Variation of photosynthetic capacity with leaf age in an alpine orchid, Cypripedium flavum

Holm oak (Quercus ilex) plants that have resprouted after fire have higher photosynthetic capacity than control plants in intact vegetation. In this study, branches detached from forest plants were fed with dithiothreitol (DTT) in the laboratory to inhibit zeaxanthin production and thus reduce the dissipation of light energy as heat. This allowed us to test the hypothesis that plants with greater photosynthetic capacity, and therefore greater photo-chemical sink strength, would suffer a lower reduction in photochemical efficiency under stressful conditions. Greater rates of photochemistry in resprouts, which exhibited increased photosynthesis (A), leaf conductance (g), quantum yield of PSII (ΔF/Fm′) and photochemical quenching (qP), were related to lower non-radiative dissipation of excess energy as indicated by 1 – (Fv′/Fm′). However, the fraction of energy remaining of that used in photo-chemistry or dissipated thermally in the PSII antennae was similar in resprouts and controls and was not affected by DTT, especially under high irradiance conditions. Zeaxanthin involvement in PSII protection operated in resprouts and controls since DTT induced the same kind of response (NPQ decrease) but was lower in resprouts. These chloro-phyll fluorescence results suggest the participation of some additional mechanism for energy dissipation. Light capture characteristics of the photosynthetic apparatus did not differ between resprouts and controls, and leaf age did not play a determining role in the differences observed.

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Rates of photosynthesis in leaves of wheat and barley varieties.

Netherlands Journal of Agricultural Science ◽

10.18174/njas.v21i3.17246 ◽

1973 ◽

Vol 21 (3) ◽

pp. 188-198

Author(s):

G. Dantuma

Keyword(s):

Protein Content ◽

Photosynthetic Capacity ◽

Spring Barley ◽

Leaf Age ◽

Low Protein ◽

N Supply ◽

Rate Of Photosynthesis ◽

The Difference ◽

High Degree ◽

Regulation Of Photosynthesis

In 18 cultivars of spring wheat the range of difference in rate of photosynthesis of leaves was 22% (range 325-414 mg co2/cm2h), and in 12 cultivars of spring barley the difference range was 20% (range 284-366 mg CO2/cm2h). Measurement difficulties were initially found because of a high degree of variability within cultivars, but these were partly resolved by improving the conditions under which the plants were grown. Rates of photosynthesis reached a maximum in leaves that had attained their ultimate area, and then decreased gradually with ageing of the leaves. No evidence was found for regulation of photosynthesis by the demand for assimilates; photosynthetic capacity was determined mainly by leaf age. Low N supply and the resulting low protein content of leaves reduced the rate of photosynthesis. In leaves of a given age, but not in leaves of different ages, rate of photosynthesis was correlated with leaf protein content. (Abstract retrieved from CAB Abstracts by CABI’s permission)

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Seasonal leaf dynamics for tropical evergreen forests in a process-based global ecosystem model

Geoscientific Model Development ◽

10.5194/gmd-5-1091-2012 ◽

2012 ◽

Vol 5 (5) ◽

pp. 1091-1108 ◽

Cited By ~ 42

Author(s):

M. De Weirdt ◽

H. Verbeeck ◽

F. Maignan ◽

P. Peylin ◽

B. Poulter ◽

...

Keyword(s):

Seasonal Variation ◽

French Guiana ◽

Photosynthetic Capacity ◽

Seasonal Pattern ◽

Leaf Age ◽

Ecosystem Model ◽

Seasonal Patterns ◽

Evergreen Forests ◽

Leaf Litterfall ◽

The Impact

Abstract. The influence of seasonal phenology on canopy photosynthesis in tropical evergreen forests remains poorly understood, and its representation in global ecosystem models is highly simplified, typically with no seasonal variation of canopy leaf properties taken into account. Including seasonal variation in leaf age and photosynthetic capacity could improve the correspondence of global vegetation model outputs with the wet–dry season CO2 patterns measured at flux tower sites in these forests. We introduced a leaf litterfall dynamics scheme in the global terrestrial ecosystem model ORCHIDEE based on seasonal variations in net primary production (NPP), resulting in higher leaf turnover in periods of high productivity. The modifications in the leaf litterfall scheme induce seasonal variation in leaf age distribution and photosynthetic capacity. We evaluated the results of the modification against seasonal patterns of three long-term in-situ leaf litterfall datasets of evergreen tropical forests in Panama, French Guiana and Brazil. In addition, we evaluated the impact of the model improvements on simulated latent heat (LE) and gross primary productivity (GPP) fluxes for the flux tower sites Guyaflux (French Guiana) and Tapajós (km 67, Brazil). The results show that the introduced seasonal leaf litterfall corresponds well with field inventory leaf litter data and times with its seasonality. Although the simulated litterfall improved substantially by the model modifications, the impact on the modelled fluxes remained limited. The seasonal pattern of GPP improved clearly for the Guyaflux site, but no significant improvement was obtained for the Tapajós site. The seasonal pattern of the modelled latent heat fluxes was hardly changed and remained consistent with the observed fluxes. We conclude that we introduced a realistic and generic litterfall dynamics scheme, but that other processes need to be improved in the model to achieve better simulations of GPP seasonal patterns for tropical evergreen forests.

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Photosynthesis in Leaves, Fruits, Stem, and Petioles of Tomato Plants Grown in Peat Bags with Different Fertigation Management

HortScience ◽

10.21273/hortsci.30.4.865a ◽

1995 ◽

Vol 30 (4) ◽

pp. 865A-865

Author(s):

Hui-lian Xu ◽

Laurent Gauthier ◽

André Gosselin

Keyword(s):

Nutrient Solution ◽

Photosynthetic Capacity ◽

Potential Evapotranspiration ◽

Dark Respiration ◽

Physiological Activity ◽

Leaf Age ◽

Net Photosynthesis ◽

Tomato Plants ◽

Use Efficiency ◽

Leaf P

Tomato plants were grown in peat bags in greenhouse to examine the effects of variation of the nutrient solution electrical conductivity (EC) and substrate water potential (Ψsub) on photosynthesis in leaves, fruits, stem, and petioles. EC of the nutrient solution delivered to peat bags varied between 1 to 4 dS·m–1 with Ψsub of either –5 kPa or –9 kPa as the setpoint for starting the irrigation. The EC variation was adjusted by a computer system according to potential evapotranspiration. Gross photosynthetic capacity (PC) decreased as the leaf age developed. PC in the 10th, 15th and 18th leaves from the top was only 76%, 37%, and 18% of PC in the 5th leaf, respectively. However, low quantum use efficiency (QUE) was only observed in the 18th leaf and low dark respiration (RD) was only in 15th and 18th leaves. Net photosynthesis (PN) was only observed in young fruits (≈10 g FW) or young petioles and no PN was observed in large fruits (50 g or more FW) and stems. Both PC and RD were lower in older fruits and petioles or in the lower part of the stem compared to the younger ones or upper parts. EC variation increased PC, QUE, and RD in most parts. Low Ψsub increased RD in most parts and decreased PC in fruits, stem, and petioles. It is suggested that EC variation increased plant physiological activity of tomato and low Ψsub increased carbon consumption, although it was not severe enough to depress leaf PC.

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Decline of photosynthetic capacity with leaf age in relation to leaf longevities for five tropical canopy tree species

American Journal of Botany ◽

10.2307/2445906 ◽

1997 ◽

Vol 84 (5) ◽

pp. 702-708 ◽

Cited By ~ 133

Author(s):

Kaoru Kitajima ◽

Stephen S. Mulkey ◽

S. Joseph Wright

Keyword(s):

Tree Species ◽

Photosynthetic Capacity ◽

Leaf Age ◽

Canopy Tree ◽

Canopy Tree Species

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Estimation of Leaf Photosynthetic Capacity From Leaf Chlorophyll Content and Leaf Age in a Subtropical Evergreen Coniferous Plantation

Journal of Geophysical Research Biogeosciences ◽

10.1029/2019jg005020 ◽

2020 ◽

Vol 125 (2) ◽

Cited By ~ 1

Author(s):

Shaoqiang Wang ◽

Yue Li ◽

Weimin Ju ◽

Bin Chen ◽

Jinghua Chen ◽

...

Keyword(s):

Chlorophyll Content ◽

Photosynthetic Capacity ◽

Leaf Age ◽

Leaf Chlorophyll Content ◽

Leaf Chlorophyll ◽

Coniferous Plantation

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Leaf Age and Position Effects on Quantum Yield and Photosynthetic Capacity in Hemp Crowns

Plants ◽

10.3390/plants9020271 ◽

2020 ◽

Vol 9 (2) ◽

pp. 271 ◽

Cited By ~ 1

Author(s):

William L. Bauerle ◽

Cole McCullough ◽

Megan Iversen ◽

Michael Hazlett

Keyword(s):

Primary Production ◽

Cannabis Sativa ◽

Photosynthetic Capacity ◽

Leaf Age ◽

Growth Period ◽

Leaf Expansion ◽

Diffuse Light ◽

Position Effects ◽

Photosynthetic Physiology ◽

Light Levels

We examined the aging of leaves prior to abscission and the consequences for estimating whole-crown primary production in Cannabis sativa L. (hemp). Leaves at three vertical positions in hemp crowns were examined from initial full leaf expansion until 42 days later. Photosynthetic capacity decreased as leaves aged regardless of crown position, light intensity, or photoperiod. Although leaves remained green, the photosynthetic capacity declined logarithmically to values of 50% and 25% of the maximum 9 and 25 days later, respectively. Plants grown under +450 μmol m−2 s−1 supplemental photosynthetically active radiation or enriched diffuse light responded similarly; there was no evidence that photoperiod or enriched diffuse light modified the gas exchange pattern. At approximately 14 days after full leaf expansion, leaf light levels >500 μmol m−2 s−1 decreased photosynthesis, which resulted in ≥10% lower maximum electron transport rate at ≥ 20 days of growth period. Furthermore, leaves were saturated at lower light levels as leaf age progressed (≤500 μmol m−2 s−1). Incorporating leaf age corrections of photosynthetic physiology is needed when estimating hemp primary production.

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Plant and leaf responses to cycles of water stress and re-watering of ‘Sangiovese’ grapevine

Folia Horticulturae ◽

10.2478/fhort-2018-0003 ◽

2018 ◽

Vol 30 (1) ◽

pp. 27-38 ◽

Cited By ~ 2

Author(s):

Vania Lanari ◽

Oriana Silvestroni ◽

Alberto Palliotti ◽

Paolo Sabbatini

Keyword(s):

Water Stress ◽

Photosynthetic Capacity ◽

Leaf Age ◽

Carbon Assimilation ◽

Distal Portion ◽

Important Variable ◽

Partial Recovery ◽

Stress Cycle ◽

The Impact ◽

Different Levels

Abstract The complex relationship between water and grapevine has been examined in several studies. The aim of this study was to understand the impact of water stress on photosynthesis, carbon-13 discrimination in leaves in different positions on the shoot, and the capacity of vines to recover from different levels of water stress intensity. The vine physiological responses to a water stress regimen followed by re-watering for two consecutive cycles was evaluated using potted ‘Sangiovese’ grapevines. The intensity and the duration of the water limitation affected the emergence and development of new leaves, but did not significantly affect leaf water potential. Leaf stomatal conductance and carbon assimilation during the first water-stress phase were reduced respectively by about 61% and 20%, while after the second water stress cycle both were lower than the initial values by 77% and 21%, respectively. After 1 day of re-watering, only the leaves located in the medial positions on the shoot showed a partial recovery of photosynthesis. After at least 2 days post-re-watering, the leaves located in the distal portion of the shoot showed a recovery of photosynthetic capacity. The results indicated that leaf position along the shoot, i.e., an indicator of leaf age, is an important variable in developing grapevine strategies in response to conditions of limited water availability.

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