Browsing by Subject "Photosynthetic capacity"

Now showing 1 - 2 of 2

Iron partitioning and photosynthetic performance in Cannabis sativa L. reveal limitations of nanoscale zero-valent iron as a fertilizer
(2025) Büser, Christian; Hartung, Jens; Deurin, Lukas; Graeff-Hönninger, Simone
Iron (Fe) is the fourth most abundant element in the Earth’s crust but remains the third most limiting nutrient for crop productivity due to its low solubility in most soils. The emergence of nanotechnology has introduced nanoscale zero-valent iron (nZVI) as a potential Fe fertilizer with high surface reactivity and improved bioavailability. However, its comparative efficacy relative to conventional chelated Fe sources remains poorly understood. This study investigated Fe partitioning, photosynthetic efficiency, biomass accumulation, and cannabinoid synthesis in Cannabis sativa L. grown hydroponically under Fe-EDTA, nZVI, or Fe-deficient (-Fe) treatments. Total Fe concentrations were markedly reduced in -Fe plants compared with both Fe-EDTA and nZVI treatments. Despite similar root Fe contents between Fe-EDTA and nZVI, only Fe-EDTA facilitated efficient translocation to shoots, while nZVI-derived Fe predominantly accumulated in roots. Consequently, nZVI-treated plants exhibited intermediate photosynthetic performance and water-use efficiency—lower than Fe-EDTA but significantly higher than -Fe. Although Fe translocation differed substantially, inflorescence biomass and cannabinoid yield were comparable between nZVI and Fe-EDTA treatments, both exceeding those of -Fe plants. These results suggest that yield reductions under Fe deficiency arise not solely from Fe scarcity but also from the metabolic costs of Strategy I Fe acquisition, which are partially circumvented by root Fe availability from nZVI. Overall, Fe-EDTA demonstrated superior nutrient use efficiency, whereas nZVI partially alleviated Fe deficiency and revealed distinctive interactions between nanomaterials and plant Fe physiology. This study advances understanding of nZVI as an alternative Fe source in C. sativa and provides new insights into nanoparticle–plant nutrient dynamics.
Significant links between photosynthetic capacity, atmospheric CO₂ and the diversification of C₃ plants during the last 80 million years
(2024) Schweiger, Andreas H.; Schweiger, Julienne M.‐I.
Changing CO₂ concentrations will continue to affect plant growth with consequences for ecosystem functioning. The adaptive capacity of C₃ photosynthesis to changing CO₂ concentrations is, however, insufficiently investigated so far. Here, we focused on the phylogenetic dynamics of maximum carboxylation rate (Vcmax) and maximum electron transport rate (Jmax)—two key determinants of photosynthetic capacity in C₃ plants—and their relation to deep-time dynamics in species diversification, speciation and atmospheric CO₂ concentrations during the last 80 million years. We observed positive relationships between photosynthetic capacity and species diversification as well as speciation rates. We furthermore observed a shift in the relationships between photosynthetic capacity, evolutionary dynamics and prehistoric CO₂ fluctuations about 30 million years ago. From this, we deduce strong links between photosynthetic capacity and evolutionary dynamics in C₃ plants. We furthermore conclude that low CO₂ environments in prehistory might have changed adaptive processes within the C₃ photosynthetic pathway.