Home favourite and second seed Zheng was thrashed by Chinese countrywoman Zhang Shuai 6-1 6-1, while Spain's Dominguez Lino, seeded third, was also beaten in straight sets, 6-0 7-6 (7/2) by Sweden's Johanna Larsson.
Johanna Konta's impressive form in Asia continued on Tuesday as she cruised into the third round.
The Sydney-born British number three reached the quarter-finals in Guangzhou last week, beating former world number 14 Shuai Peng along the way.
And she was too strong for Poland's Katarzyna Piter today in Ningbo, winning 6-1 6-1 in just 65 minutes.
Fourth seed Yvonne Meusburger of Austria avoided an upset by beating the Czech Republic's Petra Cetkovska 6-2 6-1, while there were also wins for Anabel Medina Garrigues and Anna Schmiedlova.