Variation in seed germination inhibition of Chenopodium bonus-henricus in relation to altitude of plant growth

Abstract

Chenopodium bonus-henricus achenes have poor germination whatever the temperature; this phenomenon is reinforced with increasing elevation of seed harvest. Since the excised embryo is never dormant, germination of intact seeds is prevented by the seed coat. The seed coat thickens and contains more polyphenols with increasing elevation. This process appears to be responsible for the reduced permeability of the seed coat. High germination temperatures reduce the gas solubility in water and, at the same time, increase polyphenol oxidation in the seed coat. The embryos of seeds collected at low elevation thus receive a reduced O2 flux. When high temperature is applied to seeds from high elevation, the O2 flux is drastically reduced because of the thicker seed coat and increased levels of oxidizable polyphenols.There is a high correlation between germination and the mean of the average daily temperature for the 30 days preceding harvest, high temperature prior to harvest being correlated with high germination.Progenies of plants transferred from high to low elevation (and the inverse) show the direct influence of the new environment on the seed coat inhibition of germination.