Phthalanilic acid (PPA), a plant growth regulator, has advantageous biological effects on fruit trees. However, little is known about its effects on vegetables. Thus, field trials were conducted on pepper (Capsicum annuum) plants by spraying with PPA at concentrations of 133.3, 200.0, and 266.7 mg·L⁻¹. The key physiological indicators of peppers were investigated, including the number of flowers and fruits, yield, yield components, quality, and endogenous hormones. Results showed that PPA greatly boosted the number of flowers and fruits on pepper plants. The fruit shape index, dry matter content, single fruit weight, and yield in the PPA treatment of 133.3 mg·L⁻¹ were particularly higher than those of the control, with increasing rates of 28.73%, 22.97%, 26.85%, and 35.75%, respectively. PPA considerably decreased the levels of titratable acid and nitrate while noticeably increasing the levels of soluble protein, soluble sugar, l-ascorbic acid, and capsaicin in mature green or red pepper fruits. PPA may also increase the levels of indole-3-acetic acid (IAA) in flowers, buds, and leaves, elevate the levels of abscisic acid (ABA) in leaves, raise the levels of zeatin riboside (ZR) in young fruits, but decrease the ABA content in buds. PPA actively controls fruit quality and yield in the concentration range of 133.3–200.0 mg·L⁻¹. This beneficial outcome might ultimately be connected to the regulation of endogenous hormones.

邻苯二甲酸 (PPA) 是一种植物生长调节剂，对果树具有有利的生物学效应。然而，人们对其对蔬菜的影响知之甚少。因此，通过喷洒浓度为 133.3、200.0 和 266.7 mg·L ^{-1的 PPA 对辣椒 (} Capsicum annuum ) 植物进行田间试验。对辣椒的花果数、产量、产量构成、品质、内源激素等关键生理指标进行了调查。结果表明，PPA 大大提高了辣椒植物的花和果实数量。^{PPA处理133.3 mg·L −1}的果形指数、干物质含量、单果重和产量尤其高于对照组，增长率分别为28.73%、22.97%、26.85%和35.75%。PPA 显着降低了可滴定酸和硝酸盐的水平，同时显着提高了成熟的绿色或红色辣椒果实中可溶性蛋白质、可溶性糖、 L-抗坏血酸和辣椒素的水平。PPA 还可以提高花、芽和叶中的吲哚-3-乙酸 (IAA) 水平，提高叶片中脱落酸 (ABA) 的水平，提高幼果中玉米素核苷 (ZR) 的水平，但降低芽中ABA含量。^{PPA在133.3–200.0 mg·L −1}浓度范围内积极控制果实品质和产量。这种有益的结果可能最终与内源性激素的调节有关。