Fig. 1

K⁺ deficiency phenotype and relation expression of low potassium maker gene. a Phenotype comparison between HK (Sufficient potassium) and LK (Low potassium) of sweet potato seedling. Sweet potato stems were cut into 5 cm fragments and growth in plot full with vermiculite to two leaf stage. Seedlings were then treated with HK (1 mM K) and LK (0 mM K) Hoagland solution for 14 days, Bar = 2 cm. b K⁺ content measurement. Student’s t test (**P < 0.01) was used to analyze statistical significance, n = 4. c and d Relative expression of maker gene IbHAK5 and IbCIPK23 response to low-K⁺ stress, n = 4, HK-S: sufficient potassium shoot, HK-R: sufficient potassium root, LK-S: low potassium shoot, LK-R: low potassium root