Net CO2 Assimilation Rate and Nitrogen Content of Grape Leaves Subsequent to Fruit Harvest

Williams, Larry E.; Smith, Richard

doi:10.21273/jashs.110.6.846

Cited by 12 publications

(2 citation statements)

References 18 publications

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“…Once the vines had filled up their pool of storage reserves, they simply began to shut down and initiated a premature senescence program in the leaves. Williams and Smith (1985) found that leaf nitrogen declined in concert with photosynthesis during postharvest leaf senescence in grapevines. We suggest that early leaf senescence brought about by low overall sink strength may be an adaptive strategy: vines may benefit from the ability to remobilize leaf nitrogen, as well as other nutrients, sooner for storage in the perennial structure.…”

Section: Discussionmentioning

confidence: 98%

Fruit Ripening Has Little Influence on Grapevine Cold Acclimation

Keller

Mills

Olmstead

2014

Am. J. Enol. Vitic.

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This four-year study tested whether the physiological demand of fruit ripening may interfere with grapevine cold acclimation in autumn or with midwinter hardiness. Three harvest time treatments were established in a mature vineyard of own-rooted Cabernet Sauvignon vines: clusters were removed after fruit set, at veraison, or after the first fall frost. Average yield of the late harvested vines varied from 4.2 to 5.1 kg/vine (7.5 to 9.2 t/ha) among years, and soluble solids varied from 23.4 to 25.6 Brix. The presence of fruit during ripening delayed leaf senescence, measured as chlorophyll decline. The fruit also tended to delay the senescence-associated decrease in photosynthesis. All vines showed typical patterns of autumn cold acclimation, midwinter hardiness, and spring deacclimation. Cold hardiness of buds, cane phloem, and cane xylem varied during winter depending on prevailing temperature, and during the coldest winter reached levels of -27°C for 50% bud damage and -28°C for the onset of xylem injury. Early fruit removal had no effect on cane nonstructural carbohydrates and, with few exceptions, failed to enhance cold hardiness. Depending on the year, early fruit removal improved bud hardiness on 5 to 15% and xylem hardiness on 8 to 38% of all measurement dates. On those dates, the early harvested vines tended to be 1 to 2ºC hardier than the late harvested vines, irrespective of the time of crop removal. No trend was found for phloem hardiness. These results indicate that cropping, at least within commercially acceptable limits in regions with sufficiently long or warm growing seasons, rarely impacts cold acclimation and maximum hardiness. Grapevines appear to adjust seasonal leaf physiology to meet their carbon demand for both fruit ripening and cold acclimation.

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Section: Discussionmentioning

confidence: 98%

Fruit Ripening Has Little Influence on Grapevine Cold Acclimation

Keller

Mills

Olmstead

2014

Am. J. Enol. Vitic.

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“…Since 70% of the solar radiation absorbed by a grapevine canopy takes place in the first leaf layer (16), these leaves would be expected to have the highest N concentration among leaves within the canopy. Since there is a linear relationship between leaf N concentration and net C 0 2 assimilation of grape leaves (23), the partitioning of N as demonstrated in Table 1 would optimize canopy photosynthesis by increasing N in leaves that are directly responsible for the majority of the carbon assimilated by the grapevine.…”

Section: Discussionmentioning

confidence: 99%

Growth of ‘Thompson Seedless’ Grapevines: II. Nitrogen Distribution

Williams

1987

J. Amer. Soc. Hort. Sci.

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Nitrogen content and concentration were determined on field-grown ‘Thompson Seedless’ grapevines in the San Joaquin Valley of California. Individual vine replicates were harvested throughout the growing season over a 3-year period. There was a linear increase in vine N content from budbreak to 1000 growing degree days (GDDs) later. During this time, the accumulation of N was primarily in the stems and leaves. Subsequent to 1000 GDDs, the increase in vine N was due to the accumulation of N in the clusters. Throughout the season, N concentration in all vine parts decreased. The increase in cluster N content did not appear to occur at the expense of N remobilization from the vegetative structures measured in this study. On a single date, the N concentration of leaves varied throughout the canopy—the outer layer of leaves contained 3.2% N, while leaves in the interior of vine contained 2.4% N. The loss of N from the vine through leaf fall and cane pruning was about 20 and 15 g, respectively. The data were similiar from year to year with regards to both N concentration and content in leaves, stems, and clusters when plotted vs. GDDs. The approximate requirement of N for current season’s growth of ‘Thompson Seedless’ grapevines used for raisin production was 75 g/vine, or 84 kg·ha-1.

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