Night Temperature Affects the Growth, Metabolism, and Photosynthetic Gene Expression in Astragalus membranaceus and Codonopsis lanceolata Plug Seedlings.

Ya Liu,Byoung Ryong Jeong,Xiuxia Ren

doi:10.3390/plants8100407

Abstract

Astragalus membranaceus and Codonopsis lanceolata are two important medical herbs used in traditional Oriental medicine for preventing cancer, obesity, and inflammation. Night temperature is an important factor that influences the plug seedling quality. However, little research has focused on how the night temperature affects the growth and development of plug seedlings of these two medicinal species. In this study, uniform plug seedlings were cultivated in three environmentally controlled chambers for four weeks under three sets of day/night temperatures (25/10 °C, 25/15 °C, or 25/20 °C), the same relative humidity (75%), photoperiod (12 h), and light intensity (150 μmol·m−2·s−1 PPFD) provided by white LEDs. The results showed that night temperature had a marked influence on the growth and development of both species. The night temperature of 15 °C notably enhanced the quality of plug seedlings evidenced by the increased shoot, root, and leaf dry weights, stem diameter, and Dickson’s quality index. Moreover, a night temperature of 15 °C also stimulated and increased contents of primary and secondary metabolites, including soluble sugar, starch, total phenols and flavonoids. Furthermore, the 15 °C night temperature increased the chlorophyll content and stomatal conductance and decreased the hydrogen peroxide content. Analysis of the gene expression showed that granule-bound starch synthase (GBSS), ribulose bisphosphate carboxylase large chain (RBCL), and ferredoxin (FDX) were up-regulated when the night temperature was 15 °C. Taken together, the results suggested that 15 °C is the optimal night temperature for the growth and development of plug seedlings of A. membranaceus and C. lanceolata.

Highlights

As two important medicinal herbs in Oriental medicine, Astragalus membranaceus and Codonopsis lanceolata are mainly distributed in East Asia, especially in Korea, China, and Japan [1,2]
A. membranaceus and C. lanceolata were shaped by different night temperatures
A night temperature of 15 ◦ C greatly upgraded the quality of plugs seedlings in both species, with a higher dry weight, stem diameter, and DQI

Summary

Introduction

As two important medicinal herbs in Oriental medicine, Astragalus membranaceus and Codonopsis lanceolata are mainly distributed in East Asia, especially in Korea, China, and Japan [1,2]. It has been widely reported that the roots of these two species can be used for preventing diseases including inflammation, obesity, and cancer [3,4,5]. As a high-class vegetable, C. lanceolata has been consumed as food for several centuries, especially in ancient Korea [6,7]. New medicinal compounds continue to be reported from these two species, and their medicinal mechanisms have been demonstrating [3,8,9]. There has been little work done on the cultivation of these two species in an environmentally controlled conditions for obtaining high quality plug seedlings

Methods

Results

Discussion

Conclusion