Effect of temperature and seedling cultivation period on the quality of plug seedlings of four medicinal plant

Abstract

In this study, we aimed to investigate the appropriate temperature for the greenhouse and seedling cultivation period (SCP) of four medicinal plants [lance asiabell (Codonopsis lanceolata), balloon flower (Platycodon grandiflorum), Korean angelica (Angelica gigas), and Chinese foxglove (Rehmannia glutinosa)] on their transplanting date. Seedling growth was evaluated according to the target transplanting dates (lance asiabell and ballon flower: April, May, June, October, November, and December; Korean angelica: April, May, June, July, and August; and Chinese foxglove: May, June, July, and August). The SCPs of the lance asiabell and balloon flower were set at 45, 60, or 75 days. The SCP of Korean angelica was set at 45, 60, 75, or 90 days, and that of Chinese foxgloves was set at 20, 30, 40, or 50 days. All seeds and rhizomes were sown in a medium-filled 50-cell plug tray. The emergence rates were significantly higher when the daily mean temperatures in the greenhouse were 18-30, 18-25, 18-22, and 30-34 degrees C for lance asiabell, balloon flower, Korean angelica, and Chinese foxglove, respectively. The lance asiabell and balloon flower exhibited enhanced seedling quality with SCPs and temperatures of 75 and 60 days, and 25.1 +/- 3.0 and 24.4 +/- 3.6 degrees C, respectively. Korean angelica required an SCP of 75 days at a temperature of 22.1 +/- 1.9 degrees C. Chinese foxgloves required an SCP of 40 days at a temperature of 32.2 +/- 1.8 degrees C. Our results provide data for the future production of basic medicinal plant seedlings.