PROBLEM TO BE SOLVED: To provide a plant growth promoter having high plant growth effects such as a strengthening of the plant cell walls, a promotion of photosynthesis, an activation of roots, an improvement of resistance to falling, an increase of resistance to disease damage and insect damage.SOLUTION: There is provided a plant growth promoter comprising a silica sol obtained by dispersing silica microparticles into a dispersion medium and satisfying the following conditions of 1), 2) and 3): 1) silica microparticles are contained in the silica sol by 10 to 40 mass% expressed in terms of concentration of SiO2 2) 10 to 80 mass% of the silica microparticles is a soluble silica made of monosilicic acid and polysilicic acid having a polymerization degree of 2 to 8 and 3) 30 to 80 mass% of the soluble silica is monosilicic acid.COPYRIGHT: (C)2014,JPO&INPIT【課題】植物の細胞壁の強化、光合成の促進、根の活性化、耐倒伏性の向上、病害や虫害への抵抗力増加といった植物成長効果の高い植物の成長促進剤の提供。【解決手段】シリカ微粒子が分散媒に分散してなるシリカゾルであって、次の1)、2)及び3)の条件を満たすシリカゾルを含有してなる植物の成長促進剤。1)該シリカゾルにシリカ微粒子がSiO2換算濃度で10~40質量%含まれる。2)該シリカ微粒子の10~80質量%が、モノケイ酸及び重合度2~8のポリケイ酸からなる可溶性シリカである。3)該可溶性シリカの30~80質量%が、モノケイ酸である。【選択図】なし
