Polyamines (PAs) are positively charged amines such as putrescine, spermidine and spermine that ubiquitously exist in all organisms. They have been considered as a new type of plant biostimulants, with pivotal roles in many physiological processes. Polyamine levels are controlled by intricate regulatory feedback mechanisms. PAs are directly or indirectly regulated through interaction with signaling metabolites (H₂0₂, NO), aminobutyric acid (GABA), phytohormones (abscisic acid, gibberellins, ethylene, cytokinins, auxin, jasmonic acid and brassinosteroids) and nitrogen metabolism (maintaining the balance of C:N in plants). Exogenous applications of PAs enhance the stress resistance, flowering and fruit set, synthesis of bioactive compounds and extension of agricultural crops shelf life. Up-regulation of PAs biosynthesis by genetic manipulation can be a novel strategy to increase the productivity of agricultural crops. Recently, the role of PAs in symbiosis relationships between plants and beneficial microorganisms has been confirmed. PA metabolism has also been targeted to design new harmless fungicides.

多胺 (PA) 是带正电荷的胺，如腐胺、亚精胺和精胺，普遍存在于所有生物体中。它们被认为是一种新型的植物生物刺激剂，在许多生理过程中发挥着举足轻重的作用。多胺水平由复杂的调节反馈机制控制。PA通过与信号代谢物的相互作用直接或间接调节（H ₂ 0 ₂, NO)、氨基丁酸 (GABA)、植物激素（脱落酸、赤霉素、乙烯、细胞分裂素、生长素、茉莉酸和油菜素内酯）和氮代谢（维持植物中 C:N 的平衡）。PA的外源应用增强了抗逆性、开花和坐果、生物活性化合物的合成和农作物保质期的延长。通过基因操作上调 PAs 的生物合成可能是提高农作物产量的一种新策略。最近，PA在植物与有益微生物共生关系中的作用已得到证实。PA 代谢也被用于设计新的无害杀菌剂。