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Calcium accumulation in fruit of kiwifruit grown under different windspeed conditions
No full textMany physiological disorders of fruit are associated with low fruit calcium status. This is true for kiwifruit in which fruit storage quality is closely related to fruit calcium concentration. It is well known that calcium transport to a fruit is exclusively via the xylem - calcium is not phloem mobile. Therefore, a fruit’s calcium status will depend on the cumulative inflow of xylem sap through the stalk; this will depend on fruit transpiration, and on the microenvironment in which the fruit develops. A plausible hypothesis says that if the windspeed around a developing fruit is increased, fruit transpiration will be increased, and likewise the accumulation of fruit calcium. To test this hypothesis, trials were conducted, on 10-year-old kiwifruit vines (Actinidia deliciosa 'Hayward') growing in Palmerston North, New Zealand. At fruit set, 12 small electric fans were mounted in the canopy to modify the wind environment of the immediately adjacent fruit. The fans were in operation continuously (24 h /day for several months) from fruit set through to harvest and the wind speed experienced by individual tagged fruit was measured periodically using a small vane anemometer. At harvest the calcium contents of ventilated and control fruits were analysed. The results show that increased windiness is associated with marked increases in fruit calcium
Developmental changes in xylem functionality in Kiwifruit fruit: implications for fruit calcium.
No full textIn kiwifruit, as in most fruits, storage quality is related to calcium concentration and many disorders are associated with low fruit calcium status. Previous studies show that after an early rise, fruit calcium concentration decreases because calcium influx ceases by the mid-growth stage whereas volume growth continues till harvest. Calcium transport to the fruit is exclusively via the xylem - calcium is not phloem mobile. We postulate that declining fruit xylem functionality is responsible for this pattern of calcium accumulation. Xylem functionality was measured from fruit setting to harvest in ‘Zespri GoldTM’ kiwifruit. The applied measurement technique consists in “transpiring” an apoplast-mobile dye into detached fruit through the stalk and recording the percentage of dyed (functional) bundles in sections cut along the length of the fruit. For the middle part of the fruit analysed, the dye method revealed high bundle functionality till about d10 (after bloom). A drastic reduction in the number of functional bundles occurred around d20 and, again, around d55 and d90. Some recovery was observed between these time steps. An almost complete permanent dysfunction was evident nearly at d120 up to harvest time. Fluctuations in bundle functionality are interpreted as being due to vessel
breakage (resulting from stretching caused by fruit expansion) and temporary functional recovery resulting from early season differentiation of new vessels. The length growth rate is very high in the first 8 weeks from full bloom with a maximum value of 1.3 mm d-1 at the 4th week. In this period, the fruit achieves 70% of the total length at harvest time. We conclude that patterns of xylem dysfunction in Zespri GoldTM provide a satisfactory explanation of the well-known patterns of fruit calcium accumulation
Effects of different water regimes on berry metabolism and composition of Aleatico grapevine
No full textThis work reports the results of a trial carried out on ‘Aleatico’ grapevine, a cultivar cultivated along Tuscany coasts and in Elba Island, from which a typical dessert wine is produced after partial postharvest dehydration of berries. Two different water regimes were applied in the vineyard: not irrigated (water stress, WS) and partially irrigated (moderate water deficit, MWD). WS conditions determined a decrease of stem water potential (SWP) that reached values lower than - 1.4 Mpa, whereas in MWD these SWP levels were registered only for short periods. Significant differences in stomata conductance and net photosynthetic rate values were observed between the two treatments. At harvest, berry weight was reduced of about 20% in WS plants. An effect of similar magnitude was detected for skin
weight, while seed weight was not affected. The sugar accumulation process was more pronounced in WS berries and this was paralleled by higher titratable acidity values both at veraison and harvest. Skin anthocyanin content was determined in laboratory and by a fluorimetric method, using the optical sensor Multiplex®2, an
innovative portable instrument based on chlorophyll fluorescence, that nondestructively analyzes the berries in the field, under natural light. WS induced a significant increase of anthocyanin biosynthesis as their content resulted to be higher than that of MWD samples. The cultivar ‘Aleatico’ appeared to be quite tolerant to
water stress conditions and this information could be useful also for setting up targeted postharvest dehydration strategies to produce dessert wines. An additional interesting result is represented by the validation of the use of a portable nondestructive instrument to measure skin anthocyanin content directly in the vineyard
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Le emissioni dei gas serra nella fase agricola della filiera dei prodotti agro-alimentari: il caso del vino nel Distretto Rurale della Maremma.
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