Soil water thresholds for photoinduction of redroot pigweed germination

摘要: Perception of light by phytochrome is a mechanism that triggers weed seed germination in response to soil disturbance. Photoconversion from the red absorbing form active far-red depends on hydration phytochrome. This research was conducted determine water threshold for photoinduction brief exposure occurs during disturbance, and how this affected fluence stimulus sensitivity population. Redroot pigweed seedling emergence (R) studied range potentials. Water potential gradients were established incubating seeds soils wetted various contents, or polyethylene glycol 8000 (PEG) solutions. After imposing treatments, returned fully hydrated state. Seedling R increased as volumetric content (0v) increased. At contents 4.0%, R-induced inhibited 50% compared photoinduced at highest tested. Attenuation more pronounced low vs. high fluences freshly imbibed seeds, but unaffected exhibited enhanced sensitivity. In ecosystems where seasonal moisture extremes are prevalent, may be limited dry microsites such surface crusts under extreme drought conditions.