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Is salt stress of faba bean ( Vicia faba ) caused by Na + or Cl – toxicity?
Author(s) -
Slabu Cristina,
Zörb Christian,
Steffens Diedrich,
Schubert Sven
Publication year - 2009
Publication title -
journal of plant nutrition and soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 1436-8730
DOI - 10.1002/jpln.200900052
Subject(s) - vicia faba , chemistry , toxicity , spots , sodium , wilting , horticulture , potassium , chloride , chlorophyll , sodium sulfate , nuclear chemistry , botany , biology , organic chemistry
The effect of sodium chloride (NaCl), sodium sulfate (Na 2 SO 4 ), and potassium chloride (KCl) on growth and ion concentrations of faba bean ( Vicia faba L. cv. Troy) was studied. After 14 or 15 d of isoosmotic treatment with 100 mM NaCl or 75 mM Na 2 SO 4 , respectively, plants developed toxicity symptoms. These symptoms were characterized by local and nonchlorotic wilting spots, which later turned to black, necrotic spots. In contrast to NaCl or Na 2 SO 4 treatment, plants treated with 100 mM KCl did not show these symptoms. The symptoms occurred on those leaves that accumulated highest concentrations of Na + and showed highest Na + : K + ratios. Our results indicate that Na + toxicity inducing K + deficiency is responsible for the spot necrosis of faba bean. Additionally, chlorotic symptoms occurred. The concentrations of Na + and Cl – were determined in chlorotic leaves and in isolated chloroplasts. The reduction of chlorophyll in leaves after NaCl exposure may be explained in terms of high Cl – concentrations in the chloroplasts and appears to depend on high Na + concentrations. Chlorotic toxicity symptoms can be avoided by additional Mg 2+ application.