Fruit Ethylene Research Articles

Wound-regulated accumulation of specific transcripts in tomato fruit: interactions with fruit development, ethylene and light

Regulation of three cDNA clones (pT52, pT53, and pT58) was analyzed in terms of wounding alone and wounding in conjunction with developmental and environmental cues (ripening, ethylene, and light) in tomato fruit tissue. The pT52-specific transcript level is induced by wounding in early-red and red stage fruit and by ethylene. The pT58-specific transcript level is also induced by wounding and ethylene in early-red stage fruit but is not induced by wounding in red fruit. The pT53-specific transcript level is repressed by wounding in early-red and red stage fruit. Like the pT52- and pT58-specific transcripts, the pT53-specific transcript is induced by ethylene. Furthermore, the level of the pT52-specific transcript is regulated by light. Analysis of unwounded tissue showed that the abundance of each cDNA-specific transcript changes during fruit ripening and that each of the transcripts is present in other plant organs as well. This analysis provides information about the interactions between developmental and environmental factors affecting these genes.

Daminozide, Root Pruning, Trunk Scoring, and Trunk Ringing Effects on Fruit Ripening and Storage Behavior of `McIntosh' Apple

A midsummer foliar daminozide (DZ) application (750 mg a.i./liter) to `Macspur McIntosh'/M.7 apple trees (Malus domestics Borkh.) reduced preharvest drop and retarded flesh firmness loss and starch hydrolysis when tested at harvest; DZ also reduced fruit ethylene production at harvest and after 19 weeks of storage at 0.5C. Root pruning at full bloom (May) resulted in increased soluble solids concentration (SSC) and firmer flesh and less starch hydrolysis at harvest, but not consistently each year. Full-bloom root pruning reduced the incidence of stem-cavity browning and brown core, but again not each year. Full-bloom root pruning did not influence ethylene evolution at harvest but did reduce post-storage ethylene evolution in two of three seasons. Full-bloom root pruning generally was less effective than DZ in altering fruit behavior, while root pruning later than full bloom had virtually no effect. Trunk scoring or ringing increased SSC and retarded loss of flesh firmness before harvest and following storage, but had little effect on starch hydrolysis. Scoring or ringing decreased incidence of some disorders and reduced post-storage ethylene evolution, although these treatments had little effect on ethylene production at harvest. Trunk scoring influenced some fruit characteristics more strongly than DZ. Fruit size was not affected by any treatment in any year. Chemical name used: butanedioic acid mono (2,2 -dimethylhydrazide) (daminozide).

Effects of Daminozide, Paclobutrazol, and Uniconazole Treatments on `McIntosh' Apples at Harvest and Following Storage

Foliar daminozide (DZ) applications to `McIntosh' apple trees (Malus domestics Borkh.) increased fruit color, reduced preharvest drop, resulted in greater firmness at harvest and after air storage, delayed starch hydrolysis, and reduced fruit ethylene production at harvest and after storage. Foliar paclobutrazol (PBZ) reduced preharvest drop and flesh firmness loss if applied within 5 weeks after full bloom (WAFB). Later applications had no effect. PBZ did not influence the progress of starch hydrolysis or ethylene production at harvest but reduced poststorage ethylene production in one season. Stem-cavity browning and brown core were increased by PBZ applied at 5 and 9 WAFB in 1987. In 1988, fruit soluble solids content (SSC) was reduced by a double application of PBZ and by uniconazole (UCZ). UCZ had little effect on `McIntosh' fruit other than the reduction in SSC. PBZ applications were less consistent in their effects than DZ. Chemical names used: butanedioic acid mono(2,2-dimethylhydrazide) (daminozide); ß-[(4-chlorophenyl) methyl]-α- -(l,l-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol); ß-[(4-chlorophenyl)methylene]-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (uniconazole).

Stimulation of Fruit Ethylene Production by Wounding and by Botrytis cinerea and Geotrichum candidum Infection in Normal and Non‐Ripening Tomatoes

AbstractInoculations with both Botrytis cinerea and Geotrichum candidum stimulated ethylene evolution in the pre‐climacteric normal tomato fruit and the non‐ripening nor mutant which did not show any rise in ethylene when uninfected. In the post‐climacteric normal fruits, new peaks in ethylene production were formed. The rise in ethylene evolution in all types of infected fruits has already been detected during the incubation period of the disease. Ethylene peaks were detected earlier and were higher in fruits infected with B. cinerea than with G. candidum, coinciding with the faster rate of growth of the former. Mechanical wounding also stimulated ethylene synthesis by the non‐ripening fruits, production being directly proportional to wound dimension. Considerably higher rates of ethylene were recorded for infected fruits than for mechanically‐injured fruits in which wound dimensions were similar to those of lesion development.Applying aminoxyacetic acid at the site of inoculation inhibited ethylene production by 55–60 % in the normal fruits and by about 80 % in the nor mutant fruits. A similar pathway of ethylene synthesis was suggested for normally ripening tomato fruit and non‐ripening infected tissues.

Regulation of Gene Expression by Ethylene in Wild-Type and rin Tomato (Lycopersicon esculentum) Fruit

Levels of ethylene biosynthesis and ethylene-inducible gene expression in wild-type tomato (Lycopersicon esculentum) fruit and in nonripening fruit from the tomato mutant rin (ripening inhibitor) were compared in order to investigate the mechanism of ethylene action. Whereas wild-type tomato fruit dramatically increase the rate of ethylene biosynthesis at the onset of ripening, rin fruit constitutively produce ethylene at a low basal level. We have compared the mRNA levels and transcription rates of four cloned ethylene-inducible genes (JE Lincoln, S Cordes, E Read, RL Fischer 1987 Proc Natl Acad Sci USA 84: 2793-2797) during wild-type and rin fruit development. In wild-type fruit, both mRNA levels and transcription rates of these genes increase. The effect of the rin mutation on gene expression is different for each ethylene-inducible gene. In one case expression is completely suppressed, while in other instances it is either partially inhibited or relatively unaffected by the mutation. The mRNA levels of each of these genes in response to exogenous ethylene in rin fruit was also measured. The mRNAs for all four genes accumulate to similar levels in both ethylene treated rin and ethylene treated wild-type fruit. These results are discussed with regard to the response of plants to ethylene hormone at the level of gene expression.

Genetic Variation of Ethylene Production in Harvested Muskmelon Fruits

Abstract Two netted and three nonnetted (casaba) muskmelon (Cucumis melo L.) cultigens and their hybrids were examined after harvest for ethylene production and for concentration of ethylene in the cavity. Whole fruit ethylene production was related to cavity concentrations. Netted muskmelon fruit produced appreciable amounts of ethylene at or near harvest while nonnetted fruit did not produce ethylene until as late as 20 days postharvest. Hybrids were generally intermediate to the parents in rate and time of production of ethylene, thus demonstrating that rates of ethylene production and cavity concentrations of ethylene in muskmelon fruit appear under genetic control.

Regulation by CO2 of 1‐aminocyclopropane‐1‐carboxylic acid conversion to ethylene in climacteric fruits

Cheverry, J. L., Sy, M. O., Pouliquen, J. and Marcellin, P. 1988. Regulation by CO2 of 1‐aminocyclopropane‐1‐carboxylic acid conversion to ethylene in climateric fruits. ‐ Physiol. Plant. 72: 535–540.A high CO2 concentration (20%) at 20°C rapidly and strongly inhibited the development of the climacteric ethylene burst in apple (Malus domestica Borkh. cv. Granny Smith) and avocado (Persea americana Mill. cv. Fuerte) fruits and did not change 1‐aminocyclopropane‐l‐carboxylic acid (ACC) content. Treatment with 20% CO2 markedly decreased ACC‐dependent ethylene biosynthesis at 20°C in climacteric pericarp tissues. It is suggested, therefore, that high CO2 levels inhibit conversion of ACC to ethylene.Synthesis of the ethylene forming enzyme (EFE) was enhanced when intact preclimacteric apples or early climacteric avocados were pretreated for 40 h with 10 μ11‐1 ethylene. When CO2 (20%) and ethylene were both applied, a reduced stimulatory effect of ethylene on EFE synthesis was observed. A high CO2 concentration enhanced EFE acivity in excised tissues of apples and avocados incubated with ACC (2 mM) and cycloheximide (1 mM) or 2–5‐norbornadiene (5 ml 1‐1). In the autocatalytic process, 20% CO2 antagonized the stimulation of EFE synthesis by ethylene, but promoted EFE activity.

Tomato Polygalacturonase Elicits Ethylene Production in Tomato Fruit

Abstract Fungal cell-wall lysing enzymes have been shown to induce ethylene production in different plant systems. The effect of endogenous plant cell-wall lysing enzymes on ethylene synthesis in fruit has received only limited attention. Therefore, tomato fruit (Lycopersicon esculentum, Mill.) were vacuum–infiltrated with the tomato cell-wall enzymes, polygalacturonase I and II (PG I, PG II) and pectinmethylesterase (PME). Fruit ethylene levels were observed to increase relative to either salt, buffer, or boiled enzyme controls. This increase in ethylene production occurred in green ‘Cherry’ tomato fruit as well as in the mutants rin, nor, and Cornell 111. Enzyme-induced ethylene synthesis generally peaked at or before 17 to 20 hr and decreased to lower or basal levels in most immature normal cultivars by 42 hr after treatment. Ethylene was maintained at high levels, however, in some (possibly more mature) green fruit, as well as in all mutant lines. PG II was more effective than PG I in inducing ethylene production and PME seemed to enhance the ethylene-inducing activity of PG II.

Night-temperature effects on rate of apple fruit maturation and fruit quality

Potted ‘Red Chief’ apple trees were exposed to 26°C day and either 22°C (warm) or 11°C (cool) night temperatures during fruit development and maturation. The onset of fruit ethylene (C 2H 4) production occurred at approximately the same time regardless of temperature. ACC (1-aminocyclopropane-1-carboxylic acid) levels in the fruits were not statistically different between temperature treatments during fruit maturation. Ethylene-forming enzyme (EFE) activity was measured by applying saturating amounts of exogenous ACC to fruit tissue and measuring C 2H 4 production. Cool-night fruit developed EFE activity earlier than warm-night fruit. Firmness and soluble solid content of the fruit were not statistically different between the temperature treatments. Although fruit maturity was unaffected by night temperature, fruit abscission occurred earlier in cool-night fruit. Warm-night fruit had less red skin color than cool-night fruit. Fruit diameter and length were not affected by night temperature.

AVOCADO FRUIT RIPENING AND ETHYLENE BIOSYNTHESIS

AVOCADO FRUIT RIPENING AND ETHYLENE BIOSYNTHESIS

Promotion by Ethylene of the Capability to Convert 1-Aminocyclopropane-1-carboxylic Acid to Ethylene in Preclimacteric Tomato and Cantaloupe Fruits

The intact fruits of preclimacteric tomato (Lycopersicon esculentum Mill) or cantaloupe (Cucumis melo L.) produced very little ethylene and had low capability of converting 1-aminocyclopropane-1-carboxylic acid (ACC) to ethylene. When these unripe tomato or cantaloupe fruits were treated with ethylene for 16 hours there was no increase in ACC content or in ethylene production rate, but the tissue's capability to convert ACC to ethylene increased markedly. Such an effect was also observed in fruits of tomato mutants rin and nor, which do not undergo ripening and the climacteric increase in ethylene production during the senescence. The development of this ethylene-forming capability induced by ethylene increased with increasing ethylene concentration (from 0.1 to 100 microliters per liter) and duration (1 to 24 hours); when ethylene was removed this capability remained high for sometime (more than 24 hours). Norbornadiene, a competitive inhibitor of ethylene action, effectively eliminated the promotive effect of ethylene in tomato fruit. These data indicate that the development of the capability to convert ACC to ethylene in preclimacteric tomato and cantaloupe fruits are sensitive to ethylene treatment and that when these fruits are exposed to exogenous ethylene, the increase in ethylene-forming enzyme precedes the increase in ACC synthase.

Effect of CGA-15281, an Ethylene-generating Material, on Maturity of ‘Delicious’ Apple1

Abstract Application of (2-chloroethyl)methylbis (phenylmethoxy) silane (CGA-15281) in combination with butanedioic acid mono-2-2-dimethylhydrazide (daminozide) and naphthaleneacetic acid (NAA) increased fruit color of ‘Delicious’ apple (Malus domestica Bork.) in 1980 within 5 days after treatment at concentrations of 250 and 500 ppm, but was not significantly better than untreated controls at harvest. Fruit firmness was reduced within 10 days by the application of 500 ppm CGA in the absence of daminozide. In 1981, application of CGA at various rates from 250 to 1000 ppm did not significantly alter percent soluble solids, starch index, surface color or fruit firmness in comparison to a 500-ppm ethephon treatment. Fruit ethylene levels of all CGA treated fruit were higher 2 hours after treatment in comparison to ethephon at 500 ppm. Ethylene levels of 1000 ppm CGA treatment remained higher than ethephon treatment until 24 hours after treatment.

Biosynthesis of ethylene in higher plants: the metabolic site of inhibition by phosphate*

Abstract. Phosphate inhibited endogenous as well as 1‐aminocyclopropane‐1‐carboxylic acid (ACC)‐stimulated ethylene synthesis in slices of tomato fruit, segments of carrot root and pea hypocotyls. ACC concentrations of up to 10 mol m−3 did not overcome this inhibition. Phosphate inhibited the conversion of 14C ACC to ethylene in tomato fruit and vegetative tissue. Enzymatic conversion of ACC to ethylene by pea seedling homogenate was also inhibited by phosphate with a linear concentration dependency. The formation of ACC from S‐adenosylmethionine (SAM) by extracts of pink tomatd fruit was slightly, but not significantly, affected by phosphate. However, the SAM to ACC conversion was greater when extracts from tomato fruit were made in phosphate rather than in HEPES‐KOH buffer. Non‐enzymatic ethylene synthesis from ACC in a model system was stimulated by phosphate. We suggest that phosphate is an inhibitor of ethylene biosynthesis in higher plants and that one site of its control is the conversion of ACC to ethylene.

Regulation of Ethylene Biosynthesis1

Abstract Ethylene has long been known to have a profound effect on plants (1). The early use of smoke or of burning incense as a ripening agent is undoubtedly attributable to the ethylene content. Following the advent of sensitive gas chromatographic instruments in the early 1960's, postharvest physiologists established the essential role of ethylene as a ripening hormone (1, 30). Demonstration of the natural function of ethylene in fruit ripening has stimulated the search for other functions. As the realization has grown that ethylene is a naturally produced plant hormone, so has the list of processes which it is known to regulate. The various effects of ethylene on plants or plant parts include growth inhibition, root initiation, fruit degreening, flower initiation, modification of flower sex expression, stimulation of fruit growth, initiation of fruit ripening, participation in plant disease resistance, promotion of leaf, flower and fruit abscission and dehiscence, release of seed and bud dormancy, release of apical dominance and regulation of tissue proliferation. At each stage of crop production, ranging from germination and propagation to harvest and postharvest handling, there are plant processes subject to modification by ethylene.

Ethylene in fruits of blackberry and rabbiteye blueberry

Abstract In the paper, Ethylene in fruits of blackberry and rabbiteye blueberry by John A. Lipe (J. Amer. Soc. Hort. Sci. 103(1):76-77, 1978), the ethylene concentration in the text expressed as mg/liter should be μl/liter or ppm.

Ethylene in Fruits of Blackberry and Rabbiteye Blueberry

Abstract In the paper entitled “Ethylene in Fruits of Blackberry and Rabbiteye Blueberry” by John A. Lipe (J. Amer. Soc. Hort. Sci. 103(1):76-77. 1978) ethylene concentrations in the text are erronously expressed as mg/liter. These units should be ppm of μl/liter

Ethylene in Fruits of Blackberry and Rabbiteye Blueberry1

Abstract ‘Humble’ blackberry (Rubus arvenis Bailey) extractable ethylene content reached more than 7.0 mg/liter shortly after full bloom and dropped to well under 1.0 mg/liter for the remainder of fruit development. The low ethylene levels during the latter stages of fruit development suggests that blackberries are nonclimacteric. ‘Tifblue’ rabbiteye blueberry (Vaccinium ashei Reade) extractable ethylene was more than 5.0 mg/liter approximately 2 weeks after bloom, declined to near 1.0 mg/liter during green fruit development and peaked at 3.7 mg/liter in reddish-green (ripening) berries. The increased level of ethylene in ripening fruits suggests that rabbiteye blueberries are climacteric.

Ethylene Evolution as Related to Changes in Hydroperoxides in Ripening Tomato Fruit1

Abstract Hydroperoxide levels were determined in aqueous and lipid extracts from fruit of tomato (Lycopersicon esculentum Mill.) at 6 different stages of ripening. An increase in the levels of peroxides in both the aqueous and the lipid fractions was associated with the upsurge in ethylene evolution. The changes in peroxides in the lipid fraction corresponded to the changes in the activity of lypoxygenase. Peroxides may constitute some of the active oxygen forms occurring in vivo which are required for the synthesis of ethylene in fruit.

Ethylene and Fruit Loosening from Combinations of Citrus Abscission Chemicals1

Abstract Two and 3-way combinations of 5-chloro-3-methyl-4-nitro-1H-pyrazole (Release), cycloheximide (Acti-Aid), and chlorothalonil (Sweep) were extensively evaluated for fruit abscission and ethylene production responses on ‘Hamlin’ and ‘Valencia’ oranges (Citrus sinensis (L.) Osbeck). The combinations interact synergistically resulting in far greater fruit loosening than would be expected from additive effects of the individual chemicals. The 3-way combinations of Release plus Acti-Aid plus Sweep consistently gave better fruit abscission than the 2-way combinations of Release plus Acti-Aid and required 25% to 50% less abscission chemical compared to individual abscission chemical usage. Increased fruit abscission activity of the chemical combinations resulted from greater peak fruit ethylene production and higher sustained ethylene levels during the treatment period. Distinct fruit loosening and retightening phases were characterized and shown to be correlated with internal fruit ethylene levels.

Changes in fruit growth and pectic content in Coffea canephora (robusta) in relation to the exogenous application of ethylene

Fruit ripening in robusta coffee induced chemically by ethylene (CEPA) is clearly manifested in enhanced growths of whole fruits and mesocarp and decreased pectic substances. Pectic changes in coffee appear to be directed by endogenous auxins. Foliar application of NPK prevented these changes at lower concentrations of ethylene (150 and 360 ppm) but the blockage was removed at higher doses (720 ppm). NPK treatment necessitates higher dosage of ethylene to obtain normal ripening, as these minerals increased the thresholds of ethylene in coffee fruits by some unknown mechanism.