My plant will drop old leaves occassionally. The black tips could be anything from fertilizer burn(too much), to lack of micro nutrients. It looks like you have plenty of new growth so that is a good sign. Do a close inspection of the underside of the leaves for any insects.

Thank ohiojay

I checked underside of the leaves , no insects

Burn leaves, i think i know ....maybe i put to much fertilizer ( I am a rookie , i want to get bigger tree fast.......may bad )

Yes a lot of new growth, but why the young and old leaves is like their turning the leaves close , is this normal ?
Please take a look pic no 3 ..you can see there is 1 leave is closing

thank once again