how a wheat plant grows is the subject to this video
the information presented with applied wheat production throughout the United
States and even the world
with a couple of minor exceptions first of all we will be discussing
winter wheat which requires fertilization spring wheat
would not require that fertilization second we'll be discussing
wheat grown for both forage and for grain
this requires that the farmer plant earlier
using higher seeding rates and would expect to get more forage production in
the fall
then he would if they were growing the wheat for grain only so let's see how
wheat plant grows
every farmer hopes to have a nice looking wheat field like this
there's a lot that goes into producing a good crop of wheat
first of all there are many management decisions a farmer has to make and then
he has to depend on the weather to cooperate two particular events have
sparked my interest in developing this video
first of all many producers have had difficulty determining when
the wheat is at growth stage eight to nine which is the
time that's appropriate for application of the most popular foliar fungicide
that's being used in Oklahoma right now
and then second i've learned that many people have trouble determining
when the wheat plant has begun to join and it's important
for wheat producers to be able to identify when wheat begins to join
because it's at that time that they need to make a decision on whether they're
gonna pull cattle off wheat pasture
to get both maximum raising potential
and maximum grain yield
we're looking at different stages of
seed germination here and we'll start with just looking at a seed
and the two important parts of the seed are the major part of
the seed which is the endosperm
then if we look real close right at the very tip
we see just a little bump
that basically represents the embryo
or the little seed lining within the seed
the embryo as we see in this diagram
contains a miniature wheat seedling including the coleoptile
several leaves the shoot apex
radicle and the root cap now if we look at our whole diagram of the wheat seed
we can see that each of these parts in the embryo
is so small that generally we think that the seed is only containing the embryo
and the endosperm and then
these are seeds that have been soaking in water for
about 12 hours you notice that
its the same seed we started with only they've swelled considerably
and if you look real close on this one the embryo
has started to
just started to break through the surface of the seed coat
within 12 hours or certainly by 18 hours usually that embryo
has already started to grow the
first thing to emerge as the seed begins to germinate
is the radicle the radicle as part of the route that usually goes straight
down
and then soon after it emerges the
two lateral branches off the radicle are
adventitious roots their still part in the primary root system
well form
and then a little bit later on the coleoptile will begin to grow
within this coleoptile we have the young
the first young leaf its just beginning to grow also
the coleoptile
is a protective coating over those leaves
and protects the new leaves as the
plant makes its way up through the soil till it gets to the soil surface
when the coleoptile reaches the cell surface
it quits growing and the first leaf will break through the tip of the
coleoptile
recently it's been discovered that as the soil temperature increases
the maximum length at the coleoptile will grow to
decreases for example
as we dig here we discover three seeds were placed nearly three inches deep
in the soil
and the coleoptiles reach the soil surface this wheat was placed in soil
that was 75 degrees Fahrenheit or cooler and another example
we look at wheat that was planted in soils there with a
temperature was approximately 100 degrees Fahrenheit even though the seeds
were planted about one and a half inches deep the call the coleoptile only grew
to three quarters of an inch
never reaching the soil surface when this happens
the first leaf grows through the tip of the coleoptile
while it is still below the soil surface generally
this leaf will not reach the soil surface this is especially true
if there's been a rain between planting and the time emergence occurs
when the coleoptile doesn't reach the soil surface
we get plants that one of my students calls appropriately
yellow accordion leave plants and you can see in this
picture why he calls on that
the seedling stage begins
as the first leaf emerges from the soil and that it adds
as the first till herb against the merge from the leaf actuals
we'll first look at a two leaf plant we'll see how systematically the leaves and
till herbs emerge
the seed was attached right here
and then coleoptide grew up in an
first leaf coming out from where the coleoptide was so this is the first leaf
which is fully expanded and then secondly
is emerging now its only about half a mid-size
if we take a closer look at a leaf
we can learn more about what it really is made of
so we'll take this leaf off and look at a close-up when we think about
wheat leaf
we usually think just in this flat blade part
that
it grows away from the plant as it grows
but a leaf really is made up a combination of the leaf blade
and the leaf sheath the leaf sheath
was the part that we just pulled off from around the tiller there's a
area where the leaf blade joins the leaf sheath called the leave power
and as we watch a leaf grow more we can tell when it's fully expanded
by looking for this leaf power area but that leaf power hasn't
appeared yet that leafs not fully expanded
during the ceiling stage the primary root system continues to develop
the entire primary root system results from branching
in growth in length the radical in the two branches from the radical
which occurred early during germination group from the primary root system can
grow as deep as 4 feet into the soil
that's forming quite an extensive root system
we start with the seed right here and then first thing that was emerged is
coleoptile and this is what's left that
was the coleoptile at one time
this was the first leaf coming up over here
and the second leaf is on the opposite side of the plant and that's this one
this particular plant third ones over here you notice they're on opposite side
first one being on the left side of the plant the second one on the right
third one on the left again and then you've got the fourth leaf
that's partially emerging again
then out of the leaf axle
this leaf was around it
was looked like this one did before this tiller came off
but out of this leaf axle from the first leaf is where the first tiller
appeared in this is the beginning of the first tiller
if we plant the wheat deep enough
in the inner no develops between the seed and the crown
which is called him as a cattle or some town is referred to as the sub crown
internal the remnant at the seed is located here
and then we got them as a cattle which is near no
between the seed remnant and the crown
in here we get the crown with the crown roots in the tillers attached and you
see here there are several
crown Ridge the massacre at all does separate
the primary root system from the crown root system
crown roots all come off in the crown
grow from a crown
the tillering stage began as the first tiller emerges from the
leaf axle and it ends as the plant begins to join
the first tiller usually emerges when the plant has three to four leaves on it
tiller, wheat plant or any grass is just a branch
so it's instead of calling it a branch we call it a tiller
this tiller is attached all the way down here on what we call the crown
you now pullback this first leaf so
try not to disturb the plant enough that we can see
it is as i pull all the way back you can see
now that that for tiller's attached all the way down here the base
all the tillers that will be a
that will occur on this plant will all come from down here
it what we call the crown on the plant as a tiller grows from the crown
it is protected by a structure similar to the coleoptile that's called
the profill
once the profill gets up to the
where the leaf sheath ends and its hits light
it stops growing and the first leaf emerges from that tiller
the leaf profill that is the protective covering that
protected the the first leaf of this tiller is it was growing up through the
leaf sheath
and the prophyll looks like it stops right about here
in the remainder is this tip is the new leaf that is just broken through the
prophyll
and will now expand produce a full leaf
occasionally we have a plant
which has a tiller which originates from the No
where the seed was attached rather than at the Crown
such a tiller is called the coleoptile
tiller this is a plant where the seed had been attached
right here is the seed
has fallen off but you'll notice that it does have a tiller
that is attached to that point
and again in this picture if you look real carefully you can see that
the node did be do you know that's between where the seat was attention with the
crown was
right here wide area that shows the room and
you notice that all the rest of the tillers are attached at this point the
at the crown
i'll go ahead and pull off this coloptide tiller and pull of each of the other tillers
and demonstrate where they were attached so lets get the coptide tiller
out of the way
this is the main stem here so all the rest of these tillers branched off from
the main stem
as you get rid of those you'll notice that
yes it works better board is working
they're attached right down at the crown at the first one
this one breaking off right now near were looks like where the roots come out
here we have another leaf in the tiller pretty young tiller thats in it
its that leaf axle and and we pull that on back we find out again
it's attached right down there at the Crown
we'll go ahead and pull that one off and if I'm lucky we'll just play games and see if
there's another tiller inside this leaf
so if we pull it back and we go all the way down yet sure enough
pull it off and we'll see
right down here the very base
there's a real small tiller that's just started to expand
here we've got a plant with has 1 tiller located right here
and four to five leaves on it
and you see here the crown roots that have just started the form that little
knobs on both sides and then there's one
back behind in this plant we've got the
crown roots that are two-and-a-half three inches long
there are three of them and it you look real close right here you can see the
little nubs were there some more that are starting to grow
and then we got on this plant two tillers the first one
it was easy to see in in one right in here that's not so easy to see
and this plant we've got a couple tiller's
this be in the second one right here in its fairly small
now here you can see the primary root system
and we can even see the seagrams net it's still there
in on this one we've got one at the Crown roots that
a couple of inches long and it's grown now but we've also got these two short
pieces that are just knobs with the crown which tried to grow out they had
either dry soil or
compacted soil and quit growing and these
roots will not begin to grow again until you've got rain or something that
alleviates whatever preventative from growing initially