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Effect of potassium deficiency on antioxidant status and cadmium toxicity in rice seedlings

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ABSTRACT

Background: Cadmium (Cd) is one of the most toxic heavy metals and inhibits physiological processes of plants. Potassium (K) is an essential macronutrient in plants. K deficiency and Cd stress represent two different abiotic stress conditions that occur in the field simultaneously. In this study, effects of K deficiency on antioxidant status and Cd toxicity in rice seedlings were investigated.

Results: K deficiency significantly decreased K concentration in shoots and roots. However, fresh weight and dry weight of rice seedlings were not affected by K deficiency. The activities of antioxidant enzymes (superoxide dismutase, ascorbate peroxidase, glutathione reductase, and catalase) in K-deficient leaves were higher than respective control leaves. However, K deficiency had no effect on the content of antioxidants (ascorbate and glutathione). Cd toxicity was judged by the decrease in biomass production, chlorosis, and induction of oxidative stress. Based on these criteria, we demonstrated that K deficiency protected rice seedling from Cd stress. Moreover, chlorophyll concentration was higher in K-deficient shoots and roots than their respective control shoots and roots.

Conclusions: Our results indicated that K deficiency protects rice seedlings from Cd toxicity. This protective effect of K deficiency is mainly due to enhanced antioxidant enzyme activities but not inhibition of Cd uptake.

Electronic supplementary material: The online version of this article (doi:10.1186/1999-3110-54-2) contains supplementary material, which is available to authorized users.

No MeSH data available.


Related in: MedlinePlus

Effect of paraquat (PQ) on chlorophyll content of detached leaves from K-sufficient (control) and -deficient (−K) conditions. Rice seedlings were grown under control and − K conditions for 12 days. The second leaves were excised from control and − K seedlings and then transferred to Petri dishes containing H2O and 10 μM PQ, respectively, for 24 h under light conditions. Detached leaves were then used to determine chlorophyll content. Bars indicate standard errors (n = 4). Values with the same letter are not significantly different at P < 0.05.
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Fig7: Effect of paraquat (PQ) on chlorophyll content of detached leaves from K-sufficient (control) and -deficient (−K) conditions. Rice seedlings were grown under control and − K conditions for 12 days. The second leaves were excised from control and − K seedlings and then transferred to Petri dishes containing H2O and 10 μM PQ, respectively, for 24 h under light conditions. Detached leaves were then used to determine chlorophyll content. Bars indicate standard errors (n = 4). Values with the same letter are not significantly different at P < 0.05.

Mentions: Irrespective of the K supply, floating detached leaves in 10 μM PQ solution caused a decrease in chlorophyll content (Figure 7). The decrease in chlorophyll content by PQ became more evident in K-sufficient compared with K-deficient leaves (Figure 7).Figure 7


Effect of potassium deficiency on antioxidant status and cadmium toxicity in rice seedlings
Effect of paraquat (PQ) on chlorophyll content of detached leaves from K-sufficient (control) and -deficient (−K) conditions. Rice seedlings were grown under control and − K conditions for 12 days. The second leaves were excised from control and − K seedlings and then transferred to Petri dishes containing H2O and 10 μM PQ, respectively, for 24 h under light conditions. Detached leaves were then used to determine chlorophyll content. Bars indicate standard errors (n = 4). Values with the same letter are not significantly different at P < 0.05.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5383923&req=5

Fig7: Effect of paraquat (PQ) on chlorophyll content of detached leaves from K-sufficient (control) and -deficient (−K) conditions. Rice seedlings were grown under control and − K conditions for 12 days. The second leaves were excised from control and − K seedlings and then transferred to Petri dishes containing H2O and 10 μM PQ, respectively, for 24 h under light conditions. Detached leaves were then used to determine chlorophyll content. Bars indicate standard errors (n = 4). Values with the same letter are not significantly different at P < 0.05.
Mentions: Irrespective of the K supply, floating detached leaves in 10 μM PQ solution caused a decrease in chlorophyll content (Figure 7). The decrease in chlorophyll content by PQ became more evident in K-sufficient compared with K-deficient leaves (Figure 7).Figure 7

View Article: PubMed Central

ABSTRACT

Background: Cadmium (Cd) is one of the most toxic heavy metals and inhibits physiological processes of plants. Potassium (K) is an essential macronutrient in plants. K deficiency and Cd stress represent two different abiotic stress conditions that occur in the field simultaneously. In this study, effects of K deficiency on antioxidant status and Cd toxicity in rice seedlings were investigated.

Results: K deficiency significantly decreased K concentration in shoots and roots. However, fresh weight and dry weight of rice seedlings were not affected by K deficiency. The activities of antioxidant enzymes (superoxide dismutase, ascorbate peroxidase, glutathione reductase, and catalase) in K-deficient leaves were higher than respective control leaves. However, K deficiency had no effect on the content of antioxidants (ascorbate and glutathione). Cd toxicity was judged by the decrease in biomass production, chlorosis, and induction of oxidative stress. Based on these criteria, we demonstrated that K deficiency protected rice seedling from Cd stress. Moreover, chlorophyll concentration was higher in K-deficient shoots and roots than their respective control shoots and roots.

Conclusions: Our results indicated that K deficiency protects rice seedlings from Cd toxicity. This protective effect of K deficiency is mainly due to enhanced antioxidant enzyme activities but not inhibition of Cd uptake.

Electronic supplementary material: The online version of this article (doi:10.1186/1999-3110-54-2) contains supplementary material, which is available to authorized users.

No MeSH data available.


Related in: MedlinePlus