The Electrical Conductivity of Nutrient Solution Influenced the Growth, Centellosides Content and Gene Expression of Centella asiatica in a Hydroponic System

Abstract

Centella asiatica is a herbaceous plant containing medicinal and cosmetic properties: anti-bacterial, anti-aging, memory enhancing and wound healing. The lack of information impedes the development of suitable growth conditions for C. asiatica in the hydroponic system. Maintaining proper electrical conductivity (EC) of a nutrient solution is considered crucial for plant growth and the accumulation of bioactive compounds in a plant grown in hydroponics. This study aimed to investigate an optimal EC that enhances the growth of C. asiatica and its centellosides content. Seedlings were grown in commercial nutrient solution and treated with four different strengths of EC (0.6, 1.2, 1.8 and 2.4 indicated T1, T2, T3 and T4, respectively) under controlled environment conditions. Our results demonstrate that the number of leaves, leaf area, number of runners, shoot fresh weight and shoot dry weight were significantly increased in T2 among the treatments. However, these growth parameters were lowest in T4. Furthermore, the content of asiaticoside, madecassoside, asiatic acid and madecassic acid was the highest in plants that were treated with T2. The expression of centelloside biosynthesis-related genes is also affected by the strength of the nutrient solution. A positive correlation was observed between the number of leaves, leaf area and centellosides content. This study provides valuable background on optimal EC content in the nutrient solution in a hydroponic system with enhanced centellosides content to leverage the C. asiatica production.