Ali Shafaqat, Abbas Zohaib, Seleiman Mahmoud F, Rizwan Muhammad, YavaŞ İlkay, Alhammad Bushra Ahmed, Shami Ashwag, Hasanuzzaman Mirza, Kalderis Dimitris
Department of Environmental Sciences and Engineering, Government College University, Allama Iqbal Road, Faisalabad 38000, Pakistan.
Department of Biological Sciences and Technology, China Medical University, Taichung 40402, Taiwan.
Plants (Basel). 2020 Jul 15;9(7):896. doi: 10.3390/plants9070896.
Unexpected biomagnifications and bioaccumulation of heavy metals (HMs) in the surrounding environment has become a predicament for all living organisms together with plants. Excessive release of HMs from industrial discharge and other anthropogenic activities has threatened sustainable agricultural practices and limited the overall profitable yield of different plants species. Heavy metals at toxic levels interact with cellular molecules, leading towards the unnecessary generation of reactive oxygen species (ROS), restricting productivity and growth of the plants. The application of various osmoprotectants is a renowned approach to mitigate the harmful effects of HMs on plants. In this review, the effective role of glycine betaine (GB) in alleviation of HM stress is summarized. Glycine betaine is very important osmoregulator, and its level varies considerably among different plants. Application of GB on plants under HMs stress successfully improves growth, photosynthesis, antioxidant enzymes activities, nutrients uptake, and minimizes excessive heavy metal uptake and oxidative stress. Moreover, GB activates the adjustment of glutathione reductase (GR), ascorbic acid (AsA) and glutathione (GSH) contents in plants under HM stress. Excessive accumulation of GB through the utilization of a genetic engineering approach can successfully enhance tolerance against stress, which is considered an important feature that needs to be investigated in depth.
重金属（HMs）在周围环境中意外的生物放大和生物累积已成为包括植物在内的所有生物面临的困境。工业排放和其他人为活动中重金属的过量释放威胁到可持续农业实践，并限制了不同植物物种的总体盈利产量。有毒水平的重金属与细胞分子相互作用，导致活性氧（ROS）不必要的产生，限制了植物的生产力和生长。应用各种渗透保护剂是减轻重金属对植物有害影响的一种著名方法。在本综述中，总结了甘氨酸甜菜碱（GB）在缓解重金属胁迫方面的有效作用。甘氨酸甜菜碱是非常重要的渗透调节剂，其含量在不同植物中差异很大。在重金属胁迫下对植物施用GB成功地改善了生长、光合作用、抗氧化酶活性、养分吸收，并使过量的重金属吸收和氧化应激最小化。此外，GB激活了重金属胁迫下植物中谷胱甘肽还原酶（GR）、抗坏血酸（AsA）和谷胱甘肽（GSH）含量的调节。通过基因工程方法过量积累GB可以成功增强对胁迫的耐受性，这被认为是一个需要深入研究的重要特性。
