Photosynthetic Responses for Vitis vinifera Plants Grown at Different Photon Flux Densities Under Field Conditions (original) (raw)
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Photoinhibition of photosynthesis in mature and young leaves of grapevine ( Vitis vinifera L
Plant Science, 2003
Photoinhibition of photosynthesis was studied in young (fully expanded) and mature sun leaves of grapevine (Vitis vinifera L.), under controlled conditions (irradiation of detached leaves to about 1900 mE m (2 s (1 ). The degree of photoinhibition was determined by means of the ratio of variable to maximum chlorophyll (Chl) fluorescence (Fv/Fm) and electron transport measurements. Compared with the mature leaves, the young leaves, containing about half the amount of Chl a'/b per unit area, exhibited a higher proportion of total carotenoids as xanthophyll cycle pigments and had an increased ratio of total carotenoids to Chl a'/b. The potential efficiency of PS II, Fv/Fm, markedly declined in high light irradiated young leaves without significant increase of Fo level. In contrast, Fv/Fm ratio declined with significant increase of Fo level in mature leaves. When various photosynthetic activities were followed on isolated thylakoids, the rate of whole chain and PS II activity were markedly decreased in high light irradiated young leaves than mature leaves. A smaller inhibition of PS I activity was also observed in both leaves. In the subsequent dark incubation, fast recovery was observed in both leaves and reached maximum PSII efficiencies similar to those observed in non-photoinhibited leaves. The artificial exogenous electron donors DPC, NH 2 OH and Mn 2' failed to restore the high light induced loss of PS II activity in mature leaves, while DPC and NH 2 OH significantly restored in young leaves. It is concluded that high light inactivates on the donor side of PS II and acceptor side of PS II in young and mature leaves, respectively. Quantification of the PS II reaction center protein D1 and 33 kDa protein of water splitting complex following high light exposure of leaves showed pronounced differences between young and mature leaves. The marked loss of PS II activity in high light irradiated leaves was due to the marked loss of D1 protein of the PS II reaction center and 33 kDa protein of the water splitting complex in mature and young leaves, respectively.
Photosynthetica, 2003
Photoinhibition of photosynthesis was investigated in grapevine (Vitis vinifera L.) exposed to 2 or 4h of high irradiance (HI) (1 700–1 800 μmol m−2 s−1) leaves under field conditions at different sampling time in a day. The degree of photoinhibition was determined by means of the ratio of variable to maximum chlorophyll fluorescence (Fv/Fm) and photosynthetic electron transport measurements. When the photochemical efficiency of photosystem 2 (PS2), Fv/Fm, markedly declined, F0 increased in both 2 (HI2) and 4 h (HI4) HI leaves sampled at midday. When various photosynthetic activities were followed on isolated thylakoids, HI4 leaves showed significantly higher inhibition of whole chain and PS2 activity than the HI2 leaves sampled at midday. Later, the leaves reached maximum PS2 efficiencies similar to those observed early in the morning during sampling at evening. The artificial exogenous electron donor Mn2+ failed to restore PS2 activity in both variants of leaves, while DPC and NH2OH significantly restored PS2 activity in HI4 midday leaf samples. Quantification of the PS2 reaction centre protein D1 and 33 kDa protein of water splitting complex following midday exposure of leaves showed pronounced differences between HI2 and HI4 leaves. The marked loss of PS2 activity noticed in midday samples was mainly due to the marked loss of D1 protein in HI2, while in HI4 it was mainly 33-kDa protein.
Photoinhibition of photosynthesis in water deficit leaves of grapevine ( Vitis vinifera L.) plants
Photosynthetica, 2007
Photoinhibition under irradiance of 2 000 µmol m−2 s−1 (HI) was studied in detached control (C) and water deficit (WD) leaves of grapevine (Vitis vinifera L.) plants. The degree of photoinhibition was determined by means of the ratio of variable to maximum chlorophyll (Chl) fluorescence (Fv/Fm) and electron transport measurements. The potential efficiency of photosystem (PS) 2, Fv/Fm, marginally declined under HI in WD-leaves without significant increase of F0. In contrast, Fv/Fm ratio declined markedly with significant increase of F0 in C-leaves. In isolated thylakoids, the rate of whole chain and PS2 activity under HI were more decreased in C-than WD-leaves. The artificial exogenous electron donors diphenyl carbazide, NH2OH, and Mn2+ failed to restore the HI-induced loss of PS2 activity in both C-and WD-leaves. Thus HI operates at the acceptor side of PS2 in both leaf types. Quantification of the PS2 reaction centre protein D1 following HI exposure of leaves showed pronounced differences between C-and WD-leaves. The marked loss of PS2 activity under HI of C-leaves was due to the marked loss of D1 protein of the PS2 reaction centre.
Australian Journal of Grape and Wine Research, 1996
Field-grown grapevines (Vitis vinifera cv. Cabernet Sauvignon) were examined for photoinhibition under field conditions. Attached leaves at different positions along the shoot were investigated and their netassimilation, photorespiration and electron transport were measured. The photochemical efficiency of photosystem II was evaluated on detached, dark-adapted leaves by determining differences in chlorophyll fluorescence, using a portable fluorometer. The comparison of unshaded and artificially shaded plants allowed an estimate of direct photoinhibitory effects on their photochemical capacity. Photoinhibition was also quantified for dark-adapted leaves following exposure to moderate and high light. The immature apical leaves had a lower assimilation rate than mature leaves. This was attributable in part to greater photoinhibition in immature leaves due to greater non-photochemical quenching of fluorescence (q i) and commensurate inhibition of the photochemical efficiency of system II of photosynthesis (F v /F m). This inhibition coincided with the high levels of solar radiation at noon but became less during the afternoon. Shade-adapted leaves were more sensitive to photoinhibition than sun-adapted leaves but light acclimatisation effects were independent of photochemical quenching, as distinct from nonphotochemical quenching. The degree of photoinhibition was inversely related to photochemical quenching under both low and high light. Practical implication of fluorescence measurements are discussed. Abbreviations and Symbols A r assimilation rate; C i interior partial pressure of CO 2 ; ETR apparent electron transport rate; F 0 minimal fluorescence (dark), all reaction centres of PSII open; F m maximal fluorescence (dark), all reaction centres of PSII closed; F' m maximal fluorescence (light), F t transient fluorescence; F v variable fluorescence (dark), F v = F m-F 0 ; F v /F m maximum quantum yield of PSII photochemistry; J a electron transport rate calculated from gas exchange data; PH photorespiration rate; PPFD photosynthetic photon flux density; PSII photosystem II; Φ oxygenation/carboxylation ratio; q P photochemical quenching; q N , q i total and photoinhibitory non-photochemical quenching of variable fluorescence; q I q N after 15 min of dark relaxation; R d day respiration rate; R n night respiration rate; T leaf leaf temperature; Γ * CO 2 compensation point in the absence of respiration; v o rate of oxygenation.
Photoinhibition of Photosynthesis in Sun and Shade Grown Leaves of Grapevine ( Vitis vinifera L
Photosynthetica, 2004
The degree of photoinhibition of sun and shade grown leaves of grapevine was determined by means of the ratio of variable to maximum chlorophyll (Chl) fluorescence (Fv/Fm) and electron transport measurements. The potential efficiency of photosystem 2 (PS2), Fv/Fm, markedly declined under high irradiance (HI) in shade leaves with less than 10 % of F0 level. In contrast, Fv/Fm ratio declined with about 20 % increase of F0 level in sun leaves. In isolated thylakoids, the rate of whole chain and PS2 activity in HI shade and sun leaves was decreased by about 60 and 40 %, respectively. A smaller inhibition of photosystem 1 (PS1) activity was also observed in both leaf types. In the subsequent dark incubation, fast recovery was observed in both leaf types that reached maximum PS2 efficiencies similar to non-photoinhibited control leaves. The artificial exogenous electron donors DPC, NH2OH, and Mn2+ failed to restore the HI-induced loss of PS2 activity in sun leaves, while DPC and NH2OH were significantly restored in shade leaves. Hence HI in shade leaves inactivates on the donor side of PS2 whereas it does at the acceptor side in sun leaves, respectively. Quantification of the PS2 reaction centre protein D1 and the 33 kDa protein of water splitting complex following HI-treatment of leaves showed pronounced differences between shade and sun leaves. The marked loss of PS2 activity in HI leaves was due to the marked loss of D1 protein of the PS2 reaction centre protein and the 33 kDa protein of the water splitting complex in sun and shade leaves, respectively.
Environmental and Experimental Botany, 2006
Photoinhibition of photosynthesis is a process by which excessive light radiation, which is absorbed by the leaves, results in the inactivation and/or impairment of the chlorophyll-containing reaction centers of the chloroplasts, thus inhibiting photosynthesis. The susceptibility of leaves to photoinhibition is known to be enhanced by additional stress factors, which coincide with the light. In this work, we have studied photoinhibition of photosynthesis in control and low-night temperature (LNT) leaves of grapevine (Vitis vinifera L. cv. Riesling) under controlled conditions (irradiation of detached leaves to about 1900 mol m −2 s −1 ). The degree of photoinhibition was determined by means of the ratio of variable to maximum chlorophyll (Chl) fluorescence (F v /F m ) and electron transport measurements. The potential efficiency of PSII, F v /F m declined, F 0 increased significantly in high light (HL) irradiated LNT leaves than in control leaves. In isolated thylakoids, the rate of whole chain and PSII activity markedly decreased in HL irradiated more in leaves of LNT than in leaves of control. A smaller inhibition of PSI activity was also observed in both leaves. The artificial exogenous electron donors DPC, NH 2 OH and Mn 2+ failed to restore the HL induced loss of PSII activity in control leaves, while DPC and NH 2 OH were restored in LNT leaves. It is concluded that HL in LNT leaves inactivates both acceptor and donor side of PSII whereas it does at the acceptor side only in control leaves. Quantification of the PSII reaction center protein D1 and 33 kDa protein water splitting complex following HL exposure of leaves showed pronounced differences between control and LNT. The marked loss of PSII activity in HL irradiated LNT leaves were due to the marked loss of D1 and 33 kDa proteins. The high degree of photoinhibition observed in LNT leaves probably represents a dynamic regulatory process protecting the photosynthetic apparatus from severe damage by excess light.
Photosynthetica, 2006
Chlorophyll (Chl) a fluorescence transient and 820-nm transmission kinetic were investigated to explore the development of photosynthetic apparatus in grapevine leaves from emergence to full expansion. In this study, all leaves at various developing stages exhibited typical Chl a fluorescence transient. In newly initiating leaves, the maximum quantum yield of primary photochemistry (φ P0 ) was slightly lower (<10 %) than that in fully expanded leaves. Nevertheless, the fluorescence rise from O to J step was clearly speeded up in young leaves compared with that in fully expanded leaves. Additionally, a distinct K step appeared in young leaves at high irradiances. With leaf development, the efficiency that a trapped exciton can move an electron into the electron transport chain further than Q A -(Ψ 0 ), the quantum yield of electron transport beyond Q A (φ E0 ), electron transport flux per excited cross section (ET 0 /CS 0 ), the amount of active photosystem (PS) 2 reaction centres per excited cross section (RC/CS 0 ), and the performance index on cross section basis (PI CS ) increased gradually and rapidly. Young leaves had strikingly lower amplitude of transmission at 820 nm. A linear relationship between Ψ 0 and the transmission at 820 nm (I 30 /I 0 ) was evident. Based on these data, we suggest that (1) the primary photochemistry of PS2 may be not the limiting step of the photosynthetic capacity during leaf growth under natural irradiance; (2) oxygen evolving complex (OEC) might be not fully connected to PS2 at the beginning of leaf growth; (3) though there are a few functional PS1 and PS2 at the early stages of leaf development, they match perfectly.
Photosynthetica, 2005
Photoinhibition of photosynthesis was investigated in control (C) and chilling night (CN) leaves of grapevine under natural photoperiod at different sampling time in a day. The degree of photoinhibition was determined by means of the ratio of variable to maximum chlorophyll fluorescence (Fv/Fm) and photosynthetic electron transport measurements. When the potential efficiency of photosystem (PS) 2, Fv/Fm was measured at midday, it markedly declined with significant increase of F0 in CN leaves. In isolated thylakoids, the rate of whole chain and PS2 activity were markedly decreased in CN leaves than control leaves at midday. A smaller inhibition of PS1 activity was also observed in both leaf types. Later, the leaves reached maximum PS2 efficiencies similar to those observed in the morning during sampling at evening. The artificial exogenous electron donors diphenyl carbazide, NH2OH, and Mn2+ failed to restore the PS2 activity in both leaf types at midday. Thus CN enhanced inactivation on the acceptor side of PS2 in grapevine leaves. Quantification of the PS2 reaction centre protein D1 following midday exposure of leaves showed pronounced differences between C and CN leaves. The marked loss of PS2 activity in CN leaves noticed in midday samples was mainly due to the marked loss of D1 protein of the PS2 reaction centre.
Processes contributing to photoprotection of grapevine leaves illuminated at low temperature
Physiologia Plantarum, 2004
Photoinactivation of photosystem II (PSII) and energy dissipation at low leaf temperatures were investigated in leaves of glasshouse-grown grapevine (Vitis vinifera L. cv. Riesling). At low temperatures (, 15 C), photosynthetic rates of CO 2 assimilation were reduced. However, despite a significant increase in the amount of light excessive to that required by photosynthesis, grapevine leaves maintained high intrinsic quantum efficiencies of PSII (F v /F m ) and were highly resistant to photoinactivation compared to other species. Nonphotochemical energy dissipation involving xanthophylls and fast D1 repair were the main protective processes reducing the 'gross' rate of photoinactivation and the 'net' rate of photoinactivation, respectively. We developed an improved method of energy dissipation analysis that revealed up to 75% of absorbed light is dissipated thermally via pH-and xanthophyll-mediated non-photochemical quenching at low temperatures (5-15 C) and moderate (800 mmol quanta m À2 s À1 ) light. Up to 20% of the energy flux contributing to electron transport was dissipated via photorespiration when taking into account temperature-dependent mesophyll conductance; however, this flux used in photorespiration was only a relatively small amount of the total absorbed light energy. Photoreduction of O 2 at photosystem I (PSI) and subsequent superoxide detoxification (water-water cycle) was more sensitive to inhibition by low temperature than photorespiration. Therefore the water-water cycle represents a negligibly small energy sink below 15 C, irrespective of mesophyll conductance.
Journal of Plant Physiology, 1997
Fernao Pires and Pinot noir grapevines were grown in field-sites in Lisbon and Versailles respectively. The grapevines at the Versailles site were grown in pots in artificial media while the vines in Lisbon were grown in soil in the field. A substantial inhibition of net CO 2 assimilation from mid-morning onwards was observed at both sites. Prior to the period of measurement the Lisbon site had received no rain for 45 days but the Versailles vines were watered twice a day. In neither case was there any evidence to suggest that substantial photoinhibition was occurring during the photoperiod. The FvlFm ratio was relatively constant from dawn until dusk. The foliar zeaxanthin content showed a marked diurnal variation with maximum values obtained at midday and at minimum values at dawn and dusk. Interestingly, the total xanthophyll pool was greater in the leaves of Versailles vines than the Lisbon site. The maximum zeaxanthin levels of the former at midday were three times those of the latter. The foliar pools of ascorbate and glutathione either remained constant or increased slightly from dawn to dusk. The pools of glycine and serine in the leaves declined from mid-morning onwards at both sites but the ratio of 3-PGAltriosephosphates remained constant throughout the photoperiod. This implies that energy supply and utilisation in the leaves were well-balanced throughout the photoperiod despite the decrease in CO 2 assimilation. We conclude that similar strategies for the regulation of the photosynthetic apparatus occurred in both cases. This afforded effective protection against photoinhibition. Even though the vines grown in Lisbon were subjected to a significant period of drought they exhibited lower levels of stress-indicating substances particularly proline and zeaxanthin than the vine leaves grown in Versailles. We are drawn to the conclusion that vines grown in pots with the resultant restriction on root growth suffer greater stress than the field-grown vines. The cooler growth conditions encountered in Versailles may be suboptimal for grapevines and, hence, add additional stress factors.