Dawuda Mohammed Mujitaba, Liao Weibiao, Hu Linli, Yu Jihua, Xie Jianming, Calderón-Urrea Alejandro, Wu Yue, Tang Zhongqi
College of Horticulture, Gansu Agricultural University, Lanzhou, China.
Department of Biology, California State University, Fresno, Fresno, CA, United States of America.
PeerJ. 2020 Jul 2;8:e9270. doi: 10.7717/peerj.9270. eCollection 2020.
Cadmium (Cd) is among the toxic non-essential heavy metals that adversely affect plants metabolic processes and the safety of produce. However, plant hormones can improve plant's tolerance to various stresses. This study investigated the effect of exogenous abscisic acid (ABA) on the biochemical and physiological processes and food safety of cadmium (Cd)-sensitive lettuce genotype (). Seedlings were subjected to five treatments: [(i) Control (untreated plants), (ii) 100 µM CdCl, (iii) 100 µM CdCl+10 µg L ABA (iv) 10 µg L ABA, and (v) 0.01 g L ABA-inhibitor (fluridone)] for fourteen days in hydroponic system. The 100 µM CdCl increased the contents of hydrogen peroxide (HO) and malondialdehyde (MDA), decreased photosynthesis and plant biomass. Moreover, it decreased the contents of essential nutrients (except copper) in the leaves but increased the contents of toxic Cd in the leaves and roots of the plants. Foliar application of fluridone (0.01 g L) also caused oxidative stress by increasing the contents of HO and MDA. It also decreased the contents of nutrient elements in the leaves of the plants. However, exogenous ABA (10 µg L) mitigated the Cd-induced stress, increased antioxidant enzymes activities, photosynthesis and plant biomass under CdCl treatment. Remarkably, exogenous ABA increased the contents of essential nutrient elements but decreased the Cd content in leaves under the CdCl treatment. Our results have demonstrated that foliar application of ABA mitigates Cd stress and increases the nutritional quality and food safety of Cd-sensitive lettuce genotype under CdCl treatment.
镉（Cd）是对植物代谢过程和农产品安全产生不利影响的有毒非必需重金属之一。然而，植物激素可以提高植物对各种胁迫的耐受性。本研究调查了外源脱落酸（ABA）对镉（Cd）敏感生菜基因型的生化和生理过程以及食品安全的影响。在水培系统中，将幼苗进行五种处理：[（i）对照（未处理的植株），（ii）100 μM CdCl₂，（iii）100 μM CdCl₂ + 10 μg L⁻¹ ABA，（iv）10 μg L⁻¹ ABA，以及（v）0.01 g L⁻¹ ABA抑制剂（氟啶酮）]，处理十四天。100 μM CdCl₂增加了过氧化氢（H₂O₂）和丙二醛（MDA）的含量，降低了光合作用和植物生物量。此外，它降低了叶片中必需营养元素（除铜外）的含量，但增加了植物叶片和根系中有毒镉的含量。叶面喷施氟啶酮（0.01 g L⁻¹）也通过增加H₂O₂和MDA的含量引起氧化胁迫。它还降低了植物叶片中营养元素的含量。然而，外源ABA（10 μg L⁻¹）减轻了Cd诱导的胁迫，在CdCl₂处理下增加了抗氧化酶活性、光合作用和植物生物量。值得注意的是，外源ABA在CdCl₂处理下增加了必需营养元素的含量，但降低了叶片中的镉含量。我们的结果表明，叶面喷施ABA可减轻Cd胁迫，并提高CdCl₂处理下Cd敏感生菜基因型的营养品质和食品安全。
