Effects of silicon on mineral element uptake and distribution, yield and quality of Chinese spring onion

【Objectives】Chinese spring onion has important health function and medicinal value because of its organic sulfur compound. For the reason, some research focused on the relationship between mineral elements, such as nitrogen, phosphorus, potassium and sulfur, etc., and improving yield, quality and flavor substances of Chinese spring onions. As an accepted beneficial element, silicon plays an important role in improving crop yield and quality, but the response of Chinese spring onion to silicon was not reported. Therefore, in this experiment, effects of silicon on mineral element uptake and distribution, yield and quality of Chinese spring onions were studied for providing scientific basis for effective fertilization.【Methods】Under the condition of using Na2SiO3·9H2O as silicon source, two varieties of Chinese spring onion, ‘Tianguang’ and ‘Zhangqiu’, were selected as materials to investigate the effects of different silicon levels of nutrient solution (SiO2 0, 0.6, 1.2 and 1.8 mmol/L) and soil silicon fertilizers (SiO2 0, 150, 300 and 450 kg/hm2) on mineral element uptake and distribution, yield and quality by combining pot Hoagland nutrient solution culture and field cultivation. 【Results】The results show that the plant heights, cauloid lengths, cauloid diameters, dry weights and single plant yields of the two varieties are firstly increased and then decreased in the range of 0-1.8 mmol/L silicon. Among all treatments, the 1.2 mmol/L silicon treatment is the best, and the single plant yields of the two varieties are improved by 19.4% and 30.9% respectively compared with the control. Moreover, appropriate silicon also significantly increases the contents of free amino acids, soluble sugar, pyruvic acid of Chinese spring onions, which indicates that the Chinese spring onion quality could be enhanced by applying silicon. With the increase of silicon levels, the silicon contents in different organs of two varieties are increased significantly, and then reach the highest values under the 1.8 mmol/L silicon concentration, while the potassium contents is decreased. The nitrogen and phosphorus contents are increased firstly and then decreased, and their maximums occur under the 1.2 mmol/L silicon level. Because the application of silicon promotes the growth of Chinese spring onions, the uptake amounts of silicon, nitrogen, phosphorus and potassium are raised with the increase of silicon levels. In the field experiment, under the treatment of supplying 300 kg/hm2 silicon (SiO2), the yields of ‘Tianguang’ and ‘Zhangqiu’ are the highest and are increased by 15.4% and 25.6% compared with the control. 【Conclusions】Adding silicon significantly increases the uptake amounts of silicon, nitrogen, phosphorus and potassium of Chinese spring onions, promotes the plant growth, yield and quality. However, the yield increased rate of ‘Zhangqiu’ is significantly higher than that of ‘Tianguang’, and the changes of the two varieties with different silicon concentrations are different, indicating that different Chinese spring onion varieties had a significant differences in the sensitivity of silicon. In this experiment, the nutrient solution containing silicon 1.2 mmol/L or soil supplying 300 kg/hm2 silicon fertilizer are optimal for improving the growth, yield and quality of Chinese spring onions.