Data Sheet 1_Silicon (Si) foliar treatment modulates Capsicum annuum L. (green chilli) growth and stress responses under cadmium and lead stress.docx

Silicon (Si) plays a crucial role in improving plant resilience against abiotic stresses including heavy metals (HMs). However, little is known about its role in chilli plants during HM stresses like cadmium (Cd) and lead (Pb). The present study aimed to evaluate the role of Si in chilli plants grown under different concentrations of Cd and Pb respectively. Based on our findings, the increased levels of Cd and Pb adversely affected the physiological and biochemical traits in chilly plants. For instance, at 100 mg kg−1, Cd and Pb significantly reduced the seed germination (62.5% and 50%), vigor indices (67.2% and 56.8%), root biomass (88% and 66%), chlorophyll a (75.5% and 55.5%) and carotenoids (56.4% and 48.7%) in chilly plants. However, supplementation of Si in chilli plants aids them in recovering from Cd and Pb side effects by improving their physiological and biochemical traits. At 25 mg kg−1 soil Cd and Pb, Si significantly (p ≤ 0.05) improved the root length (17% and 24%), root biomass (23% and 27%), and carotenoids (16% and 19%) of chilli plants compared to control plants. Moreover, Si application significantly (p ≤ 0.05) reduced the oxidative stress markers; malondialdehyde (MDA), electrolyte leakage (EL), hydrogen peroxide (H2O2), and superoxide radical (O2-) in Cd and Pb stressed chilli plants as compared to non-Si treated plants. Interestingly, Si foliar application in Cd and Pb-treated chilli plants upregulates the transcript levels of POD, SOD, CAT, and GPX genes. Additionally, Si reduces the HM-induced phytotoxicity by decreasing Cd and Pb uptake in roots and shoots of chilli plants, as well as metal translocation (TF) and bioconcentration (BCF) factors. In summary, these results highlight the protective role of Si in chilli plants by mitigating the side effects of Cd and Pb stress. Hence, Si fertilizers can be used in sustainable agriculture to mitigate HM toxicity and improve crop productivity.

硅（Si）在提升植物应对包括重金属（HMs）在内的非生物胁迫抗性方面发挥着关键作用。然而，关于硅在镉（Cd）、铅（Pb）等重金属胁迫下对辣椒植株的调控作用，目前仍知之甚少。本研究旨在分别评估硅在不同浓度Cd、Pb胁迫下的辣椒植株中的作用。研究结果显示，Cd和Pb浓度升高会对辣椒植株的生理生化性状产生不利影响。例如，当浓度为100 mg kg⁻¹时，Cd和Pb会显著降低辣椒的种子萌发率（分别为62.5%和50%）、活力指数（分别为67.2%和56.8%）、根系生物量（分别为88%和66%）、叶绿素a含量（分别为75.5%和55.5%）以及类胡萝卜素含量（分别为56.4%和48.7%）。不过，对辣椒植株施加硅肥，可通过改善其生理生化性状，帮助植株缓解Cd和Pb带来的毒害效应。当土壤中Cd、Pb浓度为25 mg kg⁻¹时，与对照组相比，施硅可显著（p ≤ 0.05）提升辣椒植株的根系长度（分别为17%和24%）、根系生物量（分别为23%和27%）以及类胡萝卜素含量（分别为16%和19%）。此外，施硅还可显著（p ≤ 0.05）降低Cd、Pb胁迫下辣椒植株的氧化应激标志物水平，包括丙二醛（MDA）、电解质渗漏率（EL）、过氧化氢（H₂O₂）以及超氧阴离子（O₂⁻），相较于未施硅的处理组。值得注意的是，对Cd、Pb胁迫的辣椒植株进行硅叶面喷施，可上调过氧化物酶（POD）、超氧化物歧化酶（SOD）、过氧化氢酶（CAT）以及谷胱甘肽过氧化物酶（GPX）基因的转录水平。除此之外，硅还可通过降低辣椒植株根系和地上部分对Cd、Pb的吸收，以及降低金属迁移系数（TF）和生物富集系数（BCF），来减轻重金属诱导的植物毒性。综上，本研究结果证实了硅可通过缓解Cd和Pb胁迫的毒害效应，在辣椒植株中发挥保护作用。因此，硅肥可应用于可持续农业中，以减轻重金属毒性并提升作物生产力。