Effect of Cu stress on minerals in rice by analyzing husk based on laser-induced breakdown spectroscopy

Tto explore the stress effect of heavy-metal Cu on other minerals in rice, the laser-induced breakdown spectroscopy (LIBS) fingerprint information of typical mineral elements in husk under different Cu stress was studied. A total of 24 rice grains samples with the same variety were collected in Dexing, Yanshan, Guixi of Jiangxi province, China. The results demonstrated that the LIBS spectral intensity of Cu in rice was highest in Dexing, followed by Yanshan and Guixi. The phenomenon was consistent with the reference concentration of Cu in rice and soil obtained by atomic absorption spectroscopy (AAS). The results were consistent with the corresponding reference concentration of Cu in rice and soil. Data processing was used to analyze the distribution of mineral elements Zn, Mn, Fe, Mg, Si, and K in Cu-stressed rice. The prediction precision of minerals based on the intensity ratio between internal calibration line Ca II 393.366 nm and objective minerals was considered. And PLS model was established. The results showed that the corresponding ratio including Zn, Mn, Fe, Mg, Si, and K increased with the increase of Cu stress, which displayed a positive correlation. Moreover, the intensity ratios of Zn, Mn, Fe, Si, and K in rice under different degrees of Cu stress were significantly distinct. This investigation indicated that LIBS coupled with suitable calculation can realize early rapid diagnosis of heavy-metal Cu stress in rice and provide technical support for comprehensive prevention and control of heavy-metal pollution in crops.