Tagged: C4 photosynthesis



Savannah

Savanna tree and C4 grass acclimation responses across low-to-high CO2

By the year 2100, atmospheric CO2 concentration ([CO2]a) could reach 800 ppm, having risen from ~200 ppm since the Neogene, beginning ~24 Myr ago. Changing [CO2]a affects plant carbon–water balance, with implications for growth, drought tolerance and vegetation shifts. The evolution of C4 photosynthesis improved plant hydraulic function under low [CO2]a and preluded the establishment of savannahs, characterized by rapid transitions between open C4-dominated grassland with scattered trees and closed forest. Understanding directional vegetation trends in response to environmental change will require modelling. But models are often parameterized with characteristics observed in plants under current climatic conditions, necessitating experimental quantification...

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Changes in daily transpiration at the leaf scale in C4 species

Atmospheric change, plant water status and the origins of agriculture

The genesis of agricultural practice marks one of the most important events in human history. Low atmospheric CO2 has previously been shown to limit the productivity of the wild progenitors of C3 and C4 founder crops, in part due to the direct effect of reduced CO2 availability on photosynthesis. In this study, Cunniff et al. investigate the indirect role of low CO2 on biomass limitation mediated via plant water status in cereal crops. They find that reduced plant water status caused a negative feedback on stomatal aperture in plants at glacial CO2, thereby reducing photosynthesis. These indirect effects were stronger...

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Oenanthe oenanthe

C4 Wheat? Lend an ear to hear more

One of the Grand Challenges – and, arguably, the Holy Grail – of plant research at present is an attempt to improve the photosynthetic efficiency of plants. Somewhat surprisingly, the fundamental photosynthetic pathway – which is the ultimate piece of biochemistry used by all plants to incorporate (‘fix’) carbon dioxide into organic molecules such as sugars for the plant’s growth and energy needs – so-called C3 photosynthesis – isn’t as efficient as it could be. One of the reasons for its comparatively low conversion rate of sunlight energy into chemical energy stored within organic molecules is the phenomenon of photorespiration....

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Miscanthus

Gas exchange measurements on Miscanthus leaves

Miscanthus has a high yield potential, but even though it is less cold sensitive than other C4 species, it emerges later in spring than C3 species. Xiurong et al. identified one Miscanthus sacchariflorus with a level of cold tolerance similar to Miscanthus × giganteus. They also found a positive linear correlation between net photosynthesis and shoot growth rate as well as specific leaf area. These are relatively easy to measure and useful for the screening of productivity and cold tolerance. The Miscanthus genotype with high cold tolerance can be useful for breeding of new interspecies hybrids or cultivation in temperate...

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Image: Wikimedia Commons.

Scaring the crows…

One way of increasing crop productivity is to increase the amount of grain or other harvestable product that is actually harvested from the plant. To that end scarecrows  were invented by human beings, although their success in that regard is inconsistent at best (is there a scientific study on the effectiveness of scarecrows just waiting to be done..?). However, another variation on the scarecrow theme aims to tackle productivity more directly, and shows quirkily that clues to above-ground productivity can come from ‘down-below’. Investigating any similarities between the endodermis in roots [‘the central, innermost layer of cortex in some land...

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Image: Franz Eugen Köhler, Köhler's Medizinal-Pflanzen. Gera-Untermhaus, 1897.

Phytonumeracy

Echoing a plea from Ron Milo and Robert Last that computational methods [which is sort of ‘math(s)’…] should be used to gain deeper understanding of the fundamental principles that govern regulation of metabolic pathways in plants, here’s advance notice of The Sixth Mathematics in the Plant Sciences Study Group meeting. Taking place from 25–28th March 2013 at the University of Nottingham (UK), this annual workshop ‘gives a handful of plant and crop scientists the opportunity to present a research question to around 40 mathematicians and computer scientists’. At the 4-day number-fest modellers tackle the problems in teams, ‘resulting in a...

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