Light Penetration and Light-induced Seed Germination in Soil

Light Penetration and Light-induced Seed Germination in Soil.

Light penetration through a Drummer silty clay loam and a Broomfield sand was measured spectrophotometrically and biologically. The spectrophotometric measurements showed that less than 1% of the incident light penetrated 2.2 millimeters at any wavelength between 350 and 780 nanometers for ped sizes up to 1 millimeter. Biological measurements with light-sensitive lettuce (Lactuca sativa) seeds ...

Interactions of light and a temperature shift on seed germination.

Germination of Rumex obtusifolius L. seeds is potentiated to an observable degree in 2 minutes by a single shift in temperature from 20 to 35 C. Half-maximal potentiation requires less than 32 minutes at the higher temperature. Similar sensitivities to shifts in temperature were observed for seeds of Barbarea vulgaris, R.Br. B. verna (Mill.) Asch., and Lepidium virginicum L. A shift in temperat...

Use of light in seed potato storage

Effect of light and temperature on seed germination in Tibouchina mutabilis (Vell.) Cogn. (Melastomataceae)

The effect of light and temperature on Tibouchina mutabilis seed germination was analyzed by isothermic incubations in the range of 10 to 40 °C, with 5 °C intervals under both continuous white light (32.85 molms) and darkness and alternating temperatures (15-20; 15-25; 15-30; 15-35; 20-25; 20-30; 20-35; 25-30; 25-35 and 30-35 °C) under both photoperiod of 12 hours and continuous darkness. The s...

Comparison of light-regulated seed germination in Ficus spp. and Cecropia obtusifolia: ecological implications.

The major components of annual seed deposition in the rain forest at Los Tuxtlas, Veracruz, México are seeds of the pioneer tree species Cecropia obtusifolia and those of some species of Ficus. Cecropia obtusifolia Bertol. forms a relatively persistent viable soil seed bank, whereas seeds of Ficus are seldom found in the soil. Both genera require light for seed germination; however, the species...