Reduction In Cellulose Content Research Articles

Phosphatidylserine Synthase Controls Cell Elongation Especially in the Uppermost Internode in Rice by Regulation of Exocytosis.

The uppermost internode is one of the fastest elongating organs in rice, and is expected to require an adequate supply of cell-wall materials and enzymes to the cell surface to enhance mechanical strength. Although it has been reported that the phenotype of shortened uppermost internode 1 (sui1) is caused by mutations in PHOSPHATIDYLSERINE SYNTHASE (OsPSS), the underlying mechanism remains unclear. Here we show that the OsPSS-1, as a gene expressed predominantly in elongating cells, regulates post-Golgi vesicle secretion to intercellular spaces. Mutation of OsPSS-1 leads to compromised delivery of CESA4 and secGFP towards the cell surface, resulting in weakened intercellular adhesion and disorganized cell arrangement in parenchyma. The phenotype of sui1-4 is caused largely by the reduction in cellulose contents in the whole plant and detrimental delivery of pectins in the uppermost internode. We found that OsPSS-1 and its potential product PS (phosphatidylserine) localized to organelles associated with exocytosis. These results together suggest that OsPSS-1 plays a potential role in mediating cell expansion by regulating secretion of cell wall components.

Xyloglucan Deficiency Disrupts Microtubule Stability and Cellulose Biosynthesis in Arabidopsis, Altering Cell Growth and Morphogenesis.

Xyloglucan constitutes most of the hemicellulose in eudicot primary cell walls and functions in cell wall structure and mechanics. Although Arabidopsis (Arabidopsis thaliana) xxt1 xxt2 mutants lacking detectable xyloglucan are viable, they display growth defects that are suggestive of alterations in wall integrity. To probe the mechanisms underlying these defects, we analyzed cellulose arrangement, microtubule patterning and dynamics, microtubule- and wall-integrity-related gene expression, and cellulose biosynthesis in xxt1 xxt2 plants. We found that cellulose is highly aligned in xxt1 xxt2 cell walls, that its three-dimensional distribution is altered, and that microtubule patterning and stability are aberrant in etiolated xxt1 xxt2 hypocotyls. We also found that the expression levels of microtubule-associated genes, such as MAP70-5 and CLASP, and receptor genes, such as HERK1 and WAK1, were changed in xxt1 xxt2 plants and that cellulose synthase motility is reduced in xxt1 xxt2 cells, corresponding with a reduction in cellulose content. Our results indicate that loss of xyloglucan affects both the stability of the microtubule cytoskeleton and the production and patterning of cellulose in primary cell walls. These findings establish, to our knowledge, new links between wall integrity, cytoskeletal dynamics, and wall synthesis in the regulation of plant morphogenesis.

Down-regulation of the cotton endo-1,4-β-glucanase gene KOR1 disrupts endosperm cellularization, delays embryo development, and reduces early seedling vigour.

Towards the aim of examining the potential function of KORRIGAN (KOR), a highly conserved membrane-bound endoglucanase, in reproductive development, here transgenic evidence is provided that a cotton (Gossypium hirsutum) endoglucanase, GhKOR1, plays significant roles in endosperm and embryo development. RNA interference (RNAi)- and co-suppression-mediated down-regulation of GhKOR1 resulted in smaller filial tissue and reduced seed weight, which were characterized by disrupted endosperm cellularization and delayed embryo development, leading to a delayed germination and a weak growth of seedlings early in development. The transgenic seeds exhibited fewer and smaller endosperm cells with irregular and brittle cell walls, and their embryos developed only to the globular stage at 10 days post-anthesis (DPA) when the wild-type endosperm has become highly cellularized and the embryo has progressed to the heart stage. The transgenic seed also displayed a significant reduction of callose in the seed coat transfer cells and reduced cellulose content both in the seed coat and in mature fibres. These findings demonstrate that GhKOR1 is required for the developmental of both seed filial and maternal tissues and the establishment of seedling vigour.

The jiaoyao1 Mutant Is an Allele of korrigan1 That Abolishes Endoglucanase Activity and Affects the Organization of Both Cellulose Microfibrils and Microtubules in Arabidopsis.

In higher plants, cellulose is synthesized by plasma membrane-localized cellulose synthase complexes (CSCs). Arabidopsis thaliana GH9A1/KORRIGAN1 is a membrane-bound, family 9 glycosyl hydrolase that is important for cellulose synthesis in both primary and secondary cell walls. Most previously identified korrigan1 mutants show severe phenotypes such as embryo lethality; therefore, the role of GH9A1 in cellulose synthesis remains unclear. Here, we report a novel A577V missense mutation, designated jiaoyao1 (jia1), in the second of the glycosyl hydrolase family 9 active site signature motifs in GH9A1. jia1 is defective in cell expansion in dark-grown hypocotyls, roots, and adult plants. Consistent with its defect in cell expansion, this mutation in GH9A1 resulted in reduced cellulose content and reduced CSC velocity at the plasma membrane. Green fluorescent protein-GH9A1 is associated with CSCs at multiple locations, including the plasma membrane, Golgi, trans-Golgi network, and small CESA-containing compartments or microtubule-associated cellulose synthase compartments, indicating a tight association between GH9A1 and CSCs. GH9A1A577V abolishes the endoglucanase activity of GH9A1 in vitro but does not affect its interaction with CESAs in vitro, suggesting that endoglucanase activity is important for cellulose synthesis. Interestingly, jia1 results in both cellulose microfibril and microtubule disorganization. Our study establishes the important role of endoglucanase in cellulose synthesis and cellulose microfibril organization in plants.

Early cell-wall modifications of maize cell cultures during habituation to dichlobenil

Studies involving the habituation of plant cell cultures to cellulose biosynthesis inhibitors have achieved significant progress as regards understanding the structural plasticity of cell walls. However, since habituation studies have typically used high concentrations of inhibitors and long-term habituation periods, information on initial changes associated with habituation has usually been lost. This study focuses on monitoring and characterizing the short-term habituation process of maize (Zea mays) cell suspensions to dichlobenil (DCB). Cellulose quantification and FTIR spectroscopy of cell walls from 20 cell lines obtained during an incipient DCB-habituation process showed a reduction in cellulose levels which tended to revert depending on the inhibitor concentration and the length of time that cells were in contact with it. Variations in the cellulose content were concomitant with changes in the expression of several ZmCesA genes, mainly involving overexpression of ZmCesA7 and ZmCesA8. In order to explore these changes in more depth, a cell line habituated to 1.5μM DCB was identified as representative of incipient DCB habituation and selected for further analysis. The cells of this habituated cell line grew more slowly and formed larger clusters. Their cell walls were modified, showing a 33% reduction in cellulose content, that was mainly counteracted by an increase in arabinoxylans, which presented increased extractability. This result was confirmed by immunodot assays graphically plotted by heatmaps, since habituated cell walls had a more extensive presence of epitopes for arabinoxylans and xylans, but also for homogalacturonan with a low degree of esterification and for galactan side chains of rhamnogalacturonan I. Furthermore, a partial shift of xyloglucan epitopes toward more easily extractable fractions was found. However, other epitopes, such as these specific for arabinan side chains of rhamnogalacturonan I or homogalacturonan with a high degree of esterification, seemed to be not affected.In conclusion, the early modifications occurring in maize cell walls as a consequence of DCB-habituation involved quantitative and qualitative changes of arabinoxylans, but also other polysaccharides. Thereby some of the changes that took place in the cell walls in order to compensate for the lack of cellulose differed according to the DCB-habituation level, and illustrate the ability of plant cells to adopt appropriate coping strategies depending on the herbicide concentration and length of exposure time.

Monitoring meso-scale ordering of cellulose in intact plant cell walls using sum frequency generation spectroscopy.

Sum frequency generation (SFG) vibration spectroscopy can selectively detect crystalline cellulose without spectral interference from cell wall matrix components. Here, we show that the cellulose SFG spectrum is sensitive to cellulose microfibril alignment and packing within the cell wall. SFG intensity at 2,944 cm(-1) correlated well with crystalline cellulose contents of various regions of the Arabidopsis (Arabidopsis thaliana) inflorescence, while changes in the 3,320/2,944 cm(-1) intensity ratio suggest subtle changes in cellulose ordering as tissues mature. SFG analysis of two cellulose synthase mutants (irx1/cesa8 and irx3/cesa7) indicates a reduction in cellulose content without evidence of altered cellulose structure. In primary cell walls of Arabidopsis, cellulose exhibited a characteristic SFG peak at 2,920 and 3,320 cm(-1), whereas in secondary cell walls, it had peaks at 2,944 and 3,320 cm(-1). Starch (amylose) gave an SFG peak at 2,904 cm(-1) (CH methine) whose intensity increased with light exposure prior to harvest. Selective removal of matrix polysaccharides from primary cell walls by acid hydrolysis resulted in an SFG spectrum resembling that of secondary wall cellulose. Our results show that SFG spectroscopy is sensitive to the ordering of cellulose microfibrils in plant cell walls at the meso scale (nm to μm) that is important for cell wall architecture but cannot be probed by other spectroscopic or diffraction techniques.

Brittle culm15 encodes a membrane-associated chitinase-like protein required for cellulose biosynthesis in rice.

Plant chitinases, a class of glycosyl hydrolases, participate in various aspects of normal plant growth and development, including cell wall metabolism and disease resistance. The rice (Oryza sativa) genome encodes 37 putative chitinases and chitinase-like proteins. However, none of them has been characterized at the genetic level. In this study, we report the isolation of a brittle culm mutant, bc15, and the map-based cloning of the BC15/OsCTL1 (for chitinase-like1) gene affected in the mutant. The gene encodes the rice chitinase-like protein BC15/OsCTL1. Mutation of BC15/OsCTL1 causes reduced cellulose content and mechanical strength without obvious alterations in plant growth. Bioinformatic analyses indicated that BC15/OsCTL1 is a class II chitinase-like protein that is devoid of both an amino-terminal cysteine-rich domain and the chitinase activity motif H-E-T-T but possesses an amino-terminal transmembrane domain. Biochemical assays demonstrated that BC15/OsCTL1 is a Golgi-localized type II membrane protein that lacks classical chitinase activity. Quantitative real-time polymerase chain reaction and β-glucuronidase activity analyses indicated that BC15/OsCTL1 is ubiquitously expressed. Investigation of the global expression profile of wild-type and bc15 plants, using Illumina RNA sequencing, further suggested a possible mechanism by which BC15/OsCTL1 mediates cellulose biosynthesis and cell wall remodeling. Our findings provide genetic evidence of a role for plant chitinases in cellulose biosynthesis in rice, which appears to differ from their roles as revealed by analysis of Arabidopsis (Arabidopsis thaliana).

Plastid Uridine Salvage Activity Is Required for Photoassimilate Allocation and Partitioning in Arabidopsis

Nucleotides are synthesized from de novo and salvage pathways. To characterize the uridine salvage pathway, two genes, UKL1 and UKL2, that tentatively encode uridine kinase (UK) and uracil phosphoribosyltransferase (UPRT) bifunctional enzymes were studied in Arabidopsis thaliana. T-DNA insertions in UKL1 and UKL2 reduced transcript expression and increased plant tolerance to toxic analogs 5-fluorouridine and 5-fluorouracil. Enzyme activity assays using purified recombinant proteins indicated that UKL1 and UKL2 have UK but not UPRT activity. Subcellular localization using a C-terminal enhanced yellow fluorescent protein fusion indicated that UKL1 and UKL2 localize to plastids. The ukl2 mutant shows reduced transient leaf starch during the day. External application of orotate rescued this phenotype in ukl2, indicating pyrimidine pools are limiting for starch synthesis in ukl2. Intermediates for lignin synthesis were upregulated, and there was increased lignin and reduced cellulose content in the ukl2 mutant. Levels of ATP, ADP, ADP-glucose, UTP, UDP, and UDP-glucose were altered in a light-dependent manner. Seed composition of the ukl1 and ukl2 mutants included lower oil and higher protein compared with the wild type. Unlike single gene mutants, the ukl1 ukl2 double mutant has severe developmental defects and reduced biomass accumulation, indicating these enzymes catalyze redundant reactions. These findings point to crucial roles played by uridine salvage for photoassimilate allocation and partitioning.

Offspring of the crosses of two anti-sense potato plants exhibit additive cellulose reduction

Two transgenic potato lines, csr2-1 and csr4-8, containing two different antisense genes: csr2 and csr4, respectively, were crossed to investigate the possibility of achieving reduction in cellulose content in the tuber cell walls of the progeny. The progeny containing both transgenes (double csr2/csr4 transformant) exhibited reduction of 63% in cell wall cellulose content, while the single transformants csr2 and csr4 had a 44 and 22% reduction in cellulose content, respectively. Key words: Cellulose content, cellulose synthase, double transformant, genetic crossing, Solanum tuberosum.

Membrane trafficking mediated by OsDRP2B is specific for cellulose biosynthesis

Increasing evidence has revealed that membrane trafficking is highly associated with cell wall metabolism. Factors involved in vesicle delivery, e.g. cytoskeleton and motor proteins, have showed regulatory effects on cell wall structure and components. However, little is known about the involvement of other trafficking components in distribution of cell wall-related compartments. Dynamins are important proteins functioning in membrane tubulation and vesiculation. Recently, we have reported characterization of the rice dynamin-related protein 2B (OsDRP2B). Mutation in OsDRP2B causes a significant reduction in cellulose content. Its association with the trans-Golgi network (TGN) and clathrin-coated vesicles and the reduced CESA4 abundance at the bc3 plasma membrane suggest that BC3/OsDRP2B is involved in the transport of essential elements for cellulose synthesis. Here, we provide additional evidence for BC3 subcellular localization via observing OsDRP2B-GFP in living root hairs of transgenic plants. Uronic acid and fractional composition analyses further confirm that the amount of arabinoxylan and other noncellulosic polysaccharides is increased in bc3. However, three putative xylan synthesis genes are down-regulated in mutant plant revealed by real-time PCR analysis. These results imply that compartments delivered by OsDRP2B are specifically responsible for cellulose biosynthesis.

Isolation of a novel cell wall architecture mutant of rice with defective Arabidopsis COBL4 ortholog BC1 required for regulated deposition of secondary cell wall components

The plant secondary cell wall is a highly ordered structure composed of various polysaccharides, phenolic components and proteins. Its coordinated regulation of a number of complex metabolic pathways and assembly has not been resolved. To understand the molecular mechanisms that regulate secondary cell wall synthesis, we isolated a novel rice mutant, cell wall architecture1 (cwa1), that exhibits an irregular thickening pattern in the secondary cell wall of sclerenchyma, as well as culm brittleness and reduced cellulose content in mature internodes. Light and transmission electron microscopy revealed that the cwa1 mutant plant has regions of local aggregation in the secondary cell walls of the cortical fibers in its internodes, showing uneven thickness. Ultraviolet microscopic observation indicated that localization of cell wall phenolic components was perturbed and that these components abundantly deposited at the aggregated cell wall regions in sclerenchyma. Therefore, regulation of deposition and assembly of secondary cell wall materials, i.e. phenolic components, appear to be disturbed by mutation of the cwa1 gene. Genetic analysis showed that cwa1 is allelic to brittle culm1 (bc1), which encodes the glycosylphosphatidylinositol-anchored COBRA-like protein specifically in plants. BC1 is known as a regulator that controls the culm mechanical strength and cellulose content in the secondary cell walls of sclerenchyma, but the precise function of BC1 has not been resolved. Our results suggest that CWA1/BC1 has an essential role in assembling cell wall constituents at their appropriate sites, thereby enabling synthesis of solid and flexible internodes in rice.

Solid state fermentation of maize (<i>Zea mays</i>) cob by <i>Pleurotus ostreatus</i> strain EM-1: Biopolymer profiles and cellulose degradability

The low digestibility and low protein content of maize cob are major limitations to its use as animal feed in Ghana. The possibility of enhancing the feed potential of maize cob through solid state fermentation byPleurotus ostreatus strain EM-1 was investigated. At the end of spawn run, lignin, cellulose and hemicellulose content had decreased by 42.3, 5.6% and 41.0% respectively. No further reduction in lignin content occurredthereafter. In contrast, after 28 days, cellulose and hemicellulose had been degraded by 36.0% and 58.5% respectively. A biphasic protein profile, characterized by a 6-fold increase by day 14, followed by a dramatic decline was observed. The rate of release of reducing sugars from spent maize cobs during incubation with exogenous cellulase was 400% greater than that of untreated maize cobs. The present findings indicate that the positive effects of P. ostreatus strain EM-1 on the nutritive value of maize cob appear to be optimal after complete colonization by mycelia. At this stage, maximum biodegradation of lignin had occurred, protein content was markedly elevated and the reduction in cellulose content was negligible. Thus, solid state fermentation by Pleurotus ostreatus strain EM-1 may be an efficient means of transforming maize cob into nutritive animal feed. Keywords: Oyster mushroom, delignification, animal feed, biodegradation, cellulose, hemicellulose.

A missense mutation in the transmembrane domain of CESA4 affects protein abundance in the plasma membrane and results in abnormal cell wall biosynthesis in rice

Cellulose synthase (CESA) is a critical catalytic subunit of the cellulose synthase complex responsible for glucan chain elongation. Our knowledge about how CESA functions is still very limited. Here, we report the functional characterization of a rice mutant, brittle culm11, that shows growth retardation and dramatically reduced plant strength. Map-based cloning revealed that all the mutant phenotypes result from a missense mutation in OsCESA4 (G858R), a highly conserved residue at the end of the fifth transmembrane domain. The aberrant secondary cell wall of the mutant plants is attributed to significantly reduced cellulose content, abnormal secondary wall structure of sclerenchyma cells, and overall altered wall composition, as detected by chemical analyses and immunochemical staining. Importantly, we have found that this point mutation decreases the abundance of OsCESA4 in the plasma membrane, probably due to a defect in the process of CESA complex secretion. The data from our biochemical, genetic, and pharmacological analyses indicate that this residue is critical for maintaining the normal level of CESA proteins in the plasma membrane.

Cellulose content of tuber cell walls of progeny from a cross between two transgenic potato lines

Two transgenic potato lines, csr2-1 and csr4-8, containing two different antisense genes, csr2 and csr4, respectively, were crossed to investigate the possibility of achieving reduction in cellulose content in the tuber cell walls of the progeny. The progeny containing both transgenes (double csr2/csr4 transformant) exhibited reduction of 63% in cell wall cellulose content, while the single transformants csr2 and csr4 had a 44% and 22% reduction in cellulose content, respectively. Keywords : Cellulose content, cellulose synthase, double transformant, genetic crossing, Solanum tuberosum Cameroon Journal of Experimental Microbiology Vol. 4 (2) 2008: pp. 80-83

Alpha-glucosidase I is required for cellulose biosynthesis and morphogenesis in Arabidopsis.

Novel mutations in the RSW1 and KNOPF genes were identified in a large-scale screen for mutations that affect cell expansion in early Arabidopsis embryos. Embryos from both types of mutants were radially swollen with greatly reduced levels of crystalline cellulose, the principal structural component of the cell wall. Because RSW1 was previously shown to encode a catalytic subunit of cellulose synthase, the similar morphology of knf and rsw1-2 embryos suggests that the radially swollen phenotype of knf mutants is largely due to their cellulose deficiency. Map-based cloning of the KNF gene and enzyme assays of knf embryos demonstrated that KNF encodes α-glucosidase I, the enzyme that catalyzes the first step in N-linked glycan processing. The strongly reduced cellulose content of knf mutants indicates that N-linked glycans are required for cellulose biosynthesis. Because cellulose synthase catalytic subunits do not appear to be N glycosylated, the N-glycan requirement apparently resides in other component(s) of the cellulose synthase machinery. Remarkably, cellular processes other than extracellular matrix biosynthesis and the formation of protein storage vacuoles appear unaffected in knf embryos. Thus in Arabidopsis cells, like yeast, N-glycan trimming is apparently required for the function of only a small subset of N-glycoproteins.

Resistance against herbicide isoxaben and cellulose deficiency caused by distinct mutations in same cellulose synthase isoform CESA6.

Isoxaben is a pre-emergence herbicide that inhibits cellulose biosynthesis in higher plants. Two loci identified by isoxaben-resistant mutants (ixr1-1, ixr1-2, and ixr2-1) in Arabidopsis have been reported previously. IXR1 was recently shown to encode the cellulose synthase catalytic subunit CESA3 (W.-R. Scheible, R. Eshed, T. Richmond, D. Delmer, and C. Somerville [2001] Proc Natl Acad Sci USA 98: 10079-10084). Here, we report on the cloning of IXR2, and show that it encodes another cellulose synthase isoform, CESA6. ixr2-1 carries a mutation substituting an amino acid close to the C terminus of CESA6 that is highly conserved among CESA family members. Transformation of wild-type plants with the mutated gene and not with the wild-type gene conferred increased resistance against the herbicide. The simplest interpretation for the existence of these two isoxaben-resistant loci is that CESA3 and CESA6 have redundant functions. However, loss of function procuste1 alleles of CESA6 were previously shown to have a strong growth defect and reduced cellulose content in roots and dark-grown hypocotyls. This indicates that in these mutants, the presence of CESA3 does not compensate for the absence of CESA6 in roots and dark-grown hypocotyls, which argues against redundant functions for CESA3 and CESA6. Together, these observations are compatible with a model in which CESA6 and CESA3 are active as a protein complex.

Collapsed xylem phenotype of Arabidopsis identifies mutants deficient in cellulose deposition in the secondary cell wall.

Recessive mutations at three loci cause the collapse of mature xylem cells in inflorescence stems of Arabidopsis. These irregular xylem (irx) mutations were identified by screening plants from a mutagenized population by microscopic examination of stem sections. The xylem cell defect was associated with an up to eightfold reduction in the total amount of cellulose in mature inflorescence stems. The amounts of cell wall-associated phenolics and polysaccharides were unaffected by the mutations. Examination of the cell walls by using electron microscopy demonstrated that the decreases in cellulose content of irx lines resulted in an alteration of the spatial organization of cell wall material. This suggests that a normal pattern of cellulose deposition may be required for assembly of lignin or polysaccharides. The reduced cellulose content of the stems also resulted in a decrease in stiffness of the stem material. This is consistent with the irregular xylem phenotype and suggests that the walls of irx plants are not resistant to compressive forces. Because lignin was implicated previously as a major factor in resistance to compressive forces, these results suggest either that cellulose has a direct role in providing resistance to compressive forces or that it is required for the development of normal lignin structure. The irx plants had a slight reduction in growth rate and stature but were otherwise normal in appearance. The mutations should be useful in facilitating the identification of factors that control the synthesis and deposition of cellulose and other cell wall components.

Changes of Cell Wall Composition and Polymer Size in Primary Roots of Cotton Seedlings Under High Salinity

The aim of this study was to investigate changes in cell wall chemical composition and polymer size in the root tip of intact cotton seedlings (Gossypium hirsutum L. cv. Acala SJ-2) grown in saline environments, in order to relate the interaction between high salinity and root growth to possible changes in cell wall metabolism. Cotton seedlings were grown in modified Hoagland nutrient solution with various combinations of NaCl and CaCl 2 . Cell walls were fractionated into four fractions (pectin, hemicellulose 1 and 2, cellulose), and analysed for their total sugar content, neutral sugar composition and size of polysaccharides. At 1 mol m −3 Ca, 150 mol m −3 NaCl resulted in a significant increase in the cell wall uronic acid content, but a reduction in cellulose content on a per unit dry weight basis

Effects of salinity on cotton yield and quality

Abstract Three cotton cultivars (Gossypium hirsutum L.) were grown in sand culture in a glasshouse. The nutrient solution contained no or additional sodium chloride (43 or 86 mol m−3) and overall had electrical conductives ( ec ) of 1.4, 4.0 and 6.6 mmho cm−1. Cotton yield was lowered by salt but lint percent was increased. Fibre properties were lower in one group of plants, which flowered and were harvested later, than in the other, earlier group. Cotton raised at high ec values were shown to have a higher sugar content but decreased cellulose content. The fibers were thus of reduced maturity. Since fibre perimeters appeared to be unaffected, it would seem that the immature fibres would be lighter and weaker than their counterparts, and that this would explain the fact that micronaire values, linear density, maturity percent and ratio were all found to be lowered at high ec values. Similarly, moisture-regain values were increased. Attachment strength of the lint to the seed was also reduced at high ec values, although it is less certain that this was due to reduced cellulose content. The results show that both yield and quality of cotton can be affected by increases in electrical conductivity, and that the quality is probably related to decreased maturity of the individual fibres.

The cotton fibre

Three cotton cultivars (Gossypium hirsutum L.) were grown in sand culture in a glasshouse. The nutrient solution contained no or additional sodium chloride (43 or 86 mol m−3) and overall had electrical conductives (ec) of 1.4, 4.0 and 6.6 mmho cm−1. Cotton yield was lowered by salt but lint percent was increased. Fibre properties were lower in one group of plants, which flowered and were harvested later, than in the other, earlier group. Cotton raised at high ec values were shown to have a higher sugar content but decreased cellulose content. The fibers were thus of reduced maturity. Since fibre perimeters appeared to be unaffected, it would seem that the immature fibres would be lighter and weaker than their counterparts, and that this would explain the fact that micronaire values, linear density, maturity percent and ratio were all found to be lowered at high ec values. Similarly, moisture-regain values were increased. Attachment strength of the lint to the seed was also reduced at high ec values, although it is less certain that this was due to reduced cellulose content. The results show that both yield and quality of cotton can be affected by increases in electrical conductivity, and that the quality is probably related to decreased maturity of the individual fibres.