Sperm Cells in Apiaceae
Two types of sperm cells are found in mature pollen grains of Apiaceae. For example Eryngium campestre (Fig.l) shows the plasma-rich sperm cell type having numerous organelles, mainly mitochondria and dictyosomes. The mitochondria (m) are smaller than those in the vegetative cytoplasm (M). The nucleus is elongated and slightly sickle-shaped. The folded sperm cell wall consists of two plasma membranes, which form broad projections on both poles of the cell. Inbetween the plasma membranes there is a deposition of wall material.