Income tax on joint account

Hi, I and my wife have joint saving a/c and loan a/c. My wife used to work before 2 years back and both of us used to transfer our salary to our joint a/c. Now she is not working and If I make investment , withdrawing amount from joint a/c (only which she contributed), then income from those investment will be considered her income or will be clubbed in my income while filling tax. I am the primary a/c holder in joint a/c. Thanks Puru