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

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.

Nanoceria seed priming enhanced salt tolerance in rapeseed through modulating ROS homeostasis and α-amylase activities

“…Whereas, under salinity stress, priming cotton seeds with cerium oxide nanoparticles does not result in improvement of germination rate [ 27 ]. Under 150 mM NaCl, after 8 h priming (same as in the current study), the highest difference of seed germination rate in lettuce ( Lactuca sativa variety Parris Island) was found between non-primed seeds and seeds primed with carbon nanoparticles at day 9 [ 43 ]. It suggests that in terms of the germination time and seed germination rate, factors such as plant species and types of nanoparticles affect the outcome of seed nanopriming.…”

“…Under salt stress, nanopriming with calcium silicate (Ca 2 SiO 4 ) in lettuce improved seed germination through triggering antioxidant enzymes including SOD, CAT and GR (glutathione reductase) to effectively scavenge the over-produced ROS [ 45 ]. Water soluble carbon nanoparticles (CNPs) promoted lettuce germination and lateral root growth under salt stress [ 43 ]. Titanium dioxide (TiO 2 ) nanopriming positively affected germination and seedling growth under salt stress by promoting antioxidant enzymes, relative water content, proline content, K + content, and reduced Na + content in maize crop [ 26 ].…”

Dual Effect of Nanomaterials on Germination and Seedling Growth: Stimulation vs. Phytotoxicity

“…In case of drought-stressed Glycine max seeds, however, SWCNTs improved germination and seedling growth by reducing lipid peroxidation and H 2 O 2 content but increasing ascorbic acid (AsA) content and SOD, CAT, peroxidase (POD) activities suggesting that SWCNTs may play an important role in the improvement of antioxidant capacity of soybean seedlings under drought stress [ 77 ]. In the work of Baz et al [ 78 ], twenty-seven varieties of L. sativa (lettuce) were compared for their sensitivity to salt stress, and the seeds were pre-treated with CNTs. Pre-treatment with CNPs significantly improved seed germination in the case of salt exposure (150 mM NaCl), and high temperature; however, different lettuce varieties exhibited distinct responses to nanoparticle treatments drawing attention to the genotype-dependent effect of CNTs [ 78 ].…”

“…In the work of Baz et al [ 78 ], twenty-seven varieties of L. sativa (lettuce) were compared for their sensitivity to salt stress, and the seeds were pre-treated with CNTs. Pre-treatment with CNPs significantly improved seed germination in the case of salt exposure (150 mM NaCl), and high temperature; however, different lettuce varieties exhibited distinct responses to nanoparticle treatments drawing attention to the genotype-dependent effect of CNTs [ 78 ].…”

Nanoceria Seed Priming Improves Salt Tolerance in Rapeseed Through Modulating ROS Homeostasis and α-Amylase Activities

“…Under salt stress, nanopriming with calcium silicate (Ca 2 SiO 4 ) in lettuce improved seed germination through triggering antioxidant enzymes including SOD, CAT and GR (glutathione reductase) to effectively scavenge the over-produced ROS [28]. Water soluble carbon nanoparticles (CNPs) promoted lettuce germination and lateral root growth under salt stress [29]. Titanium dioxide (TiO 2 ) nanopriming positively affected germination and seedling growth under salt stress by promoting antioxidant enzymes, relative water content, proline content, K + content, and reduced Na + content in maize crop [18].…”