Response of Stomatal Conductance to Dynamic Light Intensity

 

Effects of Diffuse Light on Radiation Use Efficiency of Two Anthurium Cultivars Depend on the Response of Stomatal Conductance to Dynamic Light Intensity

by Li T.Thumb_203_203,

Kromdijk J., Heuvelink E., van Noort F. R., Kaiser E., 

Marcelis L. F. M.Thumb_203_203

(2016)

in Front. Plant Sci., 04 February 2016 | http://dx.doi.org/10.3389/fpls.2016.00056 – 

http://journal.frontiersin.org/article/10.3389/fpls.2016.00056/full 

fpls-07-00056-g003

FIGURE 3. Stomatal conductance (gs, dashed line) and PPFD (solid line) in compartment with clear glass (control: A–D) and diffuse glass (E,F). ‘Pink Champion’ is shown in (A,C,E) and ‘Royal Champion’ in (B,D,F). The measurements were taken at 1 min interval.

Abstract

The stimulating effect of diffuse light on radiation use efficiency (RUE) of crops is often explained by the more homogeneous spatial light distribution, while rarely considering differences in temporal light distribution at leaf level.

This study investigated whether diffuse light effects on crop RUE can be explained by dynamic responses of leaf photosynthesis to temporal changes of photosynthetic photon flux density (PPFD).

Two Anthurium andreanum cultivars (‘Pink Champion’ and ‘Royal Champion’) were grown in two glasshouses covered by clear (control) and diffuse glass, with similar light transmission. On clear days, diffusing the light resulted in less temporal fluctuations of PPFD.

Stomatal conductance (gs) varied strongly in response to transient PPFD in ‘Royal Champion,’ whereas it remained relatively constant in ‘Pink Champion.’

Instantaneous net leaf photosynthesis (Pn) in both cultivars approached steady state Pn in diffuse light treatment. In control treatment this only occurred in ‘Pink Champion.’ These cultivar differences were reflected by a higher RUE (8%) in ‘Royal Champion’ in diffuse light treatment compared with control, whereas no effect on RUE was observed in ‘Pink Champion.’

We conclude that the stimulating effect of diffuse light on RUE depends on the stomatal response to temporal PPFD fluctuations, which response is cultivar dependent.

 

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On the formation of subsidiary cells of maize stomata

 

Research on stomata

by Smith L. (x)

in https://biology.ucsd.edu/research/faculty/lgsmith

Research

………..

Our current work focuses on orientation of asymmetric cell divisions. In plants, as in other eukaryotes, asymmetric divisions are associated with pattern formation during embryogenesis, establishment of new cell lineages, and the formation of specialized cell types. In all of these processes, developmental asymmetry is closely tied to division polarity, but little is known about polarizing cues that orient asymmetric divisions in plants, or how cells respond to them to establish asymmetric division planes. Our studies in this area have focused on the formation of subsidiary cells of maize stomata, which are created by asymmetric divisions of subsidiary mother cells (SMCs, Figure 2). We have discovered a cooperatively acting pair of receptor-like proteins, PAN1 and PAN2, that are implicated in transmission or amplification of a cue from adjacent guard mother cells that polarizes the asymmetric divisions of SMCs (Cartwright et al., 2009 and unpublished work on PAN2). ROP GTPases act downstream of PAN1 to polarize SMC divisions (Humphries et al., 2011). Ongoing work utilizes proteomic and molecular genetic approaches to identify additional components of the SMC division polarity pathway.

figure 2

Figure 2. Stomatal development in wild type and pan mutant maize. All stages are illustrated schematically; Toluidine Blue O-stained mature epidermis is also shown for wild type (top) and pan mutant (bottom). Subsidiary cells form via asymmetric divisions of subsidiary mother cells (SMCs), which are polarized by a cue from the adjacent guard mother cell (GMC). PANs function together with ROP GTPases to polarize premitotic SMCs.

An optimal stomatal model

 

Optimal stomatal behaviour around the world

by Lin Y.-S.Medlyn B. E., Duursma R. A.Prentice I. C.Wang H.Baig S.Eamus D.Resco de Dios V.Mitchell P.Ellsworth D. S.Op de Beeck M.Wallin G., Uddling J.Tarvainen L.Linderson M.-L.Cernusak L. A.Nippert J. B.Ocheltree T. O.Tissue D. T.Martin-StPaul N. K.Rogers A.Warren J. M.De Angelis P.Hikosaka K.Han Q. et al. (2015)

in Nature Climate Change5,459–464(2015)doi:10.1038/nclimate2550

http://www.nature.com/nclimate/journal/v5/n5/full/nclimate2550.html?WT.ec_id=NCLIMATE-201505

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Figure 1: Climatic space covered by the Stomatal Behaviour Synthesis Database, shown as mean temperature during the period with daily mean temperatures above 0 °C and moisture index. – Coloured circles represent climatic space for the database, with different colours indicating different plant functional types. Grey hexagons represent global climatic space for which vegetation is present. – http://www.nature.com/nclimate/journal/v5/n5/carousel/nclimate2550-f1.jpg

Abstract

Stomatal conductance (gs) is a key land-surface attribute as it links transpiration, the dominant component of global land evapotranspiration, and photosynthesis, the driving force of the global carbon cycle. Despite the pivotal role of gs in predictions of global water and carbon cycle changes, a global-scale database and an associated globally applicable model of gs that allow predictions of stomatal behaviour are lacking.

Here, we present a database of globally distributed gs obtained in the field for a wide range of plant functional types (PFTs) and biomes. We find that stomatal behaviour differs among PFTs according to their marginal carbon cost of water use, as predicted by the theory underpinning the optimal stomatal model1 and the leaf and wood economics spectrum2, 3.

We also demonstrate a global relationship with climate. These findings provide a robust theoretical framework for understanding and predicting the behaviour of gacross biomes and across PFTs that can be applied to regional, continental and global-scale modelling of ecosystem productivity, energy balance and ecohydrological processes in a future changing climate.

AtALMT9 is controlling stomata aperture

 

 

AtALMT9 is a malate-activated vacuolar chloride channel required for stomatal opening in Arabidopsis.

by De Angeli A., Zhang J., Meyer S., Martinoia E. (2013)

in Nat Commun 4:1804 –

CrossRef PubMed PubMedCentral – 

http://www.nature.com/ncomms/journal/v4/n4/full/ncomms2815.html 

ncomms2815-f6
Figure 6: Model for the role of AtALMT9 in stomatal opening. – When stomata are closed (at the end of the dark period), the vacuolar membrane potential is close to 0 mV and cytosolic malate concentrations are low (left panel). In these conditions, AtALMT9 is not active and does mediate anion accumulation into the vacuole. During stomatal opening (right panel), the membrane potential of the vacuole drops to values close to −60 mV. Starch is degraded to malate, which is also taken up from the apoplast inducing a raise of the cytosolic malate concentration. These conditions activate AtALMT9. At the same time, chloride enters into guard cells. To sustain the opening of stomata, solutes have to be accumulated in the vacuole of guard cells to increase the water potential. In this phase, AtALMT9 mediates chloride accumulation in the vacuole. – http://www.nature.com/ncomms/journal/v4/n4/images_article/ncomms2815-f6.jpg

Abstract

Water deficit strongly affects crop productivity. Plants control water loss and CO2 uptake by regulating the aperture of the stomatal pores within the leaf epidermis.

Stomata aperture is regulated by the two guard cells forming the pore and changing their size in response to ion uptake and release. While our knowledge about potassium and chloride fluxes across the plasma membrane of guard cells is advanced, little is known about fluxes across the vacuolar membrane.

Here we present the molecular identification of the long-sought-after vacuolar chloride channel. AtALMT9 is a chloride channel activated by physiological concentrations of cytosolic malate. Single-channel measurements demonstrate that this activation is due to a malate-dependent increase in the channel open probability. Arabidopsis thaliana atalmt9 knockout mutants exhibited impaired stomatal opening and wilt more slowly than the wild type.

Our findings show thatAtALMT9 is a vacuolar chloride channel having a major role in controlling stomata aperture.

Stomata in Caesalpiniaceae

Photo credit: Google

Caesalpinia pulcherrima

 

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Structure and Development of Stomata on the Vegetative and Floral Organs in Some Members of Caesalpiniaceae

by Shah G. L., Gopal B. V. (1971)

in Annals of Botany Vol. 35, No. 142 (September 1971), pp. 745-759

http://www.jstor.org/stable/pdf/42751965.pdf?seq=1#page_scan_tab_contents – 

Abstract

The structure and development of stomata in 19 species of the family Caesalpiniaceae are described. The study is mostly confined to the leaves, but observations have also been made on other vegetative and floral organs of some species.
Stomata may be paracytic, anisocytic, anomocytic, and with one subsidiary cell. Occasionally a stoma is diacytic, cyclocytic, or actinocytic. Different types occur individually or may be found side by side even on the same surface of an organ. The most prevalent type in all the genera is paracytic except in Caesalpinia where it is anomocytic.
The development of an anomocytic stoma is perigenous, but those with subsidiary cells are largely mesogenous; rarely paracytic stomata are mesoperigenous.
In spite of diversity of stomata, different types of stomata have similar patterns of development in different organs of the same plant.
The present investigation also indicates that the inconstancy of stomata in the family is due to (a) their diversity and (b) an increase in the number of subsidiary cells either by their division or by the neighbouring perigenes becoming subsidiary cell-like.
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Water use by stomata of Jatropha and Canna

Photo credit: Insight Knowledge

Fig. 1: Surface view of leaf epidermis, abaxial (A) and adaxial (B) of Jatropha gossypifolia propagated with 20 cc daily watering regime showing paracytic (p) and brachyparacytic (b) stomata and unicellular (u) and multicellular (m) trichomes x2000

Anatomical Basis for Optimal Use of Water for Maintenance of Some Mesophytic Plants.

by Abdulrahaman A. A., Oladele F. A. (2011)

in  Insight Botany, 1: 28-38 – DOI: 10.5567/BOTANY-IK.2011.28.38 –

http://insightknowledge.co.uk/fulltext/?doi=BOTANY-IK.2011.28.38

fig3-2k11-28-38
Fig. 3: Surface view of leaf epidermis, abaxial (A) and adaxial (B) of Canna indica propagated with 2.5 cc daily watering regime showing paracytic (p) and brachyparacytic (b) stomata x1600 – http://docsdrive.com/images/insightknowledge/BOTANY-IK/2011/fig3-2k11-28-38.gif

ABSTRACT:

Background: One of the strategies for mitigation of global warming and climate change is growing of more green plants. This translates to the need of water for their sustenance and against the backdrop of global water crisis; there is the need for conservation of water and prevention or minimization of water wastage in irrigation. One of the ways to reduce water wastage is lowering the frequency of watering.

Materials and methods: In this study, 3 mesophytic plants namely Jatropha curcas, Jatropha gossypifolia and Canna indica were subjected to 4 watering frequencies i.e. daily weekly, biweekly and monthly under 5 varying soil moisture contents namely 1.25, 2.25, 5, 10 and 20%. This was to determine the anatomical adaptations of the species to water stress with a view to determining the low watering regimes that can sustain them.

Results: Jatropha curcas was the most tolerant of water stress with capacity to survive and thrive at daily watering regime of 25 to 100 cc. This was possibly attributable to presence of trichome density and low transpiration rate of 4.53×10-9mol/m2/sec (abaxial) and 3.77×10-9 mol/m2/sec (adaxial). Canna indica was the least tolerant of water stress possibly due to absence of trichomes and high transpiration rate of 4.72×10-5 mol/m2/sec (abaxial) and 3.88×10-5 mol/m/sec (adaxial).

Conclusion: These 3 species which have high frequency of paracytic and brachyparacytic stomata are potential candidates for revegetation and landscape exercises with minimal use of water. Recommended daily watering regimes are 25 to 100 cc for Jatropha curcas, 200 cc for J. gossypifolia and 400 cc for Canna indica.

 

SDD1 and stomatal development

Photo credit: The Plant Cell

Figure 1.

Overview of Relevant Cell Types That Occur during the Different Stages of Stomatal Development.

A stomatal lineage is initiated by an unequal division of a stomatal initial, also called a meristemoid mother cell (MMC), creating a meristemoid (M). The meristemoid undergoes a series of additional (usually two) asymmetric divisions, after which it converts into a guard mother cell (GMC). The GMC surrounded by the clonally related neighboring cells (NC 1 to NC 3) divides symmetrically to produce two guard cells (GCs). Any neighboring cell (most frequently NC 3) also can divide asymmetrically to produce a satellite meristemoid (SM). SMs may undergo additional asymmetric divisions before they convert into GMCs and form satellite stomata. Reiteration of this process may result in the formation of even higher order stomatal complexes.

The subtilisin-like serine protease SDD1 mediates cell-to-cell signaling during Arabidopsis stomatal development.

by von Groll U., Berger D., Altmann T. (2002)

in Plant Cell 14:1527–1539. –

Abstract/FREE Full Text – 

http://www.plantcell.org/content/14/7/1527.full 

Abstract

Wild-type stomata are distributed nonrandomly, and their density is controlled by endogenous and exogenous factors. In the Arabidopsis mutant stomatal density and distribution1-1 (sdd1-1), the establishment of the stomatal pattern is disrupted, resulting in stomata clustering and twofold to fourfold increases in stomatal density.

The SDD1 gene that encodes a subtilisin-like Ser protease is expressed strongly in stomatal precursor cells (meristemoids and guard mother cells), and the SDD1 promoter is controlled negatively by a feedback mechanism. The encoded protein is exported to the apoplast and probably is associated with the plasma membrane. SDD1 overexpression in the wild type leads to a phenotype opposite to that caused by the sdd1-1 mutation, with a twofold to threefold decrease in stomatal density and the formation of arrested stomata.

While SDD1 overexpression was effective in the flp mutant, the tmm mutation acted epistatically. Thus, we propose that SDD1 generates an extracellular signal by meristemoids/guard mother cells and demonstrate that the function of SDD1 is dependent on TMM activity.

Read the full article: The Plant Cell