Pre-Sowing Treatments, Seed Components and Water Imbibition Aids Seed Germination of Gloriosa superba

Gloriosa superba L. is a horticulturally and medicinally important plant. Its seeds have poor, erratic, and deferred germination. The detailed seed structure components and water imbibition mechanism facilitating the process of seed germination in G. superba remain unexplored. Therefore, it is essential to develop methods to ensure consistent and enhanced seed germination in G. superba. Various pre-sowing treatments along with the Brunauer-Emmett-Teller (BET) surface area analysis and 3D X-ray micro-tomography (micro-T) were employed to elucidate seed structure components, porosity network, and the water imbibition mechanism during germination in G. superba. The study revealed that consistent and significantly improved seed germination (>85%) was observed using the pre-sowing treatment mechanical scarification followed by 24 h water soaking in G. superba. BET and micro-T showed that the tegmen of the seed coat exhibited porosity (21%) with a well-connected porosity network (17.50%) that helped in water movement through hilum, which was confirmed by phosphotungstic acid staining. However, the sarcotesta and endosperm were water-impermeable due to their negligible porosity. Multidisciplinary techniques such as BET and micro-T along with conventional methodologies can be employed to address the seed coat structure, porosity, and water imbibition mechanism aiding seed germination. Mechanical scarification enabled the water to penetrate internal seed layers through the permeable tegmen via the reticulate pore network, which significantly improved seed germination. The developed seed germination method can produce a large number of plants in less time and conserve the natural populations of this high-value medicinally important species.