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Global warming simulations predict warmer temperatures and a general water scarcity, which heavily affect grape ripening. The adaptation of the management techniques to mitigate the effects of climate change constitutes a major challenge in viticulture. The main objective of the Project VINSACLIMA is to transfer innovative sustainable techniques to the farmers of the Emilia-Romagna Region, focusing on reducing vine susceptibility to abiotic (high temperature and radiation, drought) and biotic stress. Moreover, the project aims to control the decoupling between berry phenolic and technological maturity, improving grape and wine quality. In 2016, experiments were set on different cultivars to compare farm canopy management with the proposed innovative cultural practices (late pruning, late defoliation, late trimming and kaolin application) in different areas of Emilia-Romagna Region. First results obtained were in line with data reported in previous scientific contributions by the Research Group in AgroEcology of Bologna University, showing the benefits of adopting these canopy strategies. Accordingly, by an appropriate soil management along with suitable decisions on winter and summer pruning date and eventually, canopy-applied kaolin, it is possible to prevent the occurrence of visible water stress symptoms, even during warm seasons. Within VINSACLIMA, dissemination activity was performed among farmers, students and citizens through demonstrative experiments, meetings and conferences.

Currently, agriculture is strongly dependent on the availability of fossil fuels, other external inputs and natural resources contributing about one fifth to the global emission of greenhouse gases into the atmosphere. There are, however, ample opportunities to mitigate the impact of agricultural activities on the climate. By appropriate soil management, organic and biodynamic woody systems can become quantitatively important sites for the provision of ecosystem services (protection of water, soil, biodiversity and landscape, carbon sequestration and efficient use of water resources), able to actively counteract climate change. The agroecological system developed proposed by the "AgroEcology Participatory Research Group” (University of Bologna), introduce, among the innovative and highly sustainable techniques of soil management, the "stripped" biodiverse grassing, already successfully adopted in Italy and abroad. The system consists in the cultivation, along the row, of legumes and grasses with low water requirements, some of which are self-reseeding (eg. subterranean clover, burclover) and of a mixture of herbaceous species (eg. French honeysuckle, field beans, barley) in the alley. Noteworthy, the inclusion of these species, particularly of self-reseeding legumes, does not imply additional water consumption during the summer period. The soil protection provided by herbaceous species after cutting (or rolling) in the alleys and by self-reseeding legumes in the row, reduce soil evaporation and organic matter oxidation phenomena. Field trials conducted in different Italian farms have demonstrated the multiple benefits of the modular sito-specific grassing enhancing carbon sequestration, biodiversity, resilience and productivity of the viticultural systems.

Background: Seed oil and flours have been attracting the interest of researchers and industry, since they contain various bioactive components. We monitored the effects of ripening on lipids, monomeric flavan-3-ols, proanthocyanidins and tocols concentration in seed extracts from organically cultivated cv. Sangiovese vines.; Results: Linoleic acid was the most abundant fatty acid, followed by oleic, palmitic and stearic acids. The tocols detected were α-tocopherol, α-tocotrienol and γ-tocotrienol. The proanthocyanidins degree of polymerisation ranged from dimers to dodecamers; moreover, monomeric flavan-3-ols and polymeric proanthocyanidins were detected. Total flavan-3-ols (monomers, oligomers and polymers) concentration in grape seeds decreased during ripening.; Conclusions: Fatty acids reached the highest level in post-veraison. The concentration of these compounds varied considerably during ripening. Capric acid has been found for the first time in grape seeds. α-Tocopherol and γ-tocotrienol decreased during ripening, while α-tocotrienol increased. The HPLC analysis with fluorimetric detection, conducted for the first time on cv. Sangiovese, revealed that the concentration of flavan-3-ols monomers, oligomeric proanthocyanidins and polymers greatly changed during ripening. These results suggest that the timing of bunch harvest plays a crucial role in the valorisation of grape seed flour. © 2016 Society of Chemical Industry.; © 2016 Society of Chemical Industry.

Peach (Prunus persica L. Batsch) was chosen as a model to shed light on the physiological role of jasmonates (JAs) during fruit ripening. To this aim, the effects of methyl jasmonate (MJ, 0.40 mM) and propyl dihydrojasmonate (PDJ, 0.22 mM), applied in planta at different fruit developmental stages, on the time-course of ethylene production and fruit quality traits were evaluated. MJ-induced changes in fruit transcriptome at harvest and the expression profiling of relevant JA-responsive genes were analysed in control and JA-treated fruit. Exogenously applied JAs affected the onset of ripening depending upon the fruit developmental stage, with PDJ being more active than MJ. Both compounds enhanced the transcription of allene oxide synthase (PpAOS1), the first specific enzyme in the biosynthesis of jasmonic acid, and altered the pattern of jasmonic acid accumulation. Microarray transcriptome profiling showed that MJ down-regulated some ripening-related genes, such as 1-aminocyclopropane-1-carboxylic acid oxidase (PpACO1) and polygalacturonase (PG), and the transcriptional modulator IAA7. MJ also altered the expression of cell wall-related genes, namely pectate lyase (PL) and expansins (EXPs), and up-regulated several stress-related genes, including some of those involved in JA biosynthesis. Time-course expression profiles of PpACO1, PL, PG, PpExp1, and the transcription factor LIM confirmed the array results. Thus, in peach fruit, exogenous JAs led to a ripening delay due to an interference with ripening- and stress/defence-related genes, as reflected in the transcriptome of treated fruit at harvest.

The present study concerned the fruit thinning efficacy of the cytokinin 6-benzyladenine (6-BA) at 150 ppm alone or in combination with the naphthalene acetic acid (NAA) at 15 ppm, on ‘Galaxy’ trees grown in two orchards, one in South Tyrol and the other in Emilia-Romagna area. Applications were carried out at different fruit sizes (5–7, 10–12, 14–16 mm of the king fruit diameter, KF O). In warm climatic conditions as in Emilia-Romagna, the best thinning efficacy was observed with the application of 6-BA alone when KF O reached 10–12 mm, while in South Tyrol, where climatic conditions are cooler than Emilia-Romagna, 6-BA alone showed its best thinning efficacy when KF O reached 14–16 mm. However, in this area, the best results were obtained with the combination 6-BA + NAA applied at 5–7 mm KF O. Moreover, all the chemical applications positively affected fruit quality traits at harvest and, in particular, soluble solid content and flesh firmness were higher in treated fruits as compared to control ones. In South Tyrol, the chemical thinners enhanced skin red colour.

Putrescine (5, 10 and 20 mM), spermidine (0.5, 1 and 2 mM) and aminoethoxyvinylglycine (AVG; 0.32, 0.64 and 1.28 mM) were applied to peach trees (Prunus persica L. Batsch cv Stark Red Gold) under open field conditions. Treatments were performed 28 (polyamines; PAs) and 21 or 7 (AVG) days before harvest at 115 dAFB. Both PAs and AVG reduced ethylene production of fruit, delayed loss of firmness, retained titratable acidity, and prevented the increase in dry matter (DM) and soluble solids concentration (SSC). Fruit drop was consistently reduced by AVG at both application times, and by the highest spermidine concentration. Endogenous PA levels in treated fruit were transiently affected (7 days after treatment), but returned to control values at harvest in both mesocarp and epicarp tissues. Northern analysis of ethylene biosynthetic genes, 1-aminocyclopropane-1-carboxylate synthase (ACS) and 1-aminocyclopropane-1-carboxylate oxidase (ACO), and of those involved in PA biosynthesis, arginine decarboxylase (ADC), ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (SAMDC), was performed in mesocarp tissue at harvest. AVG and putrescine reduced the accumulation of ACO and SAMDC message, putrescine also influenced ACS transcript levels, while spermidine did not affect any of these genes. Results are discussed on the basis of the reduction by PAs and AVG of ethylene production, and confirm the capacity of these naturally occurring substances to modulate fruit ripening.

Corolla life span of undetached flowers of Nicotiana tabacum was divided into stages from the closed corolla (stage 1) through anthesis (stage 5) to death (stage 9). Senescence began around stage 6 in the proximal part, concomitantly with DNA laddering. Nuclear blebbing, DNA laddering, cell wall modification, decline in protein, water, pigment content and membrane integrity were observed during senescence and PCD. Transglutaminase activity was measured as mono- and bis-derivatives of putrescine (mono-PU; bis-PU) and bis-derivatives of spermidine (bis-SD). Bis-derivatives decreased with the progression of senescence, while mono-PU increased during early senescence; derivatives were present in different amounts in the proximal and distal parts of the corolla. In excised flowers, exogenous spermine delayed senescence and PCD, and caused an increase in free and acid-soluble conjugated PA levels. Bis-PU was the most abundant PA-derivative before DNA laddering stage; thereafter, bis-PU generally decreased and mono-PU became the most abundant derivative.

Summary The wild type (Wt) and the polyamine-deficient strain (PA − vs) of the halotolerant Dunaliella salina were subjected to stress caused by 3.5 mol/L NaCl concentration. The chloroplasts were isolated and the molecular aspects of their reaction to salt stress were studied together with their recovery response to these hyper-saline conditions. In the Wt, the photosynthetic complexes were found to be severely affected by salt stress under light conditions. Transglutaminases, which are present in chloroplasts as two units of 25 and 50 kDa, were immunorecognized by antibodies raised against rat prostatic gland transglutaminase. The amount, in particular that of the 50 kDa unit, underwent an immediate change following hyper-saline stress. These concentration changes were found to coincide with variations in enzymic activity, which is also affected by the presence or absence of light. The PA − vs has a concentration of proteins and chlorophylls which is much lower than that of the Wt. In addition, the PA − vs appeared to be more severely affected by both salt and subculture stresses. Its recovery time was also longer. Its TGase activity increased after salt stress and was always higher in the light than in the dark, except soon after subculture, showing an additive stress effect of salt and light. In the PA − vs acclimated to high salinity, or immediately after stress application, the chloroplast content of chlorophyll a and b was considerably enhanced, like the TGase activity (by two-fold or more), and these changes exhibited almost coincident behaviours. Some transglutaminase substrates (proteins of 68, 55, 29 and 27 kDa) were found to be similar to those present in higher plants (thylakoid photosynthetic complexes and Rubisco). They were more markedly labelled by [1,4- 14 C] polyamines when the transglutaminase assay was performed in the light than in the dark, and much more in algae already acclimated to hyper-saline conditions than in those cultured in the optimal saline medium, or subjected to stress. The amount of 68 and 55 kDa polypeptides was particularly high in the 3.5 mol/L NaCl acclimated cells. The possible role of polyamine conjugation in the assembly of chloroplast proteins in cells affected by salt stress is discussed.

We investigated polyamine linkage to different structural proteins in pollen of Malus domestica Borkh. cv Red Chief at different phases of germination. This linkage has the characteristics of covalent linkages, indeed, it could be catalyzed by transglutaminase (TGase; EC 2.3.2.13). This assumption is supported by: (1) formation of a labelled TCA pellet and selective labelling of endogenous proteins by covalent binding of radioactive polyamines and (2) cross-reactivity of two different polyclonal antibodies against mammalian TGases; western blot analysis allowed us to detect a protein of about 80 kDa in both rehydrated ungerminated and germinated pollen. TGase activity was high at 90 min after germination and was influenced by Ca2+ supply only in the rehydrated ungerminated pollen. Extraction by Triton X-100 suggests that pollen TGase was at least partially membrane-bound. The enzyme catalyzed the incorporation of polyamines mainly into proteins having a molecular mass of 43 kDa and 52–58 kDa in both ungerminated and germinated pollen. These bands matched immunolabelled spots identified by mouse monoclonal anti-actin and anti-α-tubulin antibodies. Supplying exogenous actin and tubulin in a cell-free extract of rehydrated ungerminated and germinated pollen enhanced the activity. Autoradiography of the SDS-PAGE of these samples clearly showed that both actin and tubulin were substrates of TGase. Thus, the pollen TGase may be involved in the rapid cytoskeletal rearrangement which takes place during rehydration of ungerminated pollen and organization and growth of pollen tubes.

The nuclear DNA content in dormant tubers of Helianthus tuberosus L. cv OB1 and in explants activated for several hours by 2,4-D was measured by in situ cytometry of Feulgen-stained nuclei and by flow cytofluorimetry of isolated DAPI-stained nuclei. The pattern of variation of mean nuclear DNA content was nearly the same using either method. During activation, DNA content reached a maximum at 9 h. Cytophotometric analysis of optical density profiles of the nuclei and molecular analysis of restricted DNAs indicated that the observed increase at 9 h is probably not related to chromatin decondensation due to a different pattern of cytosine methylation but rather to DNA synthesis. At 15 h amitoses occurred and generated pairs of similar sized nuclei, having an equal DNA content. Concomitantly, the class of nuclei with the highest DNA value disappeared whilst a class with a lower DNA content increased. Between 9 and 20–25 h, DNA content decreased, then increased up to 35 h, when a single DNA class acc...

Our objective was to investigate the effect of fertilization (mineral vs. organic) and ripening stage (pre-climacteric vs. climacteric) on the emission of volatile organic compounds (VOCs) and antioxidant activity of nectarine [Prunus persica, Batsch var. nectarina (Ait) Maxim.]. The trial was carried out in 2007 in an experimental orchard of cv. Stark RedGold grafted to GF677 peach x almond hybrid planted in 2001. The trees were subjected to mineral (N, 120 kg ha -1 year -1 ) or organic (compost, 10 t DW ha -1 year -1 ) fertilization from plantation, with treatments applied 40 days after full bloom at 60% of the annual rate and in September at 40%. A fruit sample was collected every day from 22 July to 3 August. The difference in the absorbance index (I AD ) of each fruit at each sampling date was measured by visible/near infrared spectroscopy (VIS/NIRs). Fruits were sorted into two groups corresponding to two ripening stages: pre-climacteric (l AD >0.9 and flesh firmness > 50N) and climacteric (I AD

Summary Methyl jasmonate (MJ, 0.20 mM) and its synthetic analog n-propyl dihydrojasmonate (PDJ, 0.22 mM) were applied to peach fruit (Prunus persica L. Batsch) at a late developmental stage under field conditions (in planta). On the basis of a previously demonstrated jasmonate (JA)-induced ripening delay in peach, the effects of JAs on the time course of the endogenous polyamine (PA) accumulation and expression of their biosynthetic genes arginine decarboxylase (ADC), ornithine decarboxylase (ODC), spermidine synthase (SPDS) and S-adenosylmethionine decarboxylase (SAMDC) were evaluated in control and JA-treated fruit during the 21-d trial period. In parallel, the main ripening-related parameters (ethylene production, flesh firmness and soluble solids contents) were measured, and transcription profiles of aminocyclopropane-1-carboxylic acid oxidase (PpACO1) and of two ethylene perception genes were evaluated. PDJ, but not MJ, reduced ethylene production and fruit softening, impaired PpACO1 transcription and altered the expression of PpERS1 (ethylene sensor 1), but not the expression of PpETR1 (ethylene receptor 1). In the epicarp and mesocarp, the pattern of PA accumulation was altered in a biphasic manner leading to a higher overall PA level in PDJ-treated fruit. Short and long term increases in putrescine, spermidine and/or spermine, the latter only in the epicarp, were observed in PDJ-treated fruit. MJ induced this behavior only with putrescine in the mesocarp. PpADC transcription was also enhanced soon after the PDJ treatment. Since PDJ-treated fruit were less ripe, their higher PA concentrations in treated fruit are discussed in light of the dual role of these molecules as stress/defense protective compounds and rejuvenating effectors.

Jasmonates (JAs), which derive from α -linolenic acid through allene oxide synthase (AOS), are signal molecules which elicit stress responses through JA-induced proteins (JIPs). They are also involved in growth processes such as cell division, tuber formation and fruit development. JAs induce various biological responses mostly correlated with defense responses; however, their reciprocal relationships with ethylene are not well established. In apple and cherries endogenous JAs peak during the early phase of fruit growth; but only in apple they rise again at climacteric. A JA derivative, methyl jasmonate (MJ), stimulates ethylene production in pre-climacteric apples but inhibits it in climacteric ones. However, MJ-induced apple degreening is partly independent of ethylene. A better established relation is be that between JAs and PAs. PAs are ubiquitous growth regulators involved in fruit set and development; when applied to developing fruit they inhibit ethylene production and delay ripening in peach and other climacteric fruit. To better understand the relationships JA-ethylene in a climacteric fruit, in the present study, MJ and its synthetic analogous propyl jasmonate (PJ) were applied to peach (Prunus persica L. Batsch, cv Stark Red Gold) branches during S2 phase (rapid growth). In treated fruit ethylene production and the evolution of the main fruit quality parameters were inhibited and transcript levels of PpACO1, PpERS1 and PpETR1 were altered in comparison to respective controls. Increases in polyamine titres were associated to JA-induced ripening delay probably contributing to the observed antisenescent effect. A fragment of PpAOS cDNA was isolated and its expression monitored during fruit ripening showing that the corresponding transcript was enhanced in JA-treated fruit. Finally, a microarray comparative trascriptome profiling of treated versus control fruit indicated that MJ down-regulate genes positively involved in ripening thus confirming that JAs slow down such process in peach fruit.

In order to establish whether in vitro model systems are suitable to study the reciprocal relationships between ethylene and polyamines (PAs) in peach fruit, whole detached fruit and fruit explants from “Redhaven” peaches and “Stark Red Gold” nectarines at two different ripening stages were subjected to in vitro treatments with 10mM putrescine (Pu), 1mMspermidine (Sd) or 0.32mM aminoethoxyvinylglycine (AVG) in the presence or in the absence of labelled Pu or methionine. Labelled Pu uptake studies showed that, in the short-term, much more label was recovered in intact nectarines than in peaches. In fact, in the former, ethylene productionwas strongly impaired by Pu and Sd at both stages, while itwas substantially unaffected in the latter. In treated fruit, flesh firmness, soluble solids content and fresh weight were only sporadically affected. Under the same experimental conditions, AVG almost totally inhibited ethylene production although fruit quality was practically unaltered. In explants obtained from fruit at the firmer ripening stage, Pu and Sd did not alter and even enhanced methionine incorporation into ethylene, while in those from softer fruit only Sd was able to counteract ethylene biosynthesis. Also in this case, AVG dramatically reduced ethylene biosynthesis. Short-term treatments of fruit explants showed that only Sd and AVG counteracted ripening. Comparing results from intact fruit and fruit explants indicates that Pu and Sd exert a differential effect on ethylene and fruit quality, depending upon ripening stage and cultivar. © 2006 Elsevier B.V. All rights reserved.

The complex series of mechanisms that characterized the ripening process depends on a interplay of several classes of plant hormones among them a central role is played by ethylene. Relative to the current knowledge about ethylene, much less is known on the interaction between this hormone and other growth substances, in particular auxins, during fruit growth and ripening in some species as for example Actinidia deliciosa. In the present work we investigated the effect of the synthetic auxin 3,5,6-trichloro-2-pyridyloxyacetic acid (3,5,6-TPA) on fruit growth and quality traits of cv Hayward (Actinidia deliciosa) and the relationship between the obtained effect and ethylene emission, biosynthetic enzyme activity and gene expression. Moreover, expression studies of genes encoding for protein involved in cell wall disassembly (polygalacturonases and expansin) were also performed. During a three-years trial, the auxin, commercially available as Maxim™, was applied at different concentrations and application times and its effects were studied throughout the fruit growing season, at harvest and during a cold storage period. The application of chemical caused a significant increase in kiwifruit weight and affected also ripening dynamics. In fact, at harvest and 1 month later, soluble solids content was lower and flesh firmness was higher in treated fruits as compared to control ones, while 3 months later an opposite trend was observed. This ripening dynamic modification was also confirmed by biochemical and molecular analyses. In fact, at harvest and 1 month later, treated fruit reached ACC-oxidase (ACO) activity and ACO, polygalacturonase C and expansin expressions lower than control fruits, while 3 months later treated fruit reached higher transcript levels in all the 3 considered genes. This suggest to further study the relationship between auxin and ethylene in modifying kiwifruit ripening and its influence on the duration of the storage.

The effect of the synthetic auxin 3,5,6-trichloro-2-pyridyloxyacetic acid (3,5,6-TPA) on kiwifruit growth and quality was investigated in a three years study carried out at the Experimental Farm of Bologna University. Different concentrations of the chemical, commercially available as Maxim®, were tested at different application times during the fruit growth period. The maximum effect was observed when the chemical was applied during cell extension. Treated fruits showed fresh weight values higher than control ones in all the trials and these data were confirmed also by the biometric parameters (diameter and length) measurements. A clear correlation between concentration and weight enhancement was observed. The chemical did not induced fruit abscission or phytotoxicity even at the highest concentration. The fruit quality traits were also affected: an increase in flesh firmness and a decrease in soluble solids content were recorded at harvest. No differences were observed in fruit quality traits after cold storage

The time course of ethylene biosynthesis and perception was investigated in ripening peach fruit (Prunus persica) following treatments with the polyamines putrescine (Pu) and spermidine (Sd), and with aminoethoxyvinylglycine (AVG). Fruit treatments were performed in planta. Ethylene production was measured by gas chromatography, and polyamine content by high-performance liquid chromatography; expression analyses were performed by Northern blot or real-time polymerase chain reaction. Differential increases in the endogenous polyamine pool in the epicarp and mesocarp were induced by treatments; in both cases, ethylene production, fruit softening and abscission were greatly inhibited. The rise in 1-aminocyclopropane-1-carboxylate oxidase (PpACO1) mRNA was counteracted and delayed in polyamine-treated fruit, whereas transcript abundance of ethylene receptors PpETR1 (ethylene receptor 1) and PpERS1 (ethylene sensor 1) was enhanced at harvest. Transcript abundance of arginine decarboxylase (ADC) and S-adenosylmethionine decarboxylase (SAMDC) was transiently reduced in both the epicarp and mesocarp. AVG, here taken as a positive control, exerted highly comparable effects to those of Pu and Sd. Thus, in peach fruit, increasing the endogenous polyamine pool in the epicarp or in the mesocarp strongly interfered, both at a biochemical and at a biomolecular level, with the temporal evolution of the ripening syndrome.

1-methylcyclopropene (1-MCP), an ethylene antagonist, is an effective device to improve the shelf-life and quality of fruits, vegetables and ornamentals. It also represents a useful tool in studies aimed at clarifying the ethylene physiology in plants. Peaches and nectarines are climacteric fruit which exibit a sharp rise in ethylene synthesis at the onset of ripening associated with changes in colour, texture, aroma and other biochemical features. Therefore, treatments with ethylene antagonist such as 1-MCP has been performed for extending postharvest storage and shelf life of peach fruit. Fruit developmental stage must be considered when applying 1-MCP, as its effects vary with fruit maturity. In fact, the efficacy of 1-MCP treatment decreases with advanced fruit development. In order to study the effects of 1-MCP on peaches and nectarines at different ripening stages, the fruit was divided into homogeneous classes by using the NIRs (Near InfraRed Spectroscopy) non destructive technology. This technology allowed to correlate the difference of absorbance at the wavelength of 670 and 720 nm (DA index) to ethylene emission levels in peach fruit. Immediately after harvest, three groups of fruit were set, with different DA index intervals: the first one included “pre-climacteric” fruit, characterised by very low or undetectable ethylene emission levels, the second one included “early-climacteric” fruit (low ethylene emission levels) and the third one “late-climacteric” fruit (high ethylene emission levels). The fruit of the three classes was treated with 1-MCP (1 or 5 l l-1) for 12 h at 25°C. Treated and control fruit was then kept at 25° C for about 1 week and the effects on ethylene emission, volatile organic compounds (VOC) and fruit quality traits (flesh firmness, total soluble solids content, titratable acidity) were evaluated.

1-Methylcyclopropene (1-MCP) inhibits ethylene action and fruit quality achievement by binding to ethylene receptors. Developmental stage, timing, concentration and storage temperature may modulate 1-MCP effects. Ethylene and the antisenescent growth regulators polyamines (PAs) share a common precursor and may exert opposite effects. Nectarines (Prunus persica L. Batsch ‘Stark Red Gold’) were harvested and treated with 1-MCP for 12 h at 25°C, and then stored for 3 days at 25 or 4°C. At 25°C, 1-MCP strongly inhibited ethylene production and Pp-ACO gene expression, and development of quality parameters (softening, SSC, loss of acidity). At 4°C, ethylene production was not inhibited, but enhanced on the third day. A transient increase in endogenous PAs is associated with 1-MCP treatment, which at 4°C is accentuated, suggesting a combined negative effect of 1-MCP and cold stress. In fact, the 1-MCP-induced increase in PA levels seems to be more correlated with the cold stress than with preventing post-harvest ripening. Thus, in nectarines a single dose of 1-MCP is sufficient to improve post-harvest storage at 25°C, but has a less beneficial effect at 4°C.

“Stark Red Gold” nectarines were harvested at 30 N of flesh firmness (FF) and 1 nl g −1 h −1 of ethylene production, and treated in sealed plastic containers with 1 μl l −1 (1 ppm) 1-methylcyclopropene (1-MCP) for 12 h at 25 °C. Treated and control fruit were then transferred either to a growth chamber at 25 °C or to a cold room at 4 °C for 3 days. At the end of treatment with 1-MCP; ethylene production in control fruit had increased relative to production at harvest, and this rise was abolished by the presence of the chemical. Moreover, treated fruit showed lower soluble solids content (SSC) and higher FF and titratable acidity (TA) compared to control ones, and putrescine and spermine levels were moderately enhanced in the mesocarp at the end of treatment. In contrast with the inhibition of ethylene production, 1-aminocyclopropane-1-carboxylate synthase (ACS) and especially 1-aminocyclopropane-1-carboxylate oxidase (ACO1 and ACO2) transcript levels were enhanced relative to controls. During storage, 1-MCP affected ethylene production and biosynthetic gene expression, fruit softening and other quality parameters in a temperature-dependent manner: in fruit held at 25 °C a strong decrease in ethylene production, a delay in ripening and lower ACS and ACO1/ACO2 levels were recorded, while in fruit held at 4 °C an opposite trend was observed. Results suggest that 1-MCP application followed by storage at 25 °C appears effective in controlling postharvest ripening. The lack of efficacy of the chemical in cold-stored fruit is discussed in relation to changes in SAMDC gene expression and putrescine accumulation in treated fruit relative to controls, which may be part of a stress response.

Gala and Fuji apples are difficult to thin properly because of their high fertility and extended bloom period under the Italian climatic conditions. Since hand thinning is too expensive, two cytokinin-like compounds which are considered among the most effective chemical thinners, BA (benzylaminopurine) and CPPU (forchlorfenuron), were compared to NAA (-naphtaleneactic acid), hand thinning and untreated control. BA and CPPU were applied on Galaxy while BA and NAA on Fuji. In Galaxy, the two cytokinins induced abscission values similar to those obtained by control, and BA fruits were larger than the control ones. In Fuji, both NAA and BA application reduced fruit load. Average fruit weight was similar among all treatments; however, the average fruit weight of the NAA and BA treated trees tended to increase with increasing concentrations. BA fruits were heavier than NAA fruits, although the thinning effect of BA was slightly lower. As a consequence, yield per tree was highest in the untreated control, followed by BA trees. It is important to assess the effectiveness of a thinning agent at an early stage, since the strategies to enhance fruit size must be applied early in the season. A modeling approach has been adapted to assess the feasibility of using such a tool to evaluate the effectiveness of a thinning agent in the early stages, and to predict fruit size at harvest

Transcript levels and activities of the polyamine biosynthetic enzymes arginine decarboxylase (ADC, EC 4.1.1.19), ornithine decarboxylase (ODC, EC 4.1.1.17) and S-adenosylmethionine decarboxylase (SAMDC, EC 4.1.1.21), as well as free polyamine titres, were analysed throughout the four growth stages S1-S4 leading up to ripening in the mesocarp from peach fruit (Prunus persica L. Batsch cv. Redhaven) grown under field conditions. SAMDC mRNA, which was northern analysed by using a PCR-generated homologous SAMDC probe, and ADC mRNA levels appeared quite stable during fruit development, while ODC transcript accumulation showed a discontinuous trend. The pattern of transcript levels during growth did not correlate with that of the relative enzyme activity, which instead correlated well with free polyamine levels. Both exhibited maximum levels in S1 and a smaller peak in S3. The behaviour of the polyamine biosynthetic machinery is discussed in relation to the different cell growth rates occurring during fruit development.

The effect of various concentrations of aminoethoxyvinylglycine (AVG; 0.32 and 1.28 mM), an ethylene biosynthesis inhibitor, and of the polyamines putrescine (10 mM), spermidine (0.1, 1 and 5 mM) and spermine (2 mM) on peach (Prunus persica L. Batsch cv. Redhaven) fruit ripening was evaluated under field conditions. Treatments were performed 19 (polyamines) and 8 (AVG) days before harvest. Fruit growth (diameter, fresh and dry weight), flesh firmness, soluble solids content and ethylene emission were determined on treated and untreated (controls) fruits. Moreover, endogenous polyamine content and S-adenosylmethionine decarboxylase (SAMDC, EC 4.1.1.21) activity were determined to check for a possible competition between polyamines and ethylene for their common precursor S-adenosylmethionine (SAM). Both treatments strongly inhibited ethylene emission and delayed flesh softening. On a biochemical level, AVG and exogenous polyamines both reduced the free-to-conjugate ratio of endogenous polyamines, and transiently altered SAMDC activity. The possible use of these compounds to control fruit ripening is discussed also in the light of their rejuvenating effect on peach fruits.

The efficacy of Prohexadione-Ca on vegetative and reproductive parameters was tested for 3 years on three apple cultivars (Golden Delicious, Braeburn, and Fuji) at concentrations ranging from 125 up to 350 ppm. The Prohexadione-ca was applied after shoots reached 5 cm length, for 1 month. In all cases, Prohexadione-Ca reduced shoot growth, showed the tendency to increase fruit size and to enhance return bloom. In addition, it increased leaf coloration and higher chlorophyll content, and it induced higher photosynthetic efficiency than the control. The relationships among shoot reduction, chlorophyll content and photosynthetic efficiency are discussed.

Summary This paper reports the protein amount and composition of tuber during its phases of formation, dormancy and sprouting. Parallely, the break of dormancy has been induced by excising slices of tuber parenchyma and treating them with 2,4-dichlorophenoxy acetic acid (2,4-D) to induce a new cell cycle; the protein composition, neosynthesis and post-translational modification by spermidine are reported during the phases of the cell cycle. From tuber formation to sprouting, protein content follows a bimodal trend. The protein bands were separated on sodium dodecyl sulfate polyacrylamide gel electrophoresis and two main bands (38 and 55 kDa) were detected. Many bands, especially of high molecular mass, changed their amount during all phases of tuber vegetative period. With the progression of the cell cycle very high molecular mass proteins increased; neosynthesis and modification by polyamines could account for this increase. Parallelly, the amount of lower molecular mass bands decreased. Many proteins are differently synthesized in the various cell cycle phases. Modification by spermidine occurred post-translationally, evident by an 18 kDa band (which in fact does not incorporate methionine), whose possible identification is discussed. A role for newly synthesized transglutaminases in the protein modification by polyamines is evaluated in the light of the immunodetection of 58 and 90 kDa bands by polyclonal anti-transglutaminase antibody.

Different biometric parameters (fresh and dry weight, diameter, volume) and biological factors (membrane permeability, detoxification mechanisms and phenols content) were investigated in peach flower buds treated with the dormancy breaking agent hydrogen cyanamide, commercially available as Dormex®. Five growing stages (S-S4) were identified based on the analysis of the biometric data. The highest bud abscission percentage was recorded after 1% Dormex® application at the S1 (end of January) or at the S4 (mid of March) stages as related to peach cultivar. Largest changes in membrane permeability were recorded at the same stages of growth. These changes were probably also due to fatty-acids desaturation of membrane lipids as confirmed by the gradual increase of the 3-desaturase transcript level in peach buds. The desaturating reaction produces hydrogen peroxide that inhibits the activity itself and, probably for this reason, we observed a correspondence between the expression of a peach Cat 1 gene, catalase activity and desaturase transcript levels. Total phenols content was mainly influenced by flavanols and Dormex® application at the S1 reduced especially flavan-3-ols levels. Phenols play an important role in the plant stress defence mechanism and their reduction in treated buds could partly explain the high abscission percentage measured after the early (S1) Dormex® application