Effects of GA₃ on growth and secondary metabolite content in ramie

To study the changes of plant hormone gibberellin A3 (GA₃) spraying on the agronomic traits of different ramie (Boehmeria nivea) germplasm traits and the contents of chlorogenic acid, flavonoids, and lignin in different organs, and to screen out the germplasm resources of fiber ramie with low lignin content, high fiber quality and high functional component content was examined under hormone control. In this experiment, 10 ramie germplasms were used as test materials. No gibberellin spray (distilled water was sprayed at the same time) was used as the control group, spraying 50 mg·L⁻¹. GA₃ was the treatment group. The results showed that: 1) After spraying 50 mg·L⁻¹ GA₃, the total fresh weight yield of ‘Sunxin’ ‘Zhongzhu No.1’ and ‘Dr Zhou sterile lines’ increased by 18.79%, 26.86%, and 10.41%, respectively. The total dry weight yield increased by 40.20%, 6.25%, and 31.50%, respectively. After spraying 50 mg·L⁻¹ GA₃, compared with the control, the contents of chlorogenic acid and flavonoids in the ramie leaves of ‘Houpizhong No.1’ and ramie sticks of ‘B’ increased. Chlorogenic acid increased by 15.87% and 44.79%, and flavonoids increased by 22.59% and 32.12%, respectively. Among them, the chlorogenic acid content of ramie sticks in nine ramie germplasms was increased by 5.93%～74.29% compared to the control. Compared to the control, the lignin content of ‘B,’ ‘Houpizhong No.1’, and ‘Zhongzhu No.1’ decreased by 0.55%, 2.54%, and 1.67%, respectively. Compared with the control, the lignin content of ramie leaves in ‘Hongpi Xiaoma’ ‘Kunchi No.1’ ‘Xiangsixianjianyong ramie No.1’ and ‘Dr Zhou sterile lines’ decreased by 4.04%, 1.87%, 4.25%, and 1.01%, respectively. Different ramie germplasm showed different responses to GA₃ regulation. Therefore, appropriate regulation methods should be selected according to the requirements when selecting ramie germplasm. 50 mg·L⁻¹ GA₃ treatment was more suitable for increasing production of ‘Sunxin’, ‘Zhongzhu No.1’, and ‘Dr Zhou sterile lines’, and contributed to accumulating secondary metabolites of ‘B’.