Analysis of the physical properties of developing cotton fibres

Production and Fiber Characteristics of Colored Cotton Cultivares under Salt Stress and H2O2

Salt stress reduces the yield and quality of colored fiber cotton production, but this problem can be mitigated by the foliar application of hydrogen peroxide in adequate concentrations. In this context, the objective of the present study was to evaluate the production and characteristics of fibers of naturally colored cotton cultivares under irrigation with low- and high-salinity water and leaf application of hydrogen peroxide. The experiment was carried out in a greenhouse under a randomized block design, arranged in 4 × 3 × 2 factorial scheme, corresponding to four concentrations of hydrogen peroxide (0, 25, 50, and 75 μM), three cultivares of colored fiber cotton ('BRS Rubi', 'BRS Topázio', and 'BRS Verde'), and two electrical conductivities of water (0.8 and 5.3 dS m^-1), with three replicates and one plant per plot. Irrigation with water of 0.8 dS m^-1 associated with a foliar application of 75 μM of hydrogen peroxide favored the lint and seed weight, strength, micronaire index, and maturity of 'BRS Topázio'. The 'BRS Rubi' cotton cultivar showed higher tolerance to salinity, followed by the 'BRS Topázio' and 'BRS Verde' cultivares regarding the yield of seed cotton weight, with reduction below 20% under water of 5.3 dS m^-1.

Ecological Insight, Anatomical Features, and Fiber Characterization of Leptadenia pyrotechnica (Forrsk.) Decne. as a Promising Resource

Wild plants are considered promising natural eco-friendly resources for fibers. Leptadenia pyrotechnica is a xerophytic shrub that flourishes in a sandy desert habitat with high biomass production; therefore, it could be a potential resource for fibers. The present study aimed to investigate the vegetation composition of L. pyrotechnica communities and their correlation with soil variables. Additionally, this study aimed to evaluate the anatomical features of the stem as well as fiber characteristics, including chemical, biometry, morphological, and optical properties. The vegetation analysis showed the presence of 60 species belonging to 22 families, with a prevalence of therophytes. Four communities were determined, dominated by L. pyrotechnica and with co-dominance of the shrubs Haloxylon salicornicum, Ochradenus baccatus, and Retama raetam. The soil organic matter, salinity, texture, and cations were parameters that substantially affect the L. pyrotechnica community. The anatomical investigation showed the structural (anatomical) adaptation of L. pyrotechnica to arid habitats. Chemical analysis of the raw plant material revealed satisfactory levels of cellulose and hemicellulose (48.61% and 18.59%), while lignin and ash contents were relatively low, compared to hardwoods and softwoods. The fiber characterization revealed that fibesr length was 0.72 mm, while width and cell wall thickness were 20.46 and 6.48 μm, respectively. The optical properties revealed a birefringence of 0.028, indicating a good refractive index. These fiber characteristics showed that L. pyrotechnica could be used as raw material for the production of good-quality paper. A further feasibility study is recommended for the evaluation of L. pyrotechnica fibers, as a promising resource for papermaking at a large scale.

Novel insights into water-deficit-responsive mRNAs and lncRNAs during fiber development in Gossypium hirsutum

BACKGROUND

The fiber yield and quality of cotton are greatly and periodically affected by water deficit. However, the molecular mechanism of the water deficit response in cotton fiber cells has not been fully elucidated.

RESULTS

In this study, water deficit caused a significant reduction in fiber length, strength, and elongation rate but a dramatic increase in micronaire value. To explore genome-wide transcriptional changes, fibers from cotton plants subjected to water deficit (WD) and normal irrigation (NI) during fiber development were analyzed by transcriptome sequencing. Analysis showed that 3427 mRNAs and 1021 long noncoding RNAs (lncRNAs) from fibers were differentially expressed between WD and NI plants. The maximum number of differentially expressed genes (DEGs) and lncRNAs (DERs) was identified in fibers at the secondary cell wall biosynthesis stage, suggesting that this is a critical period in response to water deficit. Twelve genes in cotton fiber were differentially and persistently expressed at ≥ five time points, suggesting that these genes are involved in both fiber development and the water-deficit response and could potentially be used in breeding to improve cotton resistance to drought stress. A total of 540 DEGs were predicted to be potentially regulated by DERs by analysis of coexpression and genomic colocation, accounting for approximately 15.76% of all DEGs. Four DERs, potentially acting as target mimics for microRNAs (miRNAs), indirectly regulated their corresponding DEGs in response to water deficit.

CONCLUSIONS

This work provides a comprehensive transcriptome analysis of fiber cells and a set of protein-coding genes and lncRNAs implicated in the cotton response to water deficit, significantly affecting fiber quality during the fiber development stage.

Edge Detecting Method for Microscopic Image of Cotton Fiber Cross-Section Using RCF Deep Neural Network

Currently, analyzing the microscopic image of cotton fiber cross-section is the most accurate and effective way to measure its grade of maturity and then evaluate the quality of cotton samples. However, existing methods cannot extract the edge of the cross-section intact, which will affect the measurement accuracy of maturity grade. In this paper, a new edge detection algorithm that is based on the RCF convolutional neural network (CNN) is proposed. For the microscopic image dataset of the cotton fiber cross-section constructed in this paper, the original RCF was firstly used to extract the edge of the cotton fiber cross-section in the image. After analyzing the output images of RCF in each convolution stage, the following two conclusions are drawn: (1) the shallow layers contain a lot of important edge information of the cotton fiber cross-section; (2) because the size of the cotton fiber cross-section in the image is relatively small and the receptive field of the convolutional layer gradually increases with the deepening of the number of layers, the edge information detected by the deeper layers becomes increasingly coarse. In view of the above two points, the following improvements are proposed in this paper: (1) modify the network supervision model and loss calculation structure; (2) the dilated convolution in the deeper layers is removed; therefore, the receptive field in the deeper layers is reduced to adapt to the detection of small objects. The experimental results show that the proposed method can effectively improve the accuracy of edge extraction of cotton fiber cross-section.

Micro-FTIR combined with curve fitting method to study cellulose crystallinity of developing cotton fibers

This study aimed to use micro-FTIR with transmission mode to investigate cellulose crystallinity of developing cotton fibers. Compared with ATR-FTIR method, we found that micro-FTIR can obtain more information of cellulose inside of the developing cotton fibers, especially in high wavenumber of 2800-3000 cm^-1 region. Combined with curve fitting method, a new IR crystallinity index (CI) method named wax crystallinity index (WCI) was introduced to evaluate the cellulose crystallinity in the development of cotton fibers based on the peak and area ratios of 2900 cm^-1/2850 cm^-1 and 2900 cm^-1/2920 cm^-1. The obtained WCI values demonstrated an excellent coefficient of determination with X-ray diffraction (XRD) CI method with the value up to 0.99. This study suggested that micro-FTIR was an effective technique to qualitatively analyze the crystallinity in developing cotton fibers combined with curve fitting method.

Metabolism of polysaccharides in dynamic middle lamellae during cotton fibre development

Evidence is presented that cotton fibre adhesion and middle lamella formation are preceded by cutin dilution and accompanied by rhamnogalacturonan-I metabolism. Cotton fibres are single cell structures that early in development adhere to one another via the cotton fibre middle lamella (CFML) to form a tissue-like structure. The CFML is disassembled around the time of initial secondary wall deposition, leading to fibre detachment. Observations of CFML in the light microscope have suggested that the development of the middle lamella is accompanied by substantial cell-wall metabolism, but it has remained an open question as to which processes mediate adherence and which lead to detachment. The mechanism of adherence and detachment were investigated here using glyco-microarrays probed with monoclonal antibodies, transcript profiling, and observations of fibre auto-digestion. The results suggest that adherence is brought about by cutin dilution, while the presence of relevant enzyme activities and the dynamics of rhamnogalacturonan-I side-chain accumulation and disappearance suggest that both attachment and detachment are accompanied by rhamnogalacturonan-I metabolism.

Assessment of solvents for cellulose dissolution

A necessary step in the processing of biomass is the pretreatment and dissolution of cellulose. A good solvent for cellulose involves high diffusivity, aggressiveness in decrystallization, and capability of disassociating the cellulose chains. However, it is not clear which of these factors and under what conditions should be improved in order to obtain a more effective solvent. To this end, a newly-developed phenomenological model has been applied to assess the controlling mechanism of cellulose dissolution. Among the findings, the cellulose fibers remain crystalline almost to the end of the dissolution process for decrystallization-controlled kinetics. In such solvents, decreasing the fiber crystallinity, e.g., via pretreatment, would result in a considerable increase in the dissolution rate. Such insights improve the understanding of cellulose dissolution and facilitate the selection of more efficient solvents and processing conditions for biomass. Specific examples of solvents are provided where dissolution is limited due to decrystallization or disentanglement.

Evaluation of recalcitrant features impacting enzymatic saccharification of diverse agricultural residues treated by steam explosion and dilute acid

Exploring agricultural biomass for biofuel production necessitates pretreatment as a prerequisite step.