Figure 6.

Subcellular research in Arabidopsis: Pollen organellar DNA degradation. (A) Microspore cells develop into pollen by two rounds of mitosis, producing two sperm cells within a generative cell. (B) shows microscopic sections at different developmental stages with DNA stained blue using DAPI. In wild type, organellar DNA in the vegetative cell is degraded. The dpd1 mutant, defective in an exonuclease, has persistent organellar DNA (plastidial and mitochondrial) through the tricellular stage of development. Yellow arrows indicate nuclear DNA visible in the selected section at the tricellular stage of development. Figure modified from Matsushima et al. (2011) with permission from the American Society of Plant Physiologists.