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| April 5 | |
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With the good moisture and warm temperatures the wheat continues to grow. You can see our area is improving and you can barely see the soil surface. It has a good green color that indicates it isn’t lacking nitrogen fertilizer. Early Tuesday morning the temperature was down to 25 F and it was colder other places around the state. Farmers were concerned their wheat might be damaged by the cold. There doesn’t appear to be any freeze damage. Temperatures have to be much colder to cause severe damage at this stage of growth. |
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The wheat is almost as tall as the red flags. It has grown several more inches since our last visit. It might be hard to find the flags next time. |
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We are still trying to find the first joint or node, which tells us the growing point is well above the soil surface. If you look at the large tillers on the left, center, and right, you can see a node about three inches up from the roots on each of those three tillers. Do you see the enlarged or swollen part of the stem? That’s the node. Let’s look closer. |
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This is one of the large tillers and you can see the node (at the 3 ½ mark on the ruler). I measured from the roots, so this node is about three inches above the soil surface. It reminds me of a knee or elbow joint. Now, we will start looking for the second node. |
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I cut a smaller stem without a joint or node to find the growing point and found it about an 1 ½ inches above the soil surface. Notice how small the growing point or head is. Look at the next picture. |
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This is the growing point at the time the first node is being formed. You can always find the growing point just above the node. This head is slightly bigger than the previous one because it is further up the stem. |
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This growing point is starting to look more like a wheat head. It is
bigger than the previous two. This head is about two inches above the first node. The
second node on the stem hasn’t formed yet, but it is about to become visible. As you
will see in the next few weeks, the growing point or head gets bigger and bigger as it
moves up the stem. Am I confusing you how nodes or joints are formed on the stem? Generally, a wheat stem or tiller will have three or four nodes or joints. These nodes are packed together with the growing point sitting on top of the nodes as it moves up the stem away from the roots. As the growing point moves up inside the stem, the bottom node will stop and the rest of them will continue to move up the stem. The next node will stop and the growing point will keep moving upward. This will continue until the wheat head emerges from the stem. Now, if you look at the extreme right side of this picture you will see a hollow section of the stem. This is called the internode (the section of the stem between two nodes). The first node is out of the picture to the right, so you can’t see it, but you can see where the second node is right now. The second node is the green area just to the left the hollow section or internode, but before you get to the white area. What’s the white area? The white area will be the next internode section and it will elongate pushing the growing point upward. The third node is a small, green area just to the left of the white internode section. Moving further left you can see a small, whitish-green area, which is another internode section and there will be a fourth node, I believe, just to the left of that internode. Then you have the wheat head. Pretty neat, huh? Does that explanation help? |
   
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