Influence of Pressure on Germination of Garden Cress, Leaf Mustard, and Radish Seeds at Various Temperatures

Abstract

The effects of hydrostatic pressure (0.1 - 400 MPa) and temperature (4°C, 25°C, and 35°C) on the germination of three types of seeds (garden cress, leaf mustard, and radish) were studied. The normal germination rate of the three types of seeds was decreased at high hydrostatic pressure, and germination time tended to be delayed. Pressure and temperature had two types of effects on seed germination. Germination of garden cress and leaf mustard seeds was more resistant to pressure at lower temperature. Conversely, germination of radish seeds was most pressure-sensitive at low temperature, and germination drastically decreased with treatment at 50 MPa and 4°C. Generally, pressure and temperature effects on protein structure and enzyme activity have been classified into two types, “hillside”-like (pressurization decreases the stable temperature range) and “tongue”-like (stabilizing effect of moderate pressure against heat denaturation). Therefore, the type of temperature-pressure effects on germination of garden cress and leaf mustard seeds is classified as “hillside”-like and that of radish seeds is classified as “tongue”-like, similarly to the generally observed effects on protein denaturation.