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Photosynthesis light curves: a method for screening water deficit resistance in the model legume Medicago truncatula
Author(s) -
Nunes C.,
Araújo S.S,
Silva J.M.,
Fevereiro P.,
Silva A.B.
Publication year - 2009
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.2009.00341.x
Subject(s) - photosynthesis , medicago truncatula , biology , compensation point , botany , light intensity , transpiration , genetics , physics , symbiosis , bacteria , optics
The photosynthetic performance of two transgenic Medicago truncatula lines engineered for water deficit (WD) resistance and a non‐transformed line was assessed in a growth chamber experiment in well‐watered, WD and stress recovery conditions. Direct gas exchange measurements showed that the transgenic plants had lower photosynthetic rates under well‐hydrated conditions when compared to the non‐transformed line. Photosynthesis light curves confirmed this difference but more importantly showed a progressive change in photosynthetic behaviour with intensity of dehydration. Dehydration led to sharp decreases of maximum photosynthesis (A max ), photosynthetic apparent quantum yield (Φ) and apparent light compensation point. The recovery rates showed that all plant lines had a similar capacity to regain control photosynthetic values. Furthermore, results suggested that light was more limiting for photosynthesis than atmospheric CO 2 concentration. The results are discussed in terms of the use of photosynthesis light response curves as a non‐destructive and expeditious approach to select M. truncatula transformants with improved WD resistance.