Seasonal and site relationships to acetylene reduction by actinorhizal black alder and Russian olive root nodules

Acetylene-reduction activities (ARA) by root nodules of 4- to 8-year-old black alder (Alnus glutinosa (L.) Gaertn.) on an upland Alfisol and alder and Russian olive (Elaeagnus angustifolia L.) on a bottomland Mollisol increased exponentially with soil temperature. Soil moisture content, pH and nitrogen concentration and leaf nitrogen concentration were not correlated with ARA. Soil pH and nitrogen concentration did not change with season. Bottomland soil pH was less under alder than under Russian olive. Alder ARA began about 2 weeks after bud break. Initiation of Russian olive ARA coincided with bud break. Alder ARA midday rates of 15 to 20 umoles C$\sb2$H$\sb4$/ (gram dry nodule$\cdot$hour) occurred for about 150 days. The length of the Russian olive ARA season was similar, but the rates were about 50% of the alder rates. ARA rates began declining about 9 weeks before a severe frost killed most of the foliage in November. No hydrogen evolution was detected from any nodules. Site did not affect leaf nitrogen concentration for either species. Alder leaves declined 16% in leaf nitrogen concentration prior to senescence. Russian olive nodule and leaf nitrogen concentrations were greater than those for alder and increased slightly in the fall. Nodule nitrogen concentration changed during the season for both species. Alder nodule nitrogen concentration was not affected by site, but was negatively correlated with soil moisture. Nodulation of Russian olive on the acidic upland was poor to nonexistent and Russian olive nodule senescence was high on the neutral bottomland. Soil nitrogen concentration in the top 15 cm of soil did not differ by site, species or season. Surface soil collected from both soils under both species produced effective nodules on 4- to 10-month-old seedlings of both species. In agreement with field nodulation findings, greenhouse-grown Russian olive seedlings nodulated best in both bottomland soils and did so more readily than alder. Russian olive nodulation rates were positively and linearly correlated with soil pH, while alder nodulation rates were best in the acidic upland soil, though they did not correlate with soil pH in the pot study.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Biology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Zitzer, Stephen Frederich

Contributors dc:contributor

• Dawson, Jeffrey O.

• Biology, Plant Physiology

Statement dc:rights

• Copyright 1990 Zitzer, Stephen Frederich

Language dc:language

eng

Identifier

AAI9026366
(UMI)AAI9026366

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/22303