Pollen release

Ten pictures of anthesis


Three stamens surround the carpel. Each stamen consists of a short filament and a two-lobed yellow anther. The anterior stamen is between but slightly behind the lodicules. The two posterior stamens are often partly covered by the wings of the palea.
The stamen filaments are fully grown now and the anthers are 'outside' the floret. At this point the anthers are spent. They lose their fresh yellow colour within one day but remain on the spikelet until they are rubbed off in the wind. 'Open' flowering is the most common type in wheat although 'closed' flowering types do occur.
One of the two feathery female stigmas has unfolded. The anthers have started to move apart.
The filaments have started to grow and a second stigma is seen. The stamen filaments grow rapidly to about 10mm long, six or eight times their original length.
The two lodicules at the base of the floret start to swell. This will force open the lemma and palea (in our pictures the lemma has been removed). This, in turn, will allow the stamen filaments and the anthers to fall outside the floret.
Two small pores open at the tip of each anther, one on each lobe, and pollen is released. Pollen is first released inside the floret. Later, when the anthers are ejected, pollen will blow freely in the wind.
The sticky feathery stigmas are fully unfolded and ready to receive the pollen.
The anthers are now split down half their length. Normally by now they would have been ejected from the floret. (Here we have removed the lemma to take the picture)
The lodicules collapse and the lemma and palea close up again. The newly fertilized carpel is again protected by the lemma and palea. (Here we have removed the lemma to take the picture)
Anthesis is over and the spent anthers dangle from the first two florets of this spikelet. In both 'open' and 'closed' flowering types almost all carpels are pollinated and fertilized by pollen from the same floret.