New PhotosynQ Related Publication

Check out the new publication in the American Journal of Plant Sciences, using the MultispeQ and PhotosynQ Platform (10.4236/ajps.2017.84050)

Response of Cowpea Genotypes to Drought Stress in Uganda

Saul Eric Mwale, Mildred Ochwo-Ssemakula, Kassim Sadik, Esther Achola, Valentor Okul, Paul Gibson, Richard Edema, Wales Singini, Patrick Rubaihayo

Moisture stress is a challenge to cowpea production in the drought prone areas of eastern and north eastern Uganda, with yield losses of up to 50% reported. Genotypes grown by farmers are not drought tolerant. This study was therefore, undertaken at Makerere University Agricultural Research Institute Kabanyolo to identify cowpea genotypes tolerant to drought. Thirty cowpea accessions comprising of Ugandan landraces and released varieties, Brazilian lines, Makerere University breeding lines, elite IITA germplasm and seven IITA drought tolerant lines as checks were screened for drought tolerance at vegetative and reproductive stages. The experiment was designed as a 2 × 37 factorial and laid out in a split-plot arrangement, 37 genotypes of cowpea at two soil moisture stress levels (T1, no stress and T2, severe stress) with all factorial combinations replicated two times in a screen house. The genotypes showed considerable variability in tolerance to drought. Genotypes were significantly different for chlorophyll content (P ≤ 0.01), efficiency of photosystem II (P ≤ 0.05), non-photochemical quenching (P ≤ 0.05), recovery (P ≤ 0.01), delayed leaf senescence (P ≤ 0.01), grain yield (P ≤ 0.01), 100 seed weight (P ≤ 0.05), number of pods per plant and number of seeds per pod (P ≤ 0.001). There was a highly significant positive correlation between chlorophyll content and efficiency of photosystem II (r = 0.75, P ≤ 0.001) implying that chlorophyll content and efficiency of photosystem II could be used as efficient reference indicators in the selection of drought tolerant genotypes. Genotypes SECOW 5T, SECOW 3B, SECOW 4W, WC 30 and MU 24 C gave relatively high yields under stress and no stress conditions, maintained above mean chlorophyll content, efficiency of photosystem II and had good recovery scores from stress and thus were tolerant to drought stress induced at both vegetative and reproductive stages.

More PhotosynQ related publications are available here

New PhotosynQ Related Publication

Check out the new publication in Photosynthesis Research, using the MultispeQ and PhotosynQ Platform (10.1007/s11120-017-0449-9)

Faster photosynthetic induction in tobacco by expressing cyanobacterial flavodiiron proteins in chloroplasts

Rodrigo GómezNéstor Carrillo, María P. Morelli, Suresh Tula, Fahimeh Shahinnia, Mohammad-Reza Hajirezaei, Anabella F. Lodeyro

Plants grown in the field experience sharp changes in irradiation due to shading effects caused by clouds, other leaves, etc. The excess of absorbed light energy is dissipated by a number of mechanisms including cyclic electron transport, photorespiration, and Mehler-type reactions. This protection is essential for survival but decreases photosynthetic efficiency. All phototrophs except angiosperms harbor flavodiiron proteins (Flvs) which relieve the excess of excitation energy on the photosynthetic electron transport chain by reducing oxygen directly to water. Introduction of cyanobacterial Flv1/Flv3 in tobacco chloroplasts resulted in transgenic plants that showed similar photosynthetic performance under steady-state illumination, but displayed faster recovery of various photosynthetic parameters, including electron transport and non-photochemical quenching during dark–light transitions. They also kept the electron transport chain in a more oxidized state and enhanced the proton motive force of dark-adapted leaves. The results indicate that, by acting as electron sinks during light transitions, Flvs contribute to increase photosynthesis protection and efficiency under changing environmental conditions as those found by plants in the field.

More PhotosynQ related publications are available here

The NPQ(T) Parameter

Measuring non-photochemical quenching in a few seconds without an initial long dark acclimation.

Over the past 3 years, many MultispeQ users have noticed that the NPQ(T) parameter (and ΦNPQ) can be a powerful predictor of plant stress, either biotic or abiotic. The NPQ(T) parameter has also correlated with crop yields in some PhotosynQ projects, like this project from Malawi.

Indeed, one of the big breakthroughs with the MultispeQ is the ability to estimate NPQ (Non-Photochemical Quenching) without a long dark acclimation period, which allows us to develop robust protocols that take less than 20 seconds. So how is the NPQ(T) parameter derived and how does it compare to the established NPQ parameter?

Tietz et al. out of the Kramer Lab have just published a paper in Plant, Cell and Environment describing the parameter and its derivation. Congratulations!

Read the peer reviewed publication or the story on the Michigan State University’s Plant Research Laboratories Website, Protecting plants from the power of sunlight.

Tietz, S., Hall, C. C., Cruz, J. A., Kramer, D. M. (2017) NPQ(T): a chlorophyll fluorescence parameter for rapid estimation and imaging of non-photochemical quenching of excitons in photosystem-II-associated antenna complexes Plant. Cell Environ. 40(8), 1243–1255. doi:10.1111/pce.12924

MultispeQ Beta publication in Royal Society for Open Science

Check out the first publication from the Kramer Lab about the MultispeQ Beta!

You will find comparisons to commercial devices, calibration, and use and application in the field in collaboration with Beta test partners.

It’s important to note that this is paper is about the MultispeQ Beta device, NOT the MultispeQ v1.0 which we’re working on currently.  The MultispeQ v1.0 will have its own publication.  While the v1.0 has many improved features, better quality, and higher accuracy, the v1.0 is otherwise pretty similar to the Beta and this publication is a useful starting point for understanding either device.

Congratulations to Sebastian, Dave, Dan, Marty, Robert, Isaac, Donghee, Mitch, Kevin, and Pro for their hard work on getting this paper out into the world and the many sponsers which supported us along the way.