Water-Soluble Carbon Nanoparticles Improve Seed Germination and Post-Germination Growth of Lettuce under Salinity Stress

Hanna Baz,Haijun Gong,Matthew Creech,Heqiang Huo,Jianjun Chen,Kent Bradford

doi:10.3390/agronomy10081192

Abstract

Seed germination is a critical developmental phase for seedling establishment and crop production. Increasing salinity stress associated with climatic change can pose a challenge for seed germination and stand establishment of many crops including lettuce. Here, we show that water soluble carbon nanoparticles (CNPs) can significantly promote seed germination without affecting seedling growth. Twenty-seven varieties of lettuce (Lactuca sativa) were screened for sensitivity to germination in 150 and 200 mM NaCl, and six salt-sensitive varieties (Little Gem, Parris Island, Breen, Butter Crunch, Muir, and Jericho) were selected and primed with 0.3% soluble carbon nanoparticles. Pretreatment with CNPs significantly improved seed germination under 150 mM NaCl and high temperature. CNP treatment slightly inhibited the elongation of primary roots but promoted lateral root growth and accumulation of chlorophyll content of seedlings grown under salt stress. Despite different lettuce varieties exhibiting a distinct response to nanoparticle treatments, results from this study indicate that soluble nanoparticles can significantly improve lettuce seed germination under salinity stress, which provide fundamental evidence on the potential of nanoparticles in agricultural application to improve crop yield and quality under stressful conditions.

Highlights

Salinity stress is a major environmental factor that affects crop production
We report that water soluble carbon nanoparticles can substantially enhance lettuce seed germination and post-germination growth under saline conditions
Seeds of six varieties (Little Gem, Parris Island, Breen, Jericho, Muir, and Butter Crunch) had germination rates less than 35% at both salt concentrations, suggesting that they were highly sensitive to salt stress (Figure 1). These six varieties were selected to examine the effects of carbon nanoparticles (CNPs) on alleviating the salt effects on seed germination

Summary

Introduction

It is estimated that one-third of agricultural land is under salinity stress, partially due to the extensive use of brackish, saline, or reclaimed water for horticultural production [1]. Intensive land use by human beings for urbanization and organic matter oxidation in waste water runoff have led to increased alkalization and salinization of soils [2]. Salinity stress can cause various adverse effects on plant growth and productivity that may influence food supplies [3,4]. One of the most common adverse effects is the osmotic stress imposed by the high concentration of salt ions, limiting the water availability for plants [5]. The limitation in water uptake can significantly delay or inhibit seed germination and early seedling growth, posing a challenge for uniform stand establishment that substantially affects crop production. Various treatments prior to seed sowing in the field have been undertaken to improve germination under saline

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Discussion

Conclusion