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Full-Text Articles in Life Sciences

Saturating Growth Rate Against Phosphorus Concentration Explained By Macromolecular Allocation, Gabrielle Armin, Jongsun Kim, Keisuke Inomura Aug 2023

Saturating Growth Rate Against Phosphorus Concentration Explained By Macromolecular Allocation, Gabrielle Armin, Jongsun Kim, Keisuke Inomura

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

The saturating relationship between phytoplankton growth rate and environmental nutrient concentration has been widely observed, yet the mechanisms behind the relationship remain elusive. Here, we use a mechanistic model of phytoplankton and show that the saturating relationship between growth rate and phosphorous concentration can be interpreted by intracellular macromolecular allocation. At low nutrient levels, the diffusive nutrient transport linearly increases with the phosphorous concentration, while the internal phosphorous requirement increases with the growth rate, leading to a non-linear increase in the growth rate with phosphorous. This increased phosphorous requirement is due to the increased allocation to biosynthetic and photosynthetic molecules. …


Saturating Relationship Between Phytoplankton Growth Rate And Nutrient Concentration Explained By Macromolecular Allocation, Jongsun Kim, Gabrielle Armin, Keisuke Inomura Jan 2022

Saturating Relationship Between Phytoplankton Growth Rate And Nutrient Concentration Explained By Macromolecular Allocation, Jongsun Kim, Gabrielle Armin, Keisuke Inomura

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Phytoplankton account for about a half of photosynthesis in the world, making them a key player in the ecological and biogeochemical systems. One of the key traits of phytoplankton is their growth rate because it indicates their productivity and affects their competitive capability. The saturating relationship between phytoplankton growth rate and environmental nutrient concentration has been widely observed yet the mechanisms behind the relationship remain elusive. Here we use a mechanistic model and metadata of phytoplankton to show that the saturating relationship between growth rate and nitrate concentration can be interpreted by intracellular macromolecular allocation. At low nitrate levels, the …


Roles Of Intra-Fruit Oxygen And Carbon Dioxide In Controlling Pepper (Capsicum Annuum L.) Seed Development And Storage Reserve Deposition, J. Blasiak, Anxiu Kuang, Chakavak S. Farghangi, M. E. Musgrave Jan 2006

Roles Of Intra-Fruit Oxygen And Carbon Dioxide In Controlling Pepper (Capsicum Annuum L.) Seed Development And Storage Reserve Deposition, J. Blasiak, Anxiu Kuang, Chakavak S. Farghangi, M. E. Musgrave

Biology Faculty Publications and Presentations

Seeds developing within a locular space inside hollow fruit experience chronic exposure to a unique gaseous environment. Using two pepper cultivars, `Triton' (sweet) and `PI 140367' (hot), we investigated how the development of seeds is affected by the gases surrounding them. The atmospheric composition of the seed environment was characterized during development by analysis of samples withdrawn from the fruit locule with a gas-tight syringe. As seed weight plateaued during development, the seed environment reached its lowest O2 concentration (19%) and highest CO2 concentration (3%). We experimentally manipulated the seed environment by passing different humidified gas mixtures through the fruit …