Lyne, Mark John (1985) The effects of inorganic nitrate solutions on dormant seeds. Doctoral thesis, Keele University.

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Abstract

The role of nitrate solutions in stimulating the germination of seeds in soil was investigated with a series of laboratory and field experiments. Comparisons were made between ruderal species from disturbed sites, calcicole species from calcareous grassland and calcifuge species from acidic heathland.
Germination tests showed that maximum germination of four
ruderal species (Artemisia vulgaris, Cardamine hirsuta, Senecio
-2 -3
vulgaris and Stellaria media) occurred in 10 M to 10 M potassium
nitrate. Twenty-two ruderal species were incubated on a thermobar,
—2
with and without 10 M nitrate, in light and darkness in eleven temperature regimes with different diurnal temperature ranges. The greatest additional germination with nitrate in many of these species occurred at the larger diurnal temperature ranges which were already stimulatory. The calcicole and calcifuge species generally failed to respond to nitrate solutions but were stimulated by alternating temperatures.
Seeds of the four ruderal species were buried outdoors for varying periods and then incubated in controlled conditions. Their response to nitrate was lost and their responses to light and alternating temperatures were reduced. Naturally buried seedbanks of soil from the three habitats, when incubated in controlled conditions, also failed to show any stimulation by nitrate.
Field experiments to test the effects of added nitrate on seedling emergence from natural seedbanks were performed in 1981 and 1982. In 1981 a nitrification inhibitor was used to control natural nitrate levels in the soil but its apparent stimulation of emergence made interpretation difficult. The only significant response to nitrate was in Poa spp., with 20% higher germination in nitrate than in water treatments. In 1982 no responses to nitrate could be isolated.
These results were discussed in terms of the possible role of nitrate in the detection of safe sites for germination and the adaptive nature of any response to nitrate by ruderal species.

Item Type: Thesis (Doctoral)
Subjects: Q Science > QH Natural history > QH301 Biology
Divisions: Faculty of Natural Sciences > School of Life Sciences
Depositing User: Lisa Bailey
Date Deposited: 10 Dec 2019 15:37
Last Modified: 10 Dec 2019 15:37
URI: https://eprints.keele.ac.uk/id/eprint/7383

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