LAHORE - Former President Asif Ali Zardari on Saturday departed for Islamabad by special aircraft to attend National Assembly session.  During about one week stay in Lahore, the PPP Chairman held meetings with leaders of other political parties including Punjab Assembly Speaker Ch Parvez Elahi.  He also met PPP leaders including Makhdoom Faisal Saleh Hayat and Manzoor Ahmed Wattoo.  Leaders from other political parties including Ashiq Diyal and Zafar Hussain Luk also announced joining the PPP during separate meetings with Asif Ali Zardari.