Salt-Stress Induced Protein Pattern Related to Seed Germination Indices in Lemon Balm (Melissa officinalis L.)

Roghayeh Dehghani,Daryush Talei,Azra Saboora,Tayebeh Radjabian

doi:10.5539/jas.v9n12p74

Roghayeh Dehghani, Daryush Talei + Show 2 more

Open Access

https://doi.org/10.5539/jas.v9n12p74

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Abstract

Salinity is one of the major environmental stress factors that cause many adverse effects on growth and productivity of plants. The objective of the present study was to investigate the effects of salinity levels on seed germination indices and protein patterns in Melissa offcinalis seedlings. An experiment was carried out based on randomized complete block design with five concentrations of NaCl and four replicates with sand medium. The results indicated that salt stress had negative effects on the seed germination percentage (GP), mean germination time (MGT) and germination rate (GR), primary shoot and root length, as well as the protein content. After two days of salt exposure, the lowest (0%) GP was obtained for seeds treated with 12 dSm-1 salinity, as compared to the control (48.5%). Although, high salinity levels delayed seed germination, but during the experimental period GP increased and no significant differences were observed among the treatments in terms of GP after two weeks. The highest MGT (4.97 days) was obtained for plants stressed with 12 dSm-1 salinity level, as compared to the control (1.89 days). Analysis of the protein bands revealed that salinity suppressed the expression of two proteins with the size of 45 (Y1), and 40 kDa (Y2) and protein of 60 kDa (D1) was down-regulated. Also, the synthesis of four proteins of 70 (X1), 30 (X2), 25 (X3), and 20 kDa (X4) was induced in the seedlings under salinity stress. The changes in protein pattern under salinity stress indicated that the synthesis of new proteins may be associated to the stress specific proteins.

Highlights

Salinity is one of the most important environmental factors limiting crop production of marginal agricultural soils in many parts of the world (Abbasian & Moemeni, 2013)
After two days of salt exposure, the highest (48.5%) and the lowest (0%) germination percentages were obtained for control seeds and seeds treated with 12 dSm-1 salinity level, respectively
Exposing the seeds to salinity showed that increasing the salinity levels led to significant decrease in the germination percentage and germination rate, as well as the primary shoot and root lengths

Summary

Introduction

Salinity is one of the most important environmental factors limiting crop production of marginal agricultural soils in many parts of the world (Abbasian & Moemeni, 2013). Salinity and drought stresses have similar effects on plants, preventing roots from performing their osmotic activity where water and nutrients move from an area of higher concentration (the soil) into the roots. Salinity can affect growth and yield of most crops, high salinity is known to cause both hyper ionic and hyper osmotic effects in plants, leading to membrane disorganization, increase in reactive oxygen species production and metabolic toxicity (Abbasian & Moemeni, 2013). Soil salinity affects various physiological and biochemical processes which result in reduced biomass production. This adverse effect of salt stress appears on the entire plant at almost every stage of growth including germination, seedling development, jas.ccsenet.org

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