Preharvest calcium application boosts the biostimulatory effect of protein hydrolysate by improving the postharvest life of gerbera cut flower

Among the various categories of plant biostimulants currently available on the market, protein hydrolysates, primarily composed of a heterogeneous mixture of peptides and amino acids, have gradually gained prominence. Nevertheless, the positive effects of these products on the production and longevity of cut flowers are still not well-explored. The purpose of this research was thus to fill this gap by assessing the impacts of a plant-derived protein hydrolysate, with and without the addition of calcium (PH and PH+Ca), on the growth, quality, and vaselife of two cultivars of gerbera with different pigmentation (Brunello and Tommy, red and yellow, respectively). Regardless of cultivar, foliar application of PH improved growth, flower production, absorption of key nutrients, and photosynthetic performance, compared to the control. On the other hand, the PH+Ca treatment exhibited the best results during vaselife. For both cultivars, the application of PH+Ca increased the durability of gerbera flowers, reducing the weight loss by an average of 19 % on day 10 compared to untreated flowers. Although cultivar-dependent, the positive effects of the PH+Ca biostimulant were also observed on petal pigmentation during vase life. For the Tommy cultivar, for instance, the Chroma values of treated flowers remained unchanged during the post-harvest period, unlike what was observed for untreated flowers. Therefore, considering the positive effects resulting from the use of PH and PH+Ca on gerbera, it would be interesting to further investigate the use of biostimulants in floriculture to increase the sustainability of the sector and especially with regard to cut flower production, without reducing or even improving the performance that is conventionally achieved.