Ranjan Plant Physiology and Biochemistry Laboratory, Department of Botany, University of Allahabad, Prayagraj, 211002, India.
Ranjan Plant Physiology and Biochemistry Laboratory, Department of Botany, University of Allahabad, Prayagraj, 211002, India.
Plant Physiol Biochem. 2024 Nov;216:109170. doi: 10.1016/j.plaphy.2024.109170. Epub 2024 Sep 30.
Sustainable agriculture has become prime importance to feed growing population. To achieve this goal application of exogenous hormones and signaling molecules are gaining important. In this context, we have investigated potential of ethylene (25 μM ethephon; donor) and HS (10 μM NaHS; donor) in mitigating hexavalent chromium [Cr (VI), 50 μM] toxicity in two pulse seedlings: black bean and mung bean. Cr(VI) declined growth and gas exchange parameters (photosynthetic rate, stomatal conductance, sub cellular CO concentration, and transpiration level) which was accompanied by intracellular accumulation of Cr in both pulse crops and the damaging effect was greater in mung bean seedlings. The suppression in the growth and related parameters was occurred due to higher buildup of oxidative stress markers; O‾, HO, lipid peroxidation (as malondialdehyde, MDA equivalents) and membrane injury in leaf and root of both pulse crops. Cr induced disturbance in AsA-GSH cycle (reduction in the activity of glutathione reductase, ascorbate peroxidase, monodehydroascorbate reductase and dehydroascorbate reductase, and the amount of ASA and GSH) could be one of the reasons for greater accumulation of HO. Further, exogenous application of ethylene and HS significantly ameliorated Cr toxicity on growth and photosynthetic activity by significantly lowering the intracellular Cr accumulation and oxidative biomarkers, and also by strengthening the activity of AsA-GSH cycle. The exogenous application of biosynthesis inhibitors of ethylene (AVG) and HS (PAG) caused greater damaging effect on these parameters due to more accumulation of Cr(VI), thereby suggesting that the endogenous levels of these regulators are critical for Cr(VI) tolerance. Interestingly, ET did not rescue adverse effects of Cr(VI) in absence of endogenous HS, while HS could do so even without endogenous ethylene, suggesting that HS played downstream signaling to ethylene in regulating Cr(VI) toxicity. Hence, being cheap and easily available theses growth regulators may be considered for sustainable agriculture.
可持续农业对于养活不断增长的人口至关重要。为了实现这一目标，外源激素和信号分子的应用变得越来越重要。在这种情况下，我们研究了乙烯（25 μM 乙烯利；供体）和 HS（10 μM NaHS；供体）在缓解两种脉冲幼苗（黑豆和绿豆）中六价铬 [Cr（VI），50 μM] 毒性方面的潜力。Cr（VI）降低了生长和气体交换参数（光合速率、气孔导度、亚细胞 CO 浓度和蒸腾水平），同时导致两种脉冲作物细胞内 Cr 积累，绿豆苗的损伤效应更大。生长和相关参数的抑制是由于氧化应激标志物的积累增加所致；O‾、HO、脂质过氧化（如丙二醛，MDA 当量）和叶片和根中的膜损伤。Cr 诱导的抗坏血酸-谷胱甘肽循环紊乱（谷胱甘肽还原酶、抗坏血酸过氧化物酶、单脱氢抗坏血酸还原酶和脱氢抗坏血酸还原酶的活性降低，以及 ASA 和 GSH 的量减少）可能是 HO 积累较多的原因之一。此外，外源乙烯和 HS 的应用通过显著降低细胞内 Cr 积累和氧化生物标志物，以及通过增强抗坏血酸-谷胱甘肽循环的活性，显著改善了 Cr 对生长和光合作用的毒性。由于 Cr（VI）的积累更多，乙烯和 HS 生物合成抑制剂（AVG 和 PAG）的外源应用对这些参数造成了更大的破坏效应，这表明这些调节剂的内源性水平对于 Cr（VI）的耐受性至关重要。有趣的是，在没有内源性 HS 的情况下，ET 不能挽救 Cr（VI）的不利影响，而 HS 即使没有内源性乙烯也可以做到，这表明 HS 在调节 Cr（VI）毒性方面在乙烯下游发挥信号作用。因此，这些生长调节剂便宜且易于获得，可用于可持续农业。
