A Chiang Mai University greenhouse study found that Salvinia cucullata biochar was associated with higher KAH and UGT76G1 expression, modestly lower UGT74G1, reduced stevioside, and relatively stable rebaudioside A. Plant architecture changed under selected drought conditions, but leaf area, total biomass, and root weight did not consistently improve, indicating profile modulation rather than proven yield enhancement.
Key findings
- Biochar pH was 8.83±0.09, EC 6.03±0.55 dS/m, and ash 40.57±0.80%. The biochar group had stevioside 0.03±0.01 mg/g, significantly below other groups, while rebaudioside A did not differ. KAH and UGT76G1 transcripts increased, UGT74G1 decreased modestly, and lateral-shoot and antioxidant responses varied by water condition.
Why this matters globally
Converting invasive biomass into biochar could reduce disposal burdens and create a circular amendment. Aquatic-plant biochar can have high ash and electrical conductivity, requiring salinity, element, and multi-soil assessment before scale-up.
Thai researcher contribution
Chiang Mai University's Plant Bioactive Compound Laboratory, CMUAgOmics, Multidisciplinary Research Institute, and Faculty of Agriculture collaborated with the University of Foggia to connect invasive-weed management with stevia biology.
Limitations to consider
This was a short pot study; source-to-source Salvinia variability was not tested and post-amendment soil chemistry was incomplete. Gene expression does not equal enzyme activity, and lower stevioside may not be commercially beneficial.