What would be the effect of providing the experimental plants with a normal gas composition for one week, but at one-tenth the normal atmospheric pressure?

A series of experiments was run in order to determine the effects of various gases on the growth processes of plants. Each plant was cultured until fully grown in a soil containing an excellent balance of both macro- and micronutrients, and the soil was laden with adequate mycorrhizae culture. After this maturation growth phase, the plants were sealed in separate gas chambers into which a single gas was introduced to replace the normal atmospheric composition. The plants were then given adequate water provisions and observed compared to controls grown under normal atmospheric conditions.