Exogenous Application of Multi-Walled Carbon Nanotubes (MWCNTs) and Nano-Selenium (Nano-Se) Alleviated the PEG-Induced Water Deficit Stress and Improved the Crop Performance of Camelina

Abstract

While previous studies have shown camelina drought tolerance relative to other oilseed crops, drought has been documented to severely influence the productivity of camelina. To date, little information is available on the drought tolerance of camelina genotypes. This study was conducted to evaluate drought tolerance in fifteen camelina genotypes and test the alleviative effect of nanoparticles on PEG-induced water deficit stress (WDS) at the whole-plant level at the Yangzhou University Pratacultural Science Experimental Station in September 2021. Four different degrees of WDS were induced by a range of PEG solution concentrations (0, 16.7, 25.0, 37.5, and 56.3 mM). A petri dish study determined that CamK8 and CamK9 (GR50 = 19.0 and 34.3 mM, respectively) were the most sensitive and tolerant genotypes, respectively, to PEG-induced WDS. Results from the whole-plant test showed that the foliar application of MWCNTs (dose: 50 or 100 mg L−1) or nano-Se (dose: 5 or 10 mg L−1) alleviated the adverse effect of PEG-induced WDS, and increased the camelina plant height (ranges: 51.1–56.3 cm) and crop yield (ranges: 0.11–0.14 g plant−1) compared with untreated control and PEG-treated plants (height: 43.5–56.9 cm; yield: 0.06–0.12 g plant−1) in CamK8 without affecting the principal fatty acid composition and groups in camelina oil. The results of this study demonstrated that applying MWCNTs or nano-Se could alleviate WDS and maintain seed yield in camelina, providing the possibility of using these nanoparticles to manage WDS in agricultural practices.

Evaluation of the Aluminum (Al3+) Tolerance of Camelina and the Potential for Using Melatonin or Nano-Selenium to Alleviate Al3+-Induced Stress in Camelina

“…[25] and wheat (Triticum aestivum L.) [24], showed that the exogenous application of nano-Se could potentially increase the contents of defense-related chemicals (i.e., flavonoid) in plants and thus enhance plant resilience under unfavorable conditions. Our recent study also showed the potential for using nano-Se to alleviate PEG-induced drought stress and maintain the seed yield and quality in camelina [21].…”

“…In contrast to the previous studies reporting an increase in SOD activity in Al 3+ -stressed oilseed rape after melatonin treatment [29] and drought-stressed tomato (Solanum lycopersicum L.) after Se treatment [49], in this study, the SOD and CAT activities of the camelina plants co-applied with melatonin or nano-Se were maintained at a normal level similar to untreated controls. Recently, our research team also observed a relatively stable SOD activity in drought-stressed camelina plants after nano-Se treatment [21]. Because the mechanism differences in melatonin-mediated Al 3+ tolerance vary across different plant species [3] and the various defense mechanisms of plants possessed under various stresses (e.g., alteration of antioxidant enzyme activity, production of defensive pigments) [50], the increase in antioxidant enzyme activities after stress-alleviating chemical treatment may simplify the changing process of these enzyme activities under various stresses.…”

“…Additionally, foliar-applied thiourea alleviated heat stress and improved the seed yield in camelina [20]. The application of Se or nano-Se effectively alleviated the adverse effect of drought and maintained the camelina seed yield [20,21]. Another study revealed that a foliar application of melatonin increased the salinity stress tolerance and improved the seed oil quality in camelina [34].…”

“…Studies have demonstrated an alleviation of abiotic stresses (e.g., saline, drought) by the application of various biostimulants (e.g., nanoparticles, bioactive fertilizers) in many crop species [21,22]. Brassinolide, through protecting photosynthetic organs and improving the carbon assimilation potential, enhanced the salt tolerance of rice seedlings [23].…”