Respiratory Response, Ethylene Production, and Response to Ethylene of Citrus Fruit during Ontogeny
TL;DR: Evidence is presented that citrus fruits are nonclimacteric fruits after their respiratory rise and decline and exposure to 20 microliters of ethylene per liter induced an increase in the respiratory rate of all varieties at every stage of ontogeny.
Abstract: The initial respiratory rates at 20 centrigrade of detached oranges (Valencia and navel), grapefruit, and lemons decreased during ontogeny. Small attached oranges respired at the same rate as detached fruits of the same weight, and cutting the pedicel produced no shock or injury stimulus to the respiratory rate. Small oranges and grapefruit (average weight about 15 grams) showed pseudoclimacteric respiratory patterns and produced ethylene. The height of the respiratory rise and the amount of ethylene produced decreased as the fruit increased in weight until the September 4th harvest, when the fruit weights were 120, 64, and 87 grams for grapefruit, Valencia, and navel oranges, respectively; at that time no respiratory rise or ethylene production was observed. The pattern for all subsequent harvest revealed no postharvest rise in the respiratory rates. Lemon fruit, in contrast, had a continuously decreasing respiratory rate at all stages of ontogeny. Exposure to 20 microliters of ethylene per liter induced an increase in the respiratory rate of all varieties at every stage of ontogeny; this was true also in young oranges and grapefruit following their respiratory rise and decline.Evidence is presented that citrus fruits are nonclimacteric fruits.
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Book•
01 Jan 2008
TL;DR: This book is the most comprehensive reference on citrus fruit biology, biotechnology and quality and discusses biotechnological applications and potential fresh citrus fruit quality improvement.
Abstract: Post harvest biology and technology of citrus fruits is gaining importance as the therapeutic value of citrus fruits is realized and supported by the increase in health awareness among the general public This book is the most comprehensive reference on citrus fruit biology, biotechnology and quality Basic and applied scientific information is interwoven to serve the researcher, marketer, scientist, nutritionist, or dietician With discussions of fruit morphology, anatomy, physiology and biochemistry and chapters on growth phases, maturity standards, grades and physical and mechanical characteristics of citrus trees, this book provides the foundation for understanding growth, harvest and post harvest aspects of these important plants Insect-pests and diseases, irrigation, nutrition and rootstocks are also addressed * Provides practical tips for post harvest management * Includes all aspects of citrus fruit biology, technology and quality evaluation * Discusses biotechnological applications and potential fresh citrus fruit quality improvement * Evaluates medicinal and therapeutic applications and recent clinical findings * Exhaustive glossary included
407 citations
TL;DR: The ripening induced by exogenous ethylene has been considered to be qualitatively identical with that which occurs naturally, and once ripening is induced it has be considered that endogenous ethylene production rises autocatalytically.
Abstract: FLESHY fruits have been divided into two classes on the basis of their respiratory behaviour during ripening: climacteric fruit, such as bananas, which undergo a large increase in respiration (climacteric rise) accompanied by marked changes in composition and texture, and non-climacteric fruit such as citrus, which show no changes in respiration that can be associated with distinct changes in the composition of the fruit1. An increase in the level of endogenous ethylene is considered to be the immediate trigger of ripening in climacteric fruits2. Fruits of this class usually produce large amounts of ethylene once ripening is under way. They may also be induced to ripen by treatment with ethylene at concentrations above about 0.1 p.p.m. for a suitable period3. The ripening induced by exogenous ethylene has been considered to be qualitatively identical with that which occurs naturally3. In both cases, once ripening is induced it has been considered that endogenous ethylene production rises autocatalytically4. Uninjured citrus fruit have been shown to produce low amounts of ethylene5. Their respiration may be increased by treatment with ethylene6 and disappearance of chlorophyll (colouring) and ageing may be more rapid18.
393 citations
TL;DR: The elements and mechanisms whereby endogenous and environmental stimuli affect fruit growth are being interpreted and this knowledge may help to provide tools that allow optimizing production and fruit with enhanced nutritional value, the ultimate goal of the Citrus Industry.
Abstract: Citrus is the main fruit tree crop in the world and therefore has a tremendous economical, social and cultural impact in our society. In recent years, our knowledge on plant reproductive biology has increased considerably mostly because of the work developed in model plants. However, the information generated in these species cannot always be applied to citrus, predominantly because citrus is a perennial tree crop that exhibits a very peculiar and unusual reproductive biology. Regulation of fruit growth and development in citrus is an intricate phenomenon depending upon many internal and external factors that may operate both sequentially and simultaneously. The elements and mechanisms whereby endogenous and environmental stimuli affect fruit growth are being interpreted and this knowledge may help to provide tools that allow optimizing production and fruit with enhanced nutritional value, the ultimate goal of the Citrus Industry. This article will review the progress that has taken place in the physiology of citrus fruiting during recent years and present the current status of major research topics in this area.
282 citations
Cites background from "Respiratory Response, Ethylene Prod..."
...In ripe fruits, ethylene production and sensitivity is low, respiration is considerably attenuated and changes in texture and composition proceed gradually (Aharoni, 1968; Eaks, 1970; Goldschmidt et al., 1993)....
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TL;DR: The data presented suggest that chlorophyllase may not be the regulator ofchlorophyll breakdown during natural fruit ripening but is consistent with the notion that chloropyll is gradually degraded during ripening due to a negative balance between synthesis and breakdown.
Abstract: Summary
We report on the isolation, functional expression and characterization of a cDNA encoding chlorophyllase, the enzyme catalyzing the first step in the chlorophyll breakdown pathway. The Chlase1 cDNA from Valencia Orange (Citrus sinensis cv. Valencia) was obtained by RT–PCR using degenerate primers based on the amino acid sequence of the previously purified protein. Chlase1 encodes a protein of 329 amino acids, including a sequence domain characterizing serine-lipases and a putative chloroplast-directing transit peptide. The Chlase1 gene encodes an active chlorophyllase enzyme which catalyzes the dephytylation of chlorophyll as shown by in vitro recombinant enzyme assays. Chlorophyllase expression at the transcript level in Valencia orange peel was found to be low and constitutive during natural fruit development without significant increase towards color-break and ripening. However, ethylene treatment induced an increase in chlorophyllase transcript at all stages of development. An enhanced response to ethylene treatment was observed during the months of October and November, corresponding to the time of natural color-break. The senescence-delaying regulator gibberellin-A3 (GA3) inhibited the effect of ethylene on chlorophyllase transcript accumulation. The data presented suggest that chlorophyllase may not be the regulator of chlorophyll breakdown during natural fruit ripening but is consistent with the notion that chlorophyll is gradually degraded during ripening due to a negative balance between synthesis and breakdown. According to this model, exogenous application of ethylene accelerates chlorophyll breakdown due to increased de novo synthesis of chlorophyllase. Further experi- mentation on the regulation and role of chlorophyllase in planta will be facilitated by the gene tools established in this work.
279 citations
TL;DR: The findings reveal that the classification of fruits based on climacteric rise and/or ethylene production status is not very distinct or perfect, however, presence of a characteristic rise in CO2 levels and a burst in ethyleneProduction in some non-climacteric fruits as well as the presence of system 2 of ethylene Production point to a ubiquitous role for ethylene in fruit ripening.
Abstract: The process of fruit ripening is normally viewed distinctly in climacteric and non-climacteric fruits. But, many fruits such as guava, melon, Japanese plum, Asian pear and pepper show climacteric as well as non-climacteric behaviour depending on the cultivar or genotype. Investigations on in planta levels of CO2 and ethylene at various stages of fruits during ripening supported the role and involvement of changes in the rate of respiration and ethylene production in non-climacteric fruits such as strawberry, grapes and citrus. Non-climacteric fruits are also reported to respond to the exogenous application of ethylene. Comparative analysis of plant-attached and plant-detached fruits did not show similarity in their ripening behaviour. This disparity is being explained in view of 1. Hypothetical ripening inhibitor, 2. Differences in the production, release and endogenous levels of ethylene, 3. Sensitivity of fruits towards ethylene and 4. Variations in the gaseous microenvironment among fruits and their varieties. Detailed studies on genetic and inheritance patterns along with the application of ‘-omics’ research indicated that ethylene-dependent and ethylene-independent pathways coexist in both climacteric and non-climacteric fruits. Auxin levels also interact with ethylene in regulating ripening. These findings therefore reveal that the classification of fruits based on climacteric rise and/or ethylene production status is not very distinct or perfect. However, presence of a characteristic rise in CO2 levels and a burst in ethylene production in some non-climacteric fruits as well as the presence of system 2 of ethylene production point to a ubiquitous role for ethylene in fruit ripening.
246 citations
Cites background from "Respiratory Response, Ethylene Prod..."
...Earlier, it was Aharoni (1968) who reported a significant rise in ethylene evolution and respiration in young citrus fruits and latter Eaks (1970) proposed this phenomenon as “psedoclimacteric”....
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References
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TL;DR: Measurements of fruit radius and peel and pulp width, as well as determinations of fresh weight, dry weight, moisture content total and protein nitrogen content, and respiration rate were made throughout two growing seasons on Valencia oranges from the Gosford district of New South Wales.
Abstract: Measurements of fruit radius and peel and pulp width, as well as determinations of fresh weight, dry weight, moisture content total and protein nitrogen content, and respiration rate were made throughout two growing seasons on Valencia oranges from the Gosford district of New South Wales. Soluble solids, sugar, and acid were also determined in the juice. Anatomical changes during development were investigated throughout one season. Development could be divided into three stages, corresponding with changes in growth rate and coinciding on a calendar basis in both seasons. Stage I varied in length according to the date of the blossom, but was completed by mid December. This was the cell division stage; by mid December cell division was completed in all tissues except the outermost cell layers. Increase in fruit size at this stage was mainly due to increased peel thickness. Stage 11, a period of very rapid growth from mid December to mid July, was the critical period for growth and was distinguished as the cell enlargement period, rapid morphological and physiological changes occurring in the absence of cell division. The growth of the pulp was responsible for most of the increase in fruit size during Stage 11; the peel reached a maximum width early in this stage and then became thinner with very little subsequent change in thickness as the pulp continued to increase in size. Stage 111, the maturation period, lasted from mid July until the fruit was ripe, or approximately 7 months. Fruit continued to grow for as long as it was left on the tree but at a very reduced rate compared with Stage 11. Ripening occurred during Stage 111.
277 citations
"Respiratory Response, Ethylene Prod..." refers background or result in this paper
...1-6); this is in accord with previous reports by Aharoni (1), Bain (2), and Tood et al....
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...The initial respiratory rates of citrus fruit, during their development showed a rapid decline in the early stages of fruit growth followed by a gradual decline as the fruit became larger (1, 2, 21); but determinations were delayed after harvest, and so the rates may not represent rates of those exhibited while fruit was on the tree or immediately after harvest....
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01 Jan 1946
83 citations
TL;DR: Young and unripe oranges and grapefruits stored at 15 degrees or 20 degrees evidenced shortly after harvest a marked increase in respiratory rate, and then a well-defined maximum which was followed by a decrease, which was accompanied by color changes typical of maturity in the above fruits.
Abstract: Young and unripe oranges and grapefruits stored at 15 degrees or 20 degrees evidenced shortly after harvest a marked increase in respiratory rate, and then a well-defined maximum which was followed by a decrease.Ethylene production by oranges (measured by the manometric method) was observed, with curves parallel to the respiratory curves.The respiratory upsurge was accompanied by color changes typical of maturity in the above fruits, and by abscission of stem-ends.When fruit was harvested close to or at commercial maturity, it evidenced a gradual respiration decrease without any upsurge. No ethylene production was detected in oranges of this stage.
77 citations
"Respiratory Response, Ethylene Prod..." refers background or result in this paper
...Recently, Aharoni (1) presented respiratory patterns for small oranges and grapefruit that were similar to those displayed by typical climacteric fruit; in addition, the production of ethylene by small oranges paralleled the respiratory pattern of climacteric fruit....
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...The responses observed in oranges and grapefruit, reported here, appear to be due to the ethylene produced and are similar to those reported by Aharoni (1)....
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...The respiratory rise observed for small immature oranges and grapefruit by Aharoni (1), as well as in the present study, is a response to an unexplained stimulation of ethylene production by these small fruits...
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...1-6); this is in accord with previous reports by Aharoni (1), Bain (2), and Tood et al....
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...The initial respiratory rates of citrus fruit, during their development showed a rapid decline in the early stages of fruit growth followed by a gradual decline as the fruit became larger (1, 2, 21); but determinations were delayed after harvest, and so the rates may not represent rates of those exhibited while fruit was on the tree or immediately after harvest....
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76 citations