Degradation Of Cell Wall Components Research Articles

Effect of ozone treatment on the decay and cell wall metabolism during the postharvest storage of cantaloupe

Cantaloupe is a popular summer fruit with immense market potential in China. However, the cantaloupe fruits generally soften rapidly after harvest, which dramatically reduces their economic value. The ozone treatment has been found to be effective in delaying the softening of cantaloupe fruit. The results indicated that ozone treatment significantly inhibited the mycelial growth of Fusarium hypha. The ozone treatment was able to delay the decline of total soluble solids, lower the respiration rate, and maintain the fruit's firmness without damaging fruit quality. The study also indicated that the activity and gene expression of cell wall degrading enzymes such as polygalacturonase (PG), pectin methylesterase (PME), β-galactosidase (β-gal), cellulose (Cx), and α-l-arabinofuranosidase (α-l-Af), were inhibited under ozone treatment, which also suppressed the degradation of cell wall components associated with fruit softening (protopectin, soluble pectin, cellulose, and hemicellulose). These changes may contribute to the maintenance of cell wall components, thereby delaying the fruit softening. In conclusion, these results suggested that ozone can improve the fruit quality of cantaloupe by suppressing postharvest fungal diseases and delaying fruit softening, which provides a theoretical basis for further research on cell wall metabolism during cantaloupe storage.

The Zinc Finger Protein MaCCCH33-Like2 Positively Regulates Banana Fruit Ripening by Modulating Genes inStarch andCell Wall Degradation.

As zinc finger protein transcription factors (TFs), the molecular mechanism of Cys-Cys-Cys-His (CCCH) TFs in regulating plant development, growth and stress response has been well studied. However, the roles of CCCH TFs in fruit ripening are still obscure. Herein, we report that MaCCCH33-like2 TF and its associated proteins modulate the fruit softening of 'Fenjiao' bananas. MaCCCH33-like2 interacts directly with the promoters of three genes: isoamylase2 (MaISA2), sugar transporter14-like (MaSUR14-like) and β-d-xylosidase23 (MaXYL23), all of which are responsible for encoding proteins involved in the degradation of starch and cell wall components. Additionally, MaCCCH33-like2 forms interactions with abscisic acid-insensitive 5 (ABI5)-like and ethylene F-box protein 1 (MaEBF1), resulting in enhanced binding and activation of promoters of genes related to starch and cell wall degradation. When MaCCCH33-like2 is transiently and ectopically overexpressed in 'Fenjiao' banana and tomato fruit, it facilitates softening and ripening processes by promoting the degradation of cell wall components and starch and the production of ethylene. Conversely, the temporary silencing of MaCCCH33-like2 using virus-induced gene silencing (VIGS) inhibits softening and ripening in the 'Fenjiao' banana by suppressing ethylene synthesis, as well as starch and cell wall degradation. Furthermore, the promoter activity of MaCCCH33-like2 is regulated by MaABI5-like. Taken together, we have uncovered a novel MaCCCH33-like2/MaEBF1/MaABI5-like module that participates in fruit softening regulation in bananas.

Effects of inoculation with a binary mixture of Lactobacillus plantarum and Leuconostoc citreum on cell wall components of Chinese Dongbei suancai

This study aimed to investigate the effects of inoculation with a starter culture consisting of Lactobacillus plantarum LNJ002 and Leuconostoc citreum BNCC 194779 on microbial community, cell wall polysaccharide characteristics, cell wall degrading enzymes, and microstructure during Chinese Dongbei suancai fermentation. The results showed that Lactobacillus (98.75%) was the dominant genus during fermentation of Dongbei suancai. The principal coordinates analysis (PCoA) suggested that inoculation with Lactobacillus promoted the stability of microbial community structure during Chinese Dongbei suancai fermentation. Besides, the lower content in cellulose (80.28 ± 2.61 ug/mg) and pectin (53.56 ± 2.67 ug/mg) observed in the inoculated fermented suancai. Simultaneously, the inoculated fermented suancai had the most decreases in SR 1 (70.35%) and SR 3 (72.06%) and the most increase in SR 2 (950%), which suggested that inoculation intensified the decrease of the linearity and the RG-1 branching degree of pectin. The contents of polygalacturonase (PG) and pectin methylesterase (PME) in inoculated fermented suancai were 21.06% and 21.86% higher than those in naturally fermented suancai. In addition, the surface of suancai leaves gradually changed from smooth to rough during fermentation, which was accelerated by inoculation. Moreover, Lactobacillus, Aspergillus, Wallemia and Mucor were all negatively correlated with cellulose and GalA. These results revealed that inoculation promoted the formation of dominant genus structure during suancai fermentation, changed the effects of enzymes on the degradation of cell wall components, thereby accelerated the formation of Chinese Dongbei suancai texture.

Contribution of tung oil to the resistance of heat-induced wood shrinkage during thermal modification

Thermal modification is commonly employed in the wood industry as an effective commercial strategy. However, heat-induced shrinkage accompanied by treatment processes may lead to a decreased wood recovery and devaluation of the products. In this study, tung oil was used to relieve heat-induced shrinkage during the thermal modification process, and the anti-shrinkage mechanism was investigated. The results indicated that the primary cause of heat-induced shrinkage in wood was the thermal degradation of cell wall components. There was a significant correlation (Spearman correlation coefficient = 0.974, p < 0.01) between the weight percent change (WPC) and heat-induced shrinkage (HS) in the air-thermally modified samples (TMA wood). Tung oil thermally modified samples (TMO wood) presented a lower shrinkage compared to TMA wood. The thermal modification process also influenced the relative content of wood components, leading to a shift of the cell wall mesopores in TMA wood towards larger sizes as the temperature increased. On the contrary, tung oil could increase the thermal degradation temperature, improve thermal stability and decelerate thermal degradation of wood, thus preventing the enlargement of cell wall mesopores. The impregnation of tung oil into the internal structures of wood, such as vessels, fibers, and ray cells, provided additional support to the cell lumen. In addition, confocal laser scanning microscopy (CLSM) presented that tung oil was uniformly distributed in the wood cell walls and occupied portions of mesopores, reducing the total pore volume of nitrogen absorption. Therefore, tung oil is a green and renewable modifier that effectively resisted heat-induced shrinkage during thermal modification. The anti-shrinkage approach exhibits considerable potential for improving wood recovery, conserving forestry resources, and promoting the development of a sustainable wood industry.

1-Methylcyclopropene treatment delays the softening of Actinidia arguta fruit by reducing cell wall degradation and modulating carbohydrate metabolism

The rapid softening of hardy kiwifruit (Actinidia arguta) fruit significantly reduces its marketing potential. Therefore, the effect of 1-methylcyclopropene (1-MCP) on the softening of A. arguta fruit was investigated. Results indicated that A. arguta fruit treated with 1-MCP maintained a higher level of firmness, titratable acidity, ascorbic acid, total phenolics, and flavonoids content, relative to non-treated fruit. Fruit treated with 1-MCP and placed in long-term cold storage had higher sensory scores, as determined by a taste panel and supported by electronic nose and tongue data. Notably, 1-MCP delayed the degradation of cell wall components, including pectin, cellulose, and hemicellulose, by reducing the activity of cell-wall-modifying enzymes. In addition, 1-MCP reduced the activity of carbohydrate metabolism-related enzymes, resulting in fruit with higher levels of starch and sucrose and lower levels of glucose, fructose and sorbitol. Collectively, these results indicate that 1-MCP can be used to delay the softening of A. arguta fruit and extend its storage and shelf life.

Identification of the cell wall proteins associated with the softening of Lycium barbarum L. fruit by using iTRAQ technology

Excessive softening of Lycium barbarum L. (LBL) fruit can limit the storage and transportation of fresh fruit. To better understand the underlying molecular mechanisms of fruit softening in LBL, changes in the pre-climacteric (S1) and post-climacteric (S2) proteomes were investigated by iTRAQ methods. The 14-fold reduction in S2 fruit firmness compared to S1 was accompanied by increased espiratory intensity and degradation of cell wall components. A total of 258 differentially expressed proteins (DEPs) were identified, which were mainly associated with photosynthesis, carbohydrate, amino acids and fatty acids metabolism. From the functional proteomic analysis, enhanced energy metabolisms, such as glycolysis/gluconeogenesis and citrate cycle (TCA cycle) contributed to cell wall degradation and conversion to substrates for respiratory metabolism, leading to fruit softening. These findings have provided new insights into the molecular pathways associated with fruit softening in LBL and the bioinformatics analyses provided insightful information for further transcriptional studies.

Building a Flower: The Influence of Cell Wall Composition on Flower Development and Reproduction.

Floral patterning is a complex task. Various organs and tissues must be formed to fulfill reproductive functions. Flower development has been studied, mainly looking for master regulators. However, downstream changes such as the cell wall composition are relevant since they allow cells to divide, differentiate, and grow. In this review, we focus on the main components of the primary cell wall—cellulose, hemicellulose, and pectins—to describe how enzymes involved in the biosynthesis, modifications, and degradation of cell wall components are related to the formation of the floral organs. Additionally, internal and external stimuli participate in the genetic regulation that modulates the activity of cell wall remodeling proteins.

Characterization of Fruit Quality Attributes and Cell Wall Metabolism in 1-Methylcyclopropene (1-MCP)-Treated 'Summer King' and 'Green Ball' Apples During Cold Storage.

This study aimed to elucidate whether 1-methylcyclopropene (1-MCP) treatment delays the fruit softening mechanism associated with the fruit quality of the newly released apple cultivars “Summer King” and “Green Ball” during cold storage. For both cultivars, the fruit treated with 1-MCP exhibited lower internal ethylene concentration, higher firmness, and higher titratable acidity relative to the control fruit, in association with less fruit softening. In addition, the treated fruit significantly delayed fresh weight loss and reduction of soluble solids content, especially in “Green Ball.” Moreover, slower degradation of cell wall components (water-soluble pectin, sodium carbonate-soluble pectin, hemicellulose, and cellulose) was also observed in the treated fruit in comparison to the control fruit. Similarly, the enzymatic activities (of polygalacturonase, pectin methylesterase, cellulase, β-galactosidase, and α-L-arabinofuranosidase) that cause cell wall degradation were relatively lower in the treated fruit than in the control fruit for both cultivars, which was further proved by transcriptional analysis of the genes encoding the enzymes. Overall, the results suggested that the usage of 1-MCP is useful to delay fruit softening of the two cultivars during cold storage by delaying the degradation of cell wall components and enzymatic activities of cell wall hydrolysis.

Creep behavior of heat treated beech wood and the relation to its chemical structure

In this study, wood was heat treated at temperatures of 160, 175 and 190 °C and creep behavior of modified wood at various moisture contents was assessed. Fourier-transform infrared spectroscopy (FTIR) was conducted to find a relation between creep behavior and structural changes, aiming to develop their applications for constructionpurposes. FTIR results showed fundamental structural changes: removal of extractives, hemicelluloses and amorphous parts of cellulose and partial degradation of lignin. Creep results showed that unlike elastic short-term modulus, creep modulus decreased at treating temperature higher than 160 °C. Treated samples at 160 °C had an improved creep performance in moist conditions, attributable to lower degradation of cell wall components and to the lower hygroscopicity.

Infection Strategies Deployed by Botrytis cinerea, Fusarium acuminatum, and Rhizopus stolonifer as a Function of Tomato Fruit Ripening Stage.

Worldwide, 20–25% of all harvested fruit and vegetables are lost annually in the field and throughout the postharvest supply chain due to rotting by fungal pathogens. Most postharvest pathogens exhibit necrotrophic or saprotrophic lifestyles, resulting in decomposition of the host tissues and loss of marketable commodities. Necrotrophic fungi can readily infect ripe fruit leading to the rapid establishment of disease symptoms. However, these pathogens generally fail to infect unripe fruit or remain quiescent until host conditions stimulate a successful infection. Previous research on infections of fruit has mainly been focused on the host’s genetic and physicochemical factors that inhibit or promote disease. Here, we investigated if fruit pathogens can modify their own infection strategies in response to the ripening stage of the host. To test this hypothesis, we profiled global gene expression of three fungal pathogens that display necrotrophic behavior—Botrytis cinerea, Fusarium acuminatum, and Rhizopus stolonifer—during interactions with unripe and ripe tomato fruit. We assembled and functionally annotated the transcriptomes of F. acuminatum and R. stolonifer as no genomic resources were available. Then, we conducted differential gene expression analysis to compare each pathogen during inoculations versus in vitro conditions. Through characterizing patterns of overrepresented pathogenicity and virulence functions (e.g., phytotoxin production, cell wall degradation, and proteolysis) among the differentially expressed genes, we were able to determine shared strategies among the three fungi during infections of compatible (ripe) and incompatible (unripe) fruit tissues. Though each pathogen’s strategy differed in the details, interactions with unripe fruit were commonly characterized by an emphasis on the degradation of cell wall components, particularly pectin, while colonization of ripe fruit featured more heavily redox processes, proteolysis, metabolism of simple sugars, and chitin biosynthesis. Furthermore, we determined that the three fungi were unable to infect fruit from the non-ripening (nor) tomato mutant, confirming that to cause disease, these pathogens require the host tissues to undergo specific ripening processes. By enabling a better understanding of fungal necrotrophic infection strategies, we move closer to generating accurate models of fruit diseases and the development of early detection tools and effective management strategies.

Changes in pericarp morphology, physiology and cell wall composition account for flesh firmness during the ripening of blackberry (Rubus spp.) fruit

Fruit flesh firmness plays a critical role in controlling blackberry (Rubus spp.) postharvest shelf life. This work aimed to identify the underlying characteristics in pericarp morphology, cell wall hydrolase activity and cell wall composition that account for flesh firmness in soft-fruited ‘Boysen’ and firm-fruited ‘Arapaho’ cultivars that have a similar ripening time of 39 days after flowering (DAF). The fruit firmness of both fruits decreased noticeably at the onset of color change, and this decrease hastened from 33 DAF to ripening despite considerable differences in their temporal changes. The evaluation of pericarp cellular morphology revealed that the disassembly of the cell wall in both fruits was likely initiated at 33 DAF, followed by extreme degradation at 39 DAF. Cell wall hydrolase activity assays indicated that increases in polygalacturonase (PG) and cellulase activity also dramatically occurred in the late softening stages of both fruits. Notably, appreciably higher levels of cellulase, and significant increases in pectin methylesterase (PME), α-L-arabinofuranosidase (α-L-Af) and xyloglucan endotransglycosylase (XET) were only detected in the late ripening stages of ‘Boysen’. In terms of cell wall components, the levels of cell wall material (CWM), cellulose and hemicellulose declined similarly during ripening in both fruits. Comparatively, lower levels of CWM, chelator soluble pectin (CSP), sodium carbonate soluble pectin (SSP), and hemicellulose as well as higher levels of water soluble pectin (WSP) were found in ‘Boysen’ than those in ‘Arapaho’ during maturation and ripening. Overall, the loss of fruit firmness during ripening in blackberry fruit is correlated closely with biochemical changes in cell wall fractions that involve hydrolytic processes, resulting in the breakdown of cell-wall polymers. The low firmness of ‘Boysen’, as determined by cell wall degradation, could be of particular relevance to the function of cell wall degrading enzymes and to the more drastic degradation of cell wall components than that in the firm cv. ‘Arapaho’.

Alginate oligosaccharide postharvest treatment preserve fruit quality and increase storage life via Abscisic acid signaling in strawberry

Abscisic acid (ABA) has been advocated to play substantial role on ripening of non-climacteric fruit. Here we report that alginate oligosaccharide (AOS) postharvest treatments delayed the accumulation of ABA and ABA-conjugates and restrained the expression of ABA signaling genes, resulting enlarged storage life of strawberry. In addition, AOS postharvest treatments also increased the quality and reduced the degradation of cell wall components and repressed the expression of cell wall degradation genes. AOS treated fruits exhibited significant delays of hardness, decay percentage, titratable acidity, pH, total soluble solids and vitamin C content compared to untreated fruits. Moreover, AOS had a positive effect on retaining higher amount of anthocyanin, total phenol and flavonoids contents. The finding of this study suggests that AOS postharvest treatments are very useful for preserving fruit quality and enhancing shelf life by delayed ABA accretion, restrained the gene expression related to ABA signaling and cell wall degeneration.

Prediction of the Diplocarpon rosae secretome reveals candidate genes for effectors and virulence factors

Rose black spot is one of the most severe diseases of field-grown roses. Though R-genes have been characterised, little information is known about the molecular details of the interaction between pathogen and host. Based on the recently published genome sequence of the black spot fungus, we analysed gene models with various bioinformatic tools utilising the expression data of infected host tissues, which led to the prediction of 827 secreted proteins. A significant proportion of the predicted secretome comprises enzymes for the degradation of cell wall components, several of which were highly expressed during the first infection stages. As the secretome comprises major factors determining the ability of the fungus to colonise its host, we focused our further analyses on predicted effector candidates. In total, 52 sequences of 251 effector candidates matched several bioinformatic criteria of effectors, contained a Y/F/WxC motif, and did not match annotated proteins from other fungi. Additional sequences were identified based on their high expression levels during the penetration/haustorium formation phase and/or by matching known effectors from other fungi. Several host genotypes that are resistant to the sequenced isolate but differ in the R-genes responsible for this resistance are available. The combination of these genotypes with functional studies of the identified candidate effectors will allow the mechanisms of the rose black spot interaction to be dissected.

The Role of Cell Wall Degrading Enzymes in Pathogenesis of Magnaporthe oryzae.

The plant cell wall is always the physical barrier in which phytopathogenic fungi must overcome by producing an array of cell wall degrading enzymes (CWDEs) that allow them to invade host tissues through the degradation of cell wall components of plants. Magnaporthe oryzae is a causal agent of blast disease, one of the most devastating disease in rice resulting significant crop losses worldwide. The penetration of plant cuticle and cell walls induced by infection structures of M. oryzae has been known to be acquired by the association of turgor pressure and CWDEs for successful infection of M. oryzae. In this review, we focus on recent discoveries of M. oryzae CWDEs, gene regulation and their biological roles as fungal virulence factors and elicitors of host defense response leading to plant resistance against fungal pathogens.

Effects of acidic electrolyzed oxidizing water on retarding cell wall degradation and delaying softening of blueberries during postharvest storage

This study was to evaluate the effect of acidic electrolyzed oxidizing water (AEW) on extending the shelf-life of blueberries during postharvest storage. On day 0, two cultivars of blueberries (Brightwell and Camellia) were washed by AEW with available chlorine concentration (ACC) of 48 mg/L at pH 2.8 for 5 min, and then stored at 4 °C until analyzing. Quality attributes of blueberries including firmness, cell wall composition and cell wall degrading enzymes were analyzed on days 0, 3, 6, 9, 12 and 15. Results showed that Brightwell softened faster than Camellia. AEW treatment slowed down the softening of both cultivars, while it had higher efficacy on delaying the softening of Camellia blueberries than the Brightwell blueberries. In addition, AEW treatment deactivated different cell wall degrading enzymes (CWDEs, polygalacturonase (PG), cellulase and β-galactosidase) and prevented the degradation of cell wall components including Na2CO3-soluble pectin (NSP), hemicellulose and cellulose. These results suggested that AEW treatment can be used as a postharvest technique to delay the softening process of blueberries during storage through lowering CWDEs activities and preventing degradation of cell wall components.

Reversible and irreversible dimensional changes of heat-treated wood during alternate wetting and drying

Spruce wood specimens were heat-treated in saturated water vapor (steaming) and in the absence of moisture (dry heating) at 120–180 °C, and their wet volumes were measured during alternate wetting and drying cycles. After the first wetting and drying cycle, the wet volume of steamed wood decreased and then remained unchanged during the following alternate wetting and drying cycles. The wet volume regained its initial level when soaked in dimethyl sulfoxide (DMSO), followed by washing in water, but decreased again after subsequent drying and rewetting. Such reversible changes were not observed in unheated and dry-heated specimens. This suggested a hydrophobic structure formed during drying or plastic expansion of cell lumen due to steaming and soaking in DMSO. Although heat treatments reduced the hygroscopicity of the wood, steamed wood showed more swelling, i.e., lower dimensional stability than unheated and dry-heated wood. This is probably because steaming caused serious degradation of cell wall components, therefore loosening its fiber-reinforced structure restricting the swelling of the cell wall. When wood is exposed to alternate wetting and drying, steaming is not advisable because it may reduce the dimensional stability of the wood.

Surface Characteristics of Poplar Wood with High-Temperature Heat Treatment: Wettability and Surface Brittleness

The many uses of wood are greatly affected by its surface properties, which are significantly altered by heat treatment. Investigated here are the wettability and surface brittleness when treating poplar wood with heat at 160, 180, 200, and 220 °C for 2 h. Contact angles were measured by the sessile drop method, and surface free energy was calculated. Surface brittleness was expressed by hardness (HD value), roughness (Ra, Rq, Ry, and Rz values), and abrasive resistance (K value). Next, non-destructive Fourier transform near-infrared spectroscopic (FT-NIR) and X-ray photoelectron spectroscopic (XPS) measurements were employed to analyze the surface chemical changes. Scanning electron microscopy (SEM) revealed the post-heating microscopic structure. The results demonstrated that heat treatment reduces the surface wettability while increasing the surface brittleness, which becomes more apparent with increased temperature. Significant differences were determined (p < 0.05) between the surface parameters at four different temperatures. The degradation of cell wall components and the deterioration of microstructures was further expounded by FT-NIR, XPS, and SEM analyses. Furthermore, the abrasive resistance and hardness values decreased in line with the rate of weight loss (WL, %) and temperature. This indicates a strong correlation between the surface characteristics and the WL or temperature. The intensity of heat treatment appears to be predictable and easy to regulate.

Assessing the destructive behaviors of two white-rot fungi on beech wood

This research assessed the destructive behaviors of two white-rot fungi, Pleurotus ostreatus and Trametes versicolor and compared their degradation capabilities on solid oriental beech wood (Fagus orientalis Lipsky). Beech wood specimens were exposed to both fungi for a period of 120 days based on the specifications in the EN-113 standard. Mechanical properties and chemical composition of the specimens were measured every 15 days. Mass loss (ML) caused by the two fungi were not significantly different at the last stage of exposure, although T. versicolor showed higher ML at the middle exposure intervals. Compression strength parallel to grain, hardness, and impact bending values were higher in specimens exposed to P. ostreatus, although differences were not statistically significant. Microscopic images showed nearly the same decay patterns for both fungi. The results of the chemical assessment indicated that degradation of cell wall components was approximately the same for both fungi, but in some case T. versicolor showed a slightly higher potential to decay compared to P. ostreatus, especially in the early stages of exposure. The two fungi differed in their ability to reduce degree of polymerization (DP) holocellulose of beech wood. It was concluded that the destructive behaviors ability of both fungi was considerable.

Fungal pretreatment by Phanerochaete chrysosporium for enhancement of biogas production from corn stover silage.

Corn stover silage (CSS) was pretreated by Phanerochaete chrysosporium in solid-state fermentation (SSF), to enhance methane production via subsequent anaerobic digestion (AD). Effects of washing of corn stover silage (WCSS) on the lignocellulosic biodegradability in the fungal pretreatment step and on methane production in the AD step were investigated with comparison to the CSS. It was found that P. chrysosporium had the degradation of cellulose, hemicellulose, and lignin of CSS up to 19.9, 32.4, and 22.6 %, respectively. Consequently, CSS pretreated by 25 days achieved the highest methane yield of 265.1 mL/g volatile solid (VS), which was 23.0 % higher than the untreated CSS. However, the degradation of cellulose, hemicellulose, and lignin in WCSS after 30 days of SSF increased to 45.9, 48.4, and 39.0 %, respectively. Surface morphology and Fourier-transform infrared spectroscopy analyses also demonstrated that the WCSS improved degradation of cell wall components during SSF. Correspondingly, the pretreatment of WCSS improved methane production by 19.6 to 32.6 %, as compared with untreated CSS. Hence, washing and reducing organic acids (such as lactic acid, acetic acid, propionic acid, and butyric acid) present in CSS has been proven to further improve biodegradability in SSF and methane production in the AD step.

Exogenous fibrolytic enzymes to unlock nutrients: Histological investigation of its effects on fibre degradation in ruminants

There is a need for a better understanding of the mode-of-action of exogenous fibrolytic enzymes (EFE) used as additives in ruminant feeds. Four forages, treated with EFE, were evaluated in vitro and histologically, in an attempt to determine the effect of EFE on tissue degradation. Weeping love grass, kikuyu leaf material, lucerne and wheat straw stem material were histologically evaluated. Simultaneously, milled samples were incubated in the rumen fluid inoculated media for the determination of in vitro digestibility. The main focus, however, was a quantitative assessment of the degradation of the plant tissue at histological level over a 24 h incubation period. Degradation of cell wall components were quantified using the image analysis software. After 12 h of incubation, cell walls of the metaxylem of kikuyu and weeping love grass leaf material were thinner for the EFE treatment than for the control treatment. Treatment also resulted in a significant thinning effect of the cell walls of kikuyu phloem (12 h) and the adaxial epidermis (24 h). The abaxial epidermis at 12 h was thinner for weeping love grass due to EFE treatment. For stem material, a thinning of the epidermis of EFE treated lucerne was observed. Histological findings were concomitant with higher in vitro digestibilities of EFE treated lucerne and kikuyu. It was concluded that image analysis can be useful to quantify changes in cell wall due to the treatment of forages with EFE. There was a definite, subtle thinning effect of EFE on cell wall thickness of plant material which could be indicative of the mode-of-action of EFE.