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Spinach has long been used as a model for genetic and physiological studies of sex determination and expression. Although trisomic analysis from a cross between diploid and triploid plants identified the XY chromosome as the largest chromosome, no direct evidence has been provided to support this at the molecular level. In this study, the largest chromosomes of spinach from mitotic metaphase spreads were microdissected using glass needles. Degenerate oligonucleotide primed polymerase chain reaction was used to amplify the dissected chromosomes. The amplified products from the Y chromosome were identified using the male-specific marker T11A. For the first time, the largest spinach chromosome was confirmed to be a sex chromosome at the molecular level. PCR products from the isolated chromosomes were used in an in situ probe mixture for painting the Y chromosome. The fluorescence signals were mainly distributed on all chromosomes and four pair of weaker punctate fluorescence signal sites were observed on the terminal region of two pair of autosomes. These findings provide a foundation for the study of sex chromosome evolution in spinach.

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Three species of Rhytismataceae are described from needles of pines from China. Davisomycella intermedia is a new species growing on Pinus yunnanensis var. tenuifolia. Ploioderma pini-armandii and Soleella pinicola on Pinus armandii have been described previously only in Chinese with a short Latin diagnosis and therefore are presented here in detail. Naemacyclus fimbriatus, formerly regarded as belonging to the Rhytismatales, now to Helotiales, is reported for the first time for China, described, and illustrated.