Tax Liability on income from sell of shares

I have given my ownership Flat to my organization on " self lease basis. The lease amount cheque is being issued by office is on my wife's name who is also a joint owner of the flat. The lease amount given by organization gets reflected in my form-16 and I pay the i-tax on it. The lease amount is close to 60,000 Rs. per year. I don’t get HRA.
My wife invests the money, which she gets as a lease in shares/equities and earns short-term profit around 20000-25000 Rs every year. Hence total income is below 1lacs Rs so far.
Now I want to know (1) whether she has to pay any tax or is there any tax liability? (2) Is it necessary to file I-Tax return?

Thanks and regards