|Hereís our area now that heading is nearly complete. Can you find the red flags? If you look hard in the center you might be able to see one (If you canít, donít worry). Letís take a closeup view of our row.|
|As you can see, nearly all the stems in our row have headed. The next stage we need to look for is the flowering stage. (Yes, wheat plants have flowers, but their flowers arenít big like iris or daylillies.) Letís look at a plant thatís starting to flower.|
|This head has just started to flower. Youíre probably asking yourself how in the world can I tell it is flowering! Well, if you look about halfway down the head you can see a yellow object sticking out of a spikelet (each spikelet contains several florets). Do you see it? Those are anthers. The anthers are actually inside the floret. Anthers contain pollen and when anthers are sticking out of a floret then I know it has been pollinated. When the anthers are first visible they are yellow, but after they are exposed to the sunlight they turn white. They will hang there for a day or two or until the wind blows them away.|
|Flowering generally starts in the middle spikelets (or slightly above the middle) of the head. Flowering continues in the upper and lower spikelets over the next few days. This head has been flowering for at least a day. It has more anthers poking out from spikelets above and below the middle point of the head.|
|Before we go any further, letís look closely at a wheat spikelet. A spikelet is also called a row or mesh by farmers. There are usually 2 to 5 florets in each spikelet that have the potential to develop kernels. However, only 2 or 3 kernels usually form because of the growing conditions. Letís look at the different parts. The two outside structures (one on each side) with the short barbs or horns are called glumes. They protect the florets.|
|If we pull the glumes down, and open the next structure you
can see the lemma and palea. The lemma is on the left and has the long
barb, which is called the awn (beards are what farmers call awns). On the
right is a papery structure called the palea. Now, if you look at the base
of the lemma and palea (at the tip of the pointer) you can see some small
objects, these are the floral parts. This whole thing, lemma, palea, and
the floral parts, is the floret.
Letís look closer at the floral parts.
|This is inside a floret before pollination. There are three
lime-green, tri-lobed structures. These are the anthers and the pollen is
inside them. The white, fuzzy structure is the stigma. The round,
greenish-white object with a greenish crease is the ovule. When the pollen
from the anthers is released and the pollen grains attach to the stigma
pollination has occurred. Then the pollen moves from the stigma through
the style to the ovule where it is fertilized. Now, a kernel will form!
The flowering stage is the most vulnerable to freeze damage. Temperatures of 32 F or below for several hours can damage the floral parts.
Let's look at the next picture of several florets.
|On the left, you can see this floret has immature floral parts, because the stigma has not fully expanded. In the middle, the anthers have turned yellow, the filaments (the threadlike structures attached to each anther) have elongated (the anthers will soon be visible outside the floret), the stigma has expanded and is ready for pollen. Also, you can see pollen grains everywhere. (If you want to see a scanning electron micrograph of a wheat pollen grain, click here. On the right, you can see the embryo, which will soon develop into a recognizable kernel. The anthers are gone and the stigma is drying up.|