Graduate Thesis Or Dissertation

 

Seasonal changes in the CO₂ gas exchange of red fescue (Festuca rubra L.) in a montane meadow community in northern Germany Public Deposited

Downloadable Content

Download PDF
https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/9k41zk036

Descriptions

Attribute NameValues
Creator
Abstract
  • Completely climatized cuvettes were used to follow the CO₂ gas exchange of red fescue (Festuca rubra L.), growing on a fertilized and an unfertilized plot, during a growing season from May through October. Objective of the study was to determine the effect of environmental factors on the seasonal CO₂ gas exchange. Gas exchange rates were calculated on the basis of leaf dry weight, surface area and chlorophyll. There was close correlation between leaf dry weight and area. Photosynthetic rates differed between the fertilized and unfertilized plants when based on leaf dry weight or leaf surface area but were similar when based on chlorophyll. Multiple regression analysis was used to relate photosynthetic rates to radiation, temperature, vapor pressure deficit, chlorophyll content and time. A cubic regression equation based on daily radiation alone explained 75% to 88% of the variation in total daily photosynthesis for the season for the three reference bases. During the growing season the unfertilized plants had a continual decline in their photosynthetic rates until the end of the growing season. On a dry weight basis the fertilized plants had 24% higher photosynthetic rates for the growing season period; on a leaf area basis the rates were only 16% higher. Light response curves indicated greater photosynthetic rates at light saturation as well as in the light limited portion of the photosynthetic light curve for the fertilized plants. Photosynthetic rates of fertilized plants were generally depressed during periods of warm temperature and high light intensity in June and July. Photosynthetic rates declined at temperatures above 24°C. The decline was greater for the fertilized plants. A similar response was noted to increasing vapor pressure deficit, although it was difficult to separate from the temperature effect. A temperature increase to 32°C decreased photosynthetic rates 50% and a decrease in temperature to 12.5°C decreased photosynthesis by 12% for the fertilized plants in July. Maximum photosynthetic rates were found between 14° and 22°C, although there was considerable variation in the photosynthetic rates. The effects of cutting (mowing) on the gas exchange were difficult to determine due to the interaction of the environmental factors. Chlorophyll content showed significant correlation with photosynthetic rates.
Resource Type
Date Available
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Academic Affiliation
Non-Academic Affiliation
Subject
Rights Statement
Language
Digitization Specifications
  • PDF derivative scanned at 300 ppi (256 B&W, 256 Grayscale), using Capture Perfect 3.0.82, on a Canon DR-9080C. CVista PdfCompressor 4.0 was used for pdf compression and textual OCR.
Replaces
Additional Information
  • description.provenance : Approved for entry into archive by Patricia Black(patricia.black@oregonstate.edu) on 2009-10-14T14:55:12Z (GMT) No. of bitstreams: 1 RuetzWolfhardFriedrich1973.pdf: 1305335 bytes, checksum: 1121976f0de162b79fe5cb136696afbd (MD5)
  • description.provenance : Approved for entry into archive by Patricia Black(patricia.black@oregonstate.edu) on 2009-10-14T14:50:39Z (GMT) No. of bitstreams: 1 RuetzWolfhardFriedrich1973.pdf: 1305335 bytes, checksum: 1121976f0de162b79fe5cb136696afbd (MD5)
  • description.provenance : Submitted by Digital Production (digitalproduc@gmail.com) on 2009-10-12T16:35:50Z No. of bitstreams: 1 RuetzWolfhardFriedrich1973.pdf: 1305335 bytes, checksum: 1121976f0de162b79fe5cb136696afbd (MD5)
  • description.provenance : Made available in DSpace on 2009-10-14T14:55:12Z (GMT). No. of bitstreams: 1 RuetzWolfhardFriedrich1973.pdf: 1305335 bytes, checksum: 1121976f0de162b79fe5cb136696afbd (MD5)

Relationships

Parents:

This work has no parents.

Items