Image of the month (August 2006)

This image is from a figure in a research article by Nowack et al 2006. (This article is also our featured paper of the month in August). This is a DAPI stained image of an Arabidopsis thaliana pollen. DAPI staining of a pollen grain reveals a diffused body (vegetative nucleus) and highly condensed body (generative nucleus) within a pollen grain.

This figure elegantly shows the two kinds of pollen produced by a plant that is heterozygous for cdc2a mutation. Before a mature pollen grain is produced it undergoes two mitotic divisions. After the first division, the developing grain contains one vegetative and generative nucleus (d, in the figure above). In case of CDC2A pollen, the generative cell undergoes a second mitotic division and produces a grain with one generative nucleus and two sperm cells (WT, in the figure above).

However, if the meiotic end product inherits a cdc2a allele, then the pollen grain maturation proceeds normally only up until the first mitotic divisio but fails to undergo the second mitotic division. Because of this it ends up with a viable pollen grain with apparently normal vegetative nucleus and only one sperm cell! (cdc2a in the figure above).

Elegance and the stunning effect of the viability of a pollen grain despite having only one sperm cell is beautifully conveyed by this image. This image captures the phenotype of the mutant very effectively in a very simple yet powerful manner. For elegantly conveying the phenotype and image acquisition with perfect clarity/focus (a task that is not trivial considering that the authors had to capture a diffused vegetative nucleus and sharply focused sperm cells) made this to be our image of the month.

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Click here for previously featured image of the month.