Calotropis Leaf Extract Prolongs the Vase Life of Cut Gladiolus Through Regulation of Antioxidative Defence, Water Relations and Reduced Microbial Proliferation

The vase life of gladiolus, a specialty cut flower, is significantly impacted by postharvest stress. Biostimulant like Calotropis leaf extract (CLE) has positive effects on the vase life (VL) of cut flowers; however, their comparison with chemical preservatives is still scarce. Therefore, the comparative role of CLE with silver nitrate (AgNO 3 ) and sodium nitroprusside (SNP) for enhancing the VL of gladiolus (cv. White Prosperity) cut stems was investigated. The cut stems were treated with distilled water (control), CLE (2%), AgNO 3 (0.025% ≡ 250 mg L −1 ), and SNP (0.01% ≡ 100 mg L −1 ) under ambient conditions. The study was conducted using a CRD with three replications, and means were compared using the LSD test at p ≤ 0.05. Application of CLE (2%) markedly improved vase life (19 days) and relative fresh weight (34%), along with a 65% reduction in microbial proliferation. This treatment also improved the membrane stability index (36%) and chlorophyll a (1.15 mg g −1 FW) contents compared with the control. Physiological processes were also improved, as indicated by a higher net photosynthetic rate (41%) along with reduced ethylene production (32%). Furthermore, CLE enhanced catalase activity (3.83 U mg −1 protein) and superoxide dismutase activity (0.19 U mg −1 protein), while decreasing malondialdehyde (160 μmol g −1 FW) and hydrogen peroxide (24 μmol g −1 FW). Conclusively, CLE (2%) significantly prolonged the vase life of gladiolus spikes by enhancing solution uptake, delaying senescence, and preserving membrane integrity through improved enzymatic defence and reduced oxidative damage.