Despite scientific evidence supporting the biostimulant activity of protein hydrolysates (PHs) derived from vegetal or animal sources, the morpho-physiological and biochemical mechanisms underlying the biostimulant action of PHs from plant biomass or animal by-products are still poorly explored. Accordingly, we performed a greenhouse experiment for assessing the morphological, physiological and biochemical responses of sweet basil (Ocimum basilicum L.) to three nitrogen equivalent rates (0.05, 0.15, and 0.25 g N/kg) of an animal-derived protein hydrolysate (A-PH) and a vegetal-derived protein hydrolysate (V-PH). The V-PH and A-PH applications determined a quadratic-dose response regarding the number and area of leaves and the shoot fresh and dry weight, with the best results obtained using V-PH at the N equivalent rates of 0.05 and 0.15 g N/kg. Improvement of shoot fresh weight with V-PH foliar application at the rate of 0.15 g N/kg was associated with a higher leaf CO₂ assimilation and water use efficiency, with a concomitant higher uptake and translocation of K, Mg, and S in leaf tissue. The excessive accumulation of Na, Cl, and some amino acids (e.g., proline) under A-PH applications above 0.05 g N/kg induced a rapid decrease in plant photosynthetic performance, growth, and biomass production. The plants treated with A-PH at a higher dosage appeared to activate an alternative pathway involving the synthesis of alanine and GABA for storing excess ammonia, buffering cytoplasmic acidosis, and counteracting the negative effects of Na and Cl at toxic levels. The above findings demonstrated the potential benefits of protein hydrolysate application in agriculture, especially of vegetal-derived PHs, and highlighted the need to understand dose-dependent effects in order to optimize crop response.

尽管有科学证据支持植物或动物来源的蛋白质水解物（PHs）的生物刺激活性，但仍缺乏对植物生物质或动物副产物中PHs的生物刺激作用的形态生理和生化机制的研究。因此，我们进行了温室试验，以评估甜罗勒（Ocimum basilicum）的形态，生理和生化反应。L.）达到动物衍生的蛋白水解产物（A-PH）和植物衍生的蛋白水解产物（V-PH）的三个氮当量比率（0.05、0.15和0.25 g N / kg）。V-PH和A-PH应用确定了叶片数量和面积以及枝条鲜重和干重的二次剂量响应，在氮当量为0.05和0.15 g N的条件下，使用V-PH可获得最佳结果/公斤。以0.15 g N / kg的量施用V-PH叶面肥可以提高枝条鲜重，并伴随较高的叶片CO ₂含量同化和水分利用效率，同时叶片组织中K，Mg和S的吸收和转运更高。在高于0.05 g N / kg的A-PH施用下，Na，Cl和某些氨基酸（例如脯氨酸）的过量积累引起植物光合作用，生长和生物量生产的迅速下降。用较高剂量的A-PH处理的植物似乎激活了一条替代途径，该途径涉及丙氨酸和GABA的合成，用于存储过量的氨，缓冲细胞质酸中毒并抵消Na和Cl在毒性水平上的负面影响。上述发现证明了蛋白水解物在农业中的潜在益处，尤其是植物源性PH的农业应用，并强调了需要了解剂量依赖性效应以优化作物响应的必要性。