The Relationship of Temperature to Plant Morphology of Lesquerella

Abstract

There is a lack of information regarding the impact of temperature on yield‐related traits for lesquerella [Physaria fendleri (Gray)], a new crop with potential as a biofuel or bioproduct because of the high content of seed hydroxyl fatty acids. Here we determined the effect of four temperature regimes on plant branching, dry matter production, and reproductive growth in two controlled‐environment experiments. The night/day temperature treatments were (1) 4.4/12.8°C, (2) 12.8/21.1°C, (3) 21.1/29.4°C, and (4) 29.4/37.8°C. Plant branch number, biomass, and reproductive development were greatly suppressed by the coolest and warmest temperature treatments. Biomass and branch production were similar for Treatments 2 and 3, but reproductive development and was increased in Treatment 2. Treatment 2 led to more branches with reproductive structures and more buds and flowers than Treatment 3. Plants moved from the coolest treatment (1) to Treatment 2 temperature at 45 days after planting exhibited accelerated branching and production of dry matter, buds, and flowers, whereas transfer from Treatment 1 to Treatment 3 led to enhanced silique production. These results suggest that moving from a cold to a warmer temperature enhanced both biomass production and reproductive development. In addition to documenting the temperature impact on growth and reproductive development of lesquerella, the results provide evidence pertinent to defining growing regions suitable for cultivation of this new crop.