Effects of silicon on growth, photosynthetic characteristics and quality of garlic seedlings

【Objectives】The degeneration of variety and serious soil-born diseases are important inhibitors for garlic plant growth, lower yield and quality. As a beneficial element, silicon plays an important role in improving yield and product quality. A study was conducted to investigate the effects of silicon on the growth and quality of garlic seedlings.【Methods】In this study, garlic cultivar, Jinxiangbaipisuan, was taken as an experiment material and five different concentrations of silicon, 0, 0.75, 1.5, 2.25 and 3.0 mmol/L, were used to treat garlic plants, and the growth, photosynthetic characteristics and qualities of garlic seedlings were measured. 【Results】The plant fresh weight and height, pseudo stem length and diameter and pigment contents are increased with the increase of silicon concentration from 0 to 1.5 mmol/L, while these items is decreased when the silicon concentrations are from 1.5 to 3.0 mmol/L, and the photosynthetic parameter (Pn and Gs) shows a similar trend. In the treatment of 1.5 mmol/L Si contents, Pn and Gs are increased by 32.41% and 44.62% respectively. The transpiration rate are decreased firstly and then increased with the increase of silicon contents, the minimum value appeares under Si of 1.5 mmol/L, in which the transpiration is reduced by 22.00% compared with the control. The contents of soluble sugar, free amino acids and vitamin C are also increased first and then decreased. The contents of soluble sugar in leaves and pseudo stems are highest under the 1.5 mmol/L silicon content, and are improved by 25.37%-41.96% and 21.28%-40.82% higher than those with the control. The contents of free amino acids and vitamin C reach their maximum values under Si2.25, and there are no significant differences between Si2.25 and Si1.5. The content of soluble protein in leaves is reduced by 15.76%-21.62%, in pseudo stems is improved by 32.85%-53.73% when the silicon concentration is 1.5 mmol/L.【Conclusions】 Proper Si addition can significantly increase the plant fresh weight and height and the pseudo stem length and diameter, the promoting effect is more significant at later period. Adding Si increase the pigment contents and photosynthetic rate in leaves, the nutritional quality of garlic seedlings because of the significant increase of the contents of soluble sugar, free amino acids and vitamin C. Therefore proper Si fertilization will be effective way in the relief of soil\|bron diseases and the deterioration of cultivars.