Cut roses are among the most attractive and economically significant ornamental plants that serving as the national flower in ten countries, including Iran. A primary constraint in the cut rose industry is the relatively short vase life of the flowers, which is typically characterized by symptoms such as petal and leaf wilting. This post-harvest deterioration not only reduce the beauty value of the flowers but also cause severe economic losses in marketing and export. The onset of senescence and wilting is closely associated with water imbalance, microbial blockage in xylem vessels, and membrane lipid degradation. Recent studies highlight the critical role of calcium in maintaining cell wall and membrane integrity. Calcium acts as a structural cation that stabilizes phospholipids and reinforces the pectocellulosic network, thereby delaying tissue senescence and preventing bent neck. Similarly, silver nanoparticles have gained prominence as effective post-harvest elicitors; they act as antimicrobial agents and ethylene inhibitors, improving water relations, reducing fresh weight loss, and extending vase life. Furthermore, biotic elicitors such as seaweed extracts contain a rich profile of micronutrients, phytohormones, vitamins, and betaines. These compounds enhance photosynthesis, increase plant resistance to biotic stress, and improve post-harvest longevity. While the individual effects of these substances have been studied, there is a lack of comparative data regarding their pre-harvest foliar application on diverse commercial rose cultivars. Therefore, this study aimed to evaluate and compare the effects of various concentrations of biotic (seaweed extract) and abiotic (calcium chelate and silver nanoparticles) elicitors on the post-harvest morphological characteristics and vase life of four Dutch cut rose cultivars.

The effect of biotic and abiotic stimuli on morphological traits and postharvest life of rose cut flowers



Materials and Methods

A factorial experiment was conducted based on a completely randomized design (CRD) with four replications in a hydroponic greenhouse in Karaj, Iran. The first factor comprised four rose cultivars (Samurai, Avalanche, Angelina, and Delsovita), and the second consisted of ten elicitor treatments: control (distilled water), seaweed extract (1, 2, and 3 g/L), calcium chelate (1.5, 2.5, and 3.5 g/L), and silver nanoparticles (2.5, 5, and 10 mg/L). Rooted cuttings were planted in coconut peat and perlite (1:2 v/v) under controlled environmental conditions (day/night temperatures of 25–30°C and 16–18°C, respectively, and 50–55% relative humidity). Foliar applications were performed weekly during the 45-day flowering phase prior to harvest. Flowers were harvested at the secretion stage (open flower but with unopened sepals) at sunset, recut to a standard length of 40 cm, and placed in distilled water at storage room with 20±2°C, relative humidity of 50–55% and lighting of 1400 lux. Evaluated traits included relative fresh weight, flower diameter, wilting percentage, vase life, and leaf chlorophyll content (using a SPAD meter). Data were subjected to analysis of variance (ANOVA) using SAS, and mean comparisons were performed using Duncan’s multiple range test at p≤0.05. Pearson correlation coefficients were calculated using Minitab.

Results and Discussion

The results indicated that the main effects of cultivar, elicitor, and their interaction were highly significant (p≤0.01) for all measured traits. Among the cultivars, Samurai exhibited the superior genetic potential, recording the highest relative fresh weight (110.94%), flower diameter (56.82 mm), chlorophyll content (43.13 SPAD), and vase life (12.47 days), along with the lowest wilting percentage (22.24%). Regarding the elicitors, the application of silver nanoparticles at 5 mg/L yielded the maximum relative fresh weight (111.44%), while 10 mg/L silver nanoparticles produced the largest flower diameter (53.58 mm, a 27.09% increase over the control), the lowest wilting percentage (19.2%, a 53.38% decrease compared to the control), and the longest vase life (12.27 days, a 48.37% increase over the control). The highest leaf chlorophyll content (45.38 SPAD) was achieved through the application of 2.5 g/L calcium chelate. The interaction effects revealed that Samurai showed the maximum vase life (15.75 days) and a minimum wilting percentage (12.47%) with 10 mg/L silver nanoparticles. For the Delsovita cultivar, 2.5 g/L calcium chelate was the most effective treatment for improving relative fresh weight, while 3 g/L seaweed extract best reduced its wilting percentage. The improvement in vase life and reduction in wilting can be attributed to the specific physiological mechanisms of these elicitors. Silver nanoparticles effectively regulated water relations, slowed down the transpiration rate, and maintained xylem hydraulic conductivity. Calcium chelates played a vital role in stabilizing cell membranes and reinforcing the middle lamella via calcium pectate formation, which mechanically resisted bent neck and tissue collapse. Seaweed extracts enhanced chlorophyll preservation, which sustained photosynthetic assimilate production, thereby delaying petal senescence. Correlation analysis demonstrated that vase life had a significant positive correlation with relative fresh weight, flower diameter, and chlorophyll content, and a strong negative correlation with wilting percentage.

Conclusions

It can be concluded that the application of biotic and abiotic elicitors via foliar spraying during the pre-harvest stage significantly enhances the post-harvest quality of cut roses. The Samurai cultivar performed better than the other cultivars in terms of post-harvest longevity and morphological traits. Overall, the application of 10 mg/L silver nanoparticles proved to be the most effective treatment for maximizing flower diameter, extending vase life, and minimizing wilting across the cultivars. Additionally, 2.5 g/L calcium chelate was highly effective for preserving leaf greenness. Based on the interaction results, it is highly recommended to utilize 10 mg/L silver nanoparticles, 3.5 g/L calcium chelate, and 3 g/L seaweed extract as sustainable pre-harvest strategies to maintain and improve the commercial quality and vase life of cut rose flowers.