The Absorption And Accumulation Of Selenium In Camellia Oleifera And Its Effect On Soil Enzyme Activities

Selenium is one of indispensable microelements of human body.However,about 70% of our country has a shortage of selenium that effects the health of our people severely. Camellia oleifera is an advanced oil-producing tree planted only in China. We can implant selenium into Camellia oleifera from outside with a specialized technique. By intergrading selenium with Camellia oleifera naturally, we can better improve the quality of Camellia oleifera and develop a new and more refined strain, thus significantly bringing more benefits economically. In this assay, two fertilization experiments are set including young C. oleifera forestry and old C. oleifera forestry. The layout of the test of Camellia oleifera and Camellia forest fertilization based on the different concentration of selenium enriched selenium on field experiments.The three fertilization modes were soil fertilization (humic acid selenium enzyme), foliar spray (humic acid selenium titanium),soil fertilization and foliar spray together. The dissertation tests content of selenium, content of the soil selenium and activity of soil enzyme inside C. oleifera by diverse ways to use selenium and does the research on the influence that is caused by using selenium in different methods to increase content of selenium in the soil, leaves, shells and oil, soil nutrients and to effect on the activity of soil enzyme, in order to pave the way for future research theoretically.The experiment happened in the text area of young C. oleifera forestry in Sanjiang country and the test area of C. oleifera forestry in Sanmen forestry station. The young C. oleifera forestry was fertilized with selenium in July and August,2015,and was divided into 4 parts with different treatments, namely,A-1(soil fertilization),A-II(soil fertilization and foliar spray),A-III(foliar spray),A-CK(no treatment). The old C. oleifera forestry in Sanmen forestry station was fertilized with selenium in July and August,2014, and was divided into 5 parts with different treatments, namely, B-I(foliar spray once), B-II(soil fertilization and foliar spray once), B-Ⅲ(foliar spray twice), B-IV(soil fertilization and foliar spray twice),B-CK(no treatment). In the test, five soil chemical indexes were tested including:soil organic matters, soil total nitrogen, soil available K, soil available P and soil total selenium; four biological indexes were tested:the activity of urease, catalase, phosphatase, and sucrase; and selenium content in C. leaves, fruit shells, C. oil were tested.The followings are results:(1) Soil fertilization, soil fertilization and foliar spray can obviously increase the content of selenium in Camellia oil. The selenium content of Camellia oil both in young Camellia oleifera forestry and old one are significantly higher than those with no treatment (p<0.05). The selenium content of Camellia oil in old Camellia oleifera forestry with fertilization one year ago is lower than the young one in the year of fertilization.In the young Camellia, oleifera forestry, the average selenium content of C. oil is 0.055mg/kg, while the content in the non-treatment is only 0.019mg/kg. In the old one, after one year of fertilization, the average selenium content of C. oil is 0.032mg/kg, while the content in the non-treatment is only 0.017mg/kg. In year of fertilization, the selenium content of Camellia oil of soil fertilization alone and soil fertilization and foliar spray is in the range of 0.05mg/kg-0.5mg/kg that is the local standards of the selenium content in agricultural produces in Guangxi province.(2)Soil fertilization, soil fertilization and foliar spray, foliar spray can increase the content of selenium both in leaves of Camellia oleifera and in fruit shells. Also, there is a drastic difference in selenium content of the C. oleifer in one year (p<0.05). The content of selenium in soil fertilization and foliar spray is the highest one of three kinds of fertilization. In the young Camellia oleifera forestry, average selenium content of leaves and fruit shell in fertilization area is 0.79mg/kg and 0.55mg/kg respectively. Compared to the non-treatment, the increase is 88% and 71% respectively. In the old one, average selenium content of leaves and fruit shell in fertilization area is 0.66mg/kg and 0.45mg/kg respectively. Compared to the non-treatment, the increase is 66% and 40% respectively.(3)Soil fertilization with foliar spray and soil fertilization alone can both raise selenium content in soil. The content of total selenium in soil layer ranging 0-20cm is higher both in content and increase than in soil layer ranging 20-40cm.The increase of the total selenium in soil within the year of fertilization is more than fertilization in one year.In the young Camellia oleifera forestry, in soil layer ranging 0-20cm and 20-40cm, the content of selenium is between 0.43-0.78mg/kg and 0.40-0.55mg/kg respectively. The increase of selenium content in the soil fertilization alone and soil fertilization and foliar spray, in 0-20cm, is 73% and 81% respectively, while in 20-40cm,the increase is 37% and 38% respectively, compared to non-treatment. In the old one, in soil layer ranging 0-20cm and 20-40cm,the content of selenium is between 0.37-0.58mg/kg and 0.23-0.33mg/kg respectively. The increase of the selenium content in the soil fertilization+foliar spray once and soil fertilization+foliar spray twice, in soil layer ranging 0-20cm is 51% and 59% respectively, in soil layer ranging 20-40cm, the increase is 43% and 29% respectively, compared to non-treatment.(4)Soil with humic acid selenium enzyme can efficiently boost enzyme activity of soil. By contrast, it is found that, in the year of fertilization, the method of fertilizing soil alone, and fertilizing soil along with foliar spray once has an obvious effect on activity of soil urease and sucrase(p<0.05). After one year of solely fertilizing soil, and fertilizing both soil and leaves once, and then fertilizing both soil and leaves twice. Ther e was an obvious effect on activity of catalase, acid phosphatase (ACP), and sucrase (p<0.05).(5) The study shows the intimate relationship between enzyme activity of soil and soil nutrient by analyzing the relation between them.(6) The selenium content of soil has perfect positive relation to the selenium content leaves of Camellia oleifera, shells and of Camellia oleifera oil (p<0.01).In conclusion, the order of the number of selenium content in leaves of Camellia oleifera, shells and fruits:leaves>shells>oil of Camellia oleifera. Soil with humic acid selenium enzyme works longer and can boost efficiently selenium content of soil, soil nutrients and activity of soil enzyme. The relationship between activity of soil enzyme and soil nutrients is intimate, which makes them to be used as an indicator to assess soil quality. The technique is practicable that both fertilized soil and plant spraying can increase selenium content in oil, which paves the way for future research on developing new strains with abundant selenium, theoretically.