Effects of ultrasound and ascorbic acid treatments on the germination and physiological characteristics of aged Haloxylon ammodendron seeds

• ZHAO Tian, 
• LIU Xu, 
• ZHOU Wennan, 
• PAN Shengnan, 
• ZHANG Yujing, 
• ZHONG Yuan, 
• JIANG Wenbo, 
• WANG Quanzhen