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Ultraviolet photons (UV) can damage critical biochemical processes. Plants synthesize photo-protective pigments that absorb UV to minimize damage. Cannabinoids absorb UV, so increased UV has the potential to increase cannabinoid synthesis. Studies in the 1980’s provided some evidence for this hypothesis in low-cannabinoid cultivars, but recent studies did not find an increase in cannabinoid synthesis with increasing UV in high-cannabinoid cultivars. These studies used low UV photon fluxes, so we examined the effect of higher UV photon fluxes. We used fluorescent UV lights with 55% UV-B (280 to 314 nm) and 45% UV-A (315 to 399 nm). Treatments began three weeks after the start of short days and continued for five weeks until harvest. Established weighting factors were used to calculate the daily biologically effective UV photon flux (UV-PFDBE; 280 to 399 nm). Daily UV-PFDBE levels were 0, 0.02, 0.05, and 0.11 mol m-2 d-1 with a background daily light integral (DLI) of 30 mol m-2 d-1. This provided a ratio of daily UV-PFDBE to DLI of 41 to 218% of summer sunlight in the field. Cannabinoid concentration was 3 to 13% higher than the control in UV treated plants, but the effect was not statistically significant. Fv/Fm and flower yield were reduced only in the highest UV treatment. These data support recent literature and lead us to conclude that an elevated flux of UV photons is not an effective approach to increase cannabinoid concentration in high-cannabinoid cultivars.

Plants compete for sunlight and have evolved to perceive shade through both relative increases in the flux of far-red photons (FR; 700 to 750 nm) and decreases in the flux of all photons (intensity). These two signals interact to control stem elongation and leaf expansion. Although the interacting effects on stem elongation are well quantified, responses for leaf expansion are poorly characterized. Here we report a significant interaction between far-red fraction and total photon flux. Extended photosynthetic photon flux density (ePPFD; 400 to 750 nm) was maintained at three levels (50/100, 200 and 500 µmol m-2 s-1), each with a range of 2 to 33% FR. Increasing FR increased leaf expansion in three cultivars of lettuce at the highest ePPFD but decreased expansion at the lowest ePPFD. This interaction was attributed to differences in biomass partitioning between leaves and stems. Increased FR favored stem elongation and biomass partitioning to stems at low ePPFD and favored leaf expansion at high ePPFD. In cucumber, leaf expansion was increased with increasing percent FR under all ePPFD levels showing minimal interaction. The interactions (and lack thereof) have important implications for horticulture and warrant further study for plant ecology.

A crewed mission to and from Mars may include an exciting array of enabling biotechnologies that leverage inherent mass, power, and volume advantages over traditional abiotic approaches. In this perspective, we articulate the scientific and engineering goals and constraints, along with example systems, that guide the design of a surface biomanufactory. Extending past arguments for exploiting stand-alone elements of biology, we argue for an integrated biomanufacturing plant replete with modules for microbial in situ resource utilization, production, and recycling of food, pharmaceuticals, and biomaterials required for sustaining future intrepid astronauts. We also discuss aspirational technology trends in each of these target areas in the context of human and robotic exploration missions.

In 2017, NASA launched a five-year project to make life self-sustaining on Mars. Utah State University Botanist Bruce Bugbee was selected to find a way to grow plants in artificial mediums. “The central challenge is to grow food from recycled wastes in a small, closed system. We started with a recycling, hydroponic system and will gradually expand to include Martian soil,” said Bugbee. Students at USU’s Crop Physiology Lab are able to replicate conditions on Mars. Plants, like radishes and lettuce, are successfully growing, contributing to the main goal: make plant life possible on Mars.

In 2017, NASA launched a five-year project to make life self-sustaining on Mars. Utah State University Botanist Bruce Bugbee was selected to find a way to grow plants in artificial mediums. “The central challenge is to grow food from recycled wastes in a small, closed system. We started with a recycling, hydroponic system and will gradually expand to include Martian soil,” said Bugbee. Students at USU’s Crop Physiology Lab are able to replicate conditions on Mars. Plants, like radishes and lettuce, are successfully growing, contributing to the main goal: make plant life possible on Mars.

3 pages Provider Notes: Seminar Title: Effect of nutrient and water stress on the quantity and composition of root exudates in Axenic culture; Date: 04/08/2004; Time: 03:30 PM; Location: Room 117, Horticulture Building. Note: There is a reception in Rm. 116 at 3:10 p.m. View CV: http://milo.usu.edu/cpl/bgb/bgbcv.html. Website: http://milo.usu.edu/cpl/index.html . Potluck Dinner at Gioia Massa's Home. Date: Friday, April 9, 2004; Time: 6:30 PM; Location: Private; Parking: Third Street parking or on the street; Please bring your favorite dish!

3 pages Provider Notes: Seminar Title: Effect of nutrient and water stress on the quantity and composition of root exudates in Axenic culture; Date: 04/08/2004; Time: 03:30 PM; Location: Room 117, Horticulture Building. Note: There is a reception in Rm. 116 at 3:10 p.m. View CV: http://milo.usu.edu/cpl/bgb/bgbcv.html. Website: http://milo.usu.edu/cpl/index.html . Potluck Dinner at Gioia Massa's Home. Date: Friday, April 9, 2004; Time: 6:30 PM; Location: Private; Parking: Third Street parking or on the street; Please bring your favorite dish!