Seed origin, storage conditions, and gibberellic acid on in vitro germination of Campomanesia adamantium (Cambess.) O. Berg

Abstract

Campomanesia adamantium (Cambess.) O. Berg seeds (guavira) are recalcitrant and rapidly lose viability upon removal from the fruit, making difficult the long-term storage. In vitro germination could be used as an important tool to overcome the issues related to this short viability. It might help seed conservation and species propagation. The purpose of this study was to evaluate in vitro germination of guavira seeds collected from different sites and stored under different conditions. Also, the sowing of these seeds in MS medium supplemented with different concentrations of gibberellic acid (GA₃) was evaluated. Seeds from the local garden were treated with: 0, 1.0, 2.0, 3.0, or 4.0 mg L^-1 GA₃. Seeds from a local farmer’s market were treated with: 0, 2.5, 5.0, 7.5 or 10 mg L^-1 GA₃. We evaluated the germination rate, the average length of the shoot and main root, and the number of leaves. The C. adamantium seeds were sown immediately after harvest and treated with GA₃, regardless concentration, increased germination rate by at least 10%, whereas 1.0 mg L^-1 GA₃ resulted in 100% germination. The shoot length increased linearly with increasing concentration of the growth regulator. Different concentrations of GA₃ had no effect on the development of the main root and leaves. Seeds acquired from a local farmer’s market showed lower germination rate than those sown immediately after harvesting, and did not differ in the rate of germination under different treatments with GA₃. Furthermore, around 25% of those seedlings had abnormal leaf morphology. C. adamantium seeds stored at 4°C and -20°C for 60 days did not germinate successfully, suggesting that seeds under cold storage conditions cannot be used for germplasm purposes.

Keywords: Guavira, Cerrado, Myrtaceae, temperature