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Journal Article

Determination of the photosynthetic capacity of grapevine leaves

22 Oct 2015-Vitis: Journal of Grapevine Research-Vol. 30, Iss: 2, pp 49

TL;DR: To avoid reduction of photosynthesis by photoinhibition it is proposed to minimize the duration of exposure of leaves to high light and to reduce light intensity to values where photosynthesis begins to reach light saturation.

AbstractAt fully irrigated, container-grown vines (cv. Riesling) kept outdoor, measurements of stomatal conductance and photosynthesis of leaves were performed in the morning and in the afternoon. The results revealed reductions of the photosynthetic capacity (maximal net photosynthesis at saturating light conditions and at saturating CO 2 partial pressure) in the afternoon. This observation was associated with a higher sensitivity of stomata to CO 2 in the afternoon: 0.0016-mu-bar-1 in the morning, 0.0046-mu-bar-1 in the afternoon. Due to inhibition of photorespiration determinations of photosynthetic capacity in the morning at 1-2% O 2 revealed maximal values at lower CO 2 partial pressures and, thereby, at maximal stomatal conductance. These values, corrected for photorespiration, were close to those obtained at ambient O 2 and high CO 2 partial pressures. Thus, it is assumed that in our experiments stomata did not limit the rates of photosynthesis which were determined in the morning. To avoid reduction of photosynthesis by photoinhibition it is proposed to minimize the duration of exposure of leaves to high light and to reduce light intensity to values where photosynthesis begins to reach light saturation.

Topics: Photosynthetic capacity (61%), Stomatal conductance (58%), Light intensity (57%), Photoinhibition (55%), Photosynthesis (53%)

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Citations
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Journal ArticleDOI
TL;DR: Photosynthesis responded similar to individual leaf age as to leaf position, and was linearly related to c i up to non-limiting conductances for sun and shade leaves, for all ages and at all times during the season.
Abstract: The relationship of photosynthesis (A) of grapevine ( Vitis vinifera L.) sun and shade leaves of primary and secondary (lateral) shoots to insertion level was investigated over two seasons in the field. The leaf plastochron index (LPI) was used to denote leaf position on the shoot. Additionally, laboratory and field measurements of the response of A to CO 2 were conducted. An empirical model was developed to estimate carboxylation efficiency (CE) and stomatal limitations (1) of A. In sun leaves, the relationship of A to LPI changed little until the end of the season (October), whereas stomatal conductance (g) and the intercellular partial pressure of CO 2 (c i ) increased. Leaves acclimated to low light and leaves older than LPI 5 had 30 % lower A and were operating at a slightly higher ci as sun leaves. During September and October, lateral leaves had highest rates of CO 2 assimilation and CE. In mid-October, A and g decreased rapidly and simultaneously for all leaf types, leaf positions and both treatments (sun and shade). Photosynthesis responded similar to individual leaf age as to leaf position. A was linearly related to c i up to non-limiting conductances for sun and shade leaves, for all ages and at all times during the season. The CE and 1 were highest at the beginning of the season and strongly dependent on leaf position. Stomatal limitation declined continuously from about 55 % at the beginning to about 23 and 18 % for sun and shade leaves, respectively, at the end of the season.

42 citations


Journal ArticleDOI
Abstract: Establishment of vineyards is often forced towards geo-morphologically complex terroir where aspect, slope, relief and erosion are determining factors in orientation of rows. In this novel study, changes in primarily microclimate profiles and vine physiological behaviour with different row orientations were studied on a flat terrain in a semi-arid environment with the purpose of aiding vineyard management decisions and practices for production of grapes and wine. Effects of grapevine row orientation (NS, EW, NE-SW, NW-SE) of vertically trellised and shoot positioned Vitis vinifera L. Shiraz/101-14 Mgt on vineyard meso- and microclimate as well as vine physiological status, within the context of regional macroclimate, were investigated under field conditions over many seasons. Novel wind velocity and direction profiles in vineyard rows showed velocity in work rows paralleling ambient prevailing wind and direction flow patterns being affected by canopy development and row orientation; NW-SE and EW orientated rows maintained higher wind velocity in work rows than NS and NE-SW rows. Mesoclimatic photosynthetic active radiation was in line with macroclimate radiation. Microclimatically, EW orientated rows maintained lowest interior canopy light interception, NS orientation displayed highest values, peaking in morning and afternoon, whereas NE-SW and NW-SE orientations peaked primarily in afternoon and morning, respectively. The EW orientated rows captured largest portion of total radiation in the bunch zone from soil reflected radiation. Canopy interior temperature differences were likely masked by air temperature. Basal leaf water potential was relatively unaffected by row side; results point to internal regulation of whole plant water status. Leaf temperature showed minor differences. Relative humidity followed opposite trends to those of air- and leaf temperature. Leaves of EW orientated vines had highest average photosynthesis, corresponding to stomatal conductance and transpiration. Most uniform canopy photosynthesis occurred for NS and NW-SE orientations. Photosynthesis trends practically demonstrated mirror diurnal images for canopy sides of each orientation. Row orientation significantly affected meso- and microclimate, radiation in particular directly affecting energy/heat balances and concomitant canopy physiological processes. The study provided new insights into: vine physiological response to row orientation, the role of row orientation as viticulture practice; decision-making for establishment; and management of existing vineyards, irrespective of terroir soil and climatic conditions and product objectives. Results are globally relevant, especially within the context of climate change, and provide first comprehensive climatic/grapevine physiological evidence on the impact of grapevine row orientation as viticulture practice.

33 citations


Journal Article
TL;DR: Dry matter production was linearly related to stomatal conductance, photosynthesis, and the night respiration to photosynthesis ratio for all vines pooled together, in contrast, under stress conditions drymatter production was not related to any physiological parameter.
Abstract: Predawn leaf water potential, night respiration, stomatal conductance, transpiration, and photosynthesis of 4 grapevine cultivars were assessed under irrigated and non-irrigated conditions in July, August and September 1994. Predawn leaf water potential was not significantly related to either stomatal conductance or photosynthesis. Water stress induced distinct stomatal closure in all cultivars at 11 a.m. For a given stomatal conductance rate, photosynthesis of stressed vines was lower than that of nonstressed vines. At similar stomatal conductance rate, photosynthesis was lower in cv. Chardonnay than in any other cultivar. Photosynthesis was the physiological parameter mostly affected by water stress. Dry matter production was linearly related to stomatal conductance, photosynthesis, and the night respiration to photosynthesis ratio for all vines pooled together. In contrast, under stress conditions dry matter production was not related to any physiological parameter.

32 citations


Journal Article
TL;DR: It is hypothesized that both stomatal and mesophyll conductance are involved in the adaptation of the CO 2 supply to the CO 2 demand at the site of carboxylation in chloroplasts.
Abstract: From simultaneous determination of net CO 2 assimilation and transpiration at the abaxial side and of the photosynthetic electron transport rate at the adaxial side of fieldgrown, light-saturated leaves of grapevine (cv. Riesling) photorespiration, stomatal conductance for CO2, mesophyll conductance and the CO 2 concentration in intercellular spaces (Ci) and in chloroplasts (Cc) were estimated. CO 2 assimilation was saturated at about Ci = 340 ppm. At increasing ambient CO 2 concentration (Ca) photorespiration decreased (less negative values); stomatal conductance decreased significantly (- 45 %) limiting CO2 uptake into intercellular spaces. Rates of total photosynthetic electron transport were constant between Ci = 340 and 800 ppm and decreased by 34 % at low Ci. Electron flow to carboxylation was closely correlated to CO 2 assimilation rates (R 2 = 0.999). When Ca was raised, the CO 2 concentration in chloroplasts (Cc) increased but at smaller rates than Ci. Presumably due to the distinct decline of the mesophyll conductance Cc remained constant at Ci >340 ppm. At Ca = 400 ppm the Cc/Ca ratio was 0.46 - 0.48, corroborating data reported for other species (CORNIC and FRESNEAU 2002). At 2 % ambient O 2 and 400 ppm CO 2 decreased rates of photorespiration (- 69 %) were associated with a decline of total photosynthetic electron flow (- 6 %); higher stomatal and mesophyll conductances, however, led to increases of Cc and CO2 assimilation rates (+ 49 %). It is hypothesized that both stomatal and mesophyll conductance are involved in the adaptation of the CO 2 supply to the CO 2 demand at the site of carboxylation in chloroplasts.

29 citations


Journal ArticleDOI
Abstract: Non-uniform stomatal behaviour of vine leaves is associated with a heterobaric leaf structure. A microscopical analysis of cross sections of glasshouse- and in vitro-grown Silvaner leaves indicates single airspaces which are pneumatically isolated by vessels, bundle sheath extensions and the abaxial and adaxial epidermes. A pressure-regulated infiltration technique is presented by which the infiltration process and the infiltration capacity (percentage of the surface area of infiltrated airspaces) can be estimated and photographed using a light microscope. The average surface area of airspaces ranged from 0.10 mm 2 (Regent) to 0.14 mm 2 (Silvaner), the number of stomata per airspace from 35 (Regent) to 42 (Silvaner). The infiltration capacity of turgid leaves is shown to be negatively correlated with the surface tension of the infiltrated liquid and positively with stomatal conductance and with infiltration pressure, except for very low stomatal conductances (e.g. 12 mmol H 2 O m -2 s -1 ). The latter relationship follows a saturation curve confirming heterogenous stomatal aperture over the leaf blade. The distribution of stomatal apertures does not appear to be bimodal but to follow a bell-shaped curve. There is some evidence for the stomata of an airspace to behave heterogenously as well.

10 citations


References
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118 citations