Starch is the most important form of carbohydrate storage and is the major energy reserve in some seeds, especially Castanea henryi. Seed germination is the beginning of the plant’s life cycle, and starch metabolism is important for seed germination. As a complex metabolic pathway, the regulation of starch metabolism in C. henryi is still poorly understood. To explore the mechanism of starch metabolism during the germination of C. henryi, we conducted a comparative gene expression analysis at the transcriptional level using RNA-seq across four different germination stages, and analyzed the changes in the starch and soluble sugar contents. The results showed that the starch content increased in 0–10 days and decreased in 10–35 days, while the soluble sugar content continuously decreased in 0–30 days and increased in 30–35 days. We identified 49 candidate genes that may be associated with starch and sucrose metabolism. Three ADP-glucose pyrophosphorylase (AGPase) genes, two nucleotide pyrophosphatase/phosphodiesterases (NPPS) genes and three starch synthases (SS) genes may be related to starch accumulation. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to validate the expression levels of these genes. Our study combined transcriptome data with physiological and biochemical data, revealing potential candidate genes that affect starch metabolism during seed germination, and provides important data about starch metabolism and seed germination in seed plants.

A new orchid species, Cymbidium codonanthum, from Yunnan Province, China, is described and illustrated based on morphological and molecular analyses. A detailed comparison between the newly discovered orchid and other members of Cymbidium was performed. The new plant what is similar to C. cochleare, but it is characterized by several morphological features that distinguish it from the latter as well as all other known species of Cymbidium. A molecular study based on nuclear ribosomal ITS and plastid matK and rbcL DNA sequence data indicates that C. codonanthum is genetically distinct from other species and a member of Cymbidium section Cyperochis.