Seed desiccation tolerance and conservation of sapucaia, an emerging functional Brazil nut tree from the Atlantic and Amazon forest biomes

In forest ecosystems, natural regeneration is strongly associated with seed desiccation tolerance, which allows viability to be maintained under low water conditions and supports seed survival during dispersal, soil seed bank storage, and periods of environmental stress, such as heat waves. This study investigated the desiccation tolerance and ex situ viability maintenance of Lecythis pisonis seeds. Seeds were evaluated at different water contents: 30%, 15%, 10%, and 4%. In addition, part of the seeds dried to 4% water content was stored at −20 °C and −86 °C for three months. Emergence, vigor, biochemical composition, hydrogen peroxide, malondialdehyde, antioxidant enzyme activity, and late embryogenesis abundant proteins (LEA proteins) were analyzed in seeds. Initial growth, chlorophyll a and b indices, and maximum quantum yield of photosystem II (F v /F m ) were evaluated in L. pisonis seedlings. Seedling emergence decreased from 95% in freshly harvested seeds with 30% water content to 88%, 84%, and 64% in seeds dried to 15%, 10%, and 4% water content, respectively. In seeds with 4% water content stored at −20 and −86 °C, average emergence was 45%, along with a lower capacity to express vigor, which may be attributed to damage caused by post-thawing imbibition. The results indicate that L. pisonis seeds show intermediate storage behavior, since they tolerated desiccation to 15%, 10%, and 4% water content, but were sensitive to ultra-low storage temperatures when dried to 4%.