Postharvest seed treatments to improve the papaya seed germination and seedlings development
Practical technologies are required to preserve the viability of seeds particularly those known to be short-term viable species like Carica papaya (papaya). Papaya seeds were imbibed in water or chemical solutions (CaCl2 10-5 M, salicylic acid 10-4 M, and gibberellic acid 10-5 M) combined with inoculation of bacterial cell suspension to determine their effects on seed germination, plant growth, biomass production and chlorophyll accumulation. Seeds imbibed in water germinated 40 % more than control seeds and the time required to reaching 50 % seed germination was reduced two days in comparison to untreated seeds; however, the untreated seeds generated the largest (9.2 cm) and most vigorous seedlings. When seeds were imbibed in CaSG solution, a significant increase of the growth parameters such as fresh and dry biomass weight was observed. Seeds that were primed in gibberellic acid solution followed by inoculation with a mixture of Azospirillum brasilense cell suspension exhibited high seed germination (69 %), plant emergence (47 %) and seedling height (19 %), higher than the control. Differences in chlorophyll accumulation by seedlings were minimal.