Plant and Animal Cells

Pollen grain

Pollen grain showing two nuclei. The smaller (generative) nucleus form two sperm cells. Endoplasmic reticulum threads throughout the pollen grain. Several mitochondria and plastids containing starch are also visible.

Microspore cells (young pollen grains) and two multicellular developing embryos at the heart stage.

Pollen grains on the stigmatic surface of a Lotus japonieus, a legume flower.