The present study was undertaken to evaluate the metal toxicity alleviating effects of kinetin (KN, 10 nM) on growth, photosynthetic pigments and photochemistry of PS II in the cyanobacterium Nostoc muscorum exposed to chromium (Cr^VI) stress (100 and 150 µM). Chromium declined growth, photosynthetic pigments (chlorophyll a, phycocyanin and carotenoids), photosynthetic oxygen evolution rate and parameters of fluorescence kinetics (ϕP₀, F_V/F₀, ϕE₀, Ψ₀ and PI_ABS except F₀/F_V) in concentration dependent manner, while stimulating effects on respiration, energy flux parameters (ABS/RC, TR₀/RC, ET₀/RC and DI₀/RC), oxidative stress biomarkers i.e., superoxide radical (SOR), hydrogen peroxide (H₂O₂) and lipid peroxidation (TBARS contents) and antioxidative enzymes: superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and glutathione-S-transferase (GST), were observed. However, upon addition of KN in the growth medium an alleviating effect against chromium induced toxicity on growth, photosynthetic pigments and photochemistry of PS II was recorded. This had occurred due to substantial reduction in levels of oxidative stress biomarkers: SOR, H₂O₂ and TBARS contents with concomitant rise in activity of antioxidative enzymes: SOD, POD, CAT and GST and appreciable lowering in the cellular accumulation of chromium. The overall results demonstrate that KN application significantly alleviated chromium induced toxicity on growth performance of the cyanobacterium N. muscorum due to significant improvement in photosynthetic pigments and photochemistry of PS II by up-regulating the activity of antioxidative enzymes, and declining cellular accumulation of chromium. Furthermore, Cr induced toxicity at lower dose (100 µM) was found to be ameliorated more efficiently in N. muscorum following supplementation of KN.

进行本研究以评估激动素（KN，10 nM）对暴露于铬（Cr ^VI）（100和150 µM）的蓝细菌Nostoc muscorum中PS II的生长，光合色素和PS II的光化学缓解作用。铬下降生长，光合色素（叶绿素一个，藻青素和类胡萝卜素），光合氧速率和荧光动力学的参数（φP ₀，F _V / F ₀，φE ₀，Ψ ₀和PI _ABS除F ₀ / F _V）以浓度依赖的方式，同时对呼吸产生刺激作用，能量通量参数（ABS / RC，TR ₀ / RC，ET ₀ / RC和DI ₀ / RC），氧化应激生物标记物，即超氧自由基（SOR），过氧化氢（观察到H ₂ O ₂）和脂质过氧化（TBARS含量）和抗氧化酶：超氧化物歧化酶（SOD），过氧化物酶（POD），过氧化氢酶（CAT）和谷胱甘肽-S-转移酶（GST）。但是，在生长培养基中添加KN后，记录到了对铬诱导的对生长，光合色素和PS II的光化学毒性的缓解作用。发生这种情况的原因是氧化应激生物标记物SOR，H的水平大大降低₂ O ₂和TBARS含量与抗氧化酶：SOD，POD，CAT和GST的活性同时升高，并且铬在细胞中的积累显着降低。总体结果表明，由于上调抗氧化酶的活性和减少铬的细胞蓄积，KN的施用显着减轻了铬对粘虫蓝藻生长性能的毒性，这是由于光合色素和PS II的光化学显着改善所致。此外，发现补充KN后，在粘液猪笼草中，较低剂量（100 µM）的Cr诱导的毒性得到了更有效的改善。