title: Can heavy metal pollution defend seed germination against heat stress? Effect of heavy metals (Cu(2+), Cd(2+) and Hg(2+)) on maize seed germination under high temperature.
abstract: Heavy metal pollution, as well as greenhouse effect, has become a serious threat today. Both heavy metal and heat stresses can arrest seed germination. What response can be expected for seed germination under both stress conditions? Here, the effects of heavy metals (Cu(2+), Cd(2+) and Hg(2+)) on maize seed germination were investigated at 20 °C and 40 °C. Compared with 20 °C, heat stress induced thermodormancy. However, this thermodormancy could be significantly alleviated by the addition of a low concentration of heavy metals. Heavy metals, as well as heat stress induced H2O2 accumulation in germinating seeds. Interestingly, this low concentration of heavy metal that promoted seed germination could be partly blocked by DMTU (a specific ROS scavenger), irrespective of temperature. Accordingly, H2O2 addition reinforced this promoting effect on seed germination, which was induced by a low concentration of heavy metal. Furthermore, we found that the NADPH oxidase derived ROS was required for seed germination promoted by the heavy metals. Subsequently, treatment of seeds with fluridone (a specific inhibitor of ABA) or ABA significantly alleviated or aggravated thermodormancy, respectively. However, this alleviation or aggravation could be partly attenuated by a low concentration of heavy metals. In addition, germination that was inhibited by high concentrations of heavy metals was also partly reversed by fluridone. The obtained results support the idea that heavy metal-mediated ROS and hormone interaction can finally affect the thermodormancy release or not.
authors.affiliation: Heilongjiang Higher Educational Key Laboratory for Cold-regional Crop Cultivation and Germplasm Improvement, Department of Agronomy, Heilongjiang Bayi Agricultural University, Daqing, 163319, China. Electronic address: benliangdeng@163.com.
authors.forename: Benliang
authors.initials: B
authors.lastname: Deng
authors.affiliation: Heilongjiang Higher Educational Key Laboratory for Cold-regional Crop Cultivation and Germplasm Improvement, Department of Agronomy, Heilongjiang Bayi Agricultural University, Daqing, 163319, China.
authors.forename: Kejun
authors.initials: K
authors.lastname: Yang
authors.affiliation: Heilongjiang Higher Educational Key Laboratory for Cold-regional Crop Cultivation and Germplasm Improvement, Department of Agronomy, Heilongjiang Bayi Agricultural University, Daqing, 163319, China.
authors.forename: Yifei
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Heilongjiang Higher Educational Key Laboratory for Cold-regional Crop Cultivation and Germplasm Improvement, Department of Agronomy, Heilongjiang Bayi Agricultural University, Daqing, 163319, China.
authors.forename: Zuotong
authors.initials: Z
authors.lastname: Li
mesh_terms: D004785:Environmental Pollutants / Q000494:pharmacology*; D018525:Germination / Q000187:drug effects; D006358:Hot Temperature / Q000009:adverse effects*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D019216:Metals, Heavy / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D012639:Seeds / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D003313:Zea mays / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism
chemical_list: D004785:Environmental Pollutants; D019216:Metals, Heavy; D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide
keywords: Heat stress; Heavy metal; Hydrogen peroxide; Maize seed; Thermodormancy