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Carbon Costs Associated with N 2 Fixation in Vicia faba L and Pisum sativum 1. over a 14‐Day Period
Author(s) -
Schuize J.,
Adgo E.,
Merbach W.
Publication year - 1999
Publication title -
plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 1435-8603
DOI - 10.1111/j.1438-8677.1999.tb00273.x
Subject(s) - pisum , sativum , vicia faba , biology , acyrthosiphon pisum , horticulture , botany , agronomy , photosynthesis , shoot , aphididae , homoptera , pest analysis
Long‐term (14 days) carbon costs of N 2 fixation were studied in pot trials. For this purpose the CO 2 release from the root space of nodulated and non‐nodulated (urea nourished) Vicia faba L. and Pisum sativum L. plants was compared and related to the amount of fixed or assimilated N. Additional measurements of shoot CO 2 exchange and dry matter increment were carried out in order to calculate the overall carbon balance. The carbon costs for N 2 fixation in Vicia faba 1. (2.87 mg C/mg N fiX ) were higher than in Pisum sativum L. (2.03 mg C/mg N fix ). However, the better carbon efficiency in Pisum sativum 1. did not lead to a better growth performance compared to Vicia faba L. Vicia faba L. compensated for the carbon and energy expenditure by more intensive photosynthesis in the N 2 ‐fixing treatment. This was not the case with Pisum sativum L., where the carbon balance indicates that the carbon costs of N 2 fixation restricted root growth. It is proposed that low carbon costs for N 2 fixation indicate an adaptation to a critical carbon supply of roots and nodules, e.g., during the pod‐filling of grain legumes.