Molecular Biology Section, Centre for Advanced Study in Botany, Banaras Hindu University, Varanasi, 221005, India; Department of Vegetables and Field Crops, Institute of Plant Sciences, Agricultural Research Organization - The Volcani Center, Rishon LeZion, 7505101, Israel; State Key Laboratory of Cotton Biology, Henan Key Laboratory of Plant Stress Biology, School of Life Science, Henan University, Kaifeng, Henan 475004, PR China.
State Key Laboratory of Cotton Biology, Henan Key Laboratory of Plant Stress Biology, School of Life Science, Henan University, Kaifeng, Henan 475004, PR China; Department of Biology and Food Sciences, Shangqiu Normal University, Shangqiu, Henan, 476000 PR China.
Aquat Toxicol. 2018 Sep;202:36-45. doi: 10.1016/j.aquatox.2018.06.011. Epub 2018 Jun 19.
Cyanobacteria are a natural inhabitant of paddy field and enhance the crop productivity in an eco-friendly manner. Cadmium (Cd) is a perilous trace metal element which not only limits the crop productivity but also inhibits the growth and nitrogen-fixing ability of these diazotrophs as well as the biodiversity of rice field semiaquatic agroecosystems. However, the impact of Cd toxicity in diazotrophic cyanobacteria is yet not adequately addressed. Therefore, in the present study, three diazotrophic cyanobacterial species, i.e., Anabaena sp. PCC7120, Anabaena L31, and Anabaena doliolum were subjected to their LC doses of Cd, and their physiological (PSII, Psi, respiration, energy status and nitrogen fixation rate), biochemical variables (such as antioxidant contents and antioxidant enzymes) together with morphological parameters were evaluated. The results of physiological variables suggested that the Cd exposure adversely affects the photosynthesis, respiration, and biological nitrogen fixation ability across three Anabaena species. The results of biochemical variables in terms of accumulation of antioxidants (glutathione, thiol, phytochelatin and proline) content as well as antioxidant enzymes such as glutathione S-transferase (GST), glutathione reductase (GR), catalase-peroxidase (CAT), ascorbate peroxidase (APX) and superoxide dismutase (SOD) revealed that their inter-species stress tolerance behavior may be attributed to the differential accumulation of antioxidants as well as differential antioxidant enzyme activity in three species. Furthermore, the enhanced antioxidant enzymes activity such as GST, GR, CAT, and SOD in Anabaena L31 advocated significantly higher as compared to Anabaena PCC7120 and Anabaena doliolum. In conclusion, Cd-toxicity assessment regarding physiological, biochemical and morphological aspects across three species identified Anabaena L31 as Cd-resistant species than the other two tested species, i.e., Anabaena PCC7120 and Anabaena doliolum.
蓝藻是稻田的天然居民，以环保的方式提高作物生产力。镉 (Cd) 是一种危险的痕量金属元素，不仅限制了作物的生产力，还抑制了这些固氮生物的生长和固氮能力，以及稻田半水生农业生态系统的生物多样性。然而，Cd 毒性对固氮蓝藻的影响尚未得到充分解决。因此，在本研究中，三种固氮蓝藻物种，即鱼腥藻 PCC7120、鱼腥藻 L31 和鱼腥藻 doliolum，受到其 LC 剂量的 Cd 处理，并评估了它们的生理（PSII、Psi、呼吸、能量状态和固氮速率）、生化变量（如抗氧化含量和抗氧化酶）以及形态参数。生理变量的结果表明，Cd 暴露会对三种鱼腥藻的光合作用、呼吸作用和生物固氮能力产生不利影响。抗氧化剂（谷胱甘肽、巯基、植物螯合肽和脯氨酸）含量以及抗氧化酶（如谷胱甘肽 S-转移酶 (GST)、谷胱甘肽还原酶 (GR)、过氧化氢酶-过氧化物酶 (CAT)、抗坏血酸过氧化物酶 (APX) 和超氧化物歧化酶 (SOD) 的生化变量的结果表明，它们的种间应激耐受行为可能归因于三种物种中抗氧化剂的差异积累以及抗氧化酶活性的差异。此外，鱼腥藻 L31 中 GST、GR、CAT 和 SOD 等增强的抗氧化酶活性明显高于鱼腥藻 PCC7120 和鱼腥藻 doliolum。总之，对三种物种的生理、生化和形态方面的 Cd 毒性评估表明，鱼腥藻 L31 比其他两种测试物种，即鱼腥藻 PCC7120 和鱼腥藻 doliolum，更能抵抗 Cd 毒性。
