Drought poses serious threats to global crop production and its intensity is continuously soaring due to global warming.
Brassica napus
L. is an essential oilseed crop with an important place in ...global edible oil production. Drought-induced yield reduction is a big problem that needs to be addressed by knowing the targeted pathways and processes. Drought stress adversely affects germination, seedling establishment, photosynthetic efficiency, mineral uptake, shoot elongation, seed development, yield and quality in rapeseed. Plants attain various physiological and molecular protective approaches for tolerance under drought stress. The currently existing agronomic, breeding and biotechnological approaches can increase the adaptability provision of a conducive environment to
Brassica
plants facing drought stress. In the present review, we addressed the possible cross-talk among various responses of rapeseed under drought stress and discussed the potential management strategies for regulating the drought tolerance-related mechanisms. To date, various novel approaches have been tested to minimize the adverse effects of environmental stresses in
B. napus
. Despite the main improvements, there is still a big room for improvement in the drought tolerance of rapeseed cultivars. Thus, future research mainly using biotechnological and molecular approaches should be carried out to develop genetically engineered rapeseed plants with enhanced drought tolerance.
The advent of the nanotechnology era offers a unique opportunity for sustainable agriculture, and the contribution of nanoparticles (NPs) to ameliorate abiotic stresses became the new area of ...interest for researchers due to their special physiochemical characteristics in the biological system. Salinity is a key devastating abiotic factor that hinders the development and yield of rapeseed. On the flip side, the impact of nanoparticles on plant hormones upon salt stress during seed imbibition and germination has been poorly understood. Hence, we aimed to study the influence of nanopriming on plant hormones and germination processes using selenium and zinc oxide nanoparticles (SeNPs and ZnONPs) during seed imbibition and the early seedling stage upon salinity stress. Nanopriming showed a positive effect on final germination percentage, germination rate, seed microstructure, and antioxidant enzyme activity of two rapeseed cultivars under salt stress. Moreover, nano-treatment decreased the expression of abscisic acid related genes BnCYP707A1, 3, and 4 during the priming time and after sowing, where the levels of BnCYP707A1, and 3 genes showed a slightly significant difference between the nanopriming and hydropriming, which gave an evidence that the nanopriming influenced the ABA levels then elevated the seed germination with SeNPs and ZnONPs. Likewise, nanoparticles significantly elevated the expression levels of BnGA20ox, BnGA3ox and BnCPS genes during the germination stage, especially at 24 h after being sown in salt stress. That confirms the positive role of SeNPs and ZnONPs in regulating gibberellic acid level, which increases the germination in primed seeds as compared to unprimed seeds and hydroprimed seeds. Additionally, our results demonstrated that nanopriming regulated the expression level of BnCAM and BnPER during priming time and after sowing, along with the various levels of expression remarkably in BnEXP4 and BnRAB28, especially at 24 h of being sown under salt stress, which promoted seed germination and early seedling growth. Overall, this work provides new insights into mechanisms underlying the interactions of SeNPs and ZnONPs with plant hormones during the seed imbibition and early seedling stage, consequently enhanced plant growth and development. Additionally, these findings portrayed that the application of SeNPs and ZnONPs could be a new strategy and useful approach to enhance tolerance against salinity in rapeseed plants.
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•Nano-Se and -ZnO modulated the expression of ABA and GA genes during the germination stage.•NPs enhanced the germination attributes and seed microstructure and reduced the oxidative damage under salt stress.•Nanomaterials increased salinity tolerance during the early seedling stage in B. napus.
Yield and lodging related traits are essential for improving rapeseed production. The objective of the present study was to investigate the influence of plant density (D) and nitrogen (N) rates on ...morphological and physiological traits related to yield and lodging in rapeseed. We evaluated Huayouza 9 for two consecutive growing seasons (2014-2016) under three plant densities (LD, 10 plants m
; MD, 30 plants m
; HD, 60 plants m
) and four N rates (0, 60, 120, and 180 kg ha
). Experiment was laid out in split plot design using density as a main factor and N as sub-plot factor with three replications each. Seed yield was increased by increasing density and N rate, reaching a peak at HD with 180 kg N ha
. The effect of N rate was consistently positive in increasing the plant height, pod area index, 1,000 seed weight, shoot and root dry weights, and root neck diameter, reaching a peak at 180 kg N ha
. Plant height was decreased by increasing D, whereas the maximum radiation interception (~80%) and net photosynthetic rate were recorded at MD at highest N. Lodging resistance and nitrogen use efficiency significantly increased with increasing D from 10 to 30 plants m
, and N rate up to 120 kg ha
, further increase of D and N decreased lodging resistance and NUE. Hence, our study implies that planting density 30 plants m
can improve yield, nitrogen use efficiency, and enhance lodging resistance by improving crop canopy.
•Rapeseed LAI was retrieved accurately by PROSAIL and ESM based on UAV images.•PROSAIL was more robust than ESM for rapeseed LAI retrieval in different years and fields.•A canopy coverage parameter ...derived from UAV images improved LAI retrieval by the PROSAIL model.•The performance of the PROSAIL model was stable with images resolution less than 10 cm.
Leaf area index (LAI), which is an important structural parameter, plays a vital role in evaluating crop growth and yield. In this study, we used the canopy coverage (CC) derived from unmanned aerial vehicle (UAV) images as a correction parameter in the PROSAIL model coupled with a neural network (NN) to improve the accuracy of LAI inversion of rapeseed plots. CC had a significantly positive impact on the accuracy of LAI inversion especially in sparse canopy structure with the 22.24% decrease in the entire dataset and 35.76% decrease in the sparse canopy dataset. We then compared the inversion performances of an empirical statistical model (ESM) based on a vegetation index and the PROSAIL model incorporating CC correction for 2016 and 2018 datasets. The ESM performed better in modeling the 2016 dataset, but its accuracy was much lower for the 2018 dataset (2016: NRMSE = 0.131; 2018: NRSME = 0.348). Overall, the PROSAIL model was more robust over these two datasets (2016: NRMSE = 0.152; 2018: NRMSE = 0.168). In addition, the original-resolution images were resampled to six coarse resolutions to evaluate the influence of image resolution on the LAI inversion performance of the PROSAIL model. When pixel size increased to more than 10 cm, the inversion accuracy began to decrease dramatically. In conclusion, introducing a canopy coverage correction parameter in the PROSAIL model improved its performance in retrieving rapeseed LAI.
Increasing domestic rapeseed production is an important national goal in China. Researchers often use tools such as crop models to determine optimum management practices for new varieties to ...increased production. The CROPGRO-Canola model has not been used to simulate rapeseed in China. The overall goal of this work was to identify key inputs to the CROPGRO-Canola model for calibration with limited datasets in the Yangtze River basin. First, we conducted a global sensitivity analysis to identify key genetic and soil inputs that have a large effect on simulated days to flowering, days to maturity, yield, above-ground biomass, and maximum leaf area index. The extended Fourier amplitude test method (EFAST) sensitivity analysis was performed for a single year at 8 locations in the Yangtze River basin (spatial analysis) and for seven years at a location in Wuhan, China (temporal analysis). The EFAST software was run for 4520 combinations of input parameters for each site and year, resulting in a sensitivity index for each input parameter. Parameters were ranked using the top-down concordance method to determine relative sensitivity. Results indicated that the model outputs of days to flowering, days to maturity, yield, above-ground biomass, and maximum leaf area index were most sensitive to parameters that affect the duration of critical growth periods, such as emergence to flowering, and temperature response to these stages, as well as parameters that affect total biomass at harvest. The five model outputs were also sensitive to several soil parameters, including drained upper and lower limit (SDUL and SLLL) and drainage rate (SLDR). The sensitivity of parameters was generally spatially and temporally stable. The results of the sensitivity analysis were used to calibrate and evaluate the model for a single rapeseed experiment in Wuhan, China. The model was calibrated using two seasons and evaluated using three seasons of data. Excellent nRMSE values were obtained for days to flowering (≤1.71%), days to maturity (≤ 1.48%), yield (≤ 9.96%), and above-ground biomass (≤ 9.63%). The results of this work can be used to guide researchers on model calibration and evaluation across the Yangtze River basin in China.
High levels of copper released in the soil, mainly from anthropogenic activity, can be hazardous to plants, animals, and humans. The present research aimed to estimate the suitability and ...effectiveness of rapeseed (Brassica napus L.) as a possible soil remediation option and to uncover underlying adaptive mechanisms A pot experiment was conducted to explore the effect of copper stress on agronomic and yield traits for 32 rapeseed genotypes. The copper-tolerant genotype H2009 and copper-sensitive genotype ZYZ16 were selected for further physiological, metabolomic, and transcriptomic analyses. The results exhibited a significant genotypic variation in copper stress tolerance in rapeseed. Specifically, the ratio of seed yield under copper stress to control ranged from 0.29 to 0.74. Furthermore, the proline content and antioxidant enzymatic activities in the roots were greater than those in the shoots. The accumulated copper in the roots accounted for about 50% of the total amount absorbed by plants; thus, the genotypes possessing high root volumes can be used for rhizofiltration to uptake and sequester copper. Additionally, the pectin and hemicellulose contents were significantly increased by 15.6% and 162%, respectively, under copper stress for the copper-tolerant genotype, allowing for greater sequestration of copper ions in the cell wall and lower oxidative stress. Comparative analysis of transcriptomes and metabolomes revealed that excessive copper enhanced the up-regulation of functional genes or metabolites related to cell wall binding, copper transportation, and chelation in the copper-tolerant genotype. Our results suggest that copper-tolerant rapeseed can thrive in heavily copper-polluted soils with a 5.85% remediation efficiency as well as produce seed and vegetable oil without exceeding food quality standards for the industry. This multi-omics comparison study provides insights into breeding copper-tolerant genotypes that can be used for the phytoremediation of heavy metal-polluted soils.
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•A substantial genotypic variation exits in rapeseed regarding excessive copper stress.•Copper is primarily accumulated in the root and its concentration in seed is limited.•The pectin-related genes were upregulated to sequestrate copper in root cell wall.•The proline and its derived peptides contents were higherin copper-tolerant genotype.•Tolerant rapeseed genotype remediated Cu-contaminated soil with 5.85% efficiency.
Selenium nanoparticles (SeNPs) have attracted considerable attention globally due to their significant potential for alleviating abiotic stresses in plants. Accordingly, further research has been ...conducted to develop nanoparticles using chemical ways. However, our knowledge about the potential benefit or phytotoxicity of bioSeNPs in rapeseed is still unclear. Herein, we investigated the effect of bioSeNPs on growth and physiochemical attributes, and selenium detoxification pathways compared to sodium selenite (Se (IV)) during the early seedling stage under normal and salt stress conditions. Our findings showed that the range between optimal and toxic levels of bioSeNPs was wider than Se (IV), which increased the plant's ability to reduce salinity-induced oxidative stress. BioSeNPs improved the phenotypic characteristics of rapeseed seedlings without the sign of toxicity, markedly elevated germination, growth, photosynthetic efficiency and osmolyte accumulation versus Se (IV) under normal and salt stress conditions. In addition to modulation of Na
and K
uptake, bioSeNPs minimized the ROS level and MDA content by activating the antioxidant enzymes engaged in ROS detoxification by regulating these enzyme-related genes expression patterns. Importantly, the main effect of bioSeNPs and Se (IV) on plant growth appeared to be correlated with the change in the expression levels of Se-related genes. Our qRT-PCR results revealed that the genes involved in Se detoxification in root tissue were upregulated upon Se (IV) treated seedlings compared to NPs, indicating that bioSeNPs have a slightly toxic effect under higher concentrations. Furthermore, bioSeNPs might improve lateral root production by increasing the expression level of LBD16. Taken together, transamination and selenation were more functional methods of Se detoxification and proposed different degradation pathways that synthesized malformed or deformed selenoproteins, which provided essential mechanisms to increase Se tolerance at higher concentrations in rapeseed seedlings. Current findings could add more knowledge regarding the mechanisms underlying bioSeNPs induced plant growth.
Paclobutrazol was sprayed at 0, 150, and 300 mg L-1 during the closed canopy stage and the early bud stage with two high-yielding cultivars of rapeseed, Yangguang 2009 and Fengyou 520. The impact of ...paclobutrazol on the accumulation and distribution of biomass and its relationship with yield, resistance to lodging and pod shattering were determined. All the treatments increased the resistance as well as yield. The maximum yield was obtained when paclobutrazol was applied during the closed canopy stage at 150 mg L-1. The plant＇s resistance to both lodging and pod shattering was the maximum when paclobutrazol was applied during the early bud stage at 300 mg L-1. Paclobutrazol also delayed senescence, with the higher concentration or later spraying leading to more obvious effects; improved the net assimilation rate before the early bud stage; and promoted the relative growth rate of the main growth organ at each stage of growth and maximized the rate and quantities of biomass accumulation. However, at the higher concentration and later spraying, the increments were smaller. The spraying also increased the rates of biomass allocation to roots, leaves, and pods, but the rate of allocation to stems decreased as the plants grew shorter. The higher allocation to roots and the lower allocation to stems favoured resistance to both lodging and pod shattering whereas higher allocation to leaves and pods favoured yield. The higher concentration or late spraying led to excessive biomass being allocated to roots, which decreased leaf biomass during the bud stage, leading to greater resistance but lower yields.
The negative effects of salt stress vary among different rapeseed cultivars. In this study, we investigated the sodium chloride tolerance among 10 rapeseed cultivars based on membership function ...values (MFV) and Euclidean cluster analyses by exposing seedlings to 0, 100, or 200 mM NaCl. The NaCl toxicity significantly reduced growth, biomass, endogenous K
levels, relative water content and increased electrolyte leakage, soluble sugar levels, proline levels, and antioxidant enzyme activities. SPAD values were highly variable among rapeseed cultivars. We identified three divergent (tolerant, moderately tolerant, and sensitive) groups. We found that Hua6919 and Yunyoushuang2 were the most salt-tolerant cultivars and that Zhongshuang11 and Yangyou9 were the most salt-sensitive cultivars. The rapeseed cultivars were further subjected to photosynthetic gas exchange and anatomical trait analyses. Among the photosynthetic gas exchange and anatomical traits, the stomatal aperture was the most highly correlated with salinity tolerance in rapeseed cultivars and thus, is important for future studies that aim to improve salinity tolerance in rapeseed. Thus, we identified and characterized two salt-tolerant cultivars that will be useful for breeding programs that aim to develop salt-tolerant rapeseed.
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