Time-lapse light dark-shift recordings included sensor tips placed directly above the aggregate ; and inserting the tip into the central core of the aggregate. Recordings of the oxygen signal were taken every second. Light sources were 65 W halogen lamps and experiments were conducted with either 170 µmol photons m−2 s −1 , or 320 µmol photons m−2 s −1 . Dark conditions were realized by switching off the lamps, removing them from the table, and carefully placing a carton box over the entire profiling setup to avoid residual light from the room. Background light intensities under the box were < 1 µmol m−2 s −1 . Theoretical limits of oxygen and DIC flux and whole aggregate O2 flux calculations were calculated from depth concentration profiles according to Ploug et al. , with a diffusion coefficient for O2 in 3.5% saline water of 2.175 × 10−5 cm2 s −1 at 24◦C and 2.3535 × 10−5 cm2 s −1 at 27◦C. Inside the aggregate, the apparent diffusivity of O2 was assumed to be 0.95 . Carbon fixation was estimated based on a photosynthetic quotient of 1.2 . The diffusion of oxygen in agar was not found to be different than in water over a wide range of salinities . In vineyard production systems, canopy management practices are usually employed to control the source-sink balance and improve the cluster microclimate leading to an improved grape composition and resultant wines . Canopy density is usually controlled during the dormant season thought the winter pruning. Additional canopy management practices may be applied during berry development. Fruit-zone leaf removal and especially, shoot thinning have been widely used in order to increase the cluster exposure to solar radiation, reduce crop load as well as decreasing the pest pressures , 25 liter pot increasing flavonoid content and diminishing herbaceous aromas . Nevertheless, when high air temperature and excessive radiation combine, detrimental effects on berry acidity and flavonoid content have been reported in warm climate regions .

Leaf removal consists of removing basal leaves around the clusters in the east or north side during grape development increasing the cluster exposure to solar radiation. It is well known that an early leaf removal increased total soluble solids, anthocyanins, and flavonols . However, some authors reported increases in titratable acidity in Sangiovese and Teran cultivars while other authors found decreases in acidity with basal leaf removal on Tempranillo . Conversely, Sivilotti et al. reported a positive effect of leaf removal applied after flowering on Merlot grapevine by improving cluster integrity by reducing incidence of Botrytis, and lower herbaceous aromas without affecting yield and cluster mass. Contrariwise, Pastore et al. reported that defoliation at veraison reduced the anthocyanin content and increased the impact of sunburn. In fact, these authors found that leaf removal induced a general delay in the transcriptional ripening program, which was particularly apparent for structural and regulatory genes involved in the anthocyanin biosynthesis. Clearly, vineyard location, cultivar , timing of leaf removal , method , and degree of leaf removal , the growing season , among others, are all factors influencing how leaf removal affects grapevine berry composition and integrity. On the other hand, shoot thinning has been related to increased cluster and berry mass and the number of berries per cluster, with a reduction on yield . Conversely, Wang et al. observed that shoot thinning had relatively minor impacts on yield components because of a compensatory effect due to the lower cluster number with concomitant increase in cluster mass. Contrarily, shoot thinning practices on grapevine did not show a great impact on berry primary metabolism , however, secondary metabolites were affected by them . In fact, we recently reported an increase of two-fold in the flavonol content of Merlot berries when leaf or shoot removal was applied mainly by increasing the proportion of quercetin and kaempferol derivatives in detriment of the myricetin derivatives . Berry composition is dependent on a complex balance between compounds derived from primary and secondary metabolism. Between secondary metabolites, flavonoids play an important role in the quality and the antioxidant properties of grapes and are very responsive to environmental factors such as solar exposure .

Anthocyanin compounds are responsive of the berry color, and flavonols act as a UV shields, contribute to the wine antioxidant capacity, color stability, and hue through copigmentation with anthocyanins . On the other hand, the methoxypyrazines are wine key odorants contributing to their herbaceous characteristics and have been related to unripe berries and poor-quality wines when these are not part of the wine typicity . Since they can be present in grape berry and wines at high levels, they may have an important sensorial impact on wine quality . Among methoxypyrazines, the 3-isobutyl-2- methoxypyrazine is considered the most relevant to wine flavor due to its correlation with the intensity of the bell pepper character of wines and its content at harvest seems to be dependent of the solar exposure . The differences found in the literature about the effect of manipulating the canopy architecture on the flavonoid and aromatic content due to different solar exposure of berries in warm climates opens an important field of research. Therefore, we aimed to find the optimal ranges of berry solar exposure estimated as percent of kaempferol for flavonoid synthesis up regulation and the thresholds for their degradation, and to evaluate how canopy management practices such as leaf removal, shoot thinning and a combination of both affect the grapevine yield components, berry composition, flavonoid profile, and herbaceous aromas.Leaf area index was measured on 21 June to characterize grapevine canopy growth and converted into leaf area on by a smartphone based program, VitiCanopy, coupled with an iOS system . The gap fraction threshold was set to 0.75, extinction coefficient was set to 0.7, and sub-divisions were 25. A “selfie-stick” was used for an easy access to place the device about 75 cm underneath the canopy. The device was positioned with the maximum length of the screen being perpendicular to the cordon, raspberry cultivation pot and the cordon being in the middle of the screen according to previous work . In each experimental unit, three images were taken to capture half canopy of each vine, and analyzed by the software. The relationship between leaf dry mass and area was determined on a sub-sample of leaves of different sizes using a leaf area meter . Total leaf area was calculated by defoliating one grapevine per treatment replicate after harvest and using the regressive relationship between leaf dry mass and leaf area. At harvest, clusters were manually removed, counted, and weighed on a top-loading balance. Leaf area to fruit ratio was calculated by dividing leaf area with crop weight.

Dormant pruning weight was collected during the dormant season ; and crop load was calculated as the ratio between yield per vine and the pruning mass of each vine. Labor operations costs and gross income per hectare were calculated based on yield and net returns per hectare and methods presented elsewhere . Anthocyanin productivity was calculated as reported by Cook et al. .At each sampling point and experiment, 55 berries were randomly collected from the middle of each treatment-replicate and kept on ice until they were measured. Berries were weighed, and mean berry mass was determined as the average mass of the counted berries. These berries were used to determine the total soluble solids , the pH, and the titratable acidity . TSS was measured as °Brix, with a digital refractometer . The juice pH and TA was determined with an autotitrator using sodium hydroxide to titrate to an end point of pH 8.3, and it was expressed as g•L−1 of tartaric acid.For each sampling point in each experiment, 20 berries were collected, gently peeled, and berry skins were freeze-dried . Dried tissues were ground with a tissue lyser . Fifty mg of the resultant powder was extracted in methanol: water: 7 M hydrochloric acid to simultaneously determine flavonol and anthocyanin concentration and profile as previously described Martınez-Lüscher et al. . Briefly, extracts were filtered and analyzed using an Agilent 1260 series reversedphase high performance liquid chromatography system coupled to a diode array detector. Separation was performed on a reversed-phase C18 column LiChrospher® 100, 250 mm × 4 mm with a 5-µm particle size and a 4-mm guard column of the same material at 25°C with elution at 0.5 ml per minute. The mobile phase was designed to avoid co-elution of anthocyanins and flavonols consisted in a constant 5% of acetic acid and the following gradient of acetonitrile in water: 0 min 8%, at 25 min 12.2%, at 35 min 16.9, at 70 min 35.7%, 65% between 70 and 75 min, and 8% between 80 and 90 min. The identification of flavonoid compounds was conducted by determining the peak area of the absorbance at 280, 365, and 520 nm for flavan-3-ols, flavonols and anthocyanins, respectively. Identification of individual flavan-3-ols, anthocyanins, and flavonols were made by comparison of the commercial standard retention times found in the literature. Commercial standards of epicatechin, malvidin-3-O-glucoside, and quercetin-3-Oglucoside were used for the quantification of flavan-3-ols, anthocyanins, and flavonols, respectively. The determination of proanthocyanidins was performed using an Agilent HPLC-DAD after an acid catalysis in the presence of excess phloroglucinol , with minor modifications described in Martınez-Lüscher et al. .The growing season of 2017 was warmer and drier compared to the reference data for the same period within the last 20 years . Thereby, average daily temperature was 4°C higher and rainfall was 18 mm less. Overexposed berries were the smallest due to overexposure resulting in dehydration thereby reducing berry mass.

Neither total soluble solids nor titratable acidity changed regardless of the degree of exposure to which berries were subjected. However, the juice pH of the Exp+ Deg+ and Exp+ Deg++ berry must was greater compared to Exp− and Exp+ Deg− berries. Berry skin flavonoid content and composition were also affected by the degree of exposure . The berry anthocyanin content of Exp− was similar to Exp+ Deg−. However, overexposed berries resulted in berry anthocyanin content that was 70% and 90% lower when compared to the Exp− berries. Grape berry exposure to solar radiation not only affected the anthocyanin content but also modified the ratio between the tri- and di-substituted anthocyanins leading to a less stable profile in all treatments with exposed berries. Likewise, berry skin flavonol content and composition were strongly affected by the degree of exposure to solar radiation. Therefore, in Exp+ Deg− flavonol content was two-fold greater than Exp−, albeit they abruptly decreased in overexposed grapes where flavonol content was 25% and 50% lower when compared to Exp− berries. Furthermore, in overexposed berries the proportion of kaempferol and quercetin significantly increased while the proportion of myricetin decreased. Regarding proanthocyanidins in berries, mild exposure did not affect their content in Exp+ Deg− compared to Exp− berries. However, greater solar exposure decreased proanthocyanidin content in berries but to a lesser extent compared to Exp−. Finally, the content of flavan-3-ols was severely reduced in Exp+ Deg++ berries .The analyses performed on single berries from two varieties confirmed the obtained response in anthocyanins and flavonols in Cabernet Sauvignon . Thus, exposure affected the accumulation/degradation of these flavonoids. Exposed berries from the East side of the canopy decreased 8%and 36% of the anthocyanin content in Cabernet Sauvignon and Petit Verdot, respectively. Thus, Petit Verdot seemed to be more sensitive to higher level of solar exposure and degraded anthocyanins. Overexposed berries of Cabernet Sauvignon resulted in an 87% decrease of the berry skin anthocyanins when compared to the interior berries . Berry skin anthocyanins and increasing exposure showed a significant trend below the 22% of kaempferol . Conversely, analysis of the segmented regression on Petit Verdot berries did not show a clear trend below the 3.2% of Kaempferol and after the point of inflection, anthocyanins started to degrade . Regarding flavonol content, no differences were observed between cultivars . Conversely, when exposure increased to ca. 60% the content of flavonols in exposed berries of both canopy sides and in both cultivars; the overexposed berries had the lowest flavonol content . Thus, our data revealed a strong positive relationship between the berry skin flavonols and the percentage of kaempferol until 8.6% of kaempferol proportion for Cabernet Sauvignon and 7.2% Petit Verdot .

During WWII, citizens were encouraged to grow nutrient dense vegetables and were also mandated to comply with national rationing and price controls. A national Food Fights for Freedom campaign enlisted citizens in producing, conserving, and sharing food resources during the war . During both wars, gardens were a key strategy to both produce food for nutritional needs and encourage at home participation in the war efforts. During both wars significant federal and state government support assisted the rapid development of extensive garden networks. Liberty gardens in 1918 numbered 5,285,000 and produced $525 million worth of food. In 1917, the Bureau of Education’s Office of School and Home Gardening was turned into the United States School Garden Army and was funded with $250,000 in federal funds and frequently state or local funds as well . During WWII, while there was no formal School Garden Army, the Office of Education advocated for school victory gardening. The USDA took an active role in promoting victory gardens through statewide conferences and inspiring the formation of state victory garden councils, which would implement federal policy . By 1944, victory gardens provided 40% of American’s domestic food . During both wars in some locales, such as Dayton, OH, the city councils or other agencies took an active role in finding land resources for schools and other gardens, while in other locales, voluntary associations took on this task . In Chicago during WWI, a coalition of local government officials, businessmen, and social reformers worked together to map Chicago’s growing gardening projects to facilitate better coordination. They then went on to publicize garden efforts and distribute over 150,000 copies of educational material on gardening while also setting up demonstration gardens in each of the city’s major parks,growing strawberries vertically totaling seventeen demonstration gardens by 1918.

San Francisco was significantly engaged in both the liberty and victory garden efforts . In 1918 a municipally announced ‘War Garden Day’ was celebrated with a parade of over one thousand soldiers and civilians marching together next to floats decorated with homegrown vegetables, garden themed entertainment, and by breaking ground on a new demonstration garden at the local High School of Commerce .Similarly, San Francisco hosted an annual victory gardens fair from 1943-1945 that provided garden education, entertainment and vegetable exhibitions by local growers to thousands of fair attendees each year . John Brucato led the San Francisco Victory Garden Council from 1941 – 45 . Beginning with articles in the San Francisco News and San Francisco Examiner on food gardening techniques, Brucato, a UC Davis educated farmer, businessman, and politically savvy individual, built a relationship with San Francisco Junior College . This partnership led to the development of the San Francisco Victory Garden Council, which brought together garden clubs, service organizations, labor groups, and others interested in the effort. Initially the Council focused on outreach and education to homeowners, then on the cultivation of vacant lots, and then they turned their sites to the development of large community garden projects. The first of these larger developments was located in Golden Gate Park where four hundred 20×20 foot plots were allocated to families. Similar projects were developed in Glen Park Reservoir Site where 350 garden plots were allocated, and then at Laguna Honda county hospital where 400 nine hundred square foot plots were developed . By 1942 the Council had almost reached their goal of developing 60,000 Victory Gardens. Together these projects combined with the other work of the Council became known as the “Backyard Revolution”. Brucato’s work was lauded as a national model by the Department of Agriculture. It is notable to state that San Francisco has a significant presence of peri-urban gardens and truck farms in Italian, Portuguese, and Chinese communities prior to WWII . During the war period Brucato also worked to develop San Francisco’s first farmers market to support some of these truck farms and struggle farmers in surrounding rural communities.

The market attracted over 135 farmers on its first Saturday and sold produce to over 50,000 people . During both wars, home production and community gardening were emphasized. Community gardens on larger pieces of land were encouraged for their efficient use of land, tools and water and their social benefits . During WWII large community gardens with more established sets of rules became more common. Rules against theft, vandalism, and even trespassing were established to protect the work of gardeners . Homeowners were also targeted by propaganda encouraging people to take out their lawns and plant gardens. In a Columbia University War paper discussing home lawns and flower gardens, Brown argued “the most inexcusable of Idle Acres is the fertile and tended acre that fails to contribute its share to the nation’s staple food supply at a time of national need” . Home backyard garden production continued to be promoted after the end of the war. In national home ownership campaigns, the garden was a valued asset by builders, real estate agents and buyers as an essential component of the American home . Following WWII, while some advocated for the importance of permanent public gardening, vacant-lot and community gardening largely disappeared from the US urban landscape. Although subsistence gardening played a dominant role in the urban landscape in Columbus, Ohio from 1900 to 1940 , post WWII, gardens disappeared materially and discursively from city space and the telling of Columbus history. The use of urban planning and land use discourse that claimed gardening was contrary to “modern” development played a key role in this the postwar disappearance of gardens. Post-war planners increasingly saw agriculture as a threat to urban health and safety and used zoning to move this threat out of the city . In addition, the still dominant discourse of gardening as a response to crisis helped to normalize their erasure once the crisis had passed and other urban development schemes dominated. Backyard gardening was promoted as a hobby by magazines like House and Garden, but for those without access to backyards it was unclear where, if at all, gardens had a place in the city. The Washington D.C. Victory Garden commission went as far as to state, “[victory] gardening has not place as a ‘proper peacetime municipal function’” . During this period increasingly racist home lending, government benefits, and housing sales, made homeownership a reality for many white families.

Thus home gardening with secure tenure was a possibility for these families but was not for many African American, Chinese American, Japanese American, Mexican American, and other racially or ethnically excluded communities. Still gardening persisted in many of these communities as African American families with slave histories moved north and west and brought agricultural practices with them,drainage planter pot just as Mexican American landholders who had been disposed of their lands brought agricultural histories with them to California backyards and city lots. A prominent San Francisco example are the Chinese peri-urban gardens of the early 1900s. Gardening in Chinese communities in Southeast San Francisco and Oakland was a common practice and provided significant amounts of produce to local markets . Chinese gardeners were denied rights to own land and most gardeners had lost access to their gardens by the 1940s through building development or the expansion of Italian and Portuguese gardens. Work with Chinese gardeners is notably missing from Brucato’s account of WWII gardener and truck farmer assistance efforts. Post WWII home ownership became a depoliticizing force for garden efforts in white communities, as increasing numbers of individuals had access backyard gardens. At the same time, in racially marginalized communities, where home ownership was suppressed, collective garden projects grew in importance during subsequent moments of resistance to racist urban redevelopment projects that displaced communities of color.In the interwar period, during the Great Depression, several relief efforts used gardens as a means to improve the food security of and constructively occupy unemployed workers and poor families. Similar to the war gardens, relief garden efforts received significant state and federal support and funding. As such these garden efforts were more top-down than many of the urban gardens of the early twentieth century . Garden programs were more supported during the beginning of the depression from 1931-1935 than the later years . Two forms of gardens were most common: the work-relief garden and the subsistence garden. Work-relief gardens provided workers with a wage to collectively garden large tracts of land where food was produced and then sent to food relief programs. In 1934, gardens produced 36 percent of fruits and vegetables used in relief efforts. Similar to past urban gardening efforts, subsistence gardens provided gardeners with land, seeds, and education for production for home use. State and federal governments spent $3 billion on the creation of relief gardens in the three-year time span between 1932 -35 . In 1935, federal relief work shifted focus towards the Works Progress Administration and in 1937 the distribution of excess agricultural commodities through the Food Stamp Program .5Depression era garden advocates also encouraged the use of vacant or unused lands. Manuals suggested groups survey vacant land in their communities and partner with real estate boards, industry, railroads, and public agencies for use of their spaces . Many companies started gardening programs of their own to provide relief for workers who had been fired or had their hours reduced. Some national companies went as far as to require all local plants to start gardening programs. In 1932 more than forty railroad companies had encouraged their employees to garden on railroad owned land .

Some companies went beyond providing land for subsistence gardens. The B.F. Goodrich Company encouraged workers to participate in a collective farm, which used labor rotations and centralized planning to produce and distribute over one million pounds of vegetables . Cooperative farming supported by the employer was found to make significant contributions to the needs of the community during this depression period according to a company report released in 1933 . Overall, like earlier waves of gardening which relied on borrowed lands from employers, public agencies, and private owners of vacant lands usually located at the city’s edge, work relief and subsistence gardens were always intended to be temporary solutions to the problems of urban poor. The discourse on vacant lots to be filled with temporary gardens has been a persistent theme in the history of US gardening, one that Luke and Lawson identify as a barrier to the development of gardens as a permanent institution in urban land use. Community gardens resurfaced in the 1970s after a period of post-WWII disfavor. Bassett identifies two reasons for this rise of community gardening in this time of economic stagflation: the rise of food prices and the growing environmental movement. Others argue that the gardens of the 1970s were more closely connected to the civil rights and urban social movements of that time . Unlike many gardens earlier in US history, these efforts were largely gardener driven and managed in both planning and development . In urban centers across the nation, gardening was embraced as a means to resist top down urban renewal, promote more sustainable agricultural practices, and reimagine the urban environment. Gardening became a part of the alternative open space movement in which playgrounds, miniparks, and garden spaces were developed on small sites that were often overlooked but became highly integrated into community use . While community gardening experienced a lull in the 1950s and 60s, backyard gardening’s popularity continued to grow. By 1973, over 80 million Americans were gardening as a hobby . In the late sixties many sought to transform this hobby into a strategy for more ecological and sustainable living, forging a relationship between ecological agriculture and urban sustainability that is still vibrant today. Across the country many urban garden projects were explicitly connected to efforts to resist racialized urban renewal. In the 1960s and 70s in Boston, Mel King and many others organized in historically black communities to gain a voice in urban and community development . King, a leader or the Eastern Massachusetts Urban League and organizer committed to local control and governance of land, spearheaded the passage of a bill in 1976 that made it possible to claim unused land for community gardens . Six gardens were developed that summer.