Hi,
Again i must agree with some points Chuck has said, this tree is to deep in the little pot you've planted it in,
But that tree is screaming out "Give me what nature would"
The leaves are trying like hell to live, just look at them !!!!!!!!!!!!!
Question,
What did you have for dinner last night??????
Well i bet that tree is hungry, its not got a big enough plate to survive a dinner, its the feeding time of the year for all fruit trees/bushes etc and then in the winter they'll live off stored food, But if you starve the tree by trying to grow it in a small pot like this tree is in (have you fed it anything ?) Then the roots have no space to spread and seek the goodness in the soil,
I'll bet you if i had that apple tree you wouldnt know it in 5 yrs time,
If your really keen to save it just follow these instructions,
Apple tree planting,
Chooose a sight we're your happy the tree will have good light, space under and above the ground for the tree to grow both outwards above ground (the roots will grow as far underground as the branches will above ground)
So you want a site able to not be damaged by the tree's roots "these can effect concrete paths, foundations etc" Or the branches growing over neighbours gardens and dropping fruit/leaves in their gardens, or we're branches shade light from your own window's etc ???
Sun, Is important to fruit growth, Can your apple tree have sun light ?
Once you've decided the site for planting is ok, Now its time to give a little time and effort in getting it right in the planting,
Place the new apple tree in a container of warmish rather than freezing cold water until the rootball is submerged under the water
Your looking for air bubbles to come up to the surface, leave the tree in the water until the bubbles stop,
You'll able to see on the apple trunk were it was graffted (joined) to the wood (the nod) you want now to dig a hole deep enough and wide enough (24 inch space all the way around from the centre of the trees main branch) and the depth needs tobe deep enough to take at least 6inch of good drainage material ie builders gravel, or small stones, and added to this depth another 4 inch of soil/compost mixed with a slow fertilizer (10 to 12 inch total) and now you need the extra depth for the rootball to the nod Added to this 10 to 12 inch
When you've measured your total depth including the height from the bottom of the rootball to the (Nod) of the tree you will now have the total size of your hole that your going to dig out, (remember the nod needs tobe just above the ground !!!
Once you've dug the hole "Now drive in your stake, this is very important as while the tree is growing it has'nt made good strong anchorage yet, the roots will grow stronger as the tree grows and the tree needs a little help in hand when strong winter winds are blowing away and the tree can be rocked side to side and the tiny young roots have not yet anchord enough to hold the above ground tree in place?
Make sure the tree sits so the stake can be tied to the trees main trunk,
Now pre putting the tree in place you need to put the drainage in and tamp it down (stamp on it until its firmly in place) & ram the stake in place
Now you should see your stake in place with the drainage sorted,
Next the 4inch soil/compost/slow activated fertilizer (I use guano bird manure myself) Place all this in the hole,
Take the tree and place it near the stake and continue to fill the hole with all the rest of the soil/compost until your just under the "NOD"
water well and let the soil etc settle,
(a few hours later) the tree should have now settled, if needed add more soil/compost and tread it in all the way around the trees base until firm,
Lastly tie the tree to the stake,
Over the next few weeks keep the cleared soil area at the bottom of the tree watered.
Job done,
It is a little bit of work but who said gardening was easy ? I didnt,
But what i will say you get the rewards of fresh veg/fruit's if you do it right,
Do it wrong and you and you alone get the problems.
PS That tree's crying out for some understanding and your the one to give it

Fruit trees pay you back many many times over the years
just look at the cost of apples today? How much do you think they'll cost in 5 years from now?
Good gardening to you and yours.