The Distribution Of Important Minerals In Rice And Rapid Method For Determination Of Iron And Zinc

Mineral elements are essential nutrients for human well-being and they play a vital role in the effective functioning of the body activity. Currently, mineral malnutrition has been receiving more extensive attention. Increasing the beneficial mineral elements in rice grains through genetic breeding technology is considered as a sustainable approach to solve this problem. Three indica rice cultivars, namely, Zhenong 7 (long grain), Zhenong 60 (medium grain) and Zhenong 34 (short grain) with different physical properties were employed in present study. The distribution in rice for six mineral nutrient elements including Fe, Zn, Se, Mg, Ca and Mn in three rice cultivars was examined. Eleven mineral elements and nine agronomic traits of 31 different types of rice varieties were determined and the relationships among mineral elements or between minerals and agronomic traits were also analyzed in this study. The methods to determine Fe and Zn contents in rice were also improved. The bathophenanthroline (BPT) method created in this study was useful for selecting the iron-rich rice mutant(s) from 25 rice crosses of early season indica rice,93-11 and Zhenong 7 mutant populations. The main results were as follows:1. The milling times were varied for the same degree of milling in different type rice cultivars, which Zhenong 7 required longer milling time to obtain white rice compared to Zhenong 34, while Zhenong 60 required longer time than Zhenong 34 but shorter time than Zhenong 7. The results also showed that there was a wide variation in the contents of the six mineral elements in different rice varieties. Meanwhile, the same mineral element in different fractions of the same brown rice also showed significant differences. In terms of Fe, Mg, Ca and Mn contents, extremely biased distributions were observed in the fractions of the outermost part, while the distribution of Zn and Se were relatively uniform.2. The relationship results among mineral elements showed that, Mg, Al and Pb had significantly positive correlations, but did not show significant relationships with the other five mineral elements; Al, Ca, Mn, Cu and Pb were positively related; Fe was significantly positively correlated with Zn and Hg. The relationship results of minerals with agronomic traits showed that Zn and plant height as well as Se and panicle length were positively related, but Mg content and panicle length showed significantly negative correlation. Fe, Se, Cd and Hg were significantly positively correlated with single panicle weight while Mn and Pb were significantly negatively correlated with grain aspect ratio. During rice breeding, the related characters can be indirectly improved according to the correlation results of rice.3. A simple, sensitive and highly selective method was proposed for the determination of Fe2+ in rice using BPT as spectrophotometric reagent based on the extraction by hydrochloric acid. The complex was found to obey Beer's law with an optimum concentration range between 0 and 1.5ppm. The linear regression equation was y=0.357 x +0.0027 with R2=0.9999. It showed that this study provides agood result but no significant difference compared to the result from ICP-MS method. A simple, sensitive and highly selective spectrophotometric method was also created to determine Zn2+ in rice using 5-Br-PADAP as spectrophotometric reagent based on the extraction by hydrochloric acid. The complex was found to obey Beer's law with an optimum concentration range between 0 and 0.2ppm. The linear regression equation was y=2.206x+0.0162 with R2= 0.9902. Just as the BPT method, this method also showed no significant difference compared to. the ICP-MS method. These two methods were simple and effective, and can meet the requirements for rice breeding.4. The study also created a rapid method (BPT) to achieve the qualitative determination of iron in rice. It showed that this screening method has a good dyeing effect and a sensitive reaction, and can be effectively used in rice breeding. Compared with the traditional measuring method, it can provide a low-cost Fe content determination technology to the rice breeders.