2018 ASHS Annual Conference

As plants grow and develop, they acquire mineral nutrients from their environment. Developing seed embryos acquire their mineral nutrition through their mother plants. The relative proportions of these nutrients in developing seeds can vary according to their respective stages of development. Chinese chestnut (Castanea mollissima, Blume) is an economically important nut tree species in Asia. Although its cultivation in the United States is limited, it is used as a genetic source of disease resistance in breeding programs in support of restoration efforts of the American chestnut (Castanea dentata, (Marshall) Borkh.). Developing seeds from three Chinese chestnut trees located in Athens, Georgia were collected on three dates each in 2016 and 2017. The seeds were excised from their burs and their pericarp and seed coat layers were removed. The remaining kernels were then dried and analyzed for their inorganic nutrient composition at the University of Georgia’s Soil, Plant, and Water Lab.

Variations in environmental conditions can cause differences in developmental ontogeny of seeds between years. To standardize the nutrient profiles of kernels that were sampled at similar dates between years, digital images of the dried kernels were made before they were processed for analysis. These images were analyzed using Image J software to gauge the relative sizes of the kernels. These two-dimensional area measurements were correlated with their respective nutrient analyses. There were strong Pearson correlations (r ≥ |0.70|) between the average sizes of the dried kernels and their respective average levels of potassium, zinc, copper, and nickel, with moderate correlations (|0.69| ≥ r ≥ |0.50|) of average kernel size with average levels of magnesium and nitrogen.

The correlations of kernel sizes and nutrient contents will guide future research toward development of optimized fertility regimes for bearing chestnut trees as well as the formulation of optimized tissue culture media for development and maturation of chestnut somatic embryos.