Sodium exclusion by different maize genotypes under salinity in conferring salt resistance

Mahrufa Khanoom,Md Ashrafuzzaman,Md Nesar Uddin,Md Solaiman Ali Fakir,Shawon Mojumder

doi:10.3329/ajmbr.v2i4.30997

Mahrufa Khanoom, Md Ashrafuzzaman + Show 3 more

Open Access

https://doi.org/10.3329/ajmbr.v2i4.30997

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Abstract

An experiment was carried out in the pot-house of botanical garden of Bangladesh Agricultural University (BAU), Mymensingh, during June to November, 2014 to investigate the effect of NaCl on growth, Na+ accumulation and K+: Na+ ratio in maize. Four maize genotypes namely BARI Maize 5, BARI Maize 7, Plain maize line and Mosaic maize line were tested against control, without providing any NaCl and salt stress, with NaCl to reach the soil salinity of 10 dS m-1. The experiment was laid out following CRD with four replicates. Under salt stress, relative reduction in shoot fresh masses were 22 and 77% in BARI Maize 5 and BARI Maize 7, whereas the magnitude of reduction was 136 and 155% in Mosaic maize line and Plain maize line, respectively. Seven days exposure to moderate salinity (10 dS m-1) seemed to have significantly reduced total fresh masses with the concomitant increase in Na+ concentrations but decrease in K+ concentrations and K+: Na+ ratios in both young and old shoots of BARI Maize 5, Plain maize line and Mosaic maize line. In contrast, BARI Maize 7 showed significant reduction in shoot fresh mass under salinity with the concomitant increase in shoot Na+ content but no significant changes in K+ concentrations and K+: Na+ ratios were observed under salinity. It seemed that young leaf of BARI maize 7 showed unaffected growth despite of higher accumulation of Na+. It may likely that BARI maize 7 sequestered incoming excess Na+ ions in the vacuole from the cytosol to combat deleterious effect of this ion to the cytoplasmic enzymes.Asian J. Med. Biol. Res. December 2016, 2(4): 562-566

Highlights

Maize is the third most important cereal after wheat and rice and plays a significant role in human and livestock nutrition worldwide (Morris et al, 1999)
The relative reduction in shoot fresh masses in salt treated plants compared to control was 22, 77, 155 and 136% for BARI Maize 5, BARI Maize 7, Mosaic maize line and Plain maize line, respectively
BARI Maize 5 and BARI Maize 7 performed relatively better under salt stress compared to Mosaic maize line and Plain maize line

Summary

Introduction

Maize is the third most important cereal after wheat and rice and plays a significant role in human and livestock nutrition worldwide (Morris et al, 1999). When plants are grown in typical NaCl-dominated saline environments in nature, it comes to an accumulation of Na+ in the cytosol resulting in a high Na+: K+ ratio. This alteration disrupts enzymatic functions that are usually achieved in cells. In the present study four maize genotypes were grown under high NaCl concentration (10 dS m-1) to impose second phase reaction of salt stress. In this context low Na+ uptake at the root surface would contribute to low root-to-shoot translocation of Na+ which may contribute to salt resistance of maize plants. This research was based on the following objective. a) to determine shoot Na+ content as an index of Na+ exclusion at the root surface in four maize genotypes; b) to determine the K+: Na+ ratio as a salt-resistance mechanism in maize shoot

Experimental design and treatment

Results and Discussion

Conclusions