Optimal temporal–spatial fluorescence techniques for phenotyping nitrogen status in oilseed rape

Abstract Nitrogen (N) fertilizer maximizes the growth of oilseed rape (Brassica napus L.) by improving photosynthetic performance. Elucidating the dynamic relationship between fluorescence and plant N status could provide a non-destructive diagnosis of N status and the breeding of N-efficient cultivars. The aim of this study was to explore the impacts of different N treatments on photosynthesis at a spatial–temporal scale and to evaluate the performance of three fluorescence techniques for the diagnosis of N status. One-way ANOVA and linear discriminant analysis were applied to analyze fluorescence data acquired by a continuous excitation chlorophyll fluorimeter (OJIP transient analysis), pulse amplitude-modulated chlorophyll fluorescence (PAM-ChlF), and multicolor fluorescence (MCF) imaging. The results showed that the maximum quantum efficiency of PSII photochemistry (Fv/Fm) and performance index for photosynthesis (PIABS) of bottom leaves were sensitive to N status at the bolting stage, whereas the red fluorescence/far-red fluorescence ratio of top leaves was sensitive at the early seedling stage. Although the classification of N treatments by the three techniques achieved comparable accuracies, MCF imaging showed the best potential for early diagnosis of N status in field phenotyping because it had the highest sensitivity in the top leaves, at the early seedling stage. The findings of this study could facilitate research on N management and the breeding of N-efficient cultivars.

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Antioxidative and Metabolic Contribution to Salinity Stress Responses in Two Rapeseed Cultivars during the Early Seedling Stage

Antioxidants ◽

10.3390/antiox10081227 ◽

2021 ◽

Vol 10 (8) ◽

pp. 1227

Author(s):

Ali Mahmoud El-Badri ◽

Maria Batool ◽

Ibrahim A. A. Mohamed ◽

Zongkai Wang ◽

Ahmed Khatab ◽

...

Keyword(s):

Salt Stress ◽

Salinity Stress ◽

Stress Responses ◽

Antioxidant Activities ◽

Tricarboxylic Acid Cycle ◽

Seedling Stage ◽

Plant Performance ◽

Salt Tolerant ◽

Brassica Napus L ◽

Early Seedling

Measuring metabolite patterns and antioxidant ability is vital to understanding the physiological and molecular responses of plants under salinity. A morphological analysis of five rapeseed cultivars showed that Yangyou 9 and Zhongshuang 11 were the most salt-tolerant and -sensitive, respectively. In Yangyou 9, the reactive oxygen species (ROS) level and malondialdehyde (MDA) content were minimized by the activation of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) for scavenging of over-accumulated ROS under salinity stress. Furthermore, Yangyou 9 showed a significantly higher positive correlation with photosynthetic pigments, osmolyte accumulation, and an adjusted Na+/K+ ratio to improve salt tolerance compared to Zhongshuang 11. Out of 332 compounds identified in the metabolic profile, 225 metabolites were filtrated according to p < 0.05, and 47 metabolites responded to salt stress within tolerant and sensitive cultivars during the studied time, whereas 16 and 9 metabolic compounds accumulated during 12 and 24 h, respectively, in Yangyou 9 after being sown in salt treatment, including fatty acids, amino acids, and flavonoids. These metabolites are relevant to metabolic pathways (amino acid, sucrose, flavonoid metabolism, and tricarboxylic acid cycle (TCA), which accumulated as a response to salinity stress. Thus, Yangyou 9, as a tolerant cultivar, showed improved antioxidant enzyme activity and higher metabolite accumulation, which enhances its tolerance against salinity. This work aids in elucidating the essential cellular metabolic changes in response to salt stress in rapeseed cultivars during seed germination. Meanwhile, the identified metabolites can act as biomarkers to characterize plant performance in breeding programs under salt stress. This comprehensive study of the metabolomics and antioxidant activities of Brassica napus L. during the early seedling stage is of great reference value for plant breeders to develop salt-tolerant rapeseed cultivars.

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Effects of fluorine on the growth of Chinese cabbage (Brassica campestris L.) and oilseed rape (Brassica napus L.) at seedling stage

Archives of Agronomy and Soil Science ◽

10.1080/03650340.2021.1937605 ◽

2021 ◽

Author(s):

Dan Chen ◽

Yu-jie Zhou ◽

Si-fan Cui ◽

Jin-yan Yang

Keyword(s):

Brassica Napus ◽

Oilseed Rape ◽

Chinese Cabbage ◽

Brassica Campestris ◽

Seedling Stage ◽

Brassica Napus L

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A functional leaf may represent the assimilate accumulation characteristics of the whole seedling plant in winter oilseed rape (Brassica napus L.)

Crop and Pasture Science ◽

10.1071/cp14224 ◽

2015 ◽

Vol 66 (8) ◽

pp. 849 ◽

Cited By ~ 3

Author(s):

Xinghua Li ◽

Tewu Yang ◽

Zhongnan Nie ◽

Guoxing Chen ◽

Liyong Hu ◽

...

Keyword(s):

Brassica Napus ◽

Oilseed Rape ◽

Dry Matter ◽

Seedling Stage ◽

Regression Equations ◽

Winter Oilseed Rape ◽

Brassica Napus L ◽

Whole Plant ◽

Photosynthetic Assimilation ◽

Accumulation Characteristics

A single functional leaf is usually sampled to evaluate the growth and photosynthetic assimilation of crops. However, there is large variation between leaves in winter oilseed rape (Brassica napus L.) at seedling stage. In this study, the morphological and physiological characteristics of various functional leaves were compared with characteristics of the whole plant at seedling stage for 2 years by using the oilseed rape cultivars Huaza 9 and Huaza 62 as plant material. The aim of this study was to identify a leaf that can represent the whole plant for assimilate accumulation characteristics at the seedling stage of the crop. The results showed that the photosynthetic rate and the contents of non-structural carbohydrates, nutrients and soluble proteins in fourth and fifth leaf of a plant were most closely related to those of the whole plant. The area and dry matter (DM) of all functional leaves were well correlated with those of whole plant, with the fifth leaf having the highest correlations. It is therefore recommended that the fifth leaf is most suitable to represent the whole plant for evaluation of growth and assimilate accumulation for winter oilseed rape at the seedling stage. The following regression equations for whole plant (y) and fifth leaf (x, dry matter or length × width) can be used to predict (1) DM accumulation (g) and (2) total leaf area (cm2) of the whole plant: (1) y = 3.32x + 1.51 (R2 = 0.88, P < 0.001); (2) y = 1.24x + 222.69 (R2 = 0.67, P < 0.001).

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Modulation of salinity impact on early seedling stage via nano-priming application of Zinc oxide on rapeseed (Brassica napus, L.).

Plant Physiology and Biochemistry ◽

10.1016/j.plaphy.2021.05.040 ◽

2021 ◽

Author(s):

Ali M.A. El-Badri ◽

Maria Batool ◽

Ibrahim A.A. Mohamed ◽

Ahmed Khatab ◽

Ahmed Sherif ◽

...

Keyword(s):

Zinc Oxide ◽

Brassica Napus ◽

Seedling Stage ◽

Brassica Napus L ◽

Early Seedling

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Seed Yield and Sulphur Partitioning in Two Inbred Lines of Low and High Glucosinolate Oilseed Rape (Brassica napus L.) and Their Hybrids at Three Levels of Sulphur Supply

Acta Agriculturae Scandinavica Section B - Soil & Plant Science ◽

10.1080/09064719908565565 ◽

1999 ◽

Vol 49 (3) ◽

pp. 184-188

Author(s):

J. Davik ◽

A. K. Bakken

Keyword(s):

Brassica Napus ◽

Oilseed Rape ◽

Seed Yield ◽

Inbred Lines ◽

Brassica Napus L

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Genome Mining and Evaluation of the Biocontrol Potential of Pseudomonas fluorescens BRZ63, a New Endophyte of Oilseed Rape (Brassica napus L.) against Fungal Pathogens

International Journal of Molecular Sciences ◽

10.3390/ijms21228740 ◽

2020 ◽

Vol 21 (22) ◽

pp. 8740

Author(s):

Daria Chlebek ◽

Artur Pinski ◽

Joanna Żur ◽

Justyna Michalska ◽

Katarzyna Hupert-Kocurek

Keyword(s):

Brassica Napus ◽

Plant Growth ◽

Pseudomonas Fluorescens ◽

Oilseed Rape ◽

Plant Growth Promotion ◽

Fungal Pathogens ◽

Growth Promotion ◽

Genome Mining ◽

Plant Colonization ◽

Brassica Napus L

Endophytic bacteria hold tremendous potential for use as biocontrol agents. Our study aimed to investigate the biocontrol activity of Pseudomonas fluorescens BRZ63, a new endophyte of oilseed rape (Brassica napus L.) against Rhizoctonia solani W70, Colletotrichum dematium K, Sclerotinia sclerotiorum K2291, and Fusarium avenaceum. In addition, features crucial for biocontrol, plant growth promotion, and colonization were assessed and linked with the genome sequences. The in vitro tests showed that BRZ63 significantly inhibited the mycelium growth of all tested pathogens and stimulated germination and growth of oilseed rape seedlings treated with fungal pathogens. The BRZ63 strain can benefit plants by producing biosurfactants, siderophores, indole-3-acetic acid (IAA), 1-aminocyclopropane-1-carboxylate (ACC) deaminase, and ammonia as well as phosphate solubilization. The abilities of exopolysaccharide production, autoaggregation, and biofilm formation additionally underline its potential to plant colonization and hence biocontrol. The effective colonization properties of the BRZ63 strain were confirmed by microscopy observations of EGFP-expressing cells colonizing the root surface and epidermal cells of Arabidopsis thaliana Col-0. Genome mining identified many genes related to the biocontrol process, such as transporters, siderophores, and other secondary metabolites. All analyses revealed that the BRZ63 strain is an excellent endophytic candidate for biocontrol of various plant pathogens and plant growth promotion.

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