Effect of Culture Temperatures on the Initial Growth Performance of Seedlings Germinated from Cryostored Seeds of a Tropical Tree Parkia nitida Miq. (Fabaceae, Mimosoideae)

Abstract

Seedling growth is one of the most important stages for the establishment of natural and artificial regeneration. For the first time, the initial growth and biomass allocation of seedlings germinated from cryostored seeds of Parkia nitida were analyzed. P. nitida is an economically and ecologically important timber tree species distributed in Central and South America. Cryostored seeds germinated quickly after priming by scarifying a part of the seedcoat with emery paper, reaching a germination percentage of 94%. Thirteen weeks after germination, the seedlings grew to a height of 16.5 to 60.0 cm. The results of our study, under different day/night alternating culture temperatures, showed that culture temperature had a direct correlation with seedling growth, total biomass allocation, and biomass partitioning. The greatest growth (height, diameter, and number of node sections) and greatest biomass allocation (leaf, stem, and root weight) were recorded under alternating temperatures of 30/25 °C, and these decreased with decreasing culture temperatures to 25/20 °C and 20/15 °C. Shoot:Root (S:R) ratios also decreased with decreasing culture temperatures, but a statistically significant difference (p < 0.05) was only observed between 20/15 °C and 30/25 °C. However, significant differences were not observed in Photosynthetic:Non-photosynthetic organ ratios among the different alternating culture temperatures. This study provides fundamental information for the production of good-quality seedlings of the fast-growing tropical trees of the legume family.