Changes during summer drought in leaf CO2 uptake rates of macchia shrubs growing in Portugal: Limitations due to photosynthetic capacity, carboxylation efficiency, and stomatal conductance

Gas exchange measurements were made on saplings of Southern Beech, Nothofagus cunninghamii (Hook.) Oerst. collected from three altitudes (350, 780 and 1100 m above sea level) and grown in a common glasshouse trial. Plants were grown from cuttings taken 2 years earlier from a number of plants at each altitude in Mt Field National Park, Tasmania. Stomatal density increased with increasing altitude of origin, and stomatal con-ductance and carbon assimilation rate were linearly related across all samples. The altitude of origin influenced thestomatal conductance and therefore carbon assimilation rate, with plants from 780 m having a greater photosynthetic rate than those from 350 m. The intercellular concentration of CO2 as a ratio of external CO2 concentration (ci/ca) was similar in all plants despite the large variation in maximum stomatal conductance. Carboxylation efficiency was greater in plants from 780 m than in plants from 350 m. Altitude of origin has a strong influence on the photo-synthetic performance of N. cunninghamii plants even when grown under controlled conditions, and this influence is expressed in both leaf biochemistry (carboxylation efficiency) and leaf morphology (stomatal density).

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The effect of summer drought on the yield of Arundo donax is reduced by the retention of photosynthetic capacity and leaf growth later in the growing season

Annals of Botany ◽

10.1093/aob/mcy223 ◽

2018 ◽

Vol 124 (4) ◽

pp. 567-579 ◽

Cited By ~ 8

Author(s):

Matthew Haworth ◽

Giovanni Marino ◽

Ezio Riggi ◽

Giovanni Avola ◽

Cecilia Brunetti ◽

...

Keyword(s):

Mediterranean Climate ◽

Biomass Yield ◽

Photosynthetic Capacity ◽

Leaf Growth ◽

Central Italy ◽

Arundo Donax ◽

Genetic Identification ◽

Summer Drought ◽

Supplementary Irrigation ◽

Semi Arid

Abstract Background and Aims The development of Arundo donax as a biomass crop for use on drought-prone marginal lands in areas with warm to hot climates is constrained by the lack of variation within this species. We investigated the effect of morphological and physiological variation on growth and tolerance to drought under field conditions in three ecotypes of A. donax collected from habitats representing a climate gradient: a pre-desert in Morocco, a semi-arid Mediterranean climate in southern Italy and a warm sub-humid region of central Italy. Methods The three A. donax ecotypes were grown under irrigated and rain-fed conditions in a common garden field trial in a region with a semi-arid Mediterranean climate. Physiological and morphological characteristics, and carbohydrate metabolism of the ecotypes were recorded to establish which traits were associated with yield and/or drought tolerance. Key Results Variation was observed between the A. donax ecotypes. The ecotype from the most arid habitat produced the highest biomass yield. Stem height and the retention of photosynthetic capacity later in the year were key traits associated with differences in biomass yield. The downregulation of photosynthetic capacity was not associated with changes in foliar concentrations of sugars or starch. Rain-fed plants maintained photosynthesis and growth later in the year compared with irrigated plants that began to senescence earlier, thus minimizing the difference in yield. Effective stomatal control prevented excessive water loss, and the emission of isoprene stabilized photosynthetic membranes under drought and heat stress in A. donax plants grown under rain-fed conditions without supplementary irrigation. Conclusions Arundo donax is well adapted to cultivation in drought-prone areas with warm to hot climates. None of the A. donax ecotypes exhibited all of the desired traits consistent with an ‘ideotype’. Breeding or genetic (identification of quantitative trait loci) improvement of A. donax should select ecotypes on the basis of stem morphology and the retention of photosynthetic capacity.

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Carbon and oxygen isotope analysis of leaf biomass reveals contrasting photosynthetic responses to elevated CO<sub>2</sub> near geologic vents in Yellowstone National Park

Biogeosciences ◽

10.5194/bg-6-25-2009 ◽

2009 ◽

Vol 6 (1) ◽

pp. 25-31 ◽

Cited By ~ 11

Author(s):

S. Sharma ◽

D. G. Williams

Keyword(s):

Stomatal Conductance ◽

Oxygen Isotope ◽

Elevated Co2 ◽

National Park ◽

Photosynthetic Capacity ◽

Lodgepole Pine ◽

Leaf Biomass ◽

Carbon And Oxygen Isotope ◽

Co2 Levels ◽

Photosynthetic Responses

Abstract. In this study we explore the use of natural CO2 emissions in Yellowstone National Park (YNP) in Wyoming, USA to study responses of natural vegetation to elevated CO2 levels. Radiocarbon (14C) analysis of leaf biomass from a conifer (Pinus contortus; lodgepole pine) and an invasive, non-native herb (Linaria dalmatica; Dalmation toadflax) was used to trace the inputs of vent CO2 and quantify assimilation-weighted CO2 concentrations experienced by individual plants near vents and in comparable locations with no geologic CO2 exposure. The carbon and oxygen isotopic composition and nitrogen percent of leaf biomass from the same plants was used to investigate photosynthetic responses of these plants to naturally elevated atmospheric CO2 concentrations. The coupled shifts in carbon and oxygen isotope values suggest that dalmation toadflax responded to elevated CO2 exposure by increasing stomatal conductance with no change in photosynthetic capacity and lodgepole pine apparently responded by decreasing stomatal conductance and photosynthetic capacity. Lodgepole pine saplings exposed to elevated levels of CO2 likewise had reduced leaf nitrogen concentrations compared to plants with no enhanced CO2 exposure, further suggesting widespread and dominant conifer down-regulated photosynthetic capacity under elevated CO2 levels near geologic vents.

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Effects of the reciprocal grafting on the photosynthesis of two genotypes tomato offspring under selenium stress

E3S Web of Conferences ◽

10.1051/e3sconf/201913607008 ◽

2019 ◽

Vol 136 ◽

pp. 07008

Author(s):

Shiyao Shan ◽

Huizhong Luo ◽

Jinpeng Zhu ◽

Zhiyu Li ◽

Huanxiu Li

Keyword(s):

Stomatal Conductance ◽

Net Photosynthetic Rate ◽

Photosynthetic Rate ◽

Transpiration Rate ◽

Functional Activity ◽

Theoretical Basis ◽

Photosynthetic Capacity ◽

Growth Characteristics ◽

Cherry Tomato ◽

Fresh Weight

To study the effects of the reciprocal grafting on the photosynthesis of two genotypes tomato offspring under selenium stress, red ball cherry tomato cherry 5-5-1 and yellow ball cherry tomato yellow RTY-3-2 post-grafting generation (red scion, red rootstock, yellow scion and yellow rootstock) and seedlings (red CK and yellow CK) planted in 10 mg·kg-1 selenium soil, and the pot experiment was carried out to study the effects of the reciprocal grafting on the growth characteristics and the photosynthesis of tomato offspring under selenium stress. The results showed that grafting increased the fresh weight of the organs of the offspring, the ratio of root to shoot, and the functional activity of the roots of the plants, which was conducive to the growth of tomato offspring. Simultaneously, it could effectively improve the photosynthetic capacity of grafted offspring leaves at the seedling stage. The grafted offspring of rootstocks had the best effect on improving the net photosynthetic rate, stomatal conductance and transpiration rate and stomatal conductance of tomato leaves, and decreased intercellular CO2 concentration. Among them, the best effect of yellow rootstock was to provide ideas and theoretical basis for the production of selenium-enriched tomatoes in the selenium-deficient areas in the future.

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Genotypic variation in whole-plant transpiration efficiency in sorghum only partly aligns with variation in stomatal conductance

Functional Plant Biology ◽

10.1071/fp18177 ◽

2019 ◽

Vol 46 (12) ◽

pp. 1072 ◽

Cited By ~ 4

Author(s):

Geetika Geetika ◽

Erik J. van Oosterom ◽

Barbara George-Jaeggli ◽

Miranda Y. Mortlock ◽

Kurt S. Deifel ◽

...

Keyword(s):

Stomatal Conductance ◽

Photosynthetic Capacity ◽

Genotypic Variation ◽

Vapour Pressure Deficit ◽

Genotypic Differences ◽

Transpiration Efficiency ◽

Plant Transpiration ◽

Leaf Chlorophyll ◽

Residual Variation ◽

Whole Plant

Water scarcity can limit sorghum (Sorghum bicolor (L.) Moench) production in dryland agriculture, but increased whole-plant transpiration efficiency (TEwp, biomass production per unit of water transpired) can enhance grain yield in such conditions. The objectives of this study were to quantify variation in TEwp for 27 sorghum genotypes and explore the linkages of this variation to responses of the underpinning leaf-level processes to environmental conditions. Individual plants were grown in large lysimeters in two well-watered experiments. Whole-plant transpiration per unit of green leaf area (TGLA) was monitored continuously and stomatal conductance and maximum photosynthetic capacity were measured during sunny conditions on recently expanded leaves. Leaf chlorophyll measurements of the upper five leaves of the main shoot were conducted during early grain filling. TEwp was determined at harvest. The results showed that diurnal patterns in TGLA were determined by vapour pressure deficit (VPD) and by the response of whole-plant conductance to radiation and VPD. Significant genotypic variation in the response of TGLA to VPD occurred and was related to genotypic differences in stomatal conductance. However, variation in TGLA explained only part of the variation in TEwp, with some of the residual variation explained by leaf chlorophyll readings, which were a reflection of photosynthetic capacity. Genotypes with different genetic background often differed in TEwp, TGLA and leaf chlorophyll, indicating potential differences in photosynthetic capacity among these groups. Observed differences in TEwp and its component traits can affect adaptation to drought stress.

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Utilization of nitrogen and carbon by phytoplankton in Moreton Bay, Australia

Marine and Freshwater Research ◽

10.1071/mf99096 ◽

2000 ◽

Vol 51 (7) ◽

pp. 703 ◽

Cited By ~ 18

Author(s):

M. J. O'Donohue ◽

P. M. Glibert ◽

W. C. Dennison

Keyword(s):

Water Temperature ◽

Coastal Waters ◽

Inorganic Nitrogen ◽

Spatial Scales ◽

Co2 Uptake ◽

Phytoplankton Productivity ◽

Moreton Bay ◽

Uptake Rates ◽

Temporal And Spatial ◽

River Mouths

Water samples were collected within river mouths, at river plume sites and at well flushed ocean-influenced sites within Moreton Bay, a shallow subtropical embayment in south-eastern Queensland. Rates of inorganic nitrogen (NH+4 and NO-3) and carbon uptake were determined across temporal and spatial scales by use of 15N and 14C incorporation. Phytoplankton productivity, measured as CO2 uptake, was highest at the river mouths. Rates of NH+4 uptake exceeded rates of NO-3 uptake at all sites at all times. Relative preference indices demonstrated a consistent preference by phytoplankton for NH+4 uptake, and NH+4 uptake rates were higher at ocean-influenced sites than at river-mouth sites. Inorganic nutrient and chlorophyll a concentrations were highest at river mouths; however, the greatest NH+4 uptake occurred at the ocean-influenced sites, reflecting a greater dependence on ‘recycled’ N than on ‘new’ N. Biomass-independent NH+4 uptake increased with increasing water temperature; however, NO-3 uptake increased with decreasing water temperature, reflecting the lower temperature optimum for nitrate reductase. The range of NH+4 and NO-3 uptake rates was greater than ranges reported for other coastal waters, reflecting the strong temporal and spatial gradients within Moreton Bay. This trend of strong gradients in C and N dynamics from oligotrophic to river-influenced waters with seasonal flows is likely to exist in many tropical and subtropical coastal waters of Australia.

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Effect of leaf age and position on light-saturated CO2 assimilation rate, photosynthetic capacity, and stomatal conductance in rubber trees

Photosynthetica ◽

10.1007/s11099-010-0010-y ◽

2010 ◽

Vol 48 (1) ◽

pp. 67-78 ◽

Cited By ~ 20

Author(s):

B. Kositsup ◽

P. Kasemsap ◽

S. Thanisawanyangkura ◽

N. Chairungsee ◽

D. Satakhun ◽

...

Keyword(s):

Stomatal Conductance ◽

Photosynthetic Capacity ◽

Leaf Age ◽

Assimilation Rate

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Ecophysiology of the Southern Highbush blueberry cv. Biloxi in response to nitrogen fertigation

Comunicata Scientiae ◽

10.14295/cs.v11i0.3245 ◽

2020 ◽

Vol 11 ◽

pp. e3245

Author(s):

Firmino Nunes de Lima ◽

Osvaldo Kiyoshi Yamanishi ◽

Márcio de Carvalho Pires ◽

Elias Divino Saba ◽

Aline Rodrigues Pereira ◽

...

Keyword(s):

Stomatal Conductance ◽

Block Design ◽

Net Photosynthesis ◽

Federal District ◽

Co2 Concentration ◽

Carboxylation Efficiency ◽

Highbush Blueberry ◽

Mineral Fertilization ◽

Physiological Attributes ◽

Southern Highbush

In Brazil, the nutritional requirements of the blueberry are not sufficiently known, thus requiring further research on the management of mineral fertilization. In this perspective, this work aimed to evaluate physiological attributes of Southern Highbush blueberry plants cv. Biloxi as a function of nitrogen fertigation in Brasília-DF. The experiment was conducted from August 2018 to July 2019, in the Fruit Sector of the Experimental Biology Station of the University of Brasilia (UnB), Federal District. This experiment adopted a randomized block design, with four treatments: 10; 20; 30, and 40 g of N plant-1, 8 replications, and 5 plants per experimental plot. The following variables were measured: net photosynthesis rate (A), transpiration (E), stomatal conductance (gs), internal CO2 concentration (Ci), instantaneous water-use efficiency (WUE), carboxylation efficiency (CE), SPAD index (SPAD) and leaf nitrogen (N). There was an effect of the different nitrogen doses applied on the physiological attributes. The plants of the blueberry cultivar Biloxi increased their photosynthetic rates at doses up to 30 g of N plant-1. Nitrogen rates did not influence stomatal conductance nor did they provide improvements in the carboxylation efficiency of the blueberry plants. Under the conditions of the present work, the highest N leaf contents were obtained with the application of 30 g N plant-1, and values above this concentration did not correspond to higher net photosynthesis rates, transpiration, and CO2 concentration in the leaf mesophyll.

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Change in the Physiological and Biochemical Aspects of Tomato Caused by Infestation by Cryptic Species of Bemisia tabaci MED and MEAM1

Insects ◽

10.3390/insects12121105 ◽

2021 ◽

Vol 12 (12) ◽

pp. 1105

Author(s):

Claudia Aparecida de Lima Toledo ◽

Franciely da Silva Ponce ◽

Moisés Daniel Oliveira ◽

Eduardo Santana Aires ◽

Santino Seabra Júnior ◽

...

Keyword(s):

Stomatal Conductance ◽

Cryptic Species ◽

Bemisia Tabaci ◽

Co2 Assimilation ◽

Carboxylation Efficiency ◽

Total Phenol Content ◽

Offspring Performance ◽

Tomato Plants ◽

Increased Activity ◽

Physiological And Biochemical

Infestation by Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) causes damage to tomatoes with production losses of up to 100%, affecting the physiological and biochemical aspects of host plants. The objective of this study was to analyze the influence of infestation of cryptic species of B. tabaci MED and MEAM1 on the physiological and biochemical aspects of tomato. Tomato plants ‘Santa Adélia Super’ infested with B. tabaci (MED and MEAM1), and non-infested plants were evaluated for differences in gas exchange, chlorophyll - a fluorescence of photosystem II (PSII), and biochemical factors (total phenols, total flavonoids, superoxide dismutase—SOD, peroxidase—POD, and polyphenol oxidase—PPO). Plants infested with B. tabaci MED showed low rates of CO2 assimilation and stomatal conductance of 55% and 52%, respectively. The instantaneous carboxylation efficiency was reduced by 40% in MED and by 60% in MEAM1 compared to the control. Regarding biochemical aspects, plants infested by MED cryptic species showed high activity of POD and PPO enzymes and total phenol content during the second and third instars when compared to control plants. Our results indicate that B. tabaci MED infestation in tomato plants had a greater influence than B. tabaci MEAM1 infestation on physiological parameters (CO2 assimilation rate (A), stomatal conductance (gs), and apparent carboxylation efficiency (A/Ci)) and caused increased activity of POD and PPO enzymes, indicating plant resistance to attack. In contrast, B. tabaci MEAM1 caused a reduction in POD enzyme activity, favoring offspring performance.

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Physiological and climate controls on foliar mercury uptake by European tree species

10.5194/bg-2021-239 ◽

2021 ◽

Author(s):

Lena Wohlgemuth ◽

Pasi Rautio ◽

Bernd Ahrends ◽

Alexander Russ ◽

Lars Vesterdal ◽

...

Keyword(s):

Stomatal Conductance ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Tree Species ◽

Physiological Activity ◽

Growing Season ◽

Relevant Parameter ◽

Uptake Rates ◽

Mercury Uptake

Abstract. Despite the importance of vegetation uptake of atmospheric gaseous elemental mercury (Hg(0)) within the global Hg cycle, little knowledge exists on the physiological, climatic and geographic factors controlling stomatal uptake of atmospheric Hg(0) by tree foliage. We investigate controls on foliar stomatal Hg(0) uptake by combining Hg measurements of 3,569 foliage samples across Europe with data on tree species traits and environmental conditions. To account for foliar Hg accumulation over time, we normalized foliar Hg concentration over the foliar life period from the simulated start of the growing season to sample harvest. The most relevant parameter impacting daily foliar stomatal Hg uptake was tree functional group (deciduous versus coniferous trees). On average, we measured 3.2 times higher daily foliar stomatal Hg uptake rates in deciduous leaves than in coniferous needles of the same age. Across tree species, for foliage of beech and fir, and at two out of three forest plots with more than 20 samples, we found a significant (p < 0.001) increase in foliar Hg values with respective leaf nitrogen concentrations. We therefore suggest, that foliar stomatal Hg uptake is controlled by tree functional traits with uptake rates increasing from low to high nutrient content representing low to high physiological activity. For pine and spruce needles, we detected a significant linear decrease of daily foliar stomatal Hg uptake with the proportion of time, during which vapor pressure deficit (VPD) exceeded the species-specific threshold values of 1.2 kPa and 3 kPa, respectively. The proportion of time within the growing season, during which surface soil water content (ERA5-Land) in the region of forest plots was low correlated negatively with corresponding foliar Hg uptake rates of beech and pine. These findings suggest that stomatal uptake of atmospheric Hg(0) is inhibited under high VPD conditions and/or low soil water content due the regulation of stomatal conductance to reduce water loss under dry conditions. We therefore propose, that foliar Hg measurements bear the potential to serve as proxy for stomatal conductance. Other parameters associated with forest sampling sites (latitude and altitude), sampled trees (average age and diameter at breast height) or regional satellite observation-based transpiration product (GLEAM) did not significantly correlate with daily foliar Hg uptake rates. We conclude that tree physiological activity and stomatal response to VPD and soil water content should be implemented in a stomatal Hg model, to assess future Hg cycling under different anthropogenic emission scenarios and global warming.

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