Tomato plant leaves browning at tip and edges

by Teh Teong Chian
(Malaysia)

Hi,

I am planting tomato in container size 6 gallon, however noticed that one of it the leaves are turning brown at the tip and also edges. It all started from the lower leaves and some even dried up.

Weather here is hot sometimes can reach 35 c.

Would like to know what is happening and how can I save it.

Thanks!