Aminoethoxyvinylglycine Research Articles

Combined Applications of Aminoethoxyvinylglycine with Salicylic Acid or Nitric Oxide Reduce Oxidative Stress in Peach During Ripening and Cold Storage

The effects of pre-harvest application of aminoethoxyvinylglycine (AVG) alone or in combination with nitric oxide (NO) or salicylic acid (SA) on the oxidative stress and fruit quality during ripening and cold storage were investigated in peach Prunus persica L. Batsch. cv. ‘Oz Delight’. Trees were sprayed with 830 g ha−1 AVG 10 days before anticipated harvest, or post-harvest fumigated with 10 μL L−1 NO or dipped in 2 mM aqueous solution of SA for 5 min in the following treatments (untreated control, pre-harvest AVG, post-harvest NO, post-harvest SA, pre-harvest AVG + post-harvest SA and pre-harvest AVG + post-harvest NO). Combined application of pre-harvest AVG and post-harvest SA resulted in reduced ethylene production, respiration rate, fruit weight loss, SSC and SSC:TA with higher fruit firmness, CIE L *, b * and h o values and TA during ripening and cold storage, as compared with control. There was no consistent trend in the activities of antioxidant enzymes in any treatment. The activities of SOD, CAT, and POD were reduced, whereas PPO enzymes increased with advancement in fruit ripening and cold storage periods. Fruit treated with combined application of pre-harvest AVG and post-harvest SA exhibited reduced oxidative stress with higher activities of POD and PPO enzymes, as compared with control during ripening and cold storage. Fruit fumigated with NO alone or in combination with AVG showed higher radical scavenging activity during ripening as well as storage, as compared with all other treatments. In conclusions, pre-harvest application of AVG in combination with post-harvest SA treatment exhibited synergistic effect in the reduction of ethylene production, respiration rate, fruit softening, changes in fruit quality (colour, SSC, TA and SSC:TA ratio) and consequently reduced oxidative stress during peach fruit ripening and cold storage.

Nitrogen fertility and abiotic stresses management in cotton crop: a review.

This review outlines nitrogen (N) responses in crop production and potential management decisions to ameliorate abiotic stresses for better crop production. N is a primary constituent of the nucleotides and proteins that are essential for life. Production and application of N fertilizers consume huge amounts of energy, and excess is detrimental to the environment. Therefore, increasing plant N use efficiency (NUE) is important for the development of sustainable agriculture. NUE has a key role in crop yield and can be enhanced by controlling loss of fertilizers by application of humic acid and natural polymers (hydrogels), having high water-holding capacity which can improve plant performance under field conditions. Abiotic stresses such as waterlogging, drought, heat, and salinity are the major limitations for successful crop production. Therefore, integrated management approaches such as addition of aminoethoxyvinylglycine (AVG), the film antitranspirant (di-1-p-menthene and pinolene) nutrients, hydrogels, and phytohormones may provide novel approaches to improve plant tolerance against abiotic stress-induced damage. Moreover, for plant breeders and molecular biologists, it is a challenge to develop cotton cultivars that can tolerate plant abiotic stresses while having high potential NUE for the future.

Role of ethylene and phospholipid-mediated signalling in mycotoxin-induced programmed cell death in the apical part of maize roots

AbstractMaize (

Gene expression analyses in tomato near isogenic lines provide evidence for ethylene and abscisic acid biosynthesis fine-tuning during arbuscular mycorrhiza development.

Plant responses to the environment and microorganisms, including arbuscular mycorrhizal fungi, involve complex hormonal interactions. It is known that abscisic acid (ABA) and ethylene may be involved in the regulation of arbuscular mycorrhiza (AM) and that part of the detrimental effects of ABA deficiency in plants is due to ethylene overproduction. In this study, we aimed to determine whether the low susceptibility to mycorrhizal colonization in ABA-deficient mutants is due to high levels of ethylene and whether AM development is associated with changes in the steady-state levels of transcripts of genes involved in the biosynthesis of ethylene and ABA. For that, tomato (Solanum lycopersicum) ethylene overproducer epinastic (epi) mutant and the ABA-deficient notabilis (not) and sitiens (sit) mutants, in the same Micro-Tom (MT) genetic background, were inoculated with Rhizophagus clarus, and treated with the ethylene biosynthesis inhibitor aminoethoxyvinylglycine (AVG). The development of AM, as well as the steady-state levels of transcripts involved in ethylene (LeACS2, LeACO1 and LeACO4) and ABA (LeNCED) biosynthesis, was determined. The intraradical colonization in epi, not and sit mutants was significantly reduced compared to MT. The epi mutant completely restored the mycorrhizal colonization to the levels of MT with the application of 10µM of AVG, probably due to the inhibition of the ACC synthase gene expression. The steady-state levels of LeACS2 and LeACO4 transcripts were induced in mycorrhizal roots of MT, whereas the steady-state levels of LeACO1 and LeACO4 transcripts were significantly induced in sit, and the steady-state levels of LeNCED transcripts were significantly induced in all genotypes and in mycorrhizal roots of epi mutants treated with AVG. The reduced mycorrhizal colonization in sit mutants seems not to be limited by ethylene production via ACC oxidase regulation. Both ethylene overproduction and ABA deficiency impaired AM fungal colonization in tomato roots, indicating that, besides hormonal interactions, a fine-tuning of each hormone level is required for AM development.

Ethylene-induced transcriptional and hormonal responses at the onset of sugarcane ripening

The effects of ethephon as a sugarcane ripener are attributed to ethylene. However, the role of this phytohormone at the molecular level is unknown. We performed a transcriptome analysis combined with the evaluation of sucrose metabolism and hormone profiling of sugarcane plants sprayed with ethephon or aminoethoxyvinylglycine (AVG), an ethylene inhibitor, at the onset of ripening. The differential response between ethephon and AVG on sucrose level and sucrose synthase activity in internodes indicates ethylene as a potential regulator of sink strength. The correlation between hormone levels and transcriptional changes suggests ethylene as a trigger of multiple hormone signal cascades, with approximately 18% of differentially expressed genes involved in hormone biosynthesis, metabolism, signalling, and response. A defence response elicited in leaves favoured salicylic acid over the ethylene/jasmonic acid pathway, while the upper internode was prone to respond to ethylene with strong stimuli on ethylene biosynthesis and signalling genes. Besides, ethylene acted synergistically with abscisic acid, another ripening factor, and antagonistically with gibberellin and auxin. We identified potential ethylene target genes and characterized the hormonal status during ripening, providing insights into the action of ethylene at the site of sucrose accumulation. A molecular model of ethylene interplay with other hormones is proposed.

Ethylene response pathway modulates attractiveness of plant roots to soybean cyst nematode Heterodera glycines

Plant parasitic nematodes respond to root exudates to locate their host roots. In our studies second stage juveniles of Heterodera glycines, the soybean cyst nematode (SCN), quickly migrated to soybean roots in Pluronic F-127 gel. Roots of soybean and non-host Arabidopsis treated with the ethylene (ET)-synthesis inhibitor aminoethoxyvinylglycine (AVG) were more attractive to SCN than untreated roots, and significantly more nematodes penetrated into roots. Moreover, Arabidopsis ET insensitive mutants (ein2, ein2-1, ein2-5, ein3-1, ein5-1, and ein6) were more attractive than wild-type plants. Conversely, the constitutive triple-response mutant ctr1-1, was less attractive to SCN. While ET receptor gain-of-function mutant ein4-1 attracted more SCN than the wild-type, there were no significant differences in attractiveness between another gain-of-function ET receptor mutant, etr1-3, or the loss-of-function mutants etr1-7 and ers1-3 and the wild type. Expression of the reporter construct EBS: β-glucuronidase (GUS) was detected in Arabidopsis root tips as early as 6 h post infection, indicating that ET signaling was activated in Arabidopsis early by SCN infection. These results suggest that an active ET signaling pathway reduces root attractiveness to SCN in a way similar to that reported for root-knot nematodes, but opposite to that suggested for the sugar beet cyst nematode Heterodera schachtii.

Nitric oxide acts upstream of ethylene in cell wall phosphorus reutilization in phosphorus-deficient rice.

Nitric oxide (NO) and ethylene are both involved in cell wall phosphorus (P) reutilization in P-deficient rice; however, the crosstalk between them remains unclear. In the present study using P-deficient 'Nipponbare' (Nip), root NO accumulation significantly increased after 1 h and reached a maximum at 3 h, while ethylene production significantly increased after 3 h and reached a maximum at 6 h, indicating NO responded more quickly than ethylene. Irrespective of P status, addition of the NO donor sodium nitroprusside (SNP) significantly increased while the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (c-PTIO) significantly decreased the production of ethylene, while neither the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) nor the ethylene inhibitor aminoethoxyvinylglycine (AVG) had any influence on NO accumulation, suggesting NO acted upstream of ethylene. Under P-deficient conditions, SNP and ACC alone significantly increased root soluble P content through increasing pectin content, and c-PTIO addition to the ACC treatment still showed the same tendency; however, AVG+SNP treatment had no effect, further indicating that ethylene was the downstream signal affecting pectin content. The expression of the phosphate transporter gene OsPT2 showed the same tendency as the NO-ethylene-pectin pathway. Taken together, we conclude that ethylene functions downstream of NO in cell wall P reutilization in P-deficient rice.

Effects of aminoethoxyvinylglycine treatment by vacuum infiltration method on postharvest storage and shelf life of tomato fruit

The aim of this study was to determine effects of postharvest aminoethoxyvinylglycine (AVG) treatment using vacuum infiltration method on retardation of ripening, storage and shelf life of tomato fruit. In the Experiment-1, beefsteak ‘Grando F1’ tomato fruit was harvested at breaker stage and treated with AVG at six different doses (0, 62.5, 125, 250, 500 and 1000mgL−1) and three different vacuum pressures (0kPa, −20kPa and −30kPa) using vacuum infiltration method and kept at 20°C for 8d. The AVG treatment of 1000mgL−1 at −30kPa reduced ethylene production rate by 45.53%, delayed color changes and extended the number of days reaching to red ripe stage from 6 to 8 d at 20°C and was confirmed as the optimal treatment for the maximum retardation of tomato fruit ripening by response surface methodology. In Experiment-2, untreated and treated breaker ‘Grando F1’ tomato fruit with 1000mgL−1 at −30kPa were kept at 12°C for 0, 5, 10, 15 or 20d and for 2d at 20°C after cold storage. AVG treated fruit had lower ethylene production rate, lycopene content, a* and C* values and higher fruit firmness, chlorophyll content, L* and h° values, compared to control during storage and shelf life period. For shipping to distant markets, storage and shelf life of untreated fruit were 10d at 12°C plus 2 d at 20°C while AVG treatment extended storage and shelf life to 20d at 12°C plus 2d at 20°C.

The role of ethylene in abscission of sweet orange promoted by exogenous application of the abscission agent 5-chloro-3-methyl-4-nitro-1H-pyrazole (CMNP)

ABSTRACTMature ‘Valencia’ fruit were treated with 5-chloro-3-methyl-4-nitro-1H-pyrazole (CMNP), and the ethylene inhibitors aminoethoxy vinyl glycine (AVG) and silver thiosulfate (STS), to assess involvement of ethylene in abscission via CMNP. Fruit detachment force (FDF) and ethylene evolution were measured over time. Accumulation of the ethylene precursor 1-aminocyclopropane-1-carboxylate (ACC) in peel upon CMNP application was assessed and impact of application of ACC on FDF was estimated when applied 1 cm away from the abscission zone (AZ), to determine its potential as a signaling molecule in promoting fruit loosening. CMNP when applied alone reduced FDF by 50%. AVG and STS inhibited fruit loosening considerably at 500 µM and 10 mM, respectively, when applied with 2 mM CMNP. ACC accumulation in peel was highest 2 days after CMNP application, which preceded the maximum decline in FDF which occurred a day later, indicating that ACC serves as a potential signaling molecule that triggers abscission in the AZ. The results of the study support the hypothesis that abscission via CMNP application is at least partly ethylene dependent. However, the decline in FDF by ACC was less than 50% of control which suggested involvement of another pathway in abscission via CMNP in sweet orange.

Effects of ethylene on shoot initiation, leaf yellowing, and shoot tip necrosis in roses

This study was conducted to investigate the in vitro influence of ethylene on shoot branching and leaf yellowing in the rose cultivar Tineke by using different compounds that regulate ethylene inhibition and stimulation. Aminoethoxy vinyl glycine (AVG), silver thiosulfate (STS), and sodium nitroprusside (SNP) caused enhanced apical shoot initiation and reduced leaf yellowing, via inhibition of ethylene production, in the following order: AVG > SNP > STS. In contrast, the addition of 1-aminocyclopropane-1-carboxylic acid (ACC) or 3-indoleacetic acid (IAA) stimulated ethylene production and had greater negative effects on the studied parameters than the control; the negative effects of IAA were further confirmed in combination with AVG, STS, or SNP. The effects of ethylene on apical shoot initiation and leaf yellowing in Tineke were confirmed in another rose cultivar, Innocence. Hence, this study provides strong support for the hypothesis that ethylene-inhibiting agents have beneficial effects on apical shoot initiation and reduction of leaf yellowing in other rose cultivars.

Effect of sucrose on sensitivity to ethylene and enzyme activities and gene expression involved in ethylene biosynthesis in cut carnations

Application of sugars extends the vase life of many cut flowers. The role of applied sucrose in petal senescence of cut carnations (Dianthus caryophyllus cv. Barbara) was investigated. Petal senescence was significantly delayed by 5% sucrose treatment. Although glucose, fructose, and sucrose concentrations decreased in the petals of control flowers with time, these concentrations increased on sucrose treatment. To investigate the effect of sucrose on sensitivity to ethylene, flowers were pre-treated with aminoethoxyvinyl glycine (AVG) to avoid the effect of ethylene biosynthesis and placed in a sucrose solution for 0 and 5 days. Flowers were then exposed to ethylene at 0.2, 0.6, and 2μLL−1. Sucrose treatment did not delay petal senescence by ethylene exposure on day 0, suggesting that the effect of sucrose on the sensitivity to ethylene is negligible. Petal wilting was not accelerated by ethylene exposure at 0.2, 0.6, and 2μLL−1 without sucrose treatment on day 5, but sucrose treatment did not delay petal wilting, implying that sucrose treatment maintains sensitivity to ethylene in the aged flowers. Sucrose treatment delayed climacteric-like increase in the ethylene production of petals and gynoecium. 1-Aminocyclopropane-1-carboxylate (ACC) synthase (ACS) and ACC oxidase (ACO) activity in petals increased during senescence, and sucrose treatment delayed the increase in ACS activity and suppressed the increase in ACO activity. The transcript levels of the ACS gene DcACS1 and the ACO gene DcACO1 in petals increased during flower senescence, and sucrose treatment delayed the increase in the transcript levels of DcACS1 and suppressed the increase in the transcript levels of DcACO1. These results suggest that delay in petal senescence by sucrose treatment is due to maintenance of sugar level in the petals, which delays a climacteric-like increase in ethylene production. The delay in ethylene production is associated with ACS and ACO activities regulated mainly at the transcriptional level.

Ethylene is involved in the actin cytoskeleton rearrangement during the root gravitropic response of Arabidopsis thaliana

Gravitropism, the directed plant growth with respect to the gravity vector, is regulated by auxin and its polar transport system, several secondary messengers, and by the cytoskeleton. Recently we have shown that the actin cytoskeleton in the root transition zone of Arabidopsis thaliana (L.) Heynh was rearranged after gravistimulation (rotation by 90°): the fraction of axially aligned microfilaments decreased and the fraction of oblique and transversally-oriented microfilaments increased. In the present research we have studied the effect of ethylene and inhibitors of its synthesis on actin cytoskeleton rearrangement during the gravitropic response. Application of the ethylene releasing substance ethephon to A. thaliana seedlings led to the disassembly of actin microfilaments as well as their broad angle distribution in cells of the root transition zone. This actin rearrangement was escaped by treatment with the ethylene synthesis inhibitor aminoethoxyvinylglycine (AVG). Another negative regulator of ethylene, salicylic acid, was shown to disturb actin microfilament rearrangement as well. We conclude that ethylene is essential for the process of actin cytoskeleton rearrangement in root cortex cells during the gravitropic bending response.

Application of GA3, AVG and choline chloride to peach trees: Effects on nutritional status of fruit

ABSTRACTThis research was aimed to determine the effects of plant regulators such as gibberellic acid (GA3), aminoethoxyvinylglycine (AVG), and choline chloride (CC) on the nutrient components in the fruit of ‘Monroe’ peach under Isparta in Turkey ecological condition. AVG at doses of 0, 100, 150 and 200 ppm, GA3 at doses of 0, 100, 200, 300 ppm and CC at doses of 0, 1000, 2000, 3000 pmm was sprayed on the peaches 7, 21 and 30 days before commercial harvests. All concentrations of AVG treatments were found to increase the amount of nitrogen in fruits. In general, it was observed that CC and GA3 applications reduced the amount of calcium in fruits, however, AVG applications were found to not be effective. In the first year, the statistically significant of AVG treatments was seen on magnesium content only. It was determined in our study that AVG and CC treatments reduced copper content in peach fruits, all applications decreased the amount of manganese, 100 ppm AVG application increased the element zinc, and all of CC applications minimized the amount of that element.

Preharvest treatment of growth regulators influences postharvest quality and storage life of cashew apples

Growth regulators may influence fruit development and thus, their postharvest quality. This study aimed to evaluate the effects of preharvest treatment with aminoethoxyvinylglycine (AVG) or gibberellic acid (GA3) on postharvest quality and life of apples of two cashew cultivars, CCP 76 e BRS 189, during cold storage. Growth regulators (180mgL−1) were applied at maturation stage 1 and apples were harvested at stage 7, ripe. Ripe, treated and control, apples were stored at 3±2°C for CCP 76 and at 5±2°C, for BRS 189 and evaluated at harvest (0day) and every 5days up to 20days of storage. The influence of growth regulators preharvest treatment on cashew apples differed among cultivars. For BRS 189 apples, GA3 treatment slowed down mass loss, as treated samples lost 0.72% while control lost 0.81%; and avoided the development of undesirable characteristics during storage. GA3-treated samples were statistically firmer, 13.61N than control, 9.93N; and together with AVG-treated samples showed a significantly reduced pectin methyl esterase (PME) activity to 1492.88UAmg−1P when compared to control 2129.87UAmg−1P. For cv. CCP 76, GA3 treatment also slowed down mass loss, as treated samples lost 0.85% and control, 0.99%, however apples were inapt for consumption after 15days of storage. GA3-treated samples were statistically firmer, 15.40N than control, 11.38N. The constituents of the antioxidant metabolism of both cashew apples varieties were mainly affected by storage period, but not by growth regulators. Therefore, results of preharvest AVG treatment on cashew apple physiology and quality were inconsistent. However, GA3 treatment improved postharvest quality of CCP 76 e BRS 189 cashew apples through reduction of mass loss and firmness loss, without any negative impact on physicochemical variables. GA3 exerted a greater influence on BRS 189 apples which showed, besides lower mass and firmness loss, a better visual appearance and lower cell wall hydrolase PME activity, during storage.

Preharvest aminoethoxyvinylglycine spray efficacy in improving storability of ‘Bartlett’ pears is affected by application rate, timing, and fruit harvest maturity

‘Bartlett’ pear fruit has a relatively short storage life due to increased ethylene production induced by cold storage. The effects of preharvest aminoethoxyvinylglycine (AVG) (an ethylene biosynthesis inhibitor) spray rate and timing on storability of ‘Bartlett’ pear fruit at three harvest maturities [H1: control fruit firmness (CFF)≈84.5N; H2: 12 d after H1 when CFF≈76.0N; and H3: 17 d after H1 when CFF≈73.4N] were measured with respect to ethylene production, storage quality and ripening capacity during 5 months of storage at −1.1°C. Compared to non-treated control, AVG at 60mgL−1 applied 1 week before H1 (WBH1) suppressed ethylene production, respiration rate, reductions in fruit firmness and green color, and reduced senescence disorders (e.g., by 81.5% and 54.0%) while maintaining ripening capacity for H1 and H2 fruit. Compared to 60mgL−1, AVG at 120mgL−1 applied 1WBH1 had similar effects on storage quality but delayed ripening capacity by one month. AVG at 30mgL−1 applied 1 WBH1 and 120mgL−1 applied 2 WBH1 had little effect on any of the storage responses measured. AVG treatment did not affect ethylene production or storage quality of H3 fruit. AVG at 60–120mgL−1 applied 1 WBH1 and 120mgL−1 applied 2 WBH1 did not affect the initial harvest maturity (H1), but delayed fruit maturation on the tree by 5–7 d. These results suggest that preharvest AVG treatment efficacy on extending harvest window and reducing storage losses of ‘Bartlett’ pear is influenced by application rate, timing and fruit harvest maturity.

Effects of preharvest application of aminoethoxyvinylglycine (AVG) on harvest maturity and storage life of ‘Unique’ feijoa

ABSTRACTIn a previous study, feijoa harvested earlier than ‘touch-picked’ maturity appeared visually acceptable after 6 weeks of storage but had low soluble solids content (SSC) and high titratable acidity (TA). Given that feijoa display climacteric-like behaviour, manipulation of ethylene physiology prior to harvest may have the potential to alter this outcome. Subsequently, the aim of this work was to investigate the impact of preharvest aminoethoxyvinylglycine (AVG) application on feijoa quality at harvest and during subsequent storage. The experiment comprised of three preharvest AVG treatments and two harvest occasions. AVG treatment dramatically reduced preharvest fruit drop. AVG treatment at 4 weeks before current commercial harvest timing was effective in delaying maturity. AVG treatment suppressed ethylene production rates during storage. However, AVG treatment did not alter quality (firmness, SSC, TA and flesh colour) after storage. This result adds to the evidence that postharvest ripening in feijoa may be regulated independent of ethylene despite the typical climacteric increase in ethylene observed. The results also confirmed that fruit harvested early were storable for 6 weeks without exhibiting internal browning, but having a high TA and low SSC that may affect their taste acceptability.

Involvement of ethylene in gibberellic acid-induced sulfur assimilation, photosynthetic responses, and alleviation of cadmium stress in mustard

The role of gibberellic acid (GA) or sulfur (S) in stimulation of photosynthesis is known. However, information on the involvement of ethylene in GA-induced photosynthetic responses and cadmium (Cd) tolerance is lacking. This work shows that ethylene is involved in S-assimilation, photosynthetic responses and alleviation of Cd stress by GA in mustard (Brassica juncea L.). Plants grown with 200 mg Cd kg−1 soil were less responsive to ethylene despite high ethylene evolution and showed photosynthetic inhibition. Plants receiving 10 μM GA spraying plus 100 mg S kg−1 soil supplementation exhibited increased S-assimilation and photosynthetic responses under Cd stress. Application of GA plus S decreased oxidative stress of plants grown with Cd and limited stress ethylene formation to the range suitable for promoting sulfur use efficiency (SUE), glutathione (GSH) production and photosynthesis. The role of ethylene in GA-induced S-assimilation and reversal of photosynthetic inhibition by Cd was substantiated by inhibiting ethylene biosynthesis with the use of aminoethoxyvinylglycine (AVG). The suppression of S-assimilation and photosynthetic responses by inhibiting ethylene in GA plus S treated plants under Cd stress indicated the involvement of ethylene in GA-induced S-assimilation and Cd stress alleviation. The outcome of the study is important to unravel the interaction between GA and ethylene and their role in Cd tolerance in plants.

Controlling premature fruit drop of cultivar Idared by using α-naphthaleneacetic acid

Fruit drop before reaching technological maturity is one of the core problems in the apple industry. The aim of this paper is to examine the effect of the chemicals VBC 30033 based on aminoethoxyvinylglycine (AVG) and Dirager based on ?-naphtalenacetic acid on the prevention of fruit drop of apple cultivar Idared, as affected by the time of application, the number of applications and the concentration. The research was conducted from 2009 to 2011 at the experimental field of the Faculty of Agriculture in Novi Sad. The special focus was placed on the double and triple applications of NAA which were considered the most effective in preventing fruit drop. The triple application of NAA 5 ppm and NAA 10 ppm showed equal effectiveness, therefore the treatment NAA 5 ppm is recommended due to the reduced use of the chemical.

AVG application regimes play an important role on pre-harvest drop and ripening of ‘Jonagold’ apples

This study was carried out to investigate the effects of different AVG (aminoethoxyvinylglycine) treatments on pre-harvest fruit drop rates and ripening levels of ‘Jonagold’ apples. A total of 225 mg L-1 AVG dose was applied at once in a single application at different times or divided into doses and applied different times. Compared to control treatment, entire AVG treatments increased fruit removal force and significantly decreased the pre-harvest drop rates. AVG treatments applied at once (225 mg L-1) 8 or 4 weeks before the anticipated harvest time were found to be more effective than the divided treatments. AVG treatments inhibited ethylene biosynthesis and such an inhibition was more distinctive in single 225 mg L-1 treatments. AVG treatments decreased flesh softening, starch degradation rates and consequently retarded fruit ripening. The 225 mg L-1 AVG treatment applied 4 weeks before the harvest significantly increased L* value and hue angle both in the year 2010 and 2011. NAA (naphtaleneacetic acid) at 10 mg L-1 sprayed 4 and 2 weeks before anticipated harvest was found to be insignificant in control of pre-harvest fruit drops. NAA treatment decreased flesh firmness, and did not have any significant effects on ethylene biosynthesis.

PHYSICAL, MECHANICAL AND CHEMICAL PROPERTIES OF PLUMS (cv. Santa Rosa) AFFECTED BY AMINOETHOXYVINYLGLYCINE APPLICATIONS

Background: The engineering properties (physical, mechanical and chemical) are importance to post harvest technologies of the agricultural materials. To plum fruits quality, the harvest and postharvest applications, the engineering properties of plum fruits should be considered. The effect of AVG (Aminoethoxyvinylglycine) treatments on some physical, mechanical and chemical properties of plum fruits (cv. Santa Rosa) were determined. 
 Materials and Methods: For this research, the plant material ‘Santa Rosa’ plum (Prunus domestica) fruits were obtained in Tokat/Turkey (39o51' N and 40o55' E), in 2012. AVG treatments were as 0 mg L-1, 100 mg L-1 and 200 mg L-1, and three different harvest dates including 25 July, 1 August and 7 August were used. 
 Results: The geometric mean diameter, volume of fruit and surface area values increased with AVG doses, whereas, fruit density decreased as AVG doses increased. L* and b* values decreased from 43.75 to 24.14 and 20.24 to 13.21, whereas, a* value increased from -9.03 to -2.63 for flesh plum, respectively. The fruit removal force of plum fruit increased from 19.09 N to 20.20 N in magnitude with an increase in AVG doses. The friction coefficients of fruits increased as AVG doses increased and harvest dates. Total soluble solids content was higher in AVG-0 (0 mg L-1) as compared to AVG-1 and AVG-2 (100 mg L-1 and 200 mg L-1) AVG-2 applications, whereas, pH and titratable acidity were lower in 200 mg L-1 as compared to 0 mg L-1 and 100 mg L-1 treatments. Post-harvest technological applications of the plum fruits must be designed by taking criteria into consideration for plum engineering properties.