Location: Application Technology Research
Project Number: 5082-30500-001-065-A
Project Type: Cooperative Agreement
Start Date: Sep 2, 2025
End Date: Sep 1, 2026
Objective:
The overall objective will be to investigate how different environmental factors (specifically nitrogen, light intensity, carbon dioxide, and temperature) affect the sensitivity of plants to cyanobacterial (“algal”) toxins (specifically, algal extracts or purified toxin). The following hypotheses will be tested:
1. Low soil nitrogen during growth will increase toxin sensitivity.
2. High light during growth will increase toxin sensitivity.
3. High carbon dioxide during growth will decrease toxin sensitivity.
4. Heat stress during growth will increase toxin sensitivity.
Approach:
The research will be conducted as a set of factorial experiments using tomato (Solanum lycopersicum L.) cultivar ‘Early Girl’. Within each set of environmental conditions, the plants will be treated with either 1) nutrient solution, 2) broken algal cells (from toxic Anabaena or Microcystis species) in nutrient solution, or 3) pure anatoxin-a toxin in nutrient solution. For the nitrogen (N) study, plants will be grown at optimal N (5 mM nitrate, 1 mM urea, 0.5 mM ammonium) or low N (0.5 mM nitrate, 0.1 mM urea, 0.05 mM ammonium). For the light intensity study, plants will be grown at low (20% full sun) or high light (60% full sun). For the carbon dioxide (CO2) study, plants will be grown at ambient (400 ppm) or elevated (800 ppm) CO2 concentrations. For the temperature study, plants will be grown at optimal (28/22°C day/night) or heat-stress temperatures (35/29°C day/night). Treatment effects on growth, leaf photosynthesis, root respiration, and protein content of plant tissues will be assessed.