Effects of NaCi stress on germination characteristics of safflower seeds
Salt is an important factor affecting seed germination and growth.To investigate the effect of NaCl stress on safflower seed germination and growth,different varieties of safflower seeds were treated with 0,0.2%,0.4%,0.6%and 0.8%NaCl solution.The germination rate,germination potential,relative germination rate,relative germination potential,root length,bud length,dry weight and fresh weight of the tested seeds were measured under salt stress.Thetoler-ance of 7 safflower varieties to salt stress during seed germination was compared and analyzed.The results indicate that the germination rate,germination potential,relative germination rate and relative germination potential of 7 safflower vari-eties show a downward trend under salt stress.When the salt concentration is less than or equal to 0.4%,the four indica-tors of 3-10 and Yunnan safflower seeds are all above 89.44%,and the viability of the seeds are strong.The vitality of Xinjiang safflower seed is significantly lower than that of the other six varieties.The relative salt damage rate of safflower seed germination in Xinjiang is the highest under salt stress.When the salt concentration is equal to or greater than 0.4%,the relative salt damage rate is above 50%.While the relative salt damage rates of the 3-10,BH-1,H-7,Sichuan saf-flower and Yunnan safflower range from-2.34%to 3.91%,and the safflower seeds are less damaged.The root length and bud length of 3-10 and H-7 safflower varieties are superior to other varieties at a salt concentration of 0.4%.When the salt concentration is equal to or greater than 0.6%,BH-1 shows a stronger salt tolerance in root length and bud length compared with other varieties.The fresh weights of seven safflower varieties show an overall decreasing trend under salt stress.And under the same treatment,the fresh weight of Xinjiang safflower is lower than that of other varieties.Under 0.2%salt treatment,the fresh weight of H-7 and Sichuan safflower are 2.83 g and 2.90 g,respectively,with no significant difference from the control,and higher than that of other varieties under the same concentration.The fresh weight of BH-1 under 0.8%salt treatment is higher than that of other varieties under the same concentration.Compared with fresh weight,salt stress has less inhibitory effect on dry weight of safflower seedlings,and even promotes dry matter accumula-tion.By comprehensive comparison,during the seed germination of the seven safflower varieties,the local safflower 3-10,BH-1,and Yingju safflower from Xinxiang,Henan,as well as Yunnan safflower,have strong salt toler-ance,and Xinjiang safflower has the weakest tolerance.