Decrease In Fiber Length Research Articles

Pulp and Paper Characteristics of Five Lesser-known Species in Kalimantan: Effects of Re-beating

Five lesser-known species from natural forests in Central Kalimantan, viz., cempaka (Michelia champaca Linn), mentawa (Artocarpus rigidus Blume), menjalin (Xanthophyllum excelsum Miq.), kempili (Lithocarpus elegans (Blume) Hatus. Ex Soepadmo), and sempori (Dillenia sp.) were evaluated in the laboratory for their specific gravity, fiber morphology, pulping and papermaking properties. In addition, their properties after three-phase beating were also evaluated from a recycled paper point of view. The specific gravity and fiber length range were 0.58~0.68 and 1239~2479 μm, respectively. The highest value in specific gravity was observed in menjalin wood, while the longest fiber was observed in sempori. Kraft pulping with 14% active alkali (as Na2O), 23% sulfidity, 2 h at the maximum temperature showed that the highest screened yield was determined in cempaka wood (44.29%) with a kappa number of 17.6. The freeness ranges of unbeaten pulp were 675~780m mL CSF. The freeness ranges of 1st, 2nd, and 3rd beating were 539~630 mL, 235~275 mL, and 220~230 mL CSF, respectively. The 1st beating exhibited the best mechanical properties. Among the species, cempaka, kempili, and mentawa showed comparatively high tensile (57~60 Nm/g) and burst index (2.6~3.4 KPa m2/g), whereas the highest value for tear index (5.02 mNm2/g) was observed in sempori. A considerable decrease in fiber length, slenderness ratio, and mechanical properties of the paper was observed with an increased beating number. These findings suggest that cutting the fibers or decreasing the slenderness ratio was the main factor causing the strength to decrease.

Effect of Mechanical Recycling on the Mechanical Properties of PLA-Based Natural Fiber-Reinforced Composites

The present study investigates the feasibility of utilizing polylactic acid (PLA) and PLA-based natural fiber-reinforced composites (NFRCs) in mechanical recycling. A conical twin screw extrusion (CTSE) process was utilized to recycle PLA and PLA-based NFRCs consisting of 90 wt.% PLA and a 10 wt.% proportion of either basalt fibers (BFs) or halloysite nanotubes (HNTs) for up to six recycling steps. The recycled material was then injection molded to produce standard test specimens for impact strength and tensile property analysis. The mechanical recycling of virgin PLA led to significant discoloration of the polymer, indicating degradation during the thermal processing of the polymer due to the formation of chromatophores in the structure. Differential scanning calorimetry (DSC) analysis revealed an increase in glass transition temperature (Tg) with respect to increased recycling steps, indicating an increased content of crystallinity in the PLA. Impact strength testing showed no significant detrimental effects on the NFRCs’ impact strength up to six recycling steps. Tensile testing of PLA/HNT NFRCs likewise did not show major decreases in values when tested. However, PLA/BF NFRCs exhibited a significant decrease in tensile properties after three recycling steps, likely due to a reduction in fiber length beyond the critical fiber length. Scanning electron microscopy (SEM) of the fracture surface of impact specimens revealed a decrease in fiber length with respect to increased recycling steps, as well as poor interfacial adhesion between BF and PLA. This study presents a promising initial view into the mechanical recyclability of PLA-based composites.

Surface analysis and thermal behavior of the functionalized cellulose by glutaric anhydride through a solvent-free and catalyst-free process

According to the 12 principles of green chemistry, surface functionalization was performed using glutaric anhydride under solvent-free and catalyst-free conditions. FTIR spectra and DS analyses demonstrated the functionalization of HCl-hydrolyzed cellulose. The influence of two parameters, i.e., the glutaric anhydride concentration and the reaction time, on the functionalization of HCl-hydrolyzed cellulose was investigated. Protocol efficiency was studied by a degree of substitution (DS). It was found that higher concentrations of glutaric anhydride cause an enhancement of DS to 0.75 and 0.87 for GA3–12 and GA9–12, respectively. In addition, the longer reaction time increased zeta potential from −12.2 ± 1.7 for G9–6 to −34.57 ± 2.2 for GA9–12. Morphology analysis by SEM showed a decrease in fiber length for the functionalized cellulose. DSC profiles confirmed dehydration at a range of 17 to 134 °C. A glass transition was revealed at −30 to −20 °C for all studied samples. The fusion, the depolymerization of cellulose chains, the cleavage of glycosidic linkages, and the decomposition of the crystalline parts of cellulose occur at 195 to 374 °C. Therefore, an efficient and greener process was developed to functionalize the HCl-hydrolyzed cellulose by glutaric anhydride, a safe and non-toxic anhydride, in the absence of the solvent and catalyst.

Tissue specific expression of bacterial cellulose synthase (Bcs) genes improves cotton fiber length and strength

Fiber growing inside the cotton bolls is a highly demandable product and its quality is key to the success of the textile industry. Despite the various efforts to improve cotton fiber staple length Pakistan has to import millions of bales to sustain its industrial needs. To improve cotton fiber quality Bacterial cellulose synthase (Bcs) genes (acsA, acsB) were expressed in a local cotton variety CEMB-00. In silico studies revealed a number of conserved domains both in the cotton-derived and bacterial cellulose synthases which are essential for the cellulose synthesis. Transformation efficiency of 1.27% was achieved by using Agrobacterium shoot apex cut method of transformation. The quantitative mRNA expression analysis of the Bcs genes in transgenic cotton fiber was found to be many folds higher during secondary cell wall synthesis stage (35 DPA) than the expression during elongation phase (10 DPA). Average fiber length of the transgenic cotton plant lines S-00–07, S-00–11, S-00–16 and S-00–23 was calculated to be 13.02% higher than that of the non-transgenic control plants. Likewise, the average fiber strength was found to be 20.92% higher with an enhanced cellulose content of 22.45%. The mutated indigenous cellulose synthase genes of cotton generated through application of CRISPR/Cas9 resulted in 6.03% and 12.10% decrease in fiber length and strength respectively. Furthermore, mature cotton fibers of transgenic cotton plants were found to have increased number of twists with smooth surface as compared to non-transgenic control when analyzed under scanning electron microscope. XRD analysis of cotton fibers revealed less cellulose crystallinity index in transgenic cotton fibers as compared to control fibers due to deposition of more amorphous cellulose in transgenic fibers as a result of Bcs gene expression. This study paved the way towards unraveling the fact that Bcs genes influence cellulose synthase activity and this enzyme helps in determining the fate of cotton fiber length and strength.

Studi Pertumbuhan Mikroskopis: Pengaruh Suhu dan Curah Hujan terhadap Aktivitas Kambium pada Kayu Jelutung

The cambium activity in wood formation is highly affected by temperature and rainfall. The aim of the present study was to investigate the cambium activities, i.e., cell number, cell proportion, and cell size during the growth period of jelutong wood. The pinning method was employed as the marking for initiating the observations on the formation and sizes of wood cells. The results revealed three patterns of the effect of the change in temperature and rainfall. First, when both temperature and rainfall increase, the number of fiber cells number increases, while the vessel cells, parenchyma cells, and rays decrease. The size of new fiber cells alters in which cell diameter, lumen diameter, and cell wall thickness increase, but fiber length decreases. This pattern forms short cells with thick cell walls. In the observation when temperature increases and rainfall decreases, the number of fiber cells and vessel cells increases while the number of parenchyma cells and rays decreases. New fiber cells have an increase in cell diameter, lumen diameter, and fiber length, but a decrease in cell wall thickness. The cells formed in the second pattern are long cells with thin cell walls. The third observation is when the temperature increases and rainfall decreases. In this pattern, the number of fiber cells, vessel cells, and cell size decrease, but the number of parenchyma cells and rays increases. This pattern forms short cells and thick cell walls. It causes variations in the properties of wood and affects the wood quality.
 Kata kunci (Keywords): cambium activity, temperature, rainfall, wood formation.

Totally chlorine free (TCF) bleaching of wheat straw soda-anthraquinone (AQ) pulp with a low initial kappa number

The totally chlorine free (TCF) bleaching was studied for wheat straw soda-anthraquinone (AQ) pulp with a low kappa number of 8.3 using the sequence of OQPO and OQPOPO. It was found that the oxygen delignification on wheat straw pulp was still effective despite its low initial kappa number. A delignification extent of 42% and an ISO brightness increase of 10.9% were achieved. In the OQPO sequence, an ISO brightness ceiling of 87.2% was achieved as the hydrogen peroxide (H2O2) charge was increased from 2% to 6% in the PO stage. In the OQPOPO sequence, 2% H2O2 was added in the second PO stage and the pulp brightness exceeded 88% with a total charge of 4% H2O2 in the POPO bleaching. Higher brightness values of 89.5% and 90.1% were obtained under the total charges of 6% and 8% H2O2, respectively. Compared to the OQPO sequence, the higher brightness and equal viscosity of the bleached pulps were obtained under the same total charge of H2O2 in the OQPOPO sequence. The bleached pulps with high ISO brightness values (greater than 88%) retained acceptable strength properties. A slight decrease of fiber length occurred as the bleaching sequences proceeded, while the fiber width and curl index somewhat increased.

Effects of plate wear on bar forces and fiber properties in a mill scale LC-refiner

Abstract A set of piezo electric force sensors is implemented in a 52-inch mill-scale low consistency refiner to explore the effect of refiner plate wear on bar force sensor measurements. The sensor replaces a short length of a stator bar and measures normal and shear forces applied during the passage of each rotor bar. In previous work with this type of force sensor, force profiles for individual bar passing events (BPE) were investigated. In the work presented here, force profiles for individual BPEs are identified based on key features in the time domain force data. The individual bar force profiles are classified as single peak events which feature one peak corresponding to the fiber compression force and as dual peak events corresponding to fiber compression force and the corner force. The bar passing events are then analysed, based on dual peak ratio and time to peak of the early peak in the dual peak events. Force measurements are evaluated over the full run time of a set of refiner plates. Findings are compared with refiner plate wear measurements and discharge fiber analysis. It is shown that the decrease in the prevalence of the corner force correlates with the wear of the leading edge of the refiner bars or bar rounding of the run time of the refiner plate. This is accompanied by a decrease in plate performance which is represented by a decrease in fiber length and freeness reduction for the same refiner load.

Isolation of Cellulose Nanofibers from Oryza sativa Residues via TEMPO Mediated Oxidation

ABSTRACT Cellulose nanocrystals (CNCs) or cellulose nanofibers (CNFs) with different morphologies, chemical, mechanical and physical properties can be obtained when microcrystalline cellulose is subjected to enzymatic, chemical or mechanical treatment. With the aim of utilizing cellulose nanofibrils (CNFs) from Oryza sativa, we isolated microcrystalline cellulose using the Kraft process, followed by successive fiber fibrillation using mechanical grinding, then (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPO) mediated oxidation. Analysis of pulp fibers obtained after each treatment step revealed that fiber properties such as length, crystallinity and crystal size changed when the pulp was subjected to mechanical grinding, ultrasonication and TEMPO mediated oxidation. The degree of crystallinity of the fibers increased while crystal size and fiber length decreased after each treatment. TEMPO mediated oxidation led to a decrease in fiber length and an increase in degree of crystallinity of the fibers as compared to mechanical treatment and ultrasonication. It further introduced carboxyl functional groups (COOH) on the surface of the fibrils, which implies that the nanofibers obtained in this study could be further functionalized. Hence, TEMPO mediated oxidation offers the possibility of further chemical functionalization of cellulose nanofibers isolated from agricultural residues.

Physiological Significance of the Force-Velocity Relation in Skeletal Muscle and Muscle Fibers.

The relation between the force (load) and the velocity of shortening (V) in contracting skeletal muscle is part of a rectangular hyperbola: (P + a) V = b(Po − P); where Po is the maximum isometric force and a and b are constants. The force–velocity (P–V) relation suggests that muscle can regulate its energy output depending on the load imposed on it (Hill, 1938). After the establishment of the sliding filament mechanism (H.E. Huxley and Hanson, 1954), the P–V relation has been regarded to reflect the cyclic interaction between myosin heads in myosin filaments and the corresponding myosin-binding sites in actin filaments, coupled with ATP hydrolysis (A.F. Huxley, 1957). In single skeletal muscle fibers, however, the P–V relation deviates from the hyperbola at the high force region, indicating complicated characteristics of the cyclic actin–myosin interaction. To correlate the P–V relation with kinetics of actin–myosin interaction, skinned muscle fibers have been developed, in which the surface membrane is removed to control chemical and ionic conditions around the 3D lattice of actin and myosin filaments. This article also deals with experimental methods with which the structural instability of skinned fibers can be overcome by applying parabolic decreases in fiber length.

Ameliorative effects of potassium on drought-induced decreases in fiber length of cotton (Gossypium hirsutum L.) are associated with osmolyte dynamics during fiber development

Fiber length of cotton (Gossypium hirsutum L.) decreases under drought stress, potassium (K) could diminish the decreased caused by drought, but the mechanism associated with this alleviation effect is not clear. We evaluated the effect of K on fiber elongation using two cotton cultivars, Simian 3 and Siza 3, grown in well-watered and drought-stressed conditions. Potassium fertilizer (K2O) was applied 0, 150, or 300 kg ha−1 in each growing condition. Drought stress reduced the final fiber length due to a decline in the maximum rate of rapid elongation (Vmax, mm day−1). The application of K alleviated the drought-induced fiber length reduction by increasing Vmax. At 10 and 15 days post-anthesis (DPA), drought significantly reduced osmotic potential (OP) and increased K+ and malate contents at all K rates, relative to well-watered conditions, which was associated with increased activities of phosphoenolpyruvate carboxylase (PEPC), V-ATPase, PPase, and PM H+-ATPase in cotton fiber. However, the relative contribution of K+ and malate to OP declined under drought in comparison with well-watered condition. Compared with control without K, K application decreased OP and increased the accumulation of osmolytes (K+, malate and soluble sugar) as well as the activities of related enzymes in fiber irrespective of water treatments. Moreover, K application increased osmotic adjustment during drought, and improved the contribution of K+ and malate to OP, especially under drought stress. This study showed that drought decreased fiber length by reducing Vmax, and K application ameliorates the decline in fiber elongation due to drought by enhancing osmolytes accumulation and their contribution to OP in fiber cells.

OAM Modes Exchanging by Controlling Polarization of Vortex Beams Propagating Through an FMF-Based Polarization Controller

In order to exchange OAM modes in a space-division multiplexing (SDM) system, an OAM-mode-exchange concept between the first-order vortex beams (L = and −1), which is achieved by controlling the polarization of vortex beams propagating over a few-mode-fiber-based polarization controller (FMFPC), is proposed. A step-index fiber is also designed and manufactured for switching the propagated OAM beams. The feasibility of the proposed concept is not only exploited and simulated in principle, but is also verified through experiments. The simulated results show that SDM-based vortex beams (L = and −1) can be mutually exchanged by appropriately controlling the phase difference (with respect to the polarization of propagated vortex-beams) between two first-order-linear-polarized-mode beams ( $\text {LPM}_{\text {11ax/ay}}$ and $\text {LPM}_{\text {11bx/by}}$ ). An experimental setup is also proposed and established for verifying the feasibility of the proposed concept in practice. The measured experimental results are consistent with the simulation, and demonstrate that the proposed scheme is correct and reliable. To evaluate the performance of the proposed scheme, bit error rates (BERs) and constellation graphs (CGs) with respect to the exchanging ways, loop numbers, and fiber lengths, are employed and investigated, respectively. The measured BERs and CGs demonstrate that the performance can be further improved with the decrease of fiber length and crosstalk, and also can be enhanced when the coiled loops is set as an appropriate value.

Abrasive/Erosive Wear on MMCs in Plastic Molds as a Function of Volumetric Flow Rates and Glass Fiber Distribution

In injection molding wear of components is pronounced in positions with high flow rates of melt. The platelet‐wear‐test is an established method for comparative assessment of wear resistance of tool materials in such regimes. Within this study three metal matrix composites: two hard metals and one powder metallurgical steel were investigated. Results show non‐linear wear rates with increasing amount of plastic melt processed. The reasons were found in the viscous dissipation, which is based on high volumetric flow rates and the small wear gap, leading to a temperature rise, which are detrimental especially for the PM‐steel. Analysis of the processed glass fiber‐filled polymer showed dramatic decrease of fiber length due to the processing through the wear gap. This entails a high amount of free fiber ends, resulting in higher load for the surfaces through micro chipping. POLYM. ENG. SCI., 59:E302–E311, 2019. © 2018 The Authors. Polymer Engineering & Science published by Wiley Periodicals, Inc. on behalf of Society of Plastics Engineers.

A novel enzymatic approach to nanocrystalline cellulose preparation

In this work, conditions for an enzymatic pretreatment prior to NCC isolation from cotton linter were assessed. Different cellulase doses and reaction times were studied within an experimental design and NCC were obtained. At optimal enzymatic conditions (20U, 2 h), a total yield greater than 80% was achieved and the necessary enzymatic treatment time was reduced 90%. Different intensities of enzymatic treatments led to proportional decreases in fiber length and viscosity and also were inversely proportional to the amount of released oligosaccharides. These differences within fibers lead to quantitative differences in NCC: increase in acid hydrolysis yield, reduction of NCC surface charge and crystallinity increase. Benefits produced by enzymatic treatments did not have influence over other NCC characteristics such as their sulfur content (≈1%), size (≈200 nm), zeta potential (≈−50 mV) or degree of polymerization (≈200). Evidence presented in this work would reduce the use of harsh sulfuric acid generating a cleaner stream of profitable oligosaccharides.

The cotton (Gossypium hirsutum) NAC transcription factor (FSN1) as a positive regulator participates in controlling secondary cell wall biosynthesis and modification of fibers.

Cotton (Gossypium hirsutum) fibers are the highly elongated and thickened single-cell trichomes on the seed epidermis. However, little is known about the molecular base of fiber cell wall thickening in detail. In this study, a cotton NAC transcription factor (GhFSN1) that is specifically expressed in secondary cell wall (SCW) thickening fibers was functionally characterized. The GhFSN1 transgenic cotton plants were generated to study how FSN1 regulates fiber SCW formation. Up-regulation of GhFSN1 expression in cotton resulted in an increase in SCW thickness of fibers but a decrease in fiber length. Transcriptomic analysis revealed that GhFSN1 activates or represses numerous downstream genes. GhFSN1 has the ability to form homodimers, binds to its promoter to activate itself, and might be degraded by the ubiquitin-mediated proteasome pathway. The direct targets of GhFSN1 include the fiber SCW-related GhDUF231L1, GhKNL1, GhMYBL1, GhGUT1 and GhIRX12 genes. GhFSN1 binds directly to a consensus sequence (GhNBS), (C/T)(C/G/T)TN(A/T)(G/T)(A/C/G)(A/G)(A/T/G)(A/T/G)AAG, which exists in the promoters of these SCW-related genes. Our data demonstrate that GhFSN1 acts as a positive regulator in controlling SCW formation of cotton fibers by activating its downstream SCW-related genes. Thus, these findings give us novel insights into comprehensive understanding of GhFSN1 function in fiber development.

Proteomic changes in response to low-light stress during cotton fiber elongation

Numerous studies have illustrated that low light is one of the major abiotic stresses limiting cotton (Gossypium hirsutum L.) fiber length, but studies addressing molecular mechanisms contributing to reduced fiber growth under low light are lacking. To investigate the molecular mechanisms of cotton fiber elongation in response to low light, an experiment of low light caused by shading was conducted with cotton cultivar NuCOTN 33B. The results showed that low light resulted in shorter fiber length. Proteomic analysis of four developmental stages (5, 10, 15 and 20 days post-anthesis) showed that 49 proteins were significantly responsive to low light. 39 differentially expressed proteins that included some known as well as some novel low-light stress-responsive proteins were identified. These differentially expressed proteins were involved in signal transduction, carbohydrate/energy metabolism, cell wall component synthesis, protein metabolism, cytoskeleton, nitrogen metabolism and stress responses. The results also showed that the decrease in fiber length might be because the levels of signal-related protein (phospholipase D), cytoskeletal proteins (two annexins isoforms), cell wall component-related proteins (sucrose synthase, UDP-d-glucuronic acid 4-epimerase and rhamnose synthase), carbohydrate metabolism-proteins (phosphofructokinase, dihydrolipoamide dehydrogenase, vacuolar H+-ATPase catalytic subunit, malate dehydrogenase and isocitrate dehydrogenase), and stress-related proteins (peroxisomal catalase, short chain alcohol dehydrogenase) were decreased under low light.

Simulation of a short and broadband polarization splitter based on photonic crystal fiber filled with tellurite glass

A polarization splitter based on dual-core photonic crystal fiber filled with tellurite glass in the central hole is proposed. The characteristics are studied by finite element method. The influences of the parameters \(d_{1}, d_{2}, \varLambda\) on the coupling length and coupling length ratio (CLR) are analyzed. The curves of coupling lengths of X-polarization, Y-polarization light dependence on the operable wavelength \(\lambda\) are flat under the optimized structural parameters which is helpful to realize broadband polarization splitter. The simulation results indicate that the CLR could reach to 2.006 at the wavelength of \(1.55\,\upmu {\hbox {m}}\). The fiber length is only 510 \(\upmu {\hbox {m}}\) and the bandwidth of extinction ratio greater than 20 dB is 284 nm, i.e., from 1461 to 1745 nm which could be widely used in the large-capacity, broad-bandwidth and integrated optical communication systems. As the fiber length decreases, we find the bandwidth increases. But the extinction ratio at 1.55 \(\upmu {\hbox {m}}\) is lower than 20 dB as the fiber length is less than 510 \(\upmu {\hbox {m}}\).

Developing fiber specific promoter-reporter transgenic lines to study the effect of abiotic stresses on fiber development in cotton.

Cotton is one of the most important cash crops in US agricultural industry. Environmental stresses, such as drought, high temperature and combination of both, not only reduce the overall growth of cotton plants, but also greatly decrease cotton lint yield and fiber quality. The impact of environmental stresses on fiber development is poorly understood due to technical difficulties associated with the study of developing fiber tissues and lack of genetic materials to study fiber development. To address this important question and provide the need for scientific community, we have generated transgenic cotton lines harboring cotton fiber specific promoter (CFSP)-reporter constructs from six cotton fiber specific genes (Expansin, E6, Rac13, CelA1, LTP, and Fb late), representing genes that are expressed at different stages of fiber development. Individual CFSP::GUS or CFSP::GFP construct was introduced into Coker 312 via Agrobacterium mediated transformation. Transgenic cotton lines were evaluated phenotypically and screened for the presence of selectable marker, reporter gene expression, and insertion numbers. Quantitative analysis showed that the patterns of GUS reporter gene activity during fiber development in transgenic cotton lines were similar to those of the native genes. Greenhouse drought and heat stress study showed a correlation between the decrease in promoter activities and decrease in fiber length, increase in micronaire and changes in other fiber quality traits in transgenic lines grown under stressed condition. These newly developed materials provide new molecular tools for studying the effects of abiotic stresses on fiber development and may be used in study of cotton fiber development genes and eventually in the genetic manipulation of fiber quality.

Bipedally trained rats have an increased hindlimb muscle force‐generating capacity compared to quadrupedally trained rats

The shift from bipedalism to quadrupedalism in human evolution led to major morphological changes because of new demands placed on the locomotor system including include larger forces on each limb. The ability for a muscle to generate forces and length change to respond to these demands depends on the muscle's architecture, or the arrangement of fibers within a muscle. Muscle force is determined by the cross-sectional area of its fibers (physiological cross-sectional area or PCSA), while muscle excursion is determined by fiber length. In this study, we asked whether changes in muscle architecture respond to the demands of bipedal locomotion and if this response can occur during the lifetime of an individual. To test this question, we trained rats to stand or walk bipedally on a treadmill for one hour a day for five days a week over 90 days using a harness that loaded the hindlimbs to 90% of body mass. A control group was trained quadrupedally over the same time period. The rats were sacrificed and their hindlimbs were fixed in formalin. Muscles were dissected from one hindlimb each of the bipedally (BI) and quadrupedally trained rats (QU). Measurements of muscle mass, length, fiber length, sarcomere length, and pennation angle were obtained and used to calculate normalized fiber length and PCSA. PCSA was normalized to body mass. We found an increase in the mass-specific PCSA of muscles in the BI rats compared to QU rat muscles. Furthermore, the larger PCSA in BI rats was achieved through a decrease in fiber length as opposed to an increase in muscle mass. These results indicate that muscle architecture responds to the varied demands of bipedal locomotion and these changes are a plastic response that can occur over a short time period.

The R3-MYB gene GhCPC negatively regulates cotton fiber elongation.

Cotton (Gossypium spp.) fibers are single-cell trichomes that arise from the outer epidermal layer of seed coat. Here, we isolated a R3-MYB gene GhCPC, identified by cDNA microarray analysis. The only conserved R3 motif and different expression between TM-1 and fuzzless-lintless mutants suggested that it might be a negative regulator in fiber development. Transgenic evidence showed that GhCPC overexpression not only delayed fiber initiation but also led to significant decreases in fiber length. Interestingly, Yeast two-hybrid analysis revealed an interaction complex, in which GhCPC and GhTTG1/4 separately interacted with GhMYC1. In transgenic plants, Q-PCR analysis showed that GhHOX3 (GL2) and GhRDL1 were significantly down regulated in −1–5 DPA ovules and fibers. In addition, Yeast one-hybrid analysis demonstrated that GhMYC1 could bind to the E-box cis-elements and the promoter of GhHOX3. These results suggested that GhHOX3 (GL2) might be downstream gene of the regulatory complex. Also, overexpression of GhCPC in tobacco led to differential loss of pigmentation. Taken together, the results suggested that GhCPC might negatively regulate cotton fiber initiation and early elongation by a potential CPC-MYC1-TTG1/4 complex. Although the fibers were shorter in transgenic cotton lines than in the wild type, no significant difference was detected in stem or leaf trichomes, even in cotton mutants (five naked seed or fuzzless), suggesting that fiber and trichome development might be regulated by two sets of genes sharing a similar model.

Implications of fiber characteristics and mat densification on permeability, compaction and properties of kenaf fiber panels

In the manufacturing of medium density and high density fiberboards the fiber characteristics and mat density substantially influence mat permeability, compaction pressure and panel's physicomechanical properties. In this paper, the permeability and compaction response of kenaf bast fiber mats are experimentally determined at three fiber lengths for both dry and resinated fiber mats with various levels of mat densification. The mats of long fibers have demonstrated higher permeability and require higher compaction pressure than short fiber mats at the same level of densification. Furthermore, kenaf panels in the density range of 800kg/m3 to 1100kg/m3 are manufactured with commercial melamine urea formaldehyde resin and three fiber categories. The panels are evaluated to demonstrate the effects of these factors on a panel's physicomechanical properties. The higher compaction pressure and good stress distribution with long fibers have resulted in higher mechanical properties than those of short fiber panels. On the other hand, a decrease in fiber length has lowered the mat permeability, resulting in significant improvements in dimensional properties. The panel physicomechanical properties can also significantly improve by increasing the panel density. The high density kenaf panels have shown excellent mechanical properties which are well above the standard requirements of MDF and HDF panels according to (ANSI, A208.2: 2009) and (ANSI, A135.4-2012) standards.