Key Laboratory of Urban Environment and Health, Ningbo Observation and Research Station, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, CAS Haixi Industrial Technology Innovation Center in Beilun, Ningbo 315830, China.
College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China.
Sci Total Environ. 2024 Mar 20;917:170585. doi: 10.1016/j.scitotenv.2024.170585. Epub 2024 Feb 1.
Rice stem is the sole conduit for cadmium translocation from underground to aboveground. The presence of cadmium can trigger responses of rice stem multi-phenotype, affecting metabolism, reducing yield, and altering composition, which is related to crop growth, food safety, and new energy utilization. Exploring the adversity response of plant phenotypes can provide a reliable assessment of growth status. However, the phytotoxicity and mechanism of cadmium stress on rice stem remain unclear. Here, we systematically revealed the response mechanisms of cadmium accumulation, adversity physiology, and morphological characteristic in rice stem under cadmium stress for the first time with concentration gradients of CK, 5, 25, 50, and 100 μM, and duration gradients of Day 5, Day 10, Day 15, and Day 20. The results indicated that cadmium stress led to a significant increase in cadmium accumulation, accompanied by the adversity response in stem phenotypes. Specifically, cadmium can cause fluctuations in soluble protein and disturbance of malondialdehyde (MDA), which reflects lipid peroxidation induced by cadmium accumulation. Lipid peroxidation inhibited rice growth by causing (1) a reduction in stem length, diameter, and weight, (2) suppression of air cavity, vascular bundle, parenchyma, and epidermal hair, and (3) disruption of cell structure. Furthermore, rapid detection of cadmium was realized based on the combination of laser-induced breakdown spectroscopy (LIBS) and machine learning, which took less than 3 min. The established qualitative model realized the precise discrimination of cadmium stress degrees with a prediction accuracy exceeding 92 %, and the quantitative model achieved the outstanding prediction effect of cadmium, with R of 0.9944. This work systematically revealed the phytotoxicity of cadmium on rice stem multi-phenotype from a novel perspective of lipid peroxidation and realized the rapid detection of cadmium in rice stem, which provided the technical tool and theoretical foundation for accurate prevention and efficient control of heavy metal risks in crops.
水稻茎是镉从地下向地上转运的唯一通道。镉的存在会引发水稻茎多表型响应，影响代谢、降低产量并改变组成，这与作物生长、食品安全和新能源利用有关。探索植物表型逆境响应可以为生长状况提供可靠的评估。然而，镉胁迫对水稻茎的植物毒性和机制仍不清楚。在这里，我们首次系统地揭示了在镉胁迫下，水稻茎中镉积累、逆境生理学和形态特征的响应机制，采用了 CK、5、25、50 和 100μM 浓度梯度以及 5 天、10 天、15 天和 20 天的时间梯度。结果表明，镉胁迫导致镉积累显著增加，同时伴随茎表型的逆境响应。具体而言，镉会引起可溶性蛋白波动和丙二醛（MDA）紊乱，反映了镉积累引起的脂质过氧化。脂质过氧化通过以下几种方式抑制水稻生长：（1）减少茎长、直径和重量，（2）抑制气腔、维管束、薄壁组织和表皮毛，（3）破坏细胞结构。此外，还通过激光诱导击穿光谱（LIBS）和机器学习的结合实现了基于 LIBS 的快速镉检测，整个过程不到 3 分钟。建立的定性模型实现了对镉胁迫程度的精确区分，预测准确率超过 92%，定量模型实现了对镉的出色预测效果，R 值为 0.9944。这项工作从脂质过氧化的新视角系统地揭示了镉对水稻茎多表型的植物毒性，并实现了对水稻茎中镉的快速检测，为作物重金属风险的精准防控提供了技术工具和理论基础。
