Gao Xue, Tan Jianxin, Yi Kaige, Lin Baogang, Hao Pengfei, Jin Tao, Hua Shuijin
State Key Laboratory of Hulless Barley and Yak Germplasm Resources and Genetic Improvement, Lhasa 850002, China.
Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
Plants (Basel). 2024 Mar 31;13(7):1003. doi: 10.3390/plants13071003.
Continuous spring cropping of Qingke ( L. var. nudum Hook. f.) results in a reduction in grain yield in the Xizang autonomous region. However, knowledge on the influence of continuous cropping on grain yield caused by reactive oxygen species (ROS)-induced stress remains scarce. A systematic comparison of the antioxidant defensive profile at seedling, tillering, jointing, flowering, and filling stages (T1 to T5) of Qingke was conducted based on a field experiment including 23-year continuous cropping (23y-CC) and control (the first year planted) treatments. The results reveal that the grain yield and superoxide anion (SOA) level under 23y-CC were significantly decreased (by 38.67% and 36.47%), when compared to the control. The hydrogen peroxide content under 23y-CC was 8.69% higher on average than under the control in the early growth stages. The higher ROS level under 23y-CC resulted in membrane lipid peroxidation (LPO) and accumulation of malondialdehyde (MDA) at later stages, with an average increment of 29.67% and 3.77 times higher than that in control plants. Qingke plants accumulated more hydrogen peroxide at early developmental stages due to the partial conversion of SOA by glutathione (GSH) and superoxide dismutase (SOD) and other production pathways, such as the glucose oxidase (GOD) and polyamine oxidase (PAO) pathways. The reduced regeneration ability due to the high oxidized glutathione (GSSG) to GSH ratio resulted in GSH deficiency while the reduction in L-galactono-1,4-lactone dehydrogenase (GalLDH) activity in the AsA biosynthesis pathway, higher enzymatic activities (including ascorbate peroxidase, APX; and ascorbate oxidase, AAO), and lower activities of monodehydroascorbate reductase (MDHAR) all led to a lower AsA content under continuous cropping. The lower antioxidant capacity due to lower contents of antioxidants such as flavonoids and tannins, detected through both physiological measurement and metabolomics analysis, further deteriorated the growth of Qingke through ROS stress under continuous cropping. Our results provide new insights into the manner in which ROS stress regulates grain yield in the context of continuous Qingke cropping.
在西藏自治区，青稞（裸大麦变种）连作会导致粮食产量下降。然而，关于活性氧（ROS）诱导的胁迫对连作造成粮食产量影响的相关知识仍然匮乏。基于一项田间试验，对青稞在苗期、分蘖期、拔节期、开花期和灌浆期（T1至T5）的抗氧化防御状况进行了系统比较，该试验包括23年连作（23y - CC）和对照（第一年种植）处理。结果显示，与对照相比，23年连作条件下的粮食产量和超氧阴离子（SOA）水平显著下降（分别下降38.67%和36.47%）。在生长早期，23年连作条件下的过氧化氢含量平均比对照高8.69%。23年连作条件下较高的ROS水平导致后期膜脂过氧化（LPO）和丙二醛（MDA）积累，其平均增量分别比对照植株高29.67%和3.77倍。由于谷胱甘肽（GSH）和超氧化物歧化酶（SOD）对SOA的部分转化以及其他产生途径，如葡萄糖氧化酶（GOD）和多胺氧化酶（PAO）途径，青稞植株在发育早期积累了更多过氧化氢。由于氧化型谷胱甘肽（GSSG）与GSH的比例较高导致再生能力下降，进而导致GSH缺乏，同时抗坏血酸（AsA）生物合成途径中L - 半乳糖酸 - 1,4 - 内酯脱氢酶（GalLDH）活性降低、酶活性（包括抗坏血酸过氧化物酶，APX；和抗坏血酸氧化酶，AAO）升高以及单脱氢抗坏血酸还原酶（MDHAR）活性降低，所有这些都导致连作条件下AsA含量较低。通过生理测量和代谢组学分析检测到，由于类黄酮和单宁等抗氧化剂含量较低，抗氧化能力较低，这进一步通过连作条件下的ROS胁迫使青稞生长恶化。我们的研究结果为ROS胁迫在青稞连作背景下调节粮食产量的方式提供了新的见解。
