Effects of Plant Growth Regulators on Agronomic Traits and Tuberous Root Expansion of Rehmannia glutinosa

SU Ya'nan; TIAN Bolin; BI Guangyao; YANG Fan; DING Yining; ZHOU Yan; HUANG Yong; LI Hemin; QU Linyin; XIA Zhi

doi:10.15933/j.cnki.1004-3268.2026.03.006

Abstract：To investigate the effects of different concentrations of plant growth regulators on the agronomic traits and tuberous root expansion of Rehmannia glutinosa,the cultivar Jinjiu was used as experimental material,with an equal amount of distilled water serving as the control(CK).Four types of plant growth regulators including auxin(IAA),cytokinin(6-BA),methyl jasmonate(MeJA),and gibberellin(GA3)were applied,each at four concentration gradients(IAA:50,100,150,200 μmol/L;6-BA:20,40,60,100 mg/L;MeJA:50,100,150,200 μmol/L;GA3:50,100,150,200 mg/L).The regulators were sprayed onto the plants at the initial stage of tuberous root expansion to examine their effects on the agronomic traits,root diameter,and cross-sectional area of Rehmannia glutinosa.The results showed that after treatment with the four plant growth regulators,the agronomic traits of Rehmannia glutinosa including plant height,canopy width,leaf length,leaf width,leaf thickness,number of leaves,leaf fresh weight,leaf dry weight,number of roots,root fresh weight,and root dry weight generally increased.Specifically,IAA at 100-150 μmol/L,6-BA at 40-60 mg/L,MeJA at 100-150 μmol/L,and GA3 at 150 mg/L significantly promoted the growth and development of the Rehmannia glutinosa cultivar Jinjiu.After spraying 150 μmol/L IAA,60 mg/L 6-BA,150 μmol/L MeJA,and 150 mg/L GA3 at the early swollen stage of Rehmannia glutinosa,paraffin sectioning results showedIAA,6-BA,and MeJA treatments significantly increased the diameter and cross-sectional area of the root tuber,with an increase of 117.60%,54.53%,and 42.16%,respectively for the diameter.The cross-sectional area of the root tuber increased by 380.14%,136.61%,and 95.54%,respectively.Among them,IAA treatment had the most significant effect,while GA3 treatment significantly reduced the diameter and cross-sectional area of the root tuber,with a decrease of 35.71%and 63.29%,respectively.In summary,plant growth regulators have significant regulatory effects on the growth and tuber enlargement of Rehmannia glutinosa,among them,treatments with IAA,6-BA,and MeJA significantly increased tuber diameter and cross-sectional area,thereby promoting tuber enlargement.GA3 exhibits a concentration dependence of low promotion and high inhibition,and its usage concentration needs to be strictly controlled.