| Selenium is one of the necessary microelement of human beings and animal, the distribution is relatively fragmented and low-level in the environment,and has huge biological effect to human body. Plant is the main channel of human filling selenium, selenium and organic form in plants is one of the important indicators for selenium, adopting the method of accurate speciation analysis of selenium content in plants and is particularly important. Zhangjiajie city is located in Wuling mountains and has the similar natural geographical feature with Enshi of Hubei Province. The investigate and analysis for the se-enriched resources providing theoretical basis for develop and utilize the local rich selenium resources. The test samples are collect from September 2012 to November 2014 in Zhangjiajie. Analysis of the total selenium in soils and plants by HG-AFS, Continuous extraction analysis of selenium in soil samples form, HPLC-HG-AFS method was developed for the determination of selenium in plant samples of four kinds of forms(SeⅣ、SeⅥ, SeMet, SeCys), By using the AriGIS and combining with the selenium-rich soil feature of Zhangjiajie, selecting efficient method to carrying out the planning of selenium-rich plant.The main characteristics of the study and the results are as follows:1、This research found that the selenium content in soil between 0.00 ~ 5.60 μg/g, the average is about 0.38 μg/g, is belonged to selenium-rich area. Compared with China soil background value, the average selenium in soil is 1.80 times that of the average Chinese soil selenium. According to soil type of Zhangjiajie total selenium content in the black calcareous is relatively high, high up to 96.05 μg/g, belongs to the super selenium-rich soil. The selenium content in different soil types is significant differences, black calcareous soil selenium content in the highest, followed by calcareous yellow soil, fertilizer cooked dry farming, the artificial soil selenium content in paddy soil is relatively low.2、According to the sampling points of latitude and longitude, measured datas, to draw zhangjiajie selenium-rich soil profile. Zhangjiajie are mottled, sporadic selenium-rich soil, super rich selenium area scattered distribution, most soil samples in Zhangjiajie 32 township belong to moderate selenium area, has a large area of selenium-rich soil. Across the region most soil containing selenium is normal, among them, is located in the northwest of Zhangjiajie sangzhi county,Wudaoshui, Xishaping,Hekou, Chenjiahe, Liaojiaochun and other village and township, Xinqiao, Tianmen mountain,Daping, Yuanguping, Wangjiaping of Yongding area, the large area of soil selenium content in more than 0.40 mg/kg, local area more than 5.00 μg/g, belongs to the typical selenium-rich area.At the same time, Part of Wulingyuan, Tianzishan country and Zhonghu country soil selenium content is more than 0.40 μg/g, belongs to the selenium-rich soil. Study of the distribution of selenium in selenium-rich soil form, found that Zhangjiajie selenium-rich soil selenium content in effective for 0.024 μg/g-2.296 μg/g, bigger changes, accounted for average selenium 8.859% of total selenium. Selenium in soil mainly organic sulfide combination and element selenium, iron and manganese oxide residue state combination state exists in the form of selenium. Soil selenium and significantly correlated to the total selenium in soil effectively.3、Selenium content and specificities is closely to humans health. The experiments optimized the method of HG-AFS determination of selenium in plant. After sample 100 mesh sieve, add 10 mL of nitric acid cold soak overnight, 90 ℃ water bath heating 30 min cool down added 2 mL of 30% hydrogen peroxide, 200 W, 5 min;400 W, 5 min;200 W, 12 min conditions, take out after cooling, dilute with water to 25 mL.Take 10 mL solution and add 1mL hydrochloric acid, Under 15% hydrochloric acid as the carrier, under the condition of 1.5% potassium borohydride as reducing agent.The high recovery and good precision, can efficient and accurate determination of selenium in plant samples total.4、Analyzing the selenium content of plants which growed in selenium-rich soil and vegetables in market circulation in Zhangjiajie, founding that Zhangjiajie Xinqiao village, Tianmen mountain, Zhonghu village,Immortal creek, Wangjiaping, Red tuping, Yuanguping, Sancha village, Sataping township and so on selenium content relatively rich, the growth of rape, garlic, peanut, sweet potato, tea, vegetables and other crops are selenium-rich plants. Similar plants on the soil of different selenium levels have different selenium-rich ability, high level of selenium in the plant under the conditions of selenium significantly higher.Market circulation vegetables survey found that selenium content in Zhangjiajie residents daily edible vegetable selenium levels higher than the national value, the selenium content in leafy vegetables are significantly higher than plant fruits, melons and fruits.5、Studied and analyzed the HPLC-HG-AFS method determination of four different forms of selenium in plants(SeⅣ、SeⅥ、 SeMet、 SeCys).Ultrasonic pretreatment experiment found that 50% methanol extraction efficiency is highest, but the separation effect is not ideal, SeCys, Se Ⅳ, SeMet is difficult to separate, extract may occur in the process of transformation. Tendency for 25 mmol/L acetate ultrasonic extraction can successfully separate the sample in four different forms of selenium, separating degree is better and can ensure the extraction does not occur in the process of transformation, the recovery experiment showed that the extraction method can meet the needs of the experiment. Analyzed common concentration of selenium in plants four kinds of form, found that the proportion of different vegetation types including four significant differences form, now temporarily not found its regularity, needs further research.6 、 Analyzing the influence of different mass concentration of Na2SeO3 on germinating of vegetable seeds and distribution of selenium content in different organs in vegeta-bles, for screening the optimum concentration of Na2SeO3 and choose them high selenium content in vegetable to eat providing theoretical basis. With the increasing of concentration of Na2SeO3 three kinds of vegetable seed germination potential,germination rate and simple vigor index, germination index, first after rising downward trend, but there are some differences between individuals. Five kinds of total selenium content in the plant vegetables with the increase of selenium concentrations in water liquid is obviously rising trend, in 10.0 mg/L of selenium enriched ability under the condition of is Shanghai green higher than tegame, eggplant, tomatoes. Eggplant, peppers, tomatoes, three kinds of vegetables distribution of selenium content in different parts of the significant differences, organic selenium achieves more than half of total selenium, Which morganic selenium≥1/2mtotal selenium。7、Combination with the distribution of planting vegetables base、plant habit and the selenium-rich soil distribution and other factors, to planning the selenium-rich plants in Zhangjiajie city. |
PDF Full Text Request