Effects Of Total Selenium In Soils Of Different Longan Orchard And Exogenous Selenium On The Nutrition And Fruit Quality

Soil and fruit samples from different longan orchards of Guangxi were taken as study materials to analyze soil selenium content and fruit quality to understand the distribution of soil selenium in longan production areas,fruit quality and the relationship between soil selenium content and nutrients of tree and fruits.Selenium absorption enrichment capacity of different longan varieties was study by analyzing the selenium content in leaves of different varieties.Trees were sprayed with different concentrations of sodium selenite to study the effects of selenium on nutrition and quality of fruits.The results of the study showed that:1.There was significant difference among the selenium content of soil from different longan orchards.It was found that all tested soils were rich in selenium with over 400Pg · kg-1 in the surface soil.There was a significant correlation between soil selenium content of different layer of soils.The selenium content in longan fruits was within the range of 2.72-6.15?g · kg-1.There was a significant positive correlation between selenium content in 0-20cm soils and selenium content in the leaves by analyzing the content of soil selenium in different longan orchard and the N,P,K,Ca,Mg and Se content of leaves.There was significant positive correlation between soils selenium content of 0-20cm of soil layer and P content in leaves.There was a significant positive correlation between soils selenium content and fruit Ca and Se content by analyzing of the linear correlation between the content of soil selenium in different longan orchard and the main nutrient element content and quality of longan fruit.However,there was significant negative correlation between soils selenium content and P,K and Mg content in fruits.There was significant negative correlation between soils selenium content and fruit diameter and single fruit weight.There was significant positive correlation between soils selenium content and fruit Vc content.2.There was significant difference in selenium contents in 0-20cm soils in the same orchard with different longan varieties and there was no difference in selenium contents of 20-40cm soils.There was significant difference in selenium content among different longan varieties with following order:Shixia>Guixiang>Guilong 1>Sijimi>Chuliang>Shuinanyihao>Dawuyuan>Guiguanzao.There was positive or negative correlation between the N,P,K,Ca,Mg and Se content in leaves of different longan varieties and soils selenium content by analyzing the N,P,K,Ca Mg and Se content in leaves of different longan varieties and soils selenium content.Nevertheless,there was significant negative correlation between leaves selenium content and selenium content in 0-20cm soils of Guilongyihao.And,there was significant positive correlation between selenium content in 20-40cm soils and selenium content in leaves of Guilongyihao.There was significant negative correlation between selenium content in 20-40cm soils and selenium content in leaves of Chuliang.3,Selenium content of leaves increased and N,P,K,Ca and Mg content of leaves were not affected when longan trees were sprayed with different concentration of Na2SeO3.Correlation analysis showed that concentration of Na2SeO3 had significant positive correlation with N content of leaves,but it had significant negative correlation with K content of leaves.Selenium content in fruits increased when trees were sprayed with different concentration of Na2SeO3 but N,P,Ca,Mg content in fruits did not change significantly,and K content in fruits declined.Width diameter,longitudinal diameter,single fruit weight and Vc content of longan leaves when spraying with Na2SeO3 was improved,but there was no siganificant difference in effects of fruit quality when sprayed with Na2SeO3.There was positive correlation with fruit quality and different concentration of Na2SeO3,but the correlation coefficient did not reach the significant level.Treatment of spraying with 70 mg · L-1 Na2SeO3 showed the best result in improving fruit quality.The total selenium content of leaves from the mentioned treatment was 398.1626?g · kg-1 in leaves and 10.35?g ·kg-1 in fruits.The single fruit weight was 9.60g with width diameter of 26.75mm,longitudinal diameter of 27.01 mm,edible rate of 75.79%and Vc content of 0.4293 mg · g-1.