Quantifying seed germination responses of Echinops and Centaurea, to salinity and drought stresses

Ahmad Zare,Seyed A Moosavi

doi:10.15835/nsb12310723

Abstract

Seed germination may significantly interrupt by water stress due to drought and salinity condition. Salinity can cause osmotic pressure and induce drought stress. Water deficit stress affect normal seed germination and reduce seedling vigor. The objective of this investigation was to determine the effect of drought and salt stresses on germination characteristics of Echinops ritro and Centaurea virgata. Seeds were germinated with the concentrations of sodium chloride (0, 50, 100, 150 and 200 mmol) or in polyethylene glycol PEG6000 (0, -0.2, -0.4, -0.6, -0.8, -1 and -1.2 MPa). The highest values of germination parameters were obtained with no osmotic potential or salinity stress. At treatment by PEG, the germination was severely decreased at -0.6 MPa. While, no germination occurred at- 0.8 MPa by PEG. Results revealed that under 118 Mmol salinity, the seed germination of Centaurea virgata declined to 43% which was as close as half of its total seed germination. However, 50% reduction in seed germination of Echinops ritro was observed at 193 mmol salinity. Results indicated Echinops ritro and Centaurea virgata germination was sensitive to both the stresses. However, seedling growth was more sensitive to PEG than NaCl.

Highlights

Salinity and drought stress are the most widespread abiotic stresses which threatens successful agricultural productions (Forni et al, 2017)
The time course of seed germination was a sigmoidal with rapid germination rate in salinity levels below 200 Mmol compared with Centaurea virgata
For Centaurea virgata seeds, the maximum seed germination was less than 90% in control treatment (85%) while in Echinops ritro due to pappus removal from the seed coat, the seed germination was reached 100% (Figure 1)

Summary

Introduction

Salinity and drought stress are the most widespread abiotic stresses which threatens successful agricultural productions (Forni et al, 2017). Salinity caused ion imbalances in the soil water which in higher concentration resulted in hyper osmotic stress and reduced the available water to plants (Zhu, 2001). Plants use various strategies to overcome abiotic stress such as salinity and drought stress. The most sensitive part of the plant life cycle to such stresses is seed germination. Understanding the possible tolerance limit of abiotic stress at the seed germination stage will help researchers to increase biodiversity at the highly infected areas and minimize the risks of desertification and biodiversity loss.

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Discussion

Conclusion