PROBLEM TO BE SOLVED: To provide a wavelength conversion particle which can effectively utilize light inhibiting plant growth, and has high light resistance.SOLUTION: The wavelength conversion particle is provided that is used by being added to a wavelength conversion sheet converting a short-wavelength component of irradiation light into a long-wavelength component. The wavelength conversion particle contains: (a) one or more types of fluorescent substance； (b) a transparent material； and (c) light stabilizer. It is preferable that the fluorescent substance is a fluorescent substance which converts a short-wavelength component into a long-wavelength component and emits light, and has emission maximum wavelength 400 nm to 700 nm at an excitation maximum wavelength of 400 nm or less. It is preferable that the transparent material is transparent vinyl resin. It is preferable that the light stabilizer is hindered amine-based light stabilizer.SELECTED DRAWING: None【課題】 植物の生長を阻害する光の有効利用が可能な、耐光性の高い、波長変換粒子を提供する。【解決手段】 照射光の短波長成分を長波長成分に変換する波長変換シートに添加して用いる波長変換粒子であって、（ａ）１種以上の蛍光物質と、（ｂ）透明材料と、（ｃ）光安定剤と、を含む波長変換粒子。前記蛍光物質が、短波長成分を長波長成分に変換して発光する蛍光物質で、励起極大波長４００ｎｍ以下で、発光極大波長４００ｎｍ～７００ｎｍであることが好ましい。前記透明材料が、透明ビニル樹脂であることが好ましい。前記光安定剤が、ヒンダードアミン系光安定剤であると好ましい。【選択図】 なし
