Magnesium Plus Hydrogen Fertilization Enhances Mg Uptake, Growth Performance and Monoterpenoid Indole Alkaloid Biosynthesis in Catharanthus roseus

TL;DR

Adding magnesium and hydrogen fertilizers improves plant growth and production of important alkaloids in Catharanthus roseus.

Contribution

This study explores the combined use of magnesium and hydrogen fertilizers in Catharanthus roseus for the first time.

Findings

MgH2 and MgP fertilizers significantly increased plant weight by 60% and 29% compared to the control.

MgH2 and MgP led to higher Mg content, chlorophyll content, plant height, and weight than other fertilizers.

MgH2 resulted in the highest levels of catharanthine, vindoline, and ajmalicine compared to the control.

Abstract

Magnesium and hydrogen fertilization have been reported to contribute to plant growth and metabolite production. Simultaneous fertilization of magnesium and hydrogen is a promising strategy for plant development and secondary metabolism, but remains unexplored in Catharanthus roseus (L.) G.Don, which produces varieties of monoterpenoid indole alkaloids (MIAs). This study conducted a glasshouse experiment comprising five treatments: MgO, MgSO4, MgH2, magnesium powder (MgP), and the control, to investigate and compare the effects of Mg fertilizers and Mg plus H2 fertilizers on soil pH, Mg uptake, seed germination, plant growth, and MIA biosynthesis in C. roseus. Application of MgH2, MgP, and MgO fertilizers significantly raised soil pH to 6.14~6.38. MgH2 and MgP fertilization significantly increased plant weight by 60% and 29% over the control, respectively. MgH2 and MgP produced greater increases in Mg content, chlorophyll content, plant height, and weight than MgO and MgSO4. Four fertilizers up-regulated the expression of most MIA biosynthetic genes, especially those in the vindoline pathway. Among them, MgH2 yielded the highest contents of catharanthine, vindoline, and ajmalicine, reaching 167%, 149% and 517% of the control, respectively. Pearson correlation analysis showed significant positive correlations among H2 release, soil pH, and Mg uptake, as well as with plant growth and MIA content. These findings suggest that Mg plus H2 fertilizers released H2 and increased soil pH to promote Mg uptake, chlorophyll contents, plant growth, and MIA production in C. roseus, highlighting the potential of MgH2 and Mg powder as innovative fertilizers to enhance alkaloid yields in medicinal plants.

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