The Illuminating Science of Mint: How Far-Red and Ultraviolet-A Light Shape Growth and Metabolism

In Brief

This research reveals how far-red and ultraviolet-A light influence the growth, photosynthesis, and secondary metabolism of mint, uncovering strategies to enhance plant productivity and bioactive compound synthesis through tailored light treatments.

In Depth

Light Matters More Than You Think!

In a groundbreaking study, researchers explored the impacts of far-red (FR) and ultraviolet-A (UVA) light on mint (Mentha haplocalyx Briq.). Using specialized LED light treatments, they uncovered how light spectrum manipulations could revolutionize plant growth and secondary metabolite production. Let’s dive into the details and imagine future applications!

Key Findings

1. Far-Red Light Boosts Growth

• Bigger Plants: Mint exposed to FR light grew taller and wider compared to standard red-blue light (RB) or RB+UVA treatments. Plant height was up by 45.5%, and plant width expanded by 13.07%.
• More Biomass: FR-treated mint saw increases in both shoot and root fresh weights by about 40%!

2. UVA: Minimal Impact on Size, Big Impact on Metabolism

While UVA didn’t significantly influence physical growth, it enriched certain secondary metabolic pathways, demonstrating its nuanced role in mint physiology.

3. Photosynthesis Enhancement

FR light improved the photosynthetic rate (Pn), effective quantum yield, and overall photosynthesis efficiency. Mint plants under FR light better optimized light capture, increasing their energy efficiency.

The Science Behind the Magic

Transcriptomic and Metabolomic Insights

1. FR Treatment Highlights:
   • Gene Upregulation: Increased activity in pathways related to hormone signaling, flavonoid biosynthesis, and phenylpropanoid biosynthesis.
   • Metabolic Changes: Greater production of beneficial compounds like luteolin (antioxidant) and methylchavicol (antibacterial).
2. UVA Treatment Highlights:
   • Moderate increase in metabolite diversity, notably glucosinolates and specific flavonoids, offering antioxidant and defense properties.

Real-World Applications

1. Agriculture and Horticulture
   • FR light can boost yield in aromatic and medicinal crops like mint, making them more productive for culinary, cosmetic, and pharmaceutical uses.
2. Health Benefits
   • Enhanced secondary metabolites mean stronger antibacterial and antioxidant properties, potentially leading to high-value plant-based health products.
3. Controlled Environment Agriculture (CEA)
   • Customizable lighting in plant factories can optimize both growth and the desired bioactive compounds for sustainable farming.

Future Prospects

The study opens exciting doors:

• Further refining light spectrum recipes for different crops and outcomes.
• Combining FR and UVA light for synergistic effects.
• Scaling these findings to larger systems, from greenhouses to urban vertical farms.

The potential for tailoring light environments to grow plants with precise traits is a step toward smarter, more sustainable agriculture.

In Terms

Far-Red Light (FR): A type of light just beyond the red spectrum that plants can "see," known for boosting growth and elongating stems.

Ultraviolet-A (UVA): A type of ultraviolet light with longer wavelengths that influences plant metabolism and defense mechanisms.

Photosynthesis: The magical process where plants turn light into energy, fueling their growth and survival.

Flavonoids: Natural compounds in plants that act as antioxidants and give them their protective superpowers.

Phenylpropanoids: A group of plant compounds important for structure and defense, often tied to aroma and flavor.

Transcriptome: A snapshot of all the genes a plant is using at any moment, like a playlist of its current activities.

Metabolome: All the tiny molecules (like sugars and flavonoids) a plant is making to grow, survive, or defend itself.

Source

Yu, L.; Bu, L.; Li, D.; Zhu, K.; Zhang, Y.; Wu, S.; Chang, L.; Ding, X.; Jiang, Y. Effects of Far-Red Light and Ultraviolet Light-A on Growth, Photosynthesis, Transcriptome, and Metabolome of Mint (Mentha haplocalyx Briq.). Plants 2024, 13, 3495. https://doi.org/10.3390/plants13243495

From: Shanghai Institute of Technology; Shanghai Academy of Agricultural Sciences; Shanghai Sunqiaoyijia Tech-Agriculture Co., Ltd.; Shanghai Jiao Tong University.