Phenolics in the seed coat of wild soybean (Glycine soja) and their significance for seed hardness and seed germination.

Hardseededness in annual wild soybean (Glycine soja Sieb. Et Zucc.) is a valuable trait that affects the germination, viability, and quality of stored seeds. Two G. soja ecotypes native to Shandong Province of China have been used to identify the phenolics in the seed coat that correlate with the seed hardness and seed germination. Three major phenolics from the seed coat were isolated and identified as epicatechin, cyanidin 3-O-glucoside, and delphinidin 3-O-glucoside. Of the three phenolics, only the change of epicatechin exhibited a significant positive correlation with the change of hard seed percentages both under different water conditions during seed development and under different gas conditions during seed storage. Epicatechin also reveals a hormesis-like effect on the seed germination of G. soja. Epicatechin is suggested to be functionally related to coat-imposed hardseededness in G. soja.

Identification of Armillaria nabsnona in gastrodia tubers.

The symbiosis between Armillaria species and an achlorophylous orchid Gastrodia elata BLUME has been reported. The main species described as a symbiont is Armillaria mellea (VAHL: FR.) KUMMER, known widely as a primary root rot pathogen. Samples collected from the rhizomorphs attached to the tuber of G. elata were separated and analyzed. Molecular analysis based on sequencing of the intergenic spacer 1 (IGS-1) and internal transcribed spacer (ITS) regions of the ribosomal DNA (rDNA) was performed, coupled with restriction fragment length polymorphism (RFLP) of the IGS-1 region. Cultural morphology and features of basidiomata were also used to characterize the isolates. Phylogenetic analysis and morphological data strongly suggested that the fungus present in the tubers of G. elata is Armillaria nabsnona. This is the first report of occurrence of this Armillaria species in association with G. elata.