Locule Tissue Research Articles

All-flesh fruit in tomato is controlled by reduced expression dosage of AFF through a structural variant mutation in the promoter.

The formation of locule gel is an important process in tomato and is a typical characteristic of berry fruit. In this study, we examined a natural tomato mutant that produces all-flesh fruit (AFF) in which the locule tissue remains in a solid state during fruit development. We constructed different genetic populations to fine-map the causal gene for this trait and identified SlMBP3 as the locus conferring the locule gel formation, which we rename as AFF. We determined the causal mutation as a 416-bp deletion in the promoter region of AFF, which reduces its expression dosage. Generally, this sequence is highly conserved among Solanaceae, as well as within the tomato germplasm. Using BC6 near-isogenic lines, we determined that the reduced expression dosage of AFF did not affect the normal development of seeds, whilst producing unique, non-liquefied locule tissue that was distinct from that of normal tomatoes in terms of metabolic components. Combined analysis using mRNA-seq and metabolomics indicated the importance of AFF in locule tissue liquefaction. Our findings provide insights into fruit-type differentiation in Solanaceae crops and also present the basis for future applications of AFF in tomato breeding programs.

Potential for Nezara viridula (Hemiptera: Pentatomidae) to Transmit Bacterial and Fungal Pathogens into Cotton Bolls

Recently, we showed that the southern green stink bug (SGSB), Nezara viridula (L.), can transmit Pantoea agglomerans (Ewing and Fife), an opportunistic bacterium, into green cotton bolls resulting in plant disease. Here, we hypothesized that our established model could be used to determine if the SGSB was a general, non-discriminate vector by using two other opportunistic bacterial pathogens of bolls (Pantoea ananatis [Serano] and Klebsiella pneumoniae [Schroeter]) and the known fungal pathogen Nematospora coryli (Peglion). Variants of P. ananatis (strain Pa-1R) and K. pneumoniae (strain Kp 5-1R) selected for rifampicin (Rif) resistance were used as bacterial opportunists. N. coryli was detected only from laboratory-reared SGSB directly exposed to the fungus. Both Pa-1R and Kp 5-1R were recovered from SGSB previously provided a contaminated food source (2 days), sterile food (5 days), and then harvested after being caged on bolls (2 days) at levels reaching 10(3) and 10(4) colony forming units (cfus) per insect, respectively. However, bolls caged with insects infected with Pa-1R or Kp 5-1R and with evidence of feeding did not become diseased nor were either opportunists detected from boll tissues. Insects infected with N. coryli transmitted the pathogen, which resulted in diseased bolls and fungi concentrations reached 10(6) cfus/g locule tissue at 2 weeks following the caging period. Notably, each of the three pathogens independently caused boll disease when mechanically inoculated using a needle puncture. Generally, these results suggest that cotton pathogen acquisition by the SGSB was not sufficient to determine whether the insects were disease vectors of the opportunists.

Core Rot Development in Red Delicious Apples Is Affected by Susceptibility of the Seed Locule to Alternaria alternata Colonization

ABSTRACT Alternaria alternata is the causal organism of core rot decay symptoms in susceptible cv. Red Delicious but not in resistant cv. Golden Delicious. The two cultivars did not differ in natural colonization of the style and ovary during the first week after full bloom; colonization of the ovary in the susceptible cultivar subsequently decreased with increasing distance from the calycine tube. By 30 days after full bloom, Alternaria recovery from ovary 1, adjacent to the end of the calycine tube, was 100 and 40% in the susceptible and resistant cultivars, respectively. In the susceptible cultivar, Alternaria recovery decreased from 75 to 20% in ovaries 2, 3, and 4, while there was only minor incidence in the resistant cultivar. Inoculation of the mesoderms of the two cultivars induced similar decay symptoms, but inoculated locules of Red Delicious were more susceptible than those of Golden Delicious. Increased inoculum concentration or isolate virulence enhanced the difference in locule susceptibility between the cultivars. Inoculation on isolated seed locules or on media amended with susceptible locule tissue as a carbon source induced greater transcript levels of several genes than the inoculation on resistant tissue. Endo- and exoglucanase activity levels were higher at pH 4.8 than at 4.2, conditions typical of the mesoderm adjacent to the seed locules of the susceptible and resistant cultivars, respectively. Current results suggest that susceptibility of Red Delicious apples to core rot decay is dependent on the sensitivity to locule colonization and on mesoderm pH, a factor that enhances fungal virulence.

(470) Lycopene Content of Mini Watermelon Varieties Grown at Four Locations

Mini watermelons are the size of cantaloupes and weigh 1.5 to 3 kg (4 to 8 lbs). Melons of 18 selections were grown in replicated trials in North Carolina, South Carolina, and north and south Florida. Melons were harvested when ripe, and samples of heart and locule tissue were frozen and sent to Lane, Okla. A total of 960 samples, representing 6-12 melons per selection per location, were analyzed for total lycopene content using colorimeter and spectrophotometer methods. Subsamples of `Mohican', `Hazera 6007', `Vanessa', `Petite Treat', and `Precious Petite' were analyzed by HPLC for carotenoid profiles. Total lycopene content ranged from 52 to 108 μg·g-1, depending on variety. Selections were grouped into two levels of lycopene content. The varieties Precious Petite, Petite Perfection, Betsy, Bonny, Petite Treat, Valdoria, Vanessa, Hazera 5133 and 5138, RWT 8149, 8155, 8162 had 60 to 79 μg·g-1 lycopene and the varieties Hazera 6007, 5123, 5109, 5177, Mohican, and Extazy had 80 to 100 μg·g-1. Melons harvested from the Florida locations had more total lycopene than those from North and South Carolina. `Precious Petite' had more β-carotene as a percentage of total carotenoids than other varieties tested. These results indicate that lycopene content is affected primarily by germplasm and also by environment.

Phytohormones in Shoots and Fruits of Tomato; Apoplast Solution and Seedless Fruit

Indole-3-acetic acid (IAA) endogenous levels were determined by liquid chromatography-mass spectrometry, diffusible levels were determined by fluorometric detection and polar transport activity was determined by radioactive IAA in tomato plants. IAA concentration in the apoplast (AP) solution was higher than those in the symplast (SP) solution in both upper and lower parts of stems. It is suggested that the amount of polar IAA transport might be only 19% of the amount of endogenous IAA in stems. In fruits, concentrations of abscisic acid (ABA) were high in the pericarp, axis and the locule tissue in the early growth stages. In seedless fruits of parthenocarpic tomato, the levels of IAA, gibberellic acid1 (GA1), trans-zeatin (Z) and trans-zeatin riboside (ZR) were analyzed. IAA concentrations of the pericarps and partitions were higher in fruits of 8 cm in diameter (8-cm-fruit) than in 6-cm-fruit. In the partitions, IAA concentrations of SP were higher than those of AP solution. The SP of the partitions in 6-cm-fruit had the highest concentration of Z and was 2.7 times greater than the AP. The ZR concentration in locule tissues in 6-cm-fruit was the highest. These results suggest that the sites of synthesis may be the SP of partitions for IAA and Z, and locules for ZR.

Armazenamento sob atmosfera controlada de tomates com injúria interna de impacto

A injúria interna de impacto causa redução significativa da qualidade de frutos de tomate. O presente trabalho teve como objetivo avaliar a utilização do armazenamento sob atmosfera controlada na redução do desenvolvimento de uma desordem de amadurecimento conhecida como injúria interna de impacto. Tomates (Lycopersicon esculentum Mill), cv. Solimar, foram colhidos no estádio de amadurecimento verde-maduro e tratados com etileno, por 12 horas, a 20°C. Ao atingirem o estádio verde-rosado, sofreram uma queda de 40 cm de altura sobre uma superfície plana, lisa e maciça. Metade dos frutos foi então armazenada sobre atmosfera controlada (3% O2; 4% CO2; balanço com N2) por 8 dias a 20°C e 85-95% de umidade relativa, e então foram transferidos para atmosfera ambiente até completamente maduros. A outra metade dos frutos foi mantida continuamente em atmosfera ambiente à mesma temperatura e umidade relativa. Quando estavam completamente maduros, os frutos que sofreram injúria mecânica, armazenados sob atmosfera controlada e sob atmosfera ambiente, desenvolveram sintomas de injúria interna de impacto no tecido locular. O armazenamento sob atmosfera controlada não produziu efeitos significativos no conteúdo de vitamina C total e carotenóides totais para o pericarpo e o tecido locular injuriados. Entretanto, o tecido locular injuriado do tratamento armazenado sob atmosfera controlada possuía acidez titulável 15% superior (ao redor de 162 meq ácido cítrico. kg-1) do que o tratamento sob atmosfera ambiente (ao redor de 140 meq ácido cítrico. kg-1) e era similar ao tratamento não injuriado, armazenado em atmosfera ambiente (ao redor de 174 meq ácido cítrico. kg-1). O tecido pericárpico da região injuriada possuía atividade da poligalacturonase similar para os tratamentos armazenados sob ar ou sob atmosfera controlada. O extravasamento de eletrólitos do pericarpo injuriado foi similar para os tratamentos sob atmosfera ambiente e atmosfera controlada (ao redor de 50%) e de cerca de 40% para os tecidos não-injuriados em ambos os tratamentos de armazenamento. A utilização de armazenamento sob atmosfera controlada não retardou ou impediu as alterações de qualidade observadas, nas condições experimentais, de frutos submetidos a injurias mecânicas de impacto.

Internal Bruising Alters Aroma Volatile Profiles in Tomato Fruit Tissues

Tomato (Lycopersicon esculentum Mill.) fruit, cv. Solar Set, were harvested at the mature-green stage and treated with 50 μL·L-1 ethylene at 20 °C. Individual fruits at the breaker stage (<10% red color) were dropped onto a solid surface to induce internal bruising. Dropped and undropped fruit were stored at 20 °C until red-ripe, at which time pericarp, placental, and locule tissues were excised. Tissues from dropped tomatoes were examined for evidence of internal bruising and all tissues were analyzed for selected volatile profiles via headspace analysis. Individual volatile profiles of the three tissues in bruised fruit were significantly different from those of corresponding tissues in undropped, control fruit, notably: trans-2-hexenal from pericarp tissue; 1-penten-3-one, cis-3-hexenal, 6-methyl-5-hepten-2-one, cis-3-hexenol and 2-isobutylthiazole from locule tissue; and 1-penten-3-one and β-ionone from placental tissue. Alteration of volatile profiles was most pronounced in the locule tissue, which was more sensitive to internal bruising than the other tissues. Changes observed in the volatile profiles appear to be related to disruption of cellular structures.

Transient increase in locular pressure and occlusion of endocarpic apertures in ripening tomato fruit

Summary Locular pressure was monitored during ripening of tomato ( Lycopersicon esculentum Mill.) fruit and the anatomy of the endocarp surface examined using scanning electron microscopy. The manometric pressure of the locule tissue increased from 0 in mature-green fruit to 10 to 50 Pa at the turning or pink stages, and then subsided in ripe fruit. Nonclimacteric fruit containing the ripening inhibitor ( rin ) mutation showed a similar pattern of internal pressure accumulation during senescence. Build-up of locular tissue pressure occurred in fruit ripening, on or off the plant, as well as in fruit with different susceptibility to cuticle cracking. Apertures ranging from 18-31 μm in width and 33-41 μm in length, with densities ranging from 6.7 to 47.9 apertures · mm −2 were observed in the endocarp of mature-green fruit. These apertures were progressively occluded during early ripening and were absent in late ripening fruit. Aperture occlusion might result in reduced gas exchange between the locule and external fruit atmosphere, resulting in modification of the locular gas composition.

Chemical Composition and Physical Properties of Pericarp, Locule, and Placental Tissues of Tomatoes with Internal Bruising

`Solar Set' tomatoes (Lycopersicon esculentum Mill.) were harvested at the mature-green stage of development and treated with 50 μL·L-1 ethylene at 20 °C. Breaker-stage fruit were dropped from 40 cm onto a solid surface to induce internal bruising and held along with undropped fruit at 20 °C. At the ripe stage, pericarp, locule, and placental tissues were analyzed for soluble sugars, vitamin C, pigments, titratable acidity, soluble solids content, pericarp electrolyte leakage, extractable polygalacturonase activity, and locule tissue consistency. Bruising significantly affected chemical composition and physical properties of pericarp and locule tissues, but not placental tissue. For bruised locule tissue, carotenoids, vitamin C, and titratable acidity were 37%, 15%, and 15%, lower, respectively, than unbruised fruit. For bruised pericarp tissue, vitamin C content was 16% lower than for unbruised tissue, whereas bruising increased electrolyte leakage and extractable polygalacturonase activity by 25% and 33%, respectively. Evidence of abnormal ripening following impact bruising was confined to locule and pericarp tissues and may be related to the disruption of cell structure and altered enzyme activity.

Carbohydrate solutilization of tomato locule tissue cell walls: Parallels with locule tissue liquefaction during ripening

Carbohydrate solubilization and glycosidase activities were investigated in tomato (Lycopersicon esculentum Mill. cv. Solar Set) locule cell walls to identity processes involved in the liquefaction of this tissue. Cell walls were prepared from the locule tissue of fruit at the immature green, mature green, and breaker stages of development. Enzymically active walls incubated in dilute buffer released high molecular mass pectins, oligomeric carbohydrate, and the neutral sugars rhamnose, glucose, galactose, arabinose, xylose, and mannose. The release was sustained for at least 50 h at 34°C and was inhibited more than 50% by 1 mM Hg2+. Pectins released from the cell walls of locule tissue at progressive stages of liquefaction were similar in molecular mass and showed no evidence of downshifts on a Sepharose CL–2B–300 column during prolonged incubation. A cell‐free protein extract prepared from the locule tissue of mature‐green fruit promoted a net release of polymeric and monomeric carbohydrates from high‐temperature inactivated cell walls. Polygalacturonase activity was not detected in locule protein although glycosidases including β‐mannosidase (EC 3.2.1.25), α‐ and β‐galactosidases (EC 3.2.1.22–23), β‐arabinosidase (EC 3.2.1.56) and β‐glucosidase (EC 3.2.1.21) were present. Pectinmethylesterase (EC 3.1.1.1 1) activity was detected at the immature‐green stage but declined to negligible levels in mature‐green and breaker locule tissue. Parallels between the in vitro solubilization of carbohydrate from locule tissue cell walls and the changes occurring during locule liquefaction are discussed.

Carbohydrate solubilization of tomato locule tissue cell walls: Parallels with locule tissue liquefaction during ripening

Carbohydrate solubilization of tomato locule tissue cell walls: Parallels with locule tissue liquefaction during ripening

Internal Bruising Affects Chemical and Physical Composition of Tomato Fruit

Tomato (Lycopersicon esculentum L.) fruits, cv. Solarset, were harvested at the mature-green stage and treated with 50 μL/L ethylene at 20C. Breaker fruits (<10% red coloration) were dropped from 40 cm onto a smooth, solid surface and held along with undropped fruits at 20°C and 85% relative humidity. At table-ripe stage, pericarp, placental, and locular tissue were individually excised and analyzed for total carotenoids, total soluble sugars, soluble solids content, titratable acidity, density (locule tissue), polygalacturonase activity, and electrolyte efflux (pericarp tissue). Internal bruising caused by impact forces significantly affected pericarp and locule tissues, but not placental tissue. For bruised locule tissue, total carotenoids content decreased by 37.1%, vitamin C content by 15.6%, and titratable acidity by 15.3% as compared to control. However, density was increased by 3.0%. For bruised pericarp tissue, vitamin C content decreased by 16.5%, while polygalacturonase activity and electrolyte efflux increased by 33.3% and 24.8%, respectively. The development of abnormal ripening following an impact was confined to locule and pericarp tissues and appears to be related to the disruption of cellular structure and stimulation of enzymic activity.

Molecular Mass Changes in Cell Wall Pectins of Tomato Fruit Locule Tissue in Response to Deesterification

Changes in the gel filtration behavior (apparent mol mass) of cell wall pectic polymers have been observed in a number of ripening fruits, including some that express little or no detectable polygalacturonase (PG). Pectins from tomato (Lycopersicon esculentum, Mill. v. Solar Set) fruit locule tissue show limited depolymerization during ripening, although alkali-soluble polymers are of reduced mol mass relative to water- and chelator-soluble polymers (Plant Physiol. 111:447). This study addressed whether the lower mol mass of alkali-soluble polymers was a consequence of extraction or specific metabolism of these wall polymers. Pectins from sequential water and chelator extractions of ethanol-insoluble solids from mature green tomato locule tissue were subjected to alkaline conditions. The size distribution of both water- and CDTA-soluble pectins treated with weak alkali were downshifted and similar to those extracted directly by weak alkali, indicating structural similarities of the three pectin fractions. Spectrophotometric analysis showed no involvement of β-elimination hydrolysis in the apparent mol mass reduction. The alkali-treated polymers were of greatly enhanced susceptibility to PG-mediated degradation. The alkali-associated changes also occurred in response to pectinmethylesterase hydrolysis. The results indicate that deesterification can strongly influence gel filtration behavior of pectins and may explain the apparent mol mass decreases of pectins in fruits not containing PG.

Pectin Solubilization and Enzymic Activity of Tomato Fruit Locule Tissue Cell Wall

Hydrolytic activities in liquefying locule tissue of mature-green tomato (Lycopersicon esculentum Mill. `Solar Set') fruit were studied in pursuing the understanding of mechanisms involved in the rheological changes occurring in this tissue. Ethanol-insoluble solids (EIS) were prepared with and without enzyme-inactivating treatment. The release of uronic acids from enzymically active EIS incubated under autolysic conditions was 5-fold higher than recoveries from inactive EIS. Uronic acid release was partially inhibited by 1 mm Hg2+. Cell-free proteins extracts from active EIS exhibited hydrolytic activity against inactive EIS. Pectins released from active EIS showed no evidence of main-chain hydrolysis. Neutral sugars recovered as 80% ethanol-soluble products of autolytic reactions included glc, gal, rha, ara, xyl, and man. Gal was recovered at significant higher levels in autolysates of active EIS. Glycosidases present at high activities in locule tissue included α- and β-galactosidases, β-mannosidase, β-arabinosidase, and β-glucosidase. The results confirm our earlier findings that the metabolism of water, chelator, and alkali-soluble pectins in tomato locule tissue involves deglycosylation with no apparent depolymeriation. These changes alone appear to be inadequate in explaining the unique rheological characteristics in locule gel tissue.

Alterations in Structural Polysaccharides during Liquefaction of Tomato Locule Tissue.

The locule tissue of tomato (Lycopersicon esculentum, Mill.) undergoes extensive liquefaction during ripening. In this study, the solubility, molecular mass, and glycosyl composition of locule pectic and alkali-soluble polysaccharides were examined with the aim of identifying features contributing to the unique properties of this tissue. Ethanol-insoluble solids were prepared from de-seeded locule tissue from tomato fruit at the immature green (IMG), mature green, and breaker stages of development. Ethanol-insoluble pectins were extracted sequentially in H2O, 50 mM trans-1,2-diaminocyclohexane-N,N,N[prime],N[prime]-tetraacetic acid, 50 mM Na2CO3, and 4 M KOH. At the IMG stage, nearly 85% of the locule pectins were solubilized by water, trans-1,2-diaminocyclohexane-N,N,N[prime],N[prime]-tetraacetic acid, and Na2CO3 solutions. Solubility increased only slightly with further locule development. The noncovalently associated polymers were of high molecular mass throughout liquefaction. Polymers extracted in mild alkali were of considerably lower molecular mass. Locule pectins in IMG fruit were heavily glycosylated with galactose, arabinose, and xylose. All pectin classes exhibited similar deglycosylation trends during liquefaction. Locule hemicelluloses were rich in glucose, xylose, and arabinose. These polymers collectively showed molecular mass downshifts with minimal compositional changes during liquefaction. The KOH-soluble material also included xylose-rich acidic polymers not matching the neutral sugar profile of the noncovalently associated pectic polymers.

Distribution of abscisic acid in different parts of the reproductive organs of tomato

The distribution of abscisic acid (ABA) in reproductive organs of tomato ( Lycopersicon esculentum Mill. cultivar ‘Zuisyu’) from buds to fruits, was determined. The fresh weights of the pistil and calyx increased nearly two-fold from 5 days before flowering, but their ABA concentrations remained more or less constant. Five days before flowering, the ABA concentration of the stamens and petals were higher, but decreased to about one-sixth on the days of flowering. Ten days after flowering, pollinated ovaries had less ABA than unpollinated ones. In fruits, ABA concentrations changed in the various parts, independent of each other. High concentrations of ABA were encountered in the pericarp, axis and the locule tissue in the early growth stages. Even around 50 days after flowering, the locule tissue had a small peak of ABA concentration. These results show accumulation of ABA in various regions of the flower and the fruit, independently of each other, at specific growth stages, suggesting specific role(s) for ABA in reproductive development.

Accumulation of the ?-subunit of polygalacturonase 1 in normal and mutant tomato fruit

Polyclonal antiserum raised against the native PG1 isoform of tomato fruit (Lycopersicon esculentum Mill.) polygalacturonase [poly(1,4-α-d-galacturonide) glycanohydrolase, EC 3.2.1.15] bound to each of the subunits of the protein and also to a range of other fruit proteins. Affinity purification was used to remove antibody molecules that bound to the native form of the PG2 isoform. The resulting serum bound to native PG1, denatured PG2 and β-subunits of PG1 but not to native PG2 or other fruit proteins. This anti-PG1 serum was used to monitor the occurrence of the PG1 β-subunit and PG2 in detergent extracts of tomato tissues. The β-subunit polypeptide was detected in pericarp but not locule tissue of fruit, including fruit of the rin and nor mutants. It increased in amount in the pericarp tissues from an early stage to the mature green stage, clearly prior to any appreciable accumulation of the PG2 subunit. The β-subunit polypeptide was not detected in stem or leaf tissues. A PG2-specific antiserum was used to study the interaction of PG2 with the isolated β-subunit. The PG2 isoform was bound to the β-subunit over a wide range of salt concentrations and pH; the interaction was independent of the presence of reducing agents. It is concluded that strong non-covalent forces are involved in the interaction. The results are consistent with a model in which the β-subunit is positioned in the cell wall structure and provides a specific binding site for the active PG2 subunit when this is synthesised during ripening.

RIPENING OF TOMATO FRUIT LOCULE GEL TISSUE

Ethylene production by locule gel tissue excised from full-size immature- and mature-green tomato fruit was inhibited by exposure to l00μl·l-1 C2H4, and ACC content was reduced. In contrast, CO2 production, EFE activity, red color development, and tissue liquefaction were stimulated by C2H4, and, in immature gel, the onset of autocatalytic C2H4 production was hastened. The autoinhibition of C2H4 production required continuous exposure to C2H4, as transfer to air and then back to C2H4 resulted in C2H4 production first increasing to control levels, then decreasing again. Locule tissue from pink fruit responded to C2H4 treatment with increased production of both C2H4 and CO2, but ACC levels were unchanged. Inhibition of C2H4 action by pretreatment with STS inhibited both autoinhibition of C2H4 production in immature gel and autocatalytic C2H4 production in mature tissue. These results indicate that there is a transition from a negative to a positive feedback mechanism of C2H4 on C2H4 biosynthesis in locule gel during ripening. Additionally, this feedback mechanism, which involves ACC synthase, is apparently under separate control from the other manifestations of C2H4 action.

Locular Gel Formation in Developing Tomato Fruit and the Initiation of Ethylene Production

Abstract Ethylene production by developing tomato fruit (Lycopersicon esculentum Mill., cv. Sunny) increased 3- to 5-fold at the time of gel formation in the locules, followed by a larger (20-fold) increase at the breaker stage. When the levels of ACC and the activities of ACC synthase and ethylene-forming enzyme (EFE) were measured in different portions of the fruit during maturation, the first increases were observed in the locular tissue coincident with gel formation, followed by changes in the placental and columella tissue. Later changes in ACC, ACC synthase, and EFE in the radial and outer pericarp corresponded to the marked increased in ethylene production that occurred at the breaker stage. Treatment of immature fruit with 50 μl·liter−1 ethylene enhanced the rate of gel formation markedly with no apparent lag time, but the stimulation was dependent on continuous presence of ethylene. These results indicate that the onset of ethylene production occurs in the locule tissue of green tomato fruit prior to its initiation in the pericarp and that the locule cells may develop greater sensitivity to ethylene at an earlier stage than pericarp cells. Chemical name used: 1-aminocyclopropane-1-carboxylic acid (ACC).

Suberization of tomato (Lycopersicon esculentum) locule tissue

It was demonstrated by electron microscopy that wounded and cultured tomato fruit outer placental (locule) tissue generated lamellated (secondary) walls. BF3 – methanol depolymerization of an extract from these walls and its chromatographic analysis showed the presence of the polymer suberin in the tissue adjacent to the wound after 7 days in culture. Quantitative studies using Iatroscan thin-layer chromatography coupled with flame ionization detection showed close similarities between the aliphatics of this wound suberin (which constituted 70% of the total monomers recovered) and that generated by protoplasts isolated from the same tissue, particularly among the monofunctional products, but some striking differences among the difunctional products. It is proposed that the results support the concept that protoplast isolation elicits a wound response similar to that elicited by mechanical wounding of the mother tissue, but that the physiological conditions obtained during protoplast isolation and culture result in a modification of this response.