyanins as well as PAL, TAL and CI were increased but IAA was decreased coincidently with enhanced IAA-O and peroxidase. The immediate detection of the herbicide residues could conclude that growth reduction as elucidated from the decreased IAA concomitant with elevating ABA, phenolics and anthocyanin contents and enzyme activities are consequences of the herbicide persistence. The drop of IAA was preceded by the stimulation of IAA-O and peroxidase while the increased phenolics and anthocyanins followed PAL, TAL and CI stimulation confirming the regulatory roles of these enzymes. The application of NA greatly lowered the herbicide residues concurrently with ameliorations in growth parameters, GSH, GST, and maintained the balancing of secondary metabolites and plant growth regulators. Lowering Ala and Atr residues by NA in synchronization with enhanced GSH and GST could conclude that NA encouraged the detoxification of the herbicide. Moreover, the balances of IAA, ABA, phenolics and anthocyanins were mostly maintained in normal levels concomitantly with growth ameliorations suggesting that phytohormones and secondary metabolites are involved in the elevation of maize tolerance to Ala and Atr.
本研究旨在通过用萘酐（NA，按种子重量计为0.4% w/w）拌种来减轻甲草胺（Ala）或莠去津（Atr）对玉米生长的影响。将拌种和未拌种的种子萌发10天，然后分别用3.2或1.8 kg/ha的Ala或Atr处理，处理一天后测定地上部的除草剂残留量。Atr残留量高于Ala，在2天内保持在同一水平，然后持续下降直至12天。同时，谷胱甘肽（GSH）和谷胱甘肽-S-转移酶（GST）显著诱导，而生长参数降低；Atr的影响高于Ala。尽管如此，脱落酸（ABA）、酚类和花青素以及苯丙氨酸解氨酶（PAL）、酪氨酸解氨酶（TAL）和肉桂酸异构酶（CI）增加，而吲哚乙酸（IAA）减少，同时吲哚乙酸氧化酶（IAA-O）和过氧化物酶增加。除草剂残留量的即时检测可以得出结论，生长降低如从IAA减少以及ABA、酚类和花青素含量升高所阐明的那样，伴随着酶活性的变化是除草剂残留的后果。IAA的下降先于IAA-O和过氧化物酶的刺激，而酚类和花青素的增加则跟随PAL、TAL和CI的刺激，证实了这些酶的调节作用。NA的应用大大降低了除草剂残留量，同时改善了生长参数、GSH、GST，并维持了次生代谢物和植物生长调节剂的平衡。NA降低Ala和Atr残留量的同时增强了GSH和GST，可以得出结论，NA促进了除草剂的解毒。此外，IAA、ABA、酚类和花青素的平衡大多维持在正常水平，同时生长得到改善，这表明植物激素和次生代谢物参与了玉米对Ala和Atr耐受性的提高。
