Intact leaf gas exchange provides a robust method for measuring the kinetics of stomatal conductance responses to abscisic acid and other small molecules in Arabidopsis and grasses

`Early Girl' tomato plants (Lycopersicon esculentum Mill.) were grown in a medium containing peatmoss and perlite (60%:40% by volume). The medium was drenched with 0% or 5% GLK-8924 antitranspirant. Half of the plants were flushed daily with 250 mL water (leaching), and the other half were subirrigated by capillarity. The solution osmotic potential of the medium was reduced significantly by 5% GLK 8924 treatment, then recovered gradually to the control level after 3 days with leaching or 10 days without leaching. Leaf stomatal conductance, transpiration rate, and plant growth were depressed by the antitranspirant application, and the depression was alleviated by leaching. Neither antitranspirant GLK-8924 treatment nor leaching influenced leaf abscisic acid (ABA) content. The effect of the antitranspirant on leaf gas exchange and plant growth was highly related to the reduction in the solution osmotic potential of the medium, but not to leaf ABA content. Younger leaves had higher stomatal conductance and transpiration rate but lower ABA content than older leaves in general.

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The Effects of Drought on Leaf Gas Exchange and Growth of Three Species of Herbaceous Perennials

HortScience ◽

10.21273/hortsci.33.3.540a ◽

1998 ◽

Vol 33 (3) ◽

pp. 540a-540

Author(s):

K.J. Prevete ◽

R.T. Fernandez

Keyword(s):

Drought Stress ◽

Stomatal Conductance ◽

Gas Exchange ◽

Drought Tolerance ◽

Transpiration Rate ◽

Leaf Gas Exchange ◽

Gas Analysis ◽

Herbaceous Perennials ◽

Effects Of Drought ◽

Analysis System

Three species of herbaceous perennials were tested on their ability to withstand and recover from drought stress periods of 2, 4, and 6 days. Eupatorium rugosum and Boltonia asteroides `Snowbank' were chosen because of their reported drought intolerance, while Rudbeckia triloba was chosen based on its reported drought tolerance. Drought stress began on 19 Sept. 1997. Plants were transplanted into the field the day following the end of each stress period. The effects of drought on transpiration rate, stomatal conductance, and net photosynthetic rate were measured during the stress and throughout recovery using an infrared gas analysis system. Leaf gas exchange measurements were taken through recovery until there were no differences between the stressed plants and the control plants. Transpiration, stomatal conductance, and photosynthesis of Rudbeckia and Boltonia were not affected until 4 days after the start of stress. Transpiration of Eupatorium decreased after 3 days of stress. After rewatering, leaf gas exchange of Boltonia and Rudbeckia returned to non-stressed levels quicker than Eupatorium. Growth measurements were taken every other day during stress, and then weekly following transplanting. Measurements were taken until a killing frost that occurred on 3 Nov. There were no differences in the growth between the stressed and non-stressed plants in any of the species. Plants will be monitored throughout the winter, spring, and summer to determine the effects of drought on overwintering capability and regrowth.

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Normal Cyclic Variation in CO2 Concentration in Indoor Chambers Decreases Leaf Gas Exchange and Plant Growth

Plants ◽

10.3390/plants9050663 ◽

2020 ◽

Vol 9 (5) ◽

pp. 663

Author(s):

James Bunce

Keyword(s):

Stomatal Conductance ◽

Gas Exchange ◽

Leaf Gas Exchange ◽

Genetic Material ◽

Co2 Concentration ◽

Cyclic Variation ◽

Indoor Exposure ◽

Elevated Atmospheric Co2 ◽

Gas Exchange System ◽

Opening And Closing

Attempts to identify crop genetic material with larger growth stimulation at projected elevated atmospheric CO2 concentrations are becoming more common. The probability of reductions in photosynthesis and yield caused by short-term variation in CO2 concentration within elevated CO2 treatments in the free-air CO2 enrichment plots raises the question of whether similar effects occur in glasshouse or indoor chamber experiments. These experiments were designed to test whether even the normal, modest, cyclic variation in CO2 concentration typical of indoor exposure systems have persistent impacts on photosynthesis and growth, and to explore mechanisms underlying the responses observed. Wheat, cotton, soybeans, and rice were grown from seed in indoor chambers at a mean CO2 concentration of 560 μmol mol−1, with “triangular” cyclic variation with standard deviations of either 4.5 or 18.0 μmol mol−1 measured with 0.1 s sampling periods with an open path analyzer. Photosynthesis, stomatal conductance, and above ground biomass at 20 to 23 days were reduced in all four species by the larger variation in CO2 concentration. Tests of rates of stomatal opening and closing with step changes in light and CO2, and tests of responses to square-wave cycling of CO2 were also conducted on individual leaves of these and three other species, using a leaf gas exchange system. Reduced stomatal conductance due to larger amplitude cycling of CO2 during growth occurred even in soybeans and rice, which had equal rates of opening and closing in response to step changes in CO2. The gas exchange results further indicated that reduced mean stomatal conductance was not the only cause of reduced photosynthesis in variable CO2 conditions.

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The impact of kaolin clay sprays on leaf gas exchange of Ginger Gold apple trees in New Brunswick

Canadian Journal of Plant Science ◽

10.4141/p06-130 ◽

2006 ◽

Vol 86 (Special Issue) ◽

pp. 1377-1381 ◽

Cited By ~ 4

Author(s):

J. P. Privé ◽

L. Russell ◽

A. LeBlanc

Keyword(s):

Stomatal Conductance ◽

Gas Exchange ◽

New Brunswick ◽

Leaf Gas Exchange ◽

Net Photosynthesis ◽

Apple Orchard ◽

Kaolin Clay ◽

Gas Exchange Parameters ◽

Leaf Physiology ◽

The Impact

A field trial was conducted over two growing seasons in a Ginger Gold apple orchard in Bouctouche, New Brunswick, Canada to examine the impact of Surround (95% kaolin clay) on leaf gas exchange [net photosynthesis (Pn), stomatal conductance (gs), intercellular CO2 (Ci) and transpiration (E)]. In 2004, a greater rate of Pn and gs was achieved at the higher than at the lower frequency of Surround applications. This was particularly notable at leaf temperatures exceeding 35°C. In 2005, no significant (P ≤ 0.05) differences among leaf residue groupings [Trace (< 0.5 g m-2), Low (0.5 to 2 g m-2), and High (≥ 2 g m-2)] were found for the four leaf gas exchange parameters at leaf temperatures ranging from 25 to 40°C. It would appear that under New Brunswick commercial orchard conditions, the application of Surround favours or has no effect on leaf gas exchange. Key words: Surround, particle film, leaf physiology, photosynthesis, stomatal conductance, intercellular CO2, transpiration

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The interplay between irrigation and fruiting on branch growth and mortality, gas exchange and water relations of coffee trees

Tree Physiology ◽

10.1093/treephys/tpaa116 ◽

2020 ◽

Author(s):

Wellington L Almeida ◽

Rodrigo T Ávila ◽

Junior P Pérez-Molina ◽

Marcela L Barbosa ◽

Dinorah M S Marçal ◽

...

Keyword(s):

Stomatal Conductance ◽

Gas Exchange ◽

Stomatal Density ◽

Leaf Gas Exchange ◽

Water Status ◽

Co2 Concentration ◽

Plant Hydraulics ◽

Branch Growth ◽

Source To Sink ◽

Leaf Transpiration

Abstract The overall coordination between gas exchanges and plant hydraulics may be affected by soil water availability and source-to-sink relationships. Here we evaluated how branch growth and mortality, leaf gas exchange and metabolism are affected in coffee (Coffea arabica L.) trees by drought and fruiting. Field-grown plants were irrigated or not, and maintained with full or no fruit load. Under mild water deficit, irrigation per se did not significantly impact growth but markedly reduced branch mortality in fruiting trees, despite similar leaf assimilate pools and water status. Fruiting increased net photosynthetic rate in parallel with an enhanced stomatal conductance, particularly in irrigated plants. Mesophyll conductance and maximum RuBisCO carboxylation rate remained unchanged across treatments. The increased stomatal conductance in fruiting trees over nonfruiting ones was unrelated to internal CO2 concentration, foliar abscisic acid (ABA) levels or differential ABA sensitivity. However, stomatal conductance was associated with higher stomatal density, lower stomatal sensitivity to vapor pressure deficit, and higher leaf hydraulic conductance and capacitance. Increased leaf transpiration rate in fruiting trees was supported by coordinated alterations in plant hydraulics, which explained the maintenance of plant water status. Finally, by preventing branch mortality, irrigation can mitigate biennial production fluctuations and improve the sustainability of coffee plantations.

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The Lanata trichome mutation increases stomatal conductance and reduces leaf temperature in tomato

10.1101/2020.02.11.943761 ◽

2020 ◽

Author(s):

Karla Gasparini ◽

Ana Carolina R. Souto ◽

Mateus F. da Silva ◽

Lucas C. Costa ◽

Cássia Regina Fernandes Figueiredo ◽

...

Keyword(s):

Stomatal Conductance ◽

Gas Exchange ◽

Spectral Properties ◽

Growth Parameters ◽

Stomatal Density ◽

Leaf Gas Exchange ◽

Glandular Trichomes ◽

Glandular Trichome ◽

Leaf Temperature ◽

Trichome Density

ABSTRACTBackground and aimsTrichomes are epidermal structures with an enormous variety of ecological functions and economic applications. Glandular trichomes produce a rich repertoire of secondary metabolites, whereas non-glandular trichomes create a physical barrier against biotic and abiotic stressors. Intense research is underway to understand trichome development and function and enable breeding of more resilient crops. However, little is known on how enhanced trichome density would impinge on leaf photosynthesis, gas exchange and energy balance.MethodsPrevious work has compared multiple species differing in trichome density, instead here we analyzed monogenic trichome mutants in a single tomato genetic background (cv. Micro-Tom). We determined growth parameters, leaf spectral properties, gas exchange and leaf temperature in the hairs absent (h), Lanata (Ln) and Woolly (Wo) trichome mutants.Key resultsShoot dry mass, leaf area, leaf spectral properties and cuticular conductance were not affected by the mutations. However, the Ln mutant showed increased carbon assimilation (A) possibly associated with higher stomatal conductance (gs), since there were no differences in stomatal density or stomatal index between genotypes. Leaf temperature was furthermore reduced in Ln in the early hours of the afternoon.ConclusionsWe show that a single monogenic mutation can increase glandular trichome density, a desirable trait for crop breeding, whilst concomitantly improving leaf gas exchange and reducing leaf temperature.HIGHLIGHTA monogenic mutation in tomato increases trichome density and optimizes gas exchange and leaf temperature

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Determining the Effects of Abscisic Acid Drenches on Evapotranspiration and Leaf Gas Exchange of Tomato

HortScience ◽

10.21273/hortsci.46.11.1512 ◽

2011 ◽

Vol 46 (11) ◽

pp. 1512-1517 ◽

Cited By ~ 8

Author(s):

Manuel G. Astacio ◽

Marc W. van Iersel

Keyword(s):

Abscisic Acid ◽

Gas Exchange ◽

Shelf Life ◽

Water Use ◽

Water Loss ◽

Leaf Gas Exchange ◽

Short Term ◽

Leaf Physiology ◽

Rate Dependent ◽

Short Period

It is common for plants in the retail market to receive inadequate water and lose aesthetic value within a short period of time. The plant hormone abscisic acid (ABA) is naturally produced in response to drought conditions and reduces transpiration (E) by closing the stomata. Thus, ABA may lengthen shelf life of retail plants by reducing water loss. Two studies were conducted to look at effects of ABA on plant water use and shelf life over a 13-day period and short-term effects of ABA on leaf physiology. The objective of the short-term study was to determine how quickly 100-mL drenches of 250 mg·L−1 ABA solution affect leaf gas exchange of tomatoes (Solanum lycopersicum ‘Supersweet 100’). ABA drenches reduced stomatal conductance (gS), E, and photosynthetic rate (Pn) within 60 min. After 2 h, E, gs, and Pn were reduced by 66%, 72%, and 55% respectively, compared with the control plants. In the13-day study, ABA was applied to tomatoes as a 100-mL drench at concentrations ranging from 0 to 1000 mg·L−1 and ABA effects on water use and time to wilting were quantified. Half of the plants were not watered after ABA application, whereas the other plants were watered as needed. In general, higher ABA concentrations resulted in less water use by both well-watered and unwatered plants. ABA delayed wilting of unwatered plants by 2 to 8 days (dependent on the dose) as compared with control plants. In well-watered plants, ABA reduced daily evapotranspiration (ET) for 5 days, after which there were no further ABA effects. Negative side effects of the ABA application were rate-dependent chlorosis of the lower leaves followed by leaf abscission. These studies demonstrate that ABA drenches rapidly close stomata, limit transpirational water loss, and can extend the shelf life of retail plants by up to 8 days, which exemplifies its potential as a commercially applied plant growth regulator.

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Another View of Gas Exchange Model: Reflection of Leaf Surface Air to Stomatal Conductance

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.113-116.14 ◽

2010 ◽

Vol 113-116 ◽

pp. 14-17

Author(s):

Meng Hu ◽

Shao Zhong Kang ◽

Tai Sheng Du ◽

Ling Tong

Keyword(s):

Stomatal Conductance ◽

Gas Exchange ◽

Leaf Surface ◽

Leaf Gas Exchange ◽

Exchange Process ◽

Negative Relationship ◽

Co2 Concentration ◽

Reflection Function ◽

Use Efficiency ◽

Gas Exchange Process

A reflection function was established, based on leaf gas exchange process and tested with experimental data of eight kinds of plants, i.e. tomato, muskmelon, capsicum, maize, grape, onion, Haloxylon Ammodendron Bunge and Caragana Karshiskii Kom, with multifarious biological characteristic, water and growing status. The function indicated that the leaf stomatal conductance could be linearly reflected by the ratio of humidity and CO2 concentration at leaf surface, and the behaviour of its slope could be recognized as an indicator of leaf gas exchange efficiency, which had a negative relationship with leaf water use efficiency (WUE). The results maybe increase our understanding of potential influences of leaf stomatal conductance on photosynthetic and transpiration gas exchange and leaf WUE.

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IS ABSCISIC ACID INVOLVED IN THE DROUGHT RESPONSES OF BRAZILIAN GREEN DWARF COCONUT?

Experimental Agriculture ◽

10.1017/s0014479708007436 ◽

2009 ◽

Vol 45 (2) ◽

pp. 189-198 ◽

Cited By ~ 9

Author(s):

F. P. GOMES ◽

M. A. OLIVA ◽

M. S. MIELKE ◽

A-A. F. DE ALMEIDA ◽

H. G. LEITE ◽

...

Keyword(s):

Abscisic Acid ◽

Water Stress ◽

Stomatal Conductance ◽

Gas Exchange ◽

Water Potential ◽

Water Use ◽

Severe Drought ◽

Use Efficiency ◽

Recovery Cycles ◽

Mild Drought

SUMMARYAbscisic acid (ABA) accumulation in leaves of drought-stressed coconut palms and its involvement with stomatal regulation of gas exchange during and after stress were investigated. Two Brazilian Green Dwarf coconut ecotypes from hot/humid and hot/dry environments were submitted to three consecutive drying/recovery cycles under greenhouse conditions. ABA accumulated in leaflets before significant changes in pre-dawn leaflet water potential (ΨPD) and did not recover completely in the two ecotypes after 8 days of rewatering. Stomatal conductance was influenced by ABA under mild drought and by ΨPD under severe drought. There were no significant differences between the ecotypes for most variables measured. However, the ecotype from a hot/dry environment showed higher water use efficiency after repeated cycles of water stress.

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Responses of Chlorophyll Fluorescence, Stomatal Conductance, and Net Photosynthesis Rates of Four Rubber (Hevea brasiliensis) Genotypes to Drought

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.844.11 ◽

2013 ◽

Vol 844 ◽

pp. 11-14

Author(s):

Aidil Azhar ◽

Jate Sathornkich ◽

Ratchanee Rattanawong ◽

Poonpipope Kasemsap

Keyword(s):

Chlorophyll Fluorescence ◽

Stomatal Conductance ◽

Gas Exchange ◽

Leaf Gas Exchange ◽

Net Photosynthesis ◽

Partial Recovery ◽

Gas Exchange Parameters ◽

Leaf Chlorophyll ◽

Drought Conditions ◽

Leaf Chlorophyll Fluorescence

This experiment aimed to evaluate the leaf chlorophyll fluorescence and gas exchange response to drought conditions of young rubber plants with different scions. Buds from four genotypes of a progeny derived from crossed clones of RRIM600 x RRII105 from Nongkhai Rubber Research Center, T187, T186, T149 and T172, were grafted to RRIM 600 rootstocks. Eight-month old plants with two flushes were used in this study. Two levels of water treatment were used, drought condition (W1) and well-watered as control (W0). Leaf chlorophyll fluorescence, stomatal conductance (gs) and net photosynthesis rate (Pn) were investigated in three phases: before drought, during drought and after re-watering. Leaf gas exchange parameters were measured using Li-6400 (LiCor Inc.). Leaf chlorophyll fluorescence was measured using FluorPen FP 100 (Photon Systems Instruments). Before drought, genotype T186 had the greatest net photosynthesis rates followed by T172, T187 and T149; there was no difference in maximum quantum yield of photosystem II (Fv/Fm) and performance index on absorption basis (PIABS). Drought conditions caused reduction in stomatal conductance, net photosynthesis rates, and leaf chlorophyll fluorescence in all genotypes. In re-watering conditions, genotype T186 and T172 experienced quick recovery while the others showed partial recovery but the values of all parameters did not reach previous levels before treatment.

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