Inflorescence necrosis, ammonium, and evidence for ferredoxin-glutamate synthase activity in grape (Vitis vinifera L.)

Death of flower parts near bloom due to inflorescence necrosis (IN) is associated with high ammonium (NH₄⁺) concentration in flower clusters, shade, cool wet weather preceding bloom, and excessive vigor. Faults in NH₄⁺ assimilation are suspected to cause a rise in NH₄⁺ concentration to toxic levels in flower cluster but not other tissues. In this study, shading whole vines of Pinot noir increased flower NH₄⁺ concentration if applied at budbreak (early) or 1 wk before bloom (late), but only late application of shade to individual shoots raised it. Late, complete shoot defoliation raised flower cluster NH₄⁺ in all three years of the experiment. Early or late removal of lower leaves on a shoot also increased flower cluster NH₄⁺. Lamina, petiole, and other shoot tissue NH₄⁺ levels responded differently to treatments than flower clusters. IN severity was not affected by treatments; however, on shoots whose primary clusters had been removed at bloom secondary clusters did show significant differences, with IN being more severe in the early defoliation and late, lower defoliation treatments. Ethephon, sprayed on whole vines, slowed shoot growth to zero and increased IN severity greatly, however, flower cluster NH₄⁺ concentration was increased only 20% over the controls. Methionine sulfoximine applied as a cluster dip, increased flower cluster NH₄⁺ by 100%, yet resulted in little necrosis. Rootstock and clone affected Pinot noir flower cluster NH₄⁺ and IN severity. Rootstocks 420A caused lower and 101-14 and 3309 higher NH₄⁺ concentrations than the average. IN severity and flower cluster NH₄⁺ varied between vineyard sites, possibly due to environment and management differences. Pinot noir clones UCD23 and 32 had lower and UCD4 higher than average flower cluster NH₄⁺. IN in clones UCD4 and DJN115 was the least and UCD23 the most severe. A single 73kDa protein from grape shoot tissues reacted with anti-rice Fd-GOGAT IgG. An extraction method and assay for Fd-GOGAT activity from grape tissues was developed and gel filtration was used to show that the native enzyme is a dimer or trimer of the 73kDa protein. Activity was found in lamina, petiole, flower, rachis, and tendril, but not pedicel tissue

Xylem discontinuity in Vitis vinifera L. berries

Several effects of xylem discontinuity in Pinot noir and Merlot grape berries were studied. There was a reduction in the amount of apoplastic dye (Eosin Y or azosulfamide) uptake through cut pedicels into soft versus firm berries, suggesting a reduction in maximal xylem flow at that time. Both greenhouse and field grown Pinot noir berries took up less dye after softening. Merlot berries, collected on one date from the field and separated by hand into four developmental categories, took up different amounts of azosulfamide dye according to category. Soft green and just colored berries took up 30%, and fully colored berries 70%, less dye than firm green berries. The reduction in xylem conductivity was related to the developmental stage of each individual berry and not the cluster as a whole. The accumulation of K⁺ (primarily a phloem transported element) and Ca²⁺ (primarily a xylem transported element) differed in field grown Pinot noir berries during maturation. On a per berry basis K⁺ increased after veraison, suggesting greater phloem activity, but Ca content remained stable after veraison, suggesting little xylem activity. Berry diameters on pre-veraison clusters on well watered vines increased slightly; those on unwatered vines decreased, losing 0.87 mm in diameter during day 3 of the experiment. Pre-veraison berry deformabilities were 380% higher in unwatered versus watered vines on day 4. Bagging pre-veraison clusters to slow transpiration reduced the rate of berry diameter loss and softness only slightly. Pre-veraison berry shrivelling occurred before vine wilting. Post-veraison Pinot noir berry diameters and deformabilities in the greenhouse were not significantly affected by short term vine water stress. Heat girdling cluster peduncles to block phloem flow reduced pre-veraison berry growth rates to near zero and increased the rate of diameter loss significantly in post-veraison berries. Girdling had little effect on pre-veraison berry deformabilities, but a large effect on those of post-veraison berries. The different berry responses to vine water stress and peduncle girdling before and after veraison suggested a change in xylem activity. Prior to veraison there was rapid water loss from the berry to a stressed vine, but after veraison berries were more isolated, showing little response to vine water stress. Blocking phloem transport in the cluster peduncle prior to veraison reduced berry growth to almost zero but affected deformability little, which suggested that xylem was maintaining berry size and firmness. Under the same conditions post-veraison berries lost both size and firmness rapidly, which suggested little xylem activity

Effects of UV-B and water deficit on aroma precursors in grapes and flavor release during wine micro-vinification and consumption

UV-B radiation and water availability can affect amino acids(AAs) concentration in berries, resulting in the evolution of aroma compounds during alcoholic fermentation. This study investigated the effects of UV-B exposure and water availability on wine aroma compounds in Pinot noir, focusing on the role of AAs in the process.Enhanced UV-B radiation significantly decreased total AA concentrations and most individual AAs in berries and wines, while water deficit increased some individual AAs in wines. Higher alcohols, fatty acids, esters, monoterpenes, and C₁₃-norisoprenoids were affected by UV-B interaction with water deficit in wines. These results suggested individual or combined UV-B exposure and water deficit had direct effects on fruit AAs, leading to significant differences in some wine aroma compounds

Evaluation of appendicitis risk prediction models in adults with suspected appendicitis

Background Appendicitis is the most common general surgical emergency worldwide, but its diagnosis remains challenging. The aim of this study was to determine whether existing risk prediction models can reliably identify patients presenting to hospital in the UK with acute right iliac fossa (RIF) pain who are at low risk of appendicitis. Methods A systematic search was completed to identify all existing appendicitis risk prediction models. Models were validated using UK data from an international prospective cohort study that captured consecutive patients aged 16–45 years presenting to hospital with acute RIF in March to June 2017. The main outcome was best achievable model specificity (proportion of patients who did not have appendicitis correctly classified as low risk) whilst maintaining a failure rate below 5 per cent (proportion of patients identified as low risk who actually had appendicitis). Results Some 5345 patients across 154 UK hospitals were identified, of which two‐thirds (3613 of 5345, 67·6 per cent) were women. Women were more than twice as likely to undergo surgery with removal of a histologically normal appendix (272 of 964, 28·2 per cent) than men (120 of 993, 12·1 per cent) (relative risk 2·33, 95 per cent c.i. 1·92 to 2·84; P < 0·001). Of 15 validated risk prediction models, the Adult Appendicitis Score performed best (cut‐off score 8 or less, specificity 63·1 per cent, failure rate 3·7 per cent). The Appendicitis Inflammatory Response Score performed best for men (cut‐off score 2 or less, specificity 24·7 per cent, failure rate 2·4 per cent). Conclusion Women in the UK had a disproportionate risk of admission without surgical intervention and had high rates of normal appendicectomy. Risk prediction models to support shared decision‐making by identifying adults in the UK at low risk of appendicitis were identified

Viticulture: Grapevines and their management

Viticulture is the study and practice of cultivating grapevines, a vinous perennial plant that produces grapes. Grapes are used for a wide range of products, including as-is for fresh consumption, dried (raisins), cooked (jellies/preserves), juice, or fermented into wine or other alcoholic beverages. The genus Vitis includes several widely cultivated species, most importantly Vitis vinifera, but also Vitis labrusca and Vitis rotundifolia. The fruit of the grapevine is a true berry, borne on a racemose panicle, and has a double sigmoid growth curve. Ripening is characterized by véraison, a stage of development when the fruit begins to accumulate color, sweetness, and develop characteristic aroma and flavor compounds. Each species of grapevine contains many varieties and, within those, clones, leading to many subtle differences between types. Management of the vine usually involves a support system called a trellis, on which the vine is trained

Behavioral responses of European blackbirds and Australasian silvereyes to varying acid and sugar levels in artificial grapes

Diminishing acid concentrations have long been thought to be one of the effects of ripening grapes that leads to increased bird pressure approaching harvest. Blackbirds (Turdus merula) and silvereyes (Zosterops lateralis) were offered in a field context varying concentrations of tartaric and malic acids in artificial grapes, where sugar and all other ripening grape parameters were controlled. No linear response of consumption to varying acid concentration was found for either species. A response to rising sugar was confirmed, but dimin¬ishing acid concentrations in ripening grapes appear not to be a contributing factor to increasing bird pressure approaching harvest

Ammonium Metabolism in Grapes [1992-1993]

Oregon grape growers are sometimes troubled with fruit set problems. There are many types of fruit set disorders, but a recently described one is inflorescence necrosis (IN). Though many studies related to the disorder have been done at OSU and elsewhere, investigation into IN is still in its infancy. Several OSU researchers have shown that high levels of ammonium (NH4+) in inflorescences are associated with severe IN

Viticultural Factors Affecting Inflorescence Necrosis and Ammonia Metabolism [1995-1996]

Inflorescence Necrosis (IN) has been an unpredictable problem for grape growers in Oregon. The industry has seen significant losses due to this fruit set disorder in several out of the eight years since its first description in 1988, particularly in Pinot noir. Little is known of how to prevent the disorder, in fact, there is little known about its physiology. Reported here are three groups of experiments that attempt to better characterize IN (effects of shade and defoliation, rootstock, and clone), investigate the physiology of the disorder, and determine if there is a link between the ammonium ion (NH4+) and IN in the field (which has already been established in more controlled environments)

Ammonium Metabolism in Grapes [1993-1994]

The connection between the fruit-set disorder Inflorescence Necrosis (IN) and high ammonium (NI14+) in affected tissues has led to an investigation of NH4+ assimilation enzymes (principally glutamine synthetase (GS) and glutamate synthase) in grape tissues. Previous work in this department has suggested that toxic levels of NH4+ build up in cluster tissue as a result of its inadequate NH4+ assimilation capacity. Current objectives are to isolate key NH4+ assimilation enzymes from different grape tissues and to survey for both presence and activity of those enzymes in plant tissues from within a cultivar and between cultivars. It is expected that varieties more susceptible to IN will have lower NH4+ assimilation capacity. Additionally, shoots in the field have been shaded and defoliated in an attempt to manipulate NH4+ levels in flower clusters.KEYWORDS: Production Science, Viticulture, Vine Physiology, Researc

Manipulating the functionality of grape seeds products through reflective mulching and wine fermentation

Poster presentation of research carried out to investigate the effect of reflective mulching and wine fermentation on the fatty acids and the phenolics profiles of grape seed