Changes in anatomical structure and cell wall composition during male inflorescence development of <i>Castanea mollissima</i>

The Chinese chestnut ( Castanea mollissima Blume) is a dioecious plant in which the number of male inflorescences far exceeds that of female inflorescences. Therefore, it is of interest to study the differentiation of male flowers in C. mollissima. In this study, the male inflorescences of “Yanshanhongli” C. mollissima were observed. Then, the main components of the cell wall were stained by fluorescence and immunofluorescence labeling techniques to examine the changes in cell wall components. The results showed that the development of the male inflorescence of C. mollissima had different transverse elongation and longitudinal elongation. In addition, the development of male inflorescences and anthers were divided into five and four major stages, respectively, according to the microstructural changes. Immunostaining indicated that the fluorescence intensity of cellulose increased with the development of male inflorescences of C. mollissima. The fluorescence intensity of low-esterified homogalacturonan (HG) was stronger in the early stage, while the fluorescence intensity of high-esterified HG was stronger thereafter. This research provides new insights into the changes in cell wall components during the growth and development of male inflorescences of C. mollissima and important clues for exploring the growth and development mechanism of male inflorescences of C. mollissima.