Effects of NaCl treatment on the growth of pumpkin seedlings and analy-sis of salt tolerance mechanism

SUN Mengyao; WANG Zhenxian; CHEN Xuejin; JIANG Lina; ZHOU Junguo; ZHAI Yufei

doi:10.16861/j.cnki.zggc.2025.0415

Abstract：To investigate the physiological regulatory mechanism of salt stress on pumpkin growth and development,two pumpkin lines(360-3 and 20-8)with significantly different salt tolerance were used as experimental materials.A seed-ling-stage salt stress experiment was conducted to systematically analyze their physiological response characteristics.Three NaCl treatment concentrations of 0,200,and 300 mmol·L-1 were applied to examine the effects of salt stress on seedling growth,physiological metabolism,and antioxidant enzyme activity.The results showed that with the increase of NaCl concentration,the seedling height of both lines decreased significantly,with a greater reduction observed in 20-8.The relative water content(RWC)of leaves and dry fresh mass decreased with the increase of salt concentration;However,RWC in the salt-tolerant line 360-3 remained stable and was significantly better than that of 20-8.Salt stress aggravated cell membrane damage,and the relative electrical conductivity of the two pumpkin materials increased significantly with the increase of salt concentration.In the response to antioxidant enzyme activity,under the treatment of 300 mmol·L-1 Na-Cl,the activity of superoxide dismutase,peroxidase,and catalase in 360-3 were significantly increased by 230.91％,284.72％,and 40.82％,respectively,compared with the control,which were substantially higher than 103.03％,24.96％,and 22.89％of 20-8,respectively.The hydrogen peroxide content of the two materials under 300 mmol·L-1 NaCl in-creased by 37.07％and 39.95％,respectively,indicating that salt-tolerant line 360-3 more effectively alleviates oxidative damage through its antioxidant system.In conclusion,line 360-3 exhibits stronger salt tolerance than 20-8,mainly due to its superior water retention capacity and enhanced antioxidant enzyme activity under salt stress.