differences in photosynthesis efficiency related...

Heat dissipation

Photochemistry1

𝝓𝑰𝑰𝝓𝑵𝑷𝑸

2

Crop productivity can be expressed as the product of radiation intercepted, radiation use efficiency and harvest index.

Light energy absorbed by chlorophyll can undergo three competing fates:

Measuring the dynamics of chlorophyll fluorescence in response to beam pulses allow us estimating photosynthesis efficiency.

PARFluorescence3

Background

Differences in photosynthesis efficiency related parameters in a hybrid-parent barley germplasm set

Fernández-Calleja M1, Monteagudo A1, Casas AM1, Gracia MP1, Ciudad FJ2, Boutin C3, Pin PA3, Igartua E1

1 Aula Dei Experimental Station, CSIC, Avda Montañana 1005, 50059 Zaragoza, Spain (mfernandez@eead.csic.es)2 Instituto Tecnológico Agrario de Castilla y León, Finca Zamadueñas, Valladolid, Spain3 Syngenta Seeds SAS, 12 Chemin de l’Hobit, 31790 Saint Sauveur, France

REFERENCESS. Kuhlgert, G. Austic, R. Zegarac, I. Osei-Bonsu, D. Hoh, M.I. Chilvers, M.G. Roth, K. Bi, D. TerAvest, P. Weebadde, D.M. Kramer, MultispeQ Beta: a tool for large-scale plant phenotyping connected to the open PhotosynQ network, R. Soc. Open Sci. 3 (2016) 160592. doi:10.1098/rsos.160592.E.H. Murchie, T. Lawson, Chlorophyll fluorescence analysis: a guide to good practice and understanding some new applications, J. Exp. Bot. 64 (2013) 3983–3998. doi:10.1093/jxb/ert208.P. Horton, A. V. Ruban, R.G. Walters, K. Niyogi, Regulation of Light Harvesting in Green Plants (Indication by Nonphotochemical Quenching of ChlorophyllFluorescence)., Plant Physiol. 106 (1994) 415–420. doi:10.1104/pp.124.1.273.N.R. Baker, Chlorophyll Fluorescence: A Probe of Photosynthesis In Vivo, Annu. Rev. Plant Biol. 59 (2008) 89–113. doi:10.1146/annurev.arplant.59.032607.092759.

Results Are fluorescence parameters really meaningful?

Conclusions

ABA

B

60

62

64

66

SPA

D BA

B

0.40

0.45

0.50

𝜙𝑁𝑃𝑄

Yield = RI x RUE x HI

Multispeq is a sensitive medium throughput tool for measurement of photosynthetic parameters under field conditions.

Hybrids presented an asymmetric inheritance of traits, resembling the females in SPAD values, and resembling the males in other traits.

The combination of traits detected in hybrids seems favorable, and could indicate higher plant nitrogen content and improved photoprotection.

Material & Methods

Barley germplasm: 2 female parents, 46 male parents, and the corresponding 92 hybrids.

MultispeQ field fluorimeter measurements of crop physiological status (SPAD, 𝜙𝐼𝐼, 𝜙𝑁𝑃𝑄,

𝜙𝑁𝑂, leaf temperature differential - LTD).

Two sampling times: 1) after a mild water stress, and 2) after an abundant rain period. Accumulated precipitation from the previous three weeks: 1) 9.6, and 2) 90.2 mm.

Lack of appropriate equipment to study 𝜎𝐺2 for RUE components at plant breeding scale.

Responses of photosynthetic apparatus to fluctuating environmental conditions sparsely investigated under field conditions.

Knowledge gap

𝑟𝑛𝑜𝑛−𝑠𝑡𝑟𝑒𝑠𝑠𝑒𝑑 = - 0.04𝑟𝑤𝑎𝑡𝑒𝑟 𝑠𝑡𝑟𝑒𝑠𝑠𝑒𝑑 = - 0.45

𝑟𝑛𝑜𝑛−𝑠𝑡𝑟𝑒𝑠𝑠𝑒𝑑 = - 0.001𝑟𝑤𝑎𝑡𝑒𝑟 𝑠𝑡𝑟𝑒𝑠𝑠𝑒𝑑 = 0.42

𝑟𝑛𝑜𝑛−𝑠𝑡𝑟𝑒𝑠𝑠𝑒𝑑 = 0.06𝑟𝑤𝑎𝑡𝑒𝑟 𝑠𝑡𝑟𝑒𝑠𝑠𝑒𝑑 = 0.38

No significant differences in 𝜙𝐼𝐼 or 𝜙𝑁𝑂 between groups of genotypes.

Formation of ROS

𝝓𝑵𝑶

When taking into account the two sampling moments, hybrids and male parents showed a different LTD dynamic in contrast to the female parents.

Under stress conditions, there was moderate correlation between LTD (common indicator of plant stress) and chlorophyll fluorescence-based parameters.

Solar energy

Solar energy

Non-photochemical dissipation

(fluorescence)

Photochemical dissipation

(Photosynthesis)

Non-photochemical dissipation

Photochemical dissipation

However, hybrids presented higher SPAD (relative chlorophyll content) and 𝜙𝑁𝑃𝑄 than parents.

A

B

B

A

A

A

-7 -5 -3 -1

Female

Hybrid

Male

Leaf Temperature Differential (LTD)

1) Water stressed

2) Non-stressed