Zea mays L. amylacea from the Lluta Valley (Arica-Chile) tolerates salinity stress when high levels of boron are available |
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Authors: | E I Bastías M B González-Moro C González-Murua |
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Institution: | (1) Facultad de Agromomía, Universidad de Tarapacá, Casilla 6-D, Arica, Chile;(2) Departamento de Biología Vegetaly Ecología, Facultad de Ciencia y Tecnología, Universidad del País Vasco/EHU, Apdo. 644, E-48080 Bilbao, Vizcaya, Spain |
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Abstract: | Elevated levels of boron occurring naturally in soil or irrigation waters are detrimental to many crops grown in agricultural
regions of the world. If such levels of boron are accompanied by conditions of excessive salinity, as occurs in the Lluta
valley in Northern Chile, the consequences can be drastic for crops. A variety of sweet corn from this valley (Zea mays L. amylacea) has arisen as a consequence of practiced seed selection, suggesting that it is extremely tolerant to high salt
and boron levels. In the present study, seeds ofZea mays L. amylacea were collected in order to study their physiological mechanisms of tolerance to high levels of NaCl and boron.
Concentrations of 100 and 430 mM NaCl and 20 and 40 mg kg−1 boron were imposed as treatments. The plants did not exhibit symptoms of toxicity to either NaCl and boron during the 20
days of treatment. Na+ accumulation was substantial in roots, while boron was translocated to leaves. Boron alleviated the negative effect of salinity
on tissue K+ and maintained membrane integrity. The higher values of water potential seem to be related to the capacity of this ecotype
to maintain a better relative water content in leaves. Despite the fact that boron enhanced slightly the effect of salinity
on CO2 assimilation, no effect on photochemical parameters was observed in this ecotype. Osmotic adjustment allows this ecotype
to survive in high saline soils; however the presence of boron makes this strategy unnecessary since boron contributed to
the maintenance of cell wall elasticity. |
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Keywords: | boron ion content osmotic potential salt-tolerance water potential Zea mays L amylacea |
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