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In vitro proliferation and rooting capacity of 'San Castrese ' and 'Portici' apricots (Prunus armeniaca L.) were tested on modified MS medium enriched with varying growth regulator concentrations and sucrose (58.4 mM) or sorbitol (116.8 mM) as main carbon energy sources. The interaction of proliferation and rooting media was also studied.Proliferation of both cultivars was proportional to benzyladenine (BA) concentration and enhanced with sorbitol media. However, 8.8 p~M BA was often associated with hyperhydricity, particularly when shoots were grown on sucrose media. Newly proliferated shoots elongated better on sorbitol media. The positive influence of sorbitol on proliferation and shoot growth was not due to osmotic effects. Moreover, sorbitol showed a positive carryover effect in hastening rooting of 'Portici'. By contrast, when transferred to sorbitol rooting media, the shoots of both cultivars generally showed low rooting, with short, thick roots.Up to 70% of the plantlets that produced roots in sucrose media enriched with indolebutyric acid were successfully acclimatized when they were dipped in a benomyl (0.075% w/v) suspension before being transplanted with care being taken to prevent over-wetting of soil.

Grape quality for winemaking depends on sugar accumulation and metabolism in berries. Abscisic acid (ABA) and gibberellins (GAs) have been reported to control sugar allocation in economically important crops, although the mechanisms involved are still unknown. The present study tested if ABA and gibberellin A3 (GA3) enhance carbon allocation in fruits of grapevines by modifying phloem loading, phloem area and expression of sugar transporters in leaves and berries. Pot-grown Vitis vinifera cv. Malbec plants were sprayed with ABA and GA3 solutions. The amount of soluble sugars in leaves and berries related to photosynthesis were examined at three points of berry growth: pre-veraison, full veraison and post-veraison. Starch levels and amylase activity in leaves, gene expression of sugar transporters in leaves and berries and phloem anatomy were examined at full veraison. Accumulation of glucose and fructose in berries was hastened in ABA-treated plants at the stage of full veraison, which was correlated with enhancement of Vitis vinifera HEXOSE TRANSPORTER 2 (VvHT2) and Vitis vinifera HEXOSE TRANSPORTER 6 (VvHT6) gene expression, increases of phloem area and sucrose content in leaves. On the other hand, GA3 increased the quantity of photoassimilates delivered to the stem thus increasing xylem growth. In conclusion, stimulation of sugar transport by ABA and GA3 to berries and stems, respectively, was due to build-up of non-structural carbohydrates in leaves, modifications in phloem tissue and modulation in gene expression of sugar transporters.

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-Introduction. This research focused on the variation of the kernel and pellicle (seed coat) constituents during nut growth, from early development to maturity. Material and methods. Nuts of three hazelnut cultivars widely grown in Italy: 'Tonda Gentile Romana', 'Tonda di Giffoni' and 'Nocchione'. were randomly sampled weekly, from the same trees, starting from the first week of July 2007 (day of the year: DOY = 186) until the beginning of September (DOY = 249), at harvest time. Results and discussion. Oil content increased continuously during the development of the kernel, from 30-35 g 100 g −1 dry weight (DW) at the beginning of July, to 61-68 g 100 g −1 DW in the first week of September. Total monounsaturated fatty acids were the main group of fatty acids in the oil and oleic acid was the most predominant one, showing slight variations depending on the cultivar and kernel growth stage. Nitrogen content in the kernel decreased continuously during development, from 4.2 g 100 g −1 DW to 2.9 g 100 g −1 DW on average among the cultivars. Soluble sugars, mainly sucrose, showed a wide fluctuation until late July, and the content observed in the mature seed was about 5 g 100 g −1 DW in all cultivars. The organic acids, mainly represented by malic acid, showed a large decrease during the early stages (July), and reached on average a content of about 0.3-0.4 g 100 g −1 DW at the mature stage. Starch content for all cultivars was highest at the first sampling date, then decreased rapidly, coinciding with the initial kernel expansion stage. Starch levels then increased to a second peak in early August, then rapidly decreased again, followed by a gradual decline up to the time of nut ripening. The total phenol content was mainly concentrated in the pellicle and showed wide variation during the nut development both in the kernel and pellicle. Conclusion. The complexity of these dynamics can explain the different kernel taste in immature and mature states, and highlights the possibilities of optimizing the orchard management and harvesting time.

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