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Effect of UV‐B radiation on the shoot dry matter production and stable carbon isotope composition of two Arabidopsis thaliana genotypes
Author(s) -
Ormrod Douglas P.,
Schmidt Annamary,
Livingston Nigel J.
Publication year - 1997
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1997.tb01029.x
Subject(s) - arabidopsis thaliana , photosynthesis , stomatal conductance , isotopes of carbon , botany , shoot , dry matter , biology , horticulture , chemistry , mutant , environmental chemistry , biochemistry , total organic carbon , gene
An application of stable carbon isotope analysis to the mechanistic interpretation of ultraviolet‐B (UV‐B) effects on growth inhibition is described that is particularly useful for small plants such as Arabidopsis thaliana that are not well suited for gas exchange studies. Many investigators use tissue δ 13 C, relative abundance of 13 C and 12 C, as a proxy for water use efficiency and as an indicator of environmental effects on stomatal behaviour and on photosynthesis during growth. Discrimination against 13 C is enhanced by both high stomatal conductance and damage to photosynthetic machinery. Because the thinning of the stratospheric ozone layer is permitting more UV‐B to enter the biosphere, the mechanisms of action of UV‐B radiation on plants are of particular current interest. Arabidopsis thaliana wild‐type Landsberg erecta (L er ) and the UV‐B‐sensitive mutant fah I , deficient in UV‐absorbing sinapate esters, were grown in a controlled environment and exposed to UV‐B BE doses of 0 or 6–7 kJ m −2 day −1 . UV‐B exposure decreased dry matter production and δ 13 C in both genotypes, but growth inhibition was generally greater in fah I than in L er . The fah I mutant also had less leaf greenness than L er . Changes in leaf tissue δ 13 C were detected before growth inhibition and were evident in treatments of both genotypes that did not cause marked growth effects. This suggests that the effects of UV‐B contributing to increased carbon isotope discrimination in L er may have been primarily associated with high stomatal conductance, and in fah I with both high stomatal conductance and damage to photosynthetic machinery.