Speaker
Description
Cultivating duckweed (Lemnaceae) on livestock wastewater represents a leading strategy for the circular bioeconomy, particularly relevant in Campania (Italy), where about 80% of the national buffalo herd is concentrated and where sustainable wastewater management is a priority challenge.
Several image analysis techniques are now available to calculate the relative growth rate (RGR) of these macrophytes, ranging from classic RGB imaging to more sophisticated chlorophyll fluorimetry-based approaches, yet a systematic comparison of their reliability is still lacking, particularly under physiological stress. In this work, Lemna minuta (clone LER035) was grown on ozonated buffalo wastewater at different total ammoniacal nitrogen (TAN) concentrations, and RGR was calculated using three imaging methods — RGB camera, light-adapted PAM fluorimetry, and dark-adapted PAM fluorimetry — to compare their agreement.
Among the treatments showing a positive RGR, the treatment based on centrifuged digestate at low nitrogen concentration (50 mg L⁻¹ TAN, DC_low) was the only one to outperform the control (0.343 vs. 0.307 day⁻¹). Overall, light-adapted PAM and RGB showed a high, robust correlation (ρ = 0.988), confirmed when separately analyzing the positive-RGR (ρ = 0.980) and negative-RGR (ρ = 0.916) subgroups. Under stress, however, the two methods were not numerically interchangeable, with divergence ranging from negligible in healthy treatments to marked (+0.141 on average) in stressed ones.
The RGB method therefore remains valid for RGR determination; however, PAM technology detects stress well ahead of RGB, identifying growth decline approximately 4 days earlier in 81% of stressed replicates and capturing impaired photosynthetic efficiency before visible tissue disintegration.
Keywords
Lemnaceae; Image analysis; PAM; RGR
References
No reference
| Corresponding author email | alberto.giuliano@unina.it |
|---|---|
| Scientific Session | Applications |
