PROBLEM TO BE SOLVED: To provide a plant vitalizer that does not give plants chemical injury or the like and shows excellent growth promoting effect on the plants.SOLUTION: A plant vitalizer comprises as an active ingredient a lignin decomposed product that has 10 mass% or more of aldehyde yields by alkali nitrobenzene oxidation.SELECTED DRAWING: NoneCOPYRIGHT: (C)2018,JPO&INPIT【課題】植物に薬害等をもたらさず、植物に対して優れた生長促進効果を示す植物活力剤を提供する。【解決手段】アルカリニトロベンゼン酸化によるアルデヒド収率が10質量%以上であるリグニン分解物を有効成分とする植物活力剤。【選択図】なし