A hand-held, chlorophyll content meter [the delta absorbance (DA) meter] was used to develop an optimal harvest maturity model for 'Minneiska' apples (Malus domestica Borkh). Fruit from four commercial orchards in the Annapolis Valley, Nova Scotia, Canada, were sampled weekly (25 fruit per location) over eight consecutive harvests during the 2011-2013 growing seasons. At each harvest, 60 fruit were measured for their DA value (I-AD), mass, firmness, titratable acidity (TA), soluble solids content (SSC), red skin colouration, starch-to-sugar conversion and internal core ethylene concentration. Following 3-3.5 months of refrigerated air storage at 3.5 degrees C, samples were removed and assessed for fruit bruising, skin greasiness, rot and physiological disorders. Peel chlorophyll content was strongly and positively correlated with epidermal I-AD measurements. I-AD values declined significantly during fruit ripening and were negatively related to harvest week. The optimal harvest period was identified by aligning 'at harvest' I-AD, fruit quality and 'post-storage' disorder data with the corresponding harvest week. I-AD averages associated with harvests having high commercial fruit quality demarcated the optimal harvest boundaries. As the I-AD values declined during fruit maturity, the upper boundary value of 0.26 was defined as 'when to begin harvest', while the lower boundary value of 0.12 was deemed 'when to end harvest' for longer-term storage.

In this study, a new chlorophyll measurement tool, the delta absorbance (DA) meter, was used to develop an optimal harvest maturity model for 'Ambrosia' apple (Malus x domestica Borkh.) fruit. Fruit from four commercial orchards in the Annapolis Valley, Nova Scotia, Canada, were sampled (25 fruit from three or four trees per location) over nine consecutive weekly harvests during the 2011 and 2012 growing seasons, and 8 weeks in the 2013 season. At each harvest, five fruit from each orchard site had their index of absorbance difference (IAD) values, firmness, mass, titratable acidity (TA), soluble solids content (SSC), red skin colouration and internal core ethylene concentrations measured. Following approx. 3 months of storage at 3.5 degrees C, 20 fruit from each site were removed and assessed for the incidence of disorders such as senescent breakdown, cortical browning and coreflush. Chlorophyll concentrations in the epidermis were strongly and positively related to IAD values in the same tissue (P = 0.001), confirming the assumption that chlorophyll was the basis for the DA meter IAD signal. In addition, IAD values declined significantly during fruit maturity and were negatively related to harvest week (P = 0.001). The optimum harvest period was identified by aligning all 'at harvest' IAD values, fruit quality measurements, and ` post-storage' disorder data with the corresponding harvest week. IAD values associated with harvests having the highest commercial fruit quality then delineated the optimal harvest boundaries. The upper boundary IAD value of 0.47 was defined as 'when to begin harvest', while the lower boundary IAD value of 0.28 was considered to be 'when to end harvest' for long-term storage. The use of a DA meter and its IAD value to define the optimal harvest boundaries may be applicable to all commercial apple cultivars, but should be developed for each cultivar and growing region.

DeLong, J., Prange, R., Harrison, P., Nichols, D. and Wright, H. 2014. Determination of optimal harvest boundaries for Honeycrisp™ fruit using a new chlorophyll meter. Can. J. Plant Sci. 94: 361–369. In this study, a new chlorophyll measurement tool [the delta absorbance (DA) meter] was used to develop an optimal harvest maturity model for Honeycrisp™ fruit. Apples from nine commercial orchards in the Annapolis Valley, Nova Scotia, Canada, were sampled over 11 consecutive weekly harvests during the 2010, 2011 and 2012 growing seasons. At each harvest, a sample of fruit was measured for its DA (IAD) values, firmness, titratable acidity (TA),% soluble solids content (SSC), red skin coloration and internal core ethylene. Following approximately 3 mo of storage at 3.5°C, samples were removed and assessed for disorder incidence. The optimal harvest period was identified by aligning all “at harvest” IAD values, fruit quality measurements and “post-storage” disorder data with the corresponding harvest week. Then, the IAD values associated with the harvests having high commercial fruit quality and the least collective expression of disorders, delineated the optimal harvest boundaries. As IAD units declined during fruit maturity, the upper boundary value of 0.59 was deemed “when to begin” harvest, while the lower boundary value of 0.36 was deemed “when to end” harvest for long-term storage. The use of the DA model approach for optimal harvest delineation is potentially applicable to all commercial apple cultivars, but should be developed for each within a distinct growing region.

This study examined the effect of harvest date (fruit maturity) on the occurrence of post-harvest disorders in 'Honeycrisp'(TM) apple (Malus x domestica Borkh.). Fruit were sampled from six commercial orchards in the Annapolis Valley, Nova Scotia, Canada over two growing seasons and seven (in 2008) or nine harvest dates (in 2009). After 3 months storage in refrigerated air at 3.5 degrees C without delayed-cooling, soft scald, low temperature breakdown (LTB; also called soggy breakdown), bitter pit, and senescent breakdown developed in the fruit and the incidence of each varied with harvest date. Bitter pit developed in immature fruit and declined with harvest date, whereas senescent breakdown was non-existent in immature fruit and increased with harvest date. Minimum bitter pit plus senescent breakdown (combined) occurred at the mid-point of the harvest period (at approx. week-5), when internal ethylene was just beginning to appear in the fruit. An increase in fruit size (to >= 250 g) appeared to increase the occurrence of these two disorders. This study has shown that there is an optimum maturity (harvest date) in 'Honeycrisp'(TM) apples, when the fruit are of sufficient size and colour to meet market requirements, with minimum risk of manifesting the two calcium-related disorders, bitter pit and senescent breakdown. The incidence of these two disorders may increase if fruit are picked earlier (bitter pit) or later (senescent breakdown), especially in larger fruit (>= 250 g).

The effects of temperature, scan interval and rate of oxygen (O2) decline on pulse frequency modulation (PFM)-based minimum fluorescence (Fα) and the Fα-based lower oxygen limit (LOL) were investigated using ‘Honeycrisp’ apples (Malus×domestica Borkh). The effects of temperature and hypoxic stress on pulse amplitude modulation (PAM) fluorescence parameters were also investigated. The PFM scan interval had no effect on the Fα baseline, but increases in the scan interval decreased the low-O2-induced fluorescence spike intensity (ΔFα). Temperature negatively correlated with the Fα baseline while ΔFα°C−1 was greater at lower than at higher temperatures. When using a PAM fluorometer, the minimum fluorescence (Fo), and to a lesser extent the maximum fluorescence (Fm), were similarly affected by temperature as was Fα. Temperature altered the LOL in fruit. Apples stored at 20, 10, 3.5 and 0°C spiked at 0.72, 0.33, 0.22 and 0.08kPa O2, respectively, under a rapid O2 decline (i.e., 20.9 to <1kPa O2 in ≈5–6h). Although the low-O2 Fα spike apex values did not change with temperature, the spike intensity increased with temperature due to a reduced fluorescence baseline. A slower O2 decline rate produced slightly higher LOL and lower spike intensity values. In conclusion, temperature and rate of O2 decline affected the low-O2-induced PFM fluorescence spike intensity as well as the LOL, while the PFM scan interval affected the spike intensity.

Chlorophyll fluorescence was studied as a rapid technique to detect weight loss of table grape cultivars "Thompson and Flame seedless" under air storage conditions (20 degrees C) and in a 0 degrees C cold room. Grape clumps (ca. 1kg) were divided into 12 groups (six for each cultivar) and initial fresh weight, soluble solid content, titratable acidity, pH and color values were recorded. Three groups were placed inside ventilated baskets with a HarvestWatch sensor facing down on the grapes and placed in a 20 degrees C room in front of a forced air fan. These samples were used to generate continuous recording of F-alpha. The other groups were handled in a similar manner and were used to generate weight loss. The control treatments were held in a 0 degrees C cold room and constantly measured by a HarvestWatch sensor. F-alpha (F-0) ratio curve for Thompson generally declined over times, and the rate of reduction was maximal between days 1 and 6 which is equal to ca. 20 percent in weight loss. The response for Flame grapes was almost the same as for the Thompson cultivar. There were good relationships between F-alpha values and weight loss values for both cultivars. From these relationships it appears that, for both cultivars, at about 20% weight loss (equal to 0.8 weight loss ratio), the F-alpha value stopped its decline. The other fruit quality such as SSC, TA, pH and color value indicated that the drying treatment affected these responses, compared with the fruit in the control treatment. Our results indicated that chlorophyll fluorescence techniques can detect weight loss in grapes after harvest, and thus has a potential as a rapid and non-destructive method for monitoring fruit weight loss and senescence in grape during storage.

This study was conducted to determine if chlorophyll fluorescence-based lowO(2) controlled atmosphere (CA) storage maintained higher fruit quality compared with conventional CA storage of organically-grown 'Cortland' and 'Delicious' apples. Fruit from 25 year-old 'Cortland' and `Delicious' trees on MMA11 and M.26 rootstocks, respectively, were harvested in 2003 and 2004 from the same transitional organic orchard in the Annapolis Valley of Nova Scotia. Half of the 'Cortland' fruit were stored in standard CA (SCA) conditions at 2 kPa O-2 + 3 kPa CO2 and 3 degrees C, while half of the 'Delicious' apples were held at 2.0-2.2 kPa O-2 + 2.5-3.0 kPa CO2 at 0 C. The remainder of the fruit were monitored with the HarvestWatch (TM) chlorophyll fluorescence (CF) system which held 'Cortland' apples at 1.0-1.3 kPa O-2 (1.0-1.2 kPa CO2) and 3 degrees C, and 'Delicious' fruit at 0.9-1.1 kPa O-2 (1.2-1.3 kpa CO2) and 0 degrees C. Fruit were removed from all CA storage at 4 and 8 months and held in ambient air for 0, 7, 14 and 21 d at 0 C. Apple quality measurements were taken immediately following storage removal, and after 7 d at 20 C for the fruit held in refrigerated ambient air conditions. The CF system consistently maintained higher fruit firmness (2.4-11.6 N) in both cultivars compared with SCA storage at most evaluation periods. Superficial scald in 'Cortland' fruit under the CF system was markedly reduced, particularly after 7 d at 20 C for all removals. However, the CF system had less effect on superficial scald in `Delicious' apples as the expression of this disorder was generally lower. The CF technology generally maintained higher levels of soluble solids and titratable acidity in 'Cortland' fruit after the 7-d shelf life following the 8-month removal in particular, and reduced rot incidence in 'Cortland' to some degree. The results of this work show that the CF system sustained fruit quality to a greater extent than SCA storage and is an option for organic apple producers as a non-chemical means for maintaining higher fruit quality during long-term storage.

Purpose of review: C ontrolled atmosphere (CA) technology has been adopted worldwide as a sustainable postharv est technology which is not damaging to the environment and presents no risk to humans. This review offers guida nce on the latest developments in CA technology which have been adopted or are likely to influence the future use o f CA technology. Fin dings: The goal of having a dynamic CA environment which is controlled by the stored product has been ach ieved with the discovery and development of a chlorophyll fluorescence-based technology. The rapid adoption of 1- methylcyclopropene (1-MCP) as a postharvest chemical is likely to change the role of CA. CA will remain the pr e-eminent choice for storage of ‘organic’ fruits and vegetables but for ‘non-organic’ products, a combination of 1 -MCP and CA is more likely. There are interesting results from CA research on humidity, decay control with org anic volatiles, hyperbaric storage and ‘novel’ gases such as nitric and nitrous oxide. The combination of CA with on e or more complimentary techniques, although challenging, has b een attempted with some promising results. Limi tations/implications: Adop tion of chlorophyll fluorescence is limited to plant organs that contain chlorophyll. 1-MC P can have no effect or a negative influence on som e commodities. There may be b enefits demon strated with hu midity control, use of organic volatiles, hyperbaric storag e and ‘novel’ gases, but adoption may not occur due to lim ited benefit and unacceptable risks or costs. D irections for future research: I n the developed world, the increased consumption of ‘organic’ foods provides an in centive for future research and development of CA. Dynamic CA, either with chlorophyll fluorescence or with ano ther approach, will attract research. Combin ing CA with co mplementary strategies, e.g. decay or humidity contro l, delayed CA, high temperature CA, 1-MCP and other 1-cycl opropenes, is another promising research direction. Rese arch on the role of cytoplasmic acidosis in senescence and how it is affected by CA will yield useful wider anging information. Ke ywords: oxyg en; carbon dioxide; humidity; nitric oxide; nitrous oxide; chlorophyll fluorescence; dynamic contro lled atmosphere; 1-methylcyclopropene; Muscodo r albus; decay

Benzonorbornadiene 21, 7-spirocyclopropylbenzonorbornadiene 23, 7,7-dimethylbenzonorbornadiene 25, and 7-spirocyclopentylbenzonorbornadiene 27 have been reacted with 3,6-di(2-pyridyl)-s-tetrazine (rate: 21>23>25=27) to form symmetrical 4,5-dihydropyridazines which are stable towards fragmentation but rearrange with varying facility to their 1,4 isomers. The facial selectivity of attack on the π-bond changes from exo-attack for 21 and 23 to endo-attack for 25 and 27. The 7-spirocyclopropyl benzonorbornadiene 23 typically forms a mixture of dihydropyridazines with exo-stereochemistry, which undergo further stereochemical isomerisation to an exo-fused product upon acetylation (acetyl chloride in hot pyridine). Oxidation with DDQ of the dihydropyridazines individually or as mixtures gives the corresponding fused 3,6-di(2-pyridyl)pyridazines.

In a 2-year study, `McIntosh' apples were stored in a CA regime of 4.5% CO2 + 2.5% O2. Within the CA cabinets there were three humidity levels: >75% RH (CaCl2 salt in the chamber), >90% RH (ambient), or >95% RH (distilled water in the chamber). After removal at 4 and 8 months, the fruit were warmed to handling temperatures of 0C, 10C, or 20C and subjected to three levels of impact bruising of 0, 10, or 20 lb with a Ballauf pressure tester with a 1.5 × 1.5-cm tip. The results showed that low-humidity CA storage decreased visible bruising. Although visible shrivel was not observed, the low-humidity treatment may increase the possibility of its occurrence. Respiration, measured as O2 consumption or CO2 production immediately after removal from CA storage, was lowest in low humidity (>75% RH) and highest in ambient humidity (>90% RH) CA storage. The humidity treatments did not affect firmness, soluble solids, titratable acids, or ethylene production. Increasing the temperature during post-storage handling decreased the amount of visible bruising without affecting other variates such as firmness, soluble solids, titratable acids, respiration, or ethylene production.

AbstractDie Spiroverbindung (I) ergibt über die Verbindungen (II) und (III) das Olefin (IV), dessen Ozonspaltung zum Dion (Va) führt.

AbstractBeim Erhitzen von 7‐Isopropyliden‐ und 7‐Diphenylmethylen‐benzonorbornadien (Ia) und (Ib) in Gegenwart von 3,6‐Di‐(2‐pyridyl)‐symm.‐tetrazin (II) und Thiophosgen (IV) erhält man unter Annahme der Zwischenstufe (III) zunächst die Addukte (V), die sich beim Behandeln mit schwachen Säuren zu den Indenothiophenen (VIa) und (VIb) umlagern.

AbstractBei der Kondensation mit Benzaldehyd (II) erhält man aus dem spirocyclischen Benzonorbomenon (I) das Benzyliden‐Derivat (III), das durch Ozonolyse zum Diketon (IV) abgebaut wird.