Differentiation of Stylar Transmitting Tissue during Ovule Development in Female Flowers of Japanese Chestnut (Castanea crenata Sieb. et Zucc.)

Abstract

To understand the anatomical features and fertilization processes of female flowers in Japanese chestnut, we examined the differentiation of transmitting tissue. From the observation of serial transverse sections from the base of the ovary to the style, it was revealed that nine septa formed nine styles. The transmitting tissue in the style appeared in the boundary area where the two adjacent septa joined. The epidermal cells of each style were derived from the cortex parenchyma surrounding the transmitting tissue, and each style elongated cylindrically during flower development. The transmitting tissue, a solid type, was observed at the top of the stigma. Ovules with a short, thick funiculus were pendulous on the surface of the placenta under the style, and were anatropous. The interval between the terminal of the transmitting tissue and the top of the ovary contained no track for pollen tubes to migrate along. This interval might be important for pollen tube growth.