Changes to Plant Flowering Times – Forgettable or Regrettable?

Posted on March 23, 2017 by Eleanor Pike

By Eleanor Pike

On average the date that a plant first flowers is moving earlier in spring for 385 British plant species (Fitter & Fitter, 2002). This could be due to global warming making winters warmer, and tricking the plants into thinking spring has come earlier (Post et al, 2001). Global warming is a global climate change trend seen in recent years due to the excessive release of greenhouse gasses by humanity. These gasses are released through burning of fossil fuels like petrol (Hansen, 1998).

So why should we be concerned about this? Flowering plants can be important for a number of reasons. Seen here in Figure 1 is a flowering courgette plant (Cucurbita pepo var. cylindrical) which illustrates how crucial flowering plants can be with regards to providing food. Flowers are the plants sex organs which allow fertilisation of the plant to produce the fruit and vegetables that we eat (Lord & Russell, 2002). This is how plants reproduce normally though humanity has harnessed this to create crops to eat. The world is already facing severe changes and concerns with regards to feeding the growing global population.

Pollinators facilitate this fertilisation process through a number of mechanisms. The importance of these pollinators cannot be questioned, with 35% of crops relying on animal pollinators to produce fruits, vegetables or seeds (Klein et al, 2007). However if plants are flowering earlier, could it be that in enough time, there is a concerning distinction between when plants flower and when pollinators are most active?

One of the most important pollinators are bees due to their specific foraging behaviours and consistency (Corbet et al, 1991). Bees are already facing many challenges to do with emerging global change, and their decline is a large concern economically and ecologically. Bee decline has also been linked to the decline of plant species that rely on bees to reproduce (Biesmeijer et al, 2006). This is yet further evidence that the synchronicity between pollinators and plant flowering times could become a real cause for concern in the near future. There are many challenges being faced by global change scientists in modern times, and early flowering times is one of them.

Word Count: 372

References

Biesmeijer, J. et al., 2006. Parallel Declines in Pollinators and Insect-Pollinated Plants in Britain and the Netherlands. Science, 313(5785).

Corbet, S., Williams, I. & Osborne, J., 1991. Bees and the Pollination of Crops and Wild Flowers in the European Community. Bee World, 72(2), pp. 47-59.

Fitter, A. & Fitter, R., 2002. Rapid Changes in Flowering Time in British Plants. Science, 296(1689).

Hansen, J., 1998. Sir John Houghton: Global Warming: The Complete Briefing, 2nd edition. Journal of Atmospheric Chemistry, 30(409).

Klein, A. et al., 2007. Importance of pollinators in changing landscapes for world crops. Proceedings of the Royal Society- Biological Sciences, 274(1608).

Lord, E. & Russell, S., 2002. The Mechanisms of Pollination and Fertilization in Plants. Annual Review of Cell and Developmental Biology, Volume 18, pp. 81-105.

Post, E., Forchhammer, M., Stenseth, N. & Callaghan, T., 2001. The timing of life-history events in a changing climate.. Proceedings of the Royal Society: Biological Sciences, 268(1462), pp. 15-23.

Figure 1: Flowering courgette plant (https://static1.squarespace.com/static/563cf214e4b021af1b575f8a/t/56aabc8859b1f8f179bf570f/1456894203178/flower-on-zucchini-plant.jpg)

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Stomata – an ancient insight into a modern problem

Posted on March 23, 2017 by Anonymous

Findings from a pharaoh

What can an Egyptian pharaoh from 1300 BC tell us about how plants will respond to 21^st century environmental change?

Olive leaves in Tutankhamun’s tomb allowed Beerling & Chaloner to show that the number of stomata declined in response to increasing CO2. Photo credit – Discovery Times Square Museum (Available: http://www.discoverytsx.com/exhibitions/kingtut). — Olive leaves in Tutankhamun’s tomb allowed Beerling & Chaloner to show that the number of stomata declines in response to increasing levels of carbon dioxide.
Photo credit – Discovery Times Square Museum (Available: http://www.discoverytsx.com/exhibitions/kingtut).

When Howard Carter discovered King Tutankhamun’s tomb in 1922, the boy pharaoh’s treasures captivated the world. Amidst such splendor, olive leaves found in the burial chamber were overlooked. But, in 1993, two botanists, David Beerling and William Chaloner decided to compare these leaves with their modern counterparts. They found that olive leaves grown today have 33% fewer stomata (tiny ‘pores’ on the leaf surface) than they did in 1300 BC. Beerling & Chaloner linked this decline in stomata to increasing carbon dioxide (CO₂) levels.

Stomata – microscopic pores on the surface of a leaf let plants ‘breathe’.
Photo credit – University of California Museum of Paleontology’s Understanding Evolution (http://evolution.berkeley.edu).

Powerful pores

Stomata (singular – stoma) are vital to plant function. Plants use these pores to ‘breathe’. Stomata allow CO₂to enter a leaf, where it is used in photosynthesis to generate sugars, which the plant needs to survive and grow. The trade-off is stomata also let water escape. Plants, therefore, need to balance CO₂ gain and water loss.

Stomata control a vital trade-off between carbon dioxide gain and water loss.
Photo credit – University of California Museum of Paleontology’s Understanding Evolution (http://evolution.berkeley.edu).

Rising CO₂ – a certainty in an uncertain world

CO₂ is the most well known of the greenhouse gases. These gases trap the Sun’s heat within Earth’s atmosphere, causing our planet to warm up. We produce CO₂ every day when we burn oil, gas and coal to drive our cars, heat our homes and power our factories.

This has caused CO₂levels to increase by 40% since the industrial revolution started in 1750 (IPCC, 2014). CO₂levels are predicted to increase more rapidly in the future as populations and economies grow (IPCC, 2014).

With some exceptions (Bettarini et al., 1998), most scientists agree that this rise in CO₂will cause a decline in stomatal density (Woodward & Kelly, 1995; Lin et al., 2001). Paoletti et al. (1998) showed that stomata numbers will decline until CO₂ levels reach 750 μmol mol^-1.

But, how will this change impact plant function?

Some plants naturally have few stomata because they have a change in the gene that controls stomatal development (Gray et al., 2000). As CO₂levels rise, each stoma will be able to bring in more CO₂. So, a leaf will need fewer stomata to bring in the same amount of CO₂.

A leaf with fewer stomata will lose less water. As a result, the plant will have a higher water use efficiency and so has an advantage over others (Drake et al., 1997). With time, CO₂will act as a selection pressure and these plants will become more common.

Stomatal density will decline as CO2 levels rise. Photo credit - University of California Museum of Paleontology's Understanding Evolution (http://evolution.berkeley.edu). — Stomatal density will decline as carbon dioxide levels rise.
Photo credit – University of California Museum of Paleontology’s Understanding Evolution (http://evolution.berkeley.edu).

Future plants will be better able to conserve water, making them more tolerant to periods of water stress (Woodward, 1987). This is just as well as droughts are predicted to become more common (IPCC, 2014). It will also mean we will be able to grow the same amount of crops, but using less water (Drake et al., 1997).

Stomata transfer water from the land to the atmosphere. If plants have fewer stomata, less water will be transferred, which will cause increased air temperatures and runoff (Kürschner et al., 1997).

The olive leaves from King Tut’s tomb showed that stomata respond to CO₂ levels. With rises in CO₂ predicted for the 21st century, perhaps the insights provided by these leaves are the boy pharaoh’s most valuable treasure.

References

Beerling, D.J. & Chaloner, W.G. (1993) Stomatal density responses of Egyptian Olea europaea L. leaves to CO₂ change since 1327 BC. Annals of Botany. 71(5), 431-435.

Bettarini, I., Vaccari, F.P. & Miglietta, F. (1998) Elevated CO₂ concentrations and stomatal density: observations from 17 plant species growing in a CO₂ spring in central Italy. Global Change Biology. 4(1), 17-22.

Drake, B.G., Gonzàlez-Meler, M.A. & Long, S.P. (1997) More efficient plants: a consequence of rising atmospheric CO₂? Annual review of plant biology. 48(1), 609-639.

Gray, J.E., Holroyd, G.H., Van Der Lee, F.M., Bahrami, A.R., Sijmons, P.C., Woodward, F.I., Schuch, W. & Hetherington, A.M. (2000) The HIC signalling pathway links CO₂ perception to stomatal development. Nature. 408(6813), 713-716.

IPCC (2014) Summary for Policymakers. In: Pachauri. R.K. & Meyer, L.A. (eds.) Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. IPCC, Geneva, Switzerland, pp. 1-31.

Kürschner, W.M., Wagner, F., Visscher, E.H. & Visscher, H. (1997) Predicting the response of leaf stomatal frequency to a future CO₂-enriched atmosphere: constraints from historical observations. Geologische Rundschau. 86(2), 512-517.

Lin, J., Jach, M.E. & Ceulemans, R. (2001) Stomatal density and needle anatomy of Scots pine (Pinus sylvestris) are affected by elevated CO₂. New Phytologist. 150(3), 665-674.

Paoletti, E., Nourrisson, G., Garrec, J.P. & Raschi, A. (1998) Modifications of the leaf surface structures of Quercus ilex L. in open, naturally CO₂-enriched environments. Plant, Cell & Environment. 21(10), 1071-1075.

Woodward, F.I. & Kelly, C.K. (1995) The influence of CO₂ concentration on stomatal density. New Phytologist. 131(3), 311-327.

Woodward, F.I. (1987) Stomatal numbers are sensitive to increases in CO₂ from pre-industrial levels. Nature. 327(6123), 617-618.

Word count: 499

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The Grass isn’t always Greener on the other side

Posted on March 23, 2017 by Cameron Little

*Photo credit https://loristillman.files.wordpress.com/2013/04/screen-shot-2013-04-30-at-6-07-14-am.png?w=764*

Despite what certain orange men in white buildings may say. It is an inconvenient truth that Global Climate Change is occurring (Kerr, 2001) and may in fact not be a lie created by the Chinese.

What is more up for debate however, is exactly what is going to happen to the earth over the next hundred years. Among many problems better left unsaid, a concept has emerged that global climate change may lead to increased growth rates amongst plants (Nemani, 2003).

As a result of the inputs of additional carbon dioxide into the atmosphere from man-made sources, photosynthesis rates have increased; which has ultimately led to increased plant growth. On the surface of things this may sound like a good result, however below the surface i.e under the sea; this can have entirely different implications.

The increase of carbon dioxide levels in the atmosphere has also led to an increasing global temperature as well as an increasing ocean temperature (Hansen et al,. 2006). Many underwater plants may be detrimentally affected by this including the vast meadows of seagrass which support many of our favourite undersea critters such as the manatee.

*A manatee swimming, blissfully unaware of all life’s problems that may await him. Photo credit: https://www.fws.gov/caribbean/images/Moises_by_Alejandro_Avampini.jpg*

Most organisms on this planet can only live within a certain range of temperatures and when plants or animals are pushed beyond this range they can struggle to survive.

(No prizes for guessing what this means?)

Warming associated with climate change is causing many animals and plants to move beyond their comfortable ranges (Walther et al,. 2002). This is true for many species of temperate seagrasses which are struggling with rising temperatures (Short and neckless, 1999). Increasing temperatures are pushing them out of their desired temperature range of between the lower end of 21 and 32 °C; causing them to a enter a thermal stress. This facilitates a breakdown of a crucial step in photosynthesis known as ‘photosystem II’ (Koch et al,. 2012) and prevents them from photosynthesizing properly.

To make matters worse, other more tropical species of seagrass may begin to move in to temperate seagrasses habitats, as the warmer temperatures allow them to occupy and outcompete them for space. This is because as opposed to temperate species, warmer temperatures of around 27 – 33 °C tend to increase the photosynthetic rates of tropical species (Koch et al,. 2012).

*A beautiful seagrass meadow, blissfully unaware of all life’s problems that await it. Photo credit: http://www.stevedeneef.com/index/G00000uAGDq2A_UQ/thumbs*

But like all things in life the tropical seagrass species can’t have it all. As in their native tropical environments some species are far more susceptible to temperature changes and subsequent increases will cause a breakdown of photosystem II, which leads to heat-induced photoinhibition (Campbell, McKenzie and Kerville, 2006). This subsequently means its ability to photosynthesize is reduced.

In closing it appears that many of the undersea grasses found globally, that are so crucial to many species on earth are going to be negatively affected by global climate change. And if nothing is done to stop it, we could be saying goodbye to a truly beautiful part of nature.

Word count – 489

References

Campbell, S., McKenzie, L. and Kerville, S. (2006). Photosynthetic responses of seven tropical seagrasses to elevated seawater temperature. Journal of Experimental Marine Biology and Ecology, 330(2), pp.455-468.

Hansen, J., Sato, M., Ruedy, R., Lo, K., Lea, D. and Medina-Elizade, M. (2006). Global temperature change. Proceedings of the National Academy of Sciences, 103(39), pp.14288-14293.

Kerr, R. (2001). GLOBAL WARMING: Rising Global Temperature, Rising Uncertainty. Science, 292(5515), pp.192-194.

Koch, M., Bowes, G., Ross, C. and Zhang, X. (2012). Climate change and ocean acidification effects on seagrasses and marine macroalgae. Global Change Biology, 19(1), pp.103-132.

Nemani, R. (2003). Climate-Driven Increases in Global Terrestrial Net Primary Production from 1982 to 1999. Science, 300(5625), pp.1560-1563.

Short, F. and Neckles, H. (1999). The effects of global climate change on seagrasses. Aquatic Botany, 63(3-4), pp.169-196.

Walther, G., Post, E., Convey, P., Menzel, A., Parmesan, C., Beebee, T., Fromentin, J., Hoegh-Guldberg, O. and Bairlein, F. (2002). Ecological responses to recent climate change. Nature, 416(6879), pp.389-395.

Photo credits

Loristillman, (2017). The Grass is Green Where You Water It. [online] Loristillman.files.wordpress.com. Available at: https://loristillman.files.wordpress.com/2013/04/screen-shot-2013-04-30-at-6-07-14-am.png?w=764 [Accessed 19 Mar. 2017].

Steve De neef, (2017). Steve De Neef Photography. [online] Stevedeneef.com. Available at: http://www.stevedeneef.com/index/G00000uAGDq2A_UQ/thumbs [Accessed 20 Mar. 2017].

US Fish and Wildlife Service, (2017). Antillean Manatee Fact Sheet. [online] Fws.gov. Available at: https://www.fws.gov/caribbean/images/Moises_by_Alejandro_Avampini.jpg [Accessed 20 Mar. 2017].

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Rise of the planet of the grapes: climate change through rosé-tinted glasses?

Posted on March 23, 2017 by Eleanor Davis

Chardonnay, Ortega, Pinot Noir…the UK produces over 5 million bottles of wine a year (English Wine Producers, 2015). But given the changes in climate occurring across the globe, this production is said to be on the up.

An increasingly hot topic in the media, the numerous negative consequences of global warming such as extreme weather events and rising sea levels are oftendiscussed. However, the resultant increases in average annual temperature and atmospheric CO₂ concentrations have opened a window of opportunity for the UK wine industry. This increased wine production in England and Wales is now touted as the unexpected silver lining to climate change’s storm cloud.

With a predicted temperature increase of 2.2 degrees Celsius in the UK by 2100 (MetOffice, 2011), the success of grape varieties in Britain is a perfect example of the ways in which global environmental change can impact plant function.

Climate is a critical factor in viticulture (the growing of wine grapes) and increased levels of atmospheric CO₂have been shown to increase plant growth (Jakobsen et al. 2016). Bindi et al (2001) found that elevated atmospheric CO₂levels had a significant effect on the grapevine Vitis vinifera total fruit weight, leading to an increase in biomass of up to 45%. This is also the case for many other crop and wild plant species with 79 species reviewed by Jablonski et al (2002) producing more flowers, more seeds and a greater total mass.

This increased growth in response to elevated atmospheric CO₂can be attributed to plants fixing the CO₂ through photosynthesis – the process through which plants produce glucose from carbon dioxide and water. Increased abundance of CO₂ in the atmosphere leads to increased carbon fixation and hence more growth (Drake et al. 1997). As global warming trends continue, it is expected that many crops will exhibit increased growth rates as CO₂ conditions become increasingly favourable.

However, whilst viticulture in the UK are experiencing a boom, vineyards elsewhere are struggling. For example, many grape varieties in Australia are no longer able to grow due to ongoing environmental change (Mozell & Thach, 2014). This is partly because whilst the atmospheric CO₂ increase occurring is favourable for many crops, other factors such as temperature increase are not.

Temperature is a major determinant of plant development and can lead to reduced yield in crops by shortening the plants’ development stages (Craufurd &Wheeler, 2009). Increased temperatures can also vastly reduce the land area suitable for the growth of certain crops (Hannah et al, 2013). This reflects the reality of Australian viticulture at present and represents a threat to the future of many other crop species.

Ultimately, “wine grape production provides a good test case for measuring indirect impacts […] because viticulture is sensitive to climate” (Hannah et al, 2013). As such, it is important to continue investigating the impacts of environmental change on plants as it is possible that the success of viticulture in the UK represents the rise before the fall.

[497 words]

References:

Bindi, M., Fibbi, L. and Miglietta, F., 2001. Free Air CO 2 Enrichment (FACE) of grapevine (Vitis vinifera L.): II. Growth and quality of grape and wine in response to elevated CO 2 concentrations. European Journal of Agronomy, 14(2), pp.145-155.

Craufurd, P.Q. and Wheeler, T.R., 2009. Climate change and the flowering time of annual crops. Journal of Experimental Botany, 60(9), pp.2529-2539.

Drake, B.G., Gonzàlez-Meler, M.A. and Long, S.P., 1997. More efficient plants: a consequence of rising atmospheric CO2?. Annual review of plant biology, 48(1), pp.609-639.

English Wine Producers, 2015. English Wine Industry: Statistics, Facts and Figures. Available online at http://www.englishwineproducers.co.uk/background/stats/ [Accessed 17^th March 2017]

Hannah, L., Roehrdanz, P.R., Ikegami, M., Shepard, A.V., Shaw, M.R., Tabor, G., Zhi, L., Marquet, P.A. and Hijmans, R.J., 2013. Climate change, wine, and conservation. Proceedings of the National Academy of Sciences, 110(17), pp.6907-6912.

Jablonski, L.M., Wang, X. and Curtis, P.S., 2002. Plant reproduction under elevated CO2 conditions: a meta‐analysis of reports on 79 crop and wild species. New Phytologist, 156(1), pp.9-26.

Jakobsen, I., Smith, S.E., Smith, F.A., Watts-Williams, S.J., Clausen, S.S. and Grønlund, M., 2016. Plant growth responses to elevated atmospheric CO2 are increased by phosphorus sufficiency but not by arbuscular mycorrhizas. Journal of experimental botany, 67(21), pp.6173-6186.

MetOffice, 2011. Climate: Observations, projections and impacts. United Kingdom [PDF]. Available online at http://www.metoffice.gov.uk/media/pdf/t/r/UK.pdf [Accessed 17th March 2017]

Mozell, M.R. and Thach, L., 2014. The impact of climate change on the global wine industry: Challenges & solutions. Wine Economics and Policy, 3(2), pp.81-89.

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Plants – The Power of Adaptation in the Fight Against Climate Change

Posted on March 23, 2017 by Craig Turner

The adaptive power of plants could be crucial in sustaining the future of our planet! (Source: About Lifting) — The adaptive power of plants could be crucial in sustaining the future of our planet!
(Source: Aboutlifting.com)

From giant redwoods to small bonsai trees, all plants are bracing for a future of increasing global CO₂emissions.

FACT! In 2015, we as humans pumped out 36.3 GIGATONNES of CO₂ into our atmosphere (GCP, 2016).

The Dilemma: Though rising atmospheric CO₂is almost always seen as a bad thing, the astute readers among you may ask: “isn’t that a good thing for plants, seeing as how they need CO₂to photosynthesise (convert CO₂gas into sugar for food)?”

The answer is a bit more complex than yes or no.

Studies have shown that in the short-term, increased CO₂concentrations:

Improve the efficiency of plant water use (Drake et al., 1997).
Increase the rates of photosynthesis (Drake et al. 1997).
Increase plant growth and productivity (Raschi et al., 1997).

… But.

Over longer timescales (days to weeks), the photosynthetic capabilities of plants can decrease because of a process called ACCLIMATISATION. To put it briefly, acclimatisation is when there is a build-up of leaf carbohydrates, such as sugars and starch, which triggers a decrease in the amount of RUBISCO enzyme (the enzyme responsible for upholding photosynthesis) in plants (Cheng et al., 1998).

Is the future all DOOM and GLOOM?

Encouragingly, the future looks somewhat optimistic…

A study using natural springs, which already emit high concentrations of CO₂, found that over multiple generations, the “spring” plants that live there have become adapted to the elevated CO₂concentrations we can expect in the future, through the power of GENE EXPRESSION (Watson-Lazowski et al., 2016).

“Spring” and “non-spring” Plantago lanceolata plants from the Bossoleto natural spring in Italy. (Source: Herbalism) — “Spring” and “non-spring” *Plantago lanceolata* plants from the Bossoleto natural spring in Italy.
(Source: dspermaculture.wordpress.com)

Interestingly, the populations of “spring” and “non-spring/control” plants were genetically identical but over 800 genes were expressed differently between the two. Gene expression is kind of like a plug switch, genes can be turned on or off depending on the plant’s needs in order better suit its environment; it is thought that CO₂was directly regulating these changes in gene expression (Watson-Lazowski et al., 2016).

Differences in gene expression resulted in “spring” plants NOT BECOMING ACCLIMATISED to elevated CO₂conditions. In fact, the “spring” plants were able to photosynthetically fix carbon faster and produce larger carbon pools, they then used this additional carbon to enhance their growth through greater respiration (release of energy from carbon) (Watson-Lazowski et al., 2016).

Gene expression also caused the “spring” plants to increase their STOMATA (leaf pores used for gas exchange) index by 5.2% in elevated CO₂conditions, perhaps as an adaptive response (Watson-Lazowski et al., 2016). This contradicts previous studies that predict stomata numbers should have decreased.

What does this mean?

Well, it means that ability of plants to change their gene expression could be the underlying factor that enables future generations to adapt to rising atmospheric CO₂. Questions as to whether this stark change in gene expression is capable in all plants and whether it is enough to enable them to fully adapt to future CO₂ concentrations is yet to be tested; but this study shows that in the battle against climate change, plants may have a fighting chance!

References:

CHENG, S. MOORE, B. & SEEMAN, J. (1998) Effects of short- and long-term elevated CO₂on the expression of ribulose-1,5-bisphosphate carboxylase/oxygenase genes and carbohydrate accumulation in leaves of Arabidopsis thaliana (L.) Heynh. American Society of Plant Physiologists. 116 (2). pp. 715-723.
DRAKE, B. GONZALEZ-MELER, M. & LONG, S. (1997) More efficient plants: a consequence of rising atmospheric CO₂. Annual Review of Plant Physiology & Plant Molecular Biology. 48. pp. 609-639.
GLOBAL CARBON PROJECT, 2016. Global Carbon Budget. [pdf] Futurearth. Available at: http://www.globalcarbonproject.org/carbonbudget/16/files/GCP_CarbonBudget_2016.pdf.
RASCHI, A. MIGLIETTA, F. TOGNETTI, R. & VAN GARDINGEN, P. (1997) Plant Responses to Elevated CO₂: Evidence from Natural Springs. New York: Cambridge University Press.
WATSON-LAZOWSKI, A. LIN, Y. MIGLIETTA, F. EDWARDS, R. CHAPMAN, M. & TAYLOR, G. (2016) Plant adaptation or acclimation to rising CO₂? Insight from first multi-generational RNA-Seq transcriptome. Global Change Biology. 22 (11). pp. 3760 – 3773.

Word Count: 498

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Climate change even sets plants up to compete

Posted on March 23, 2017 by Selina Carlhoff

It is well known that plants photosynthesize and use carbon dioxide to produce energy and oxygen. But did you know that different photosynthetic pathways might have a huge impact on how plants will react to climate change? Continue reading “Climate change even sets plants up to compete” →

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Plants in Elevated CO2: Stimulated Photosynthesis, Good News or Bad News?

Posted on March 23, 2017 by Jiahuan Gu

Climate change, I believe people are familiar with this word, although some of them may not believe it, it is the truth that is happening right now.

Since the Industrial Revolution, a large amount of CO₂ has been released into the atmosphere due to the burning of fossil fuel. Human has obtained great development from Industrial Revolution and we are living a better life. However, the increasing concentration of CO₂ in the atmosphere is warming our planet! We already know that the high temperature, extreme weather and sea level rise are the horrible consequences of climate change, but what about the impacts on plants?

Plants are the major terrestrial carbon sink. They absorb CO₂ and water as raw materials, use sunlight as the energy source, release O₂and store sugars in organs as products, which support the plant growth and fix carbon in the wood and leaves. This process happens in the tiny chloroplast inside the cells of leaves and is called photosynthesis, which is a crucial chemical reaction on the earth, as oxygen is essential to human life.

The process of Photosynthesis. (Patrickodonkor, 2017)

It seems that the increasing atmospheric concentration of CO₂provides the plants more CO₂ input. Will it stimulate the photosynthesis process of plants? Probably. Some studies show that plants increase the photosynthesis rate in the elevated CO₂ concentration, and especially, more evidence is found for the C3 plants (plants grow in the cool, wet climate) (Kirschbaum, 2004).

Although the plants may be happy with taking in more carbon for their growth and development, the Rubisco, which is the most abundant protein playing a role in the photosynthesis, seems unhappy with the elevated CO_2.The activity of Rubisco decreases, and the Rubisco content shows a 20% drop in the elevated CO₂ condition (Long et al., 2004). Such change is the acclimation of plants to the changing environmental condition, and the elevated CO₂ decreases the photosynthesis capacity in long term.

However, even with the acclimation of photosynthesis capability, significant enhancement of carbon uptake has been found in the Free-Air Carbon dioxide Enrichment (FACE) studies of plants grow in the exposure to the CO₂concentration of estimated mid-century scenario (Leakey et al., 2009). This may be a good news, as the plants absorb more CO₂, they can somewhat offset the greenhouse emissions and slow down the climate change. Moreover, the dry matter production and seed yield of C3 plants also slightly increased, although it is not as significant as the increase of carbon uptake (Long et al., 2004).

Another general finding of plant’s response to elevated CO₂ is the increasing nitrogen use efficiency of photosynthesis. As the Rubisco decreases, less nitrogen is needed and the C: N ratio increases (Drake, Gonzàlez-Meler and Long, 1997). That is to say, the elevated CO₂ reduce the nitrogen content in plant tissue and thus fewer nutrients are provided by the plants (Cotrufo, Ineson and Scott, 1998). People have to consume more food than before to obtain the same amount of nutrients!

Can you accept this trade off?

[493 words]

Reference

Cotrufo, M., Ineson, P. and Scott, A. (1998). Elevated CO2 reduces the nitrogen concentration of plant tissues. Global Change Biology, 4(1), pp.43-54.
Drake, B., Gonzàlez-Meler, M. and Long, S. (1997). MORE EFFICIENT PLANTS: A Consequence of Rising Atmospheric CO2?. Annual Review of Plant Physiology and Plant Molecular Biology, 48(1), pp.609-639.
Kirschbaum, M. (2004). Direct and Indirect Climate Change Effects on Photosynthesis and Transpiration. Plant Biology, 6(3), pp.242-253.
Leakey, A., Ainsworth, E., Bernacchi, C., Rogers, A., Long, S. and Ort, D. (2009). Elevated CO2 effects on plant carbon, nitrogen, and water relations: six important lessons from FACE. Journal of Experimental Botany, 60(10), pp.2859-2876.
Long, S., Ainsworth, E., Rogers, A. and Ort, D. (2004). RISING ATMOSPHERIC CARBON DIOXIDE: Plants FACE the Future. Annual Review of Plant Biology, 55(1), pp.591-628.
Patrickodonkor, (2017). Process of photosynthesis. [online] YouTube. Available at: https://www.youtube.com/watch?v=krat2mnM1M0 [Accessed 19 Mar. 2017].

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How can plants cope with rising temperatures?

Posted on March 23, 2017 by Anonymous

crop

A dead crop that has experienced extreme drought Source: Inhabitat.com (2017).

Average global surface temperatures around the world are increasing (Carlowicz, 2010) as a result of increased carbon dioxide in the atmosphere.

temp

Annual average global surface temperatures since the industrial revolution. Source: Climate.gov (2017)

All organisms have a narrow temperature range within which they function best and a broader range they can tolerate. Organisms that can easily move, for example animals, will move to stay within these limits. Plants however are unable to get up and move to maintain these limits in an individual’s life time, though with subsequent generations they can, through seed dispersal (Felde, Kapfer and Grytnes, 2012). But in order to do this they need to survive in the short term.

So the question is how do they do this?

Temperature is one of the most important factors that affects plant development. It controls the rate of most of the reactions occurring inside the plant and increases the storage of sugars inside the plant. As temperatures increase, the impact of the other growth limiting factors become more apparent, especially drought, as higher temperatures increases the rate of transpiration, the process that moves water through the plant.

In general:

Warmer temperatures = Faster Growth + more water consumption

As most gardeners know, extremes of temperature can be deadly. Low temperatures can cause freezing within the plant, which although rare, causes cell death. High temperatures cause not only loss of water and therefore wilting, but with long-term/extreme exposure causes a breakdown of the proteins insides the plant cells (Mathur, Agrawal and Jajoo, 2014), reducing their function, and ultimately causing death. Differences in morphology allow for plants to have varying tolerances to temperature extremes such as fleshy leaves, classic of succulents.

wilted-plant

Healthy plant (left), Wilted plant (Right) Source: Chng, (2017)

Temperature also has a very pronounced effect on photosynthesis, the process by which plants produce food. The optimum temperature varies by species and will have adapted to work best in their given environment. The genetics of an organism may also determine the tolerance of temperature change; for example plants containing a specific gene for carbon fixation have a higher tolerance to warm temperatures compared to those who don’t have it. (Berry and Bjorkman, 1980).

Some species such as Eucalyptus pauciflora (Berry and Bjorkman, 1980), have a natural flexibility with optimal temperature for photosynthesis, which closely follows seasonal changes in air temperature. Plants with such natural flexibility will likely more readily adapt to the changing climate.

Pollination and seed development are one of the most temperature sensitive processes in the plant life cycle, but there are very few adaptations to combat this; in an experimental study (Hatfield and Prueger, 2015), the seed development in maize was reduced by 80-90% with increased temperatures. Without mechanisms in place to reduce this effect, it makes it more important for adaptations in other life cycle stages to reduce the impact of temperature variation.

adaptations

A summary of the different techniques plants can use to reduce high temperature stress. Source: Mathur, Agrawal and Jajoo, (2014)

To survive short term plants may employ a variety of techniques shown in the image above. The long term adaptation of maximizing photosynthesis allows plants to make the most of the changing environment, and allows the plant to survive long enough to reproduce.

Word Count:499

References

Berry, J. and Bjorkman, O. (1980). Photosynthetic Response and Adaptation to Temperature in Higher Plants. Annual Review of Plant Physiology, 31(1), pp.491-543.

Carlowicz, M. (2010). World of Change: Global Temperatures : Feature Articles. [online] Earthobservatory.nasa.gov. Available at: https://earthobservatory.nasa.gov/Features/WorldOfChange/decadaltemp.php [Accessed 21 Mar. 2017].

Chng, J. (2017). Healthy Wholesome Food ~ Be a WISE Consumer to safeguard your HEALTH. [online] Healthywholesomefood.blogspot.co.uk. Available at: https://healthywholesomefood.blogspot.co.uk/search/label/e%20excel%20orchestra [Accessed 21 Mar. 2017].

Climate.gov. (2017). Why did Earth’s surface temperature stop rising in the past decade? | NOAA Climate.gov. [online] Available at: https://www.climate.gov/news-features/climate-qa/why-did-earth%E2%80%99s-surface-temperature-stop-rising-past-decade [Accessed 21 Mar. 2017].

Felde, V., Kapfer, J. and Grytnes, J. (2012). Upward shift in elevational plant species ranges in Sikkilsdalen, central Norway. Ecography, 35(10), pp.922-932.

Hatfield, J. and Prueger, J. (2015). Temperature extremes: Effect on plant growth and development. Weather and Climate Extremes, 10, pp.4-10.

Inhabitat.com. (2017). Fungus-Infused Superplants Could Survive Forthcoming US Droughts. [online] Available at: http://inhabitat.com/fungus-infused-superplants-could-survive-forthcoming-us-droughts/dead-crops/ [Accessed 21 Mar. 2017].

Mathur, S., Agrawal, D. and Jajoo, A. (2014). Photosynthesis: Response to high temperature stress. Journal of Photochemistry and Photobiology B: Biology, 137, pp.116-126.

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UK Food in a climate crisis?

Posted on March 23, 2017 by Phoebe O'Brien

British food security is under threat due to Climate change.

If you haven’t heard of ‘climate change’ you‘ve either been living under a rock for the last 30 years or getting yourself elected as leader the free world. But not much has changed, Winter’s a little warmer, summer’s a little wetter? We’ve heard of extreme weather conditions in some far corners of the globe but unless you’ve been planning a trip there, it’s unlikely to affect our everyday lives. But behind supermarkets sliding doors lurks a real peril, one directly impacting Britons at their most vulnerable part, our Achilles heel, our pockets. As crop production is jeopardised, already inflated prices are set to rise, correlating with the environmental changes induced by human pollution (Lobell, 2007).

Figure 1. A familiar slight, well stocked fruit and veg for public consumption. But for how long? (WordShore (flickr), 2016)

Food security is perhaps the most important commodity provided by the planet. At a glance the effects of climate change, seem on the whole, to be exactly what farmers are looking for in terms of improving yield from their crops. It’s wet, hot, there’s more CO2, more decomposition and available nutrients, just what plants need right? But this is not always the case, although higher CO2 levels does stimulate plant growth, it is counteracted by the increase in temperature and ozone, a molecule with harmful effects on plant tissue(Hogsett, et al 1997). Warming decreases the quality of the crops produced, grains are less dense and seeds contain less oil, as well as favouring growth and proliferation of weeds into new areas, due to the differences in how they photosynthesise (Fuhrer, 2003. Martre, 2017).

Figure 2. The graph from DEFRA (Department for Environmental Food and Rural Affairs) shows billions of pounds worth of imported food, especially fruit and vegetables. (Source: DEFRA Food Statistics Pocketbook 2016) — Figure 2. This graph from DEFRA (Department for Environmental Food and Rural Affairs) shows billions of pounds worth of imported food, especially fruit and vegetables. (Source: DEFRA Food Statistics Pocketbook 2016)

It is no secret that as a nation we currently import almost half of our food and animal feed from overseas (Ruiter et al 2015). In response to huge population increases of 3 Million on average every decade since the baby boomers of the 50s(Humby, 2016) and market for year-round exotic produce. But tropical regions are likely to suffer much more, even a slight temperature increase interfering with developmental and growth processes beyond already stretched thresholds, meaning production in these areas will fall hugely(Challinor, 2008). Excess precipitation, effectively drowning roots and drought adding another uncertain dimension to the mix(Amedie, 2013).

“[In staples like wheat, maize and barley] warming has resulted in annual combined losses of $5 billion per year, as of 2002” -Lobell, 2007

Environmental change is going to effect everyone in one way or another, we rely on plants for food, clothing, oxygen, medicine and much more. Prices of everyday commodities reflect the quantity and quality of production processes. The result is innumerable aspects of our lives being changed, in some way by the unsustainable practices we are complicit to on a daily basis(Lepetz et al., 2009).

Research into genetic modification of crop plants provides some relief in the challenges ahead, improving crop plant coping mechanisms and yield potential (Martre et al 2017), as well as a decrease in the consumption of animal products due to their high carbon footprint and inefficiency(Ruiter et al 2015). For now it will be a 4p increase in a farmhouse loaf and 10p extra for sunflower oil, but immediate action is necessary to prevent a large-scale food shortage in the near future.

[500 words]

References:

Amedie, F.A., (2013). Impacts of Climate Change on Plant Growth, Ecosystem Services, Biodiversity, and Potential Adaptation Measure. , pp.1–61.

Challinor, A.J. & Wheeler, T.R., (2008). Crop yield reduction in the tropics under climate change: Processes and uncertainties. Agricultural and Forest Meteorology, 148(3), pp.343–356.

Fuhrer, J., (2003). Agroecosystem responses to combinations of elevated CO2, ozone, and global climate change. Agriculture, Ecosystems and Environment, 97(1–3), pp.1–20.

Hogsett, W.E., J.E. Weber, D. Tingey, A. Herstrom, E.H. Lee and J.A. Laurence. (1997). An approach for characterizing tropospheric ozone risk to forests. Environmental Management 21:105-120.

Humby, P. (2016). Overview of the UK population: February 2016. [ONLINE] Available at: https://www.ons.gov.uk/peoplepopulationandcommunity/populationandmigration/populationestimates/articles/overviewoftheukpopulation/february2016. [Accessed 13 March 2017].

Lepetz V., Massot, M. & Schmeller, D.S., & Clobert, J., (2009). Biodiversity monitoring: some proposals to adequately study species’ responses to climate change. Biodiversity and Conservation 18, 3185- 3203

Lobell, D.B. & Field, C.B., (2007). Global scale climate–crop yield relationships and the impacts of recent warming. Environmental Research Letters, 2(1), p.14002.

Martre, P., Yin, X. & Ewert, F., (2017). Modeling crops from genotype to phenotype in a changing climate. Field Crops Research, 202, pp.1–4. Available at: http://linkinghub.elsevier.com/retrieve/pii/S0378429017300242.

Ruiter, H. de et al., (2015). Global cropland and greenhouse gas impacts of UK food supply are increasingly located overseas. Journal of The Royal Society Interface, 13(114). Available at: http://rsif.royalsocietypublishing.org/content/13/114/20151001.abstract.

WordShore (flickr), (2016), Fruit (WordShore)[ONLINE]. Available at: https://hiveminer.com/Tags/hebrides,solas [Accessed 15 March 2017].

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It’s getting hot in here! Can plants handle global warming?

Posted on March 23, 2017 by Catherine Savage

Looking at the potential future impacts of climate change on global plant life By Catherine Savage, University of Southampton student

The human race is turning over a new leaf – but not in a good way.

As we enter a new era, the Anthropocene, what will be the fate for plant life on earth?

Everyone knows what climate change is, everyone knows that it is a current hot topic, but does everyone know what is happening to our plants because of it?

Global temperatures have risen 0.9 degrees throughout the last century (IPCC, 2013). This is predicted to rise by 4 degrees before 2100 (Thuiller, 2007). A shocking reality to grasp, yet global temperature change is only one aspect encompassed in the concept of climate change. What about changes in rainfall? Ice sheet melting? Sea level rise?

So, what are the underlying causes of climate change? Out of the greenhouse gases, carbon dioxide contributes the most to global warming at 65%. Current carbon dioxide concentration in the atmosphere is 387ppm, exceeding the safe level of 350ppm (Hansen et al., 2015). This has been heightened by fossil fuel burning and land-use change. The extra CO₂ increases the greenhouse effect, resulting in trapped heat in the atmosphere which causes warming of the planet (Oktyabrskiy, 2016). For plants, this could either be a blessing or a curse.

Plate 2. The world map showing projected daily temperatures in July by 2100, under predicted carbon dioxide levels of 935ppm (Gray, 2015). — **Plate 1.** The world map showing projected daily temperatures in July by 2100, under predicted carbon dioxide levels of 935ppm (Gray, 2015).

The good…

Climate change may be beneficial for plants:

Enhanced CO₂ can increase the photosynthetic rate of plants, which could balance the effect of temperature increases (Thuiller, 2007).
With warmer soils, the decomposition rate of organic matter will increase, allowing plants a higher mineral and nutrient availability.
Growing seasons for crops may be extended and we could witness an improved agricultural productivity (Brown et al., 2016).

The bad…

However, it would be reckless to keep adding CO₂ to the atmosphere. Too much of a good thing can be a bad thing right? Once you increase one substance, plants need to increase the rest too! Plants will be incapable of meeting these new requirements.

Changes in rainfall patterns and temperatures can further exacerbate abiotic stresses such as (Naithani, 2016):

Drought
Waterlogged soils
Saltwater inversion
Metal contamination

These impacts and more make it hard for plants to thrive, with the overarching impact of stunted growth (Worland, 2015).

Plate 2. The invasive Bromus tectorum, a species of the genum Bromus. It is known as the drooping brome or cheat grass. — **Plate 2**. The invasive Bromus tectorum, a species of the genum *Bromus*. It is known as the drooping brome or cheat grass. (Source: www.biology.csusb.edu)

Plus, non-native plant species may cross frontiers as conditions become more suitable, out-competing native plants (Thuiller, 2007; Smith et al., 2016; Walter et al., 2002).

The species of long grass, Bromus tectorum, has risen above native plant species in western North America due to being more suited to changes in the wet seasons (Smith et al., 2000).

The ugly…

The human race is a selfish species, perhaps the only way to kick people into action is to present the fact that no plants means no food. Crops won’t grow, land will become barren and food insecurity will explode (Worland, 2015). Could climate change wipe out homo sapiens as well as the worlds plants?

On a lighter note, the outlook may seem dire, but it is not too late for change. As the UN Secretary General Ban Ki-Moon quite rightly stated we are “the last generation that can end climate change”. We can protect and preserve our plants that will provide security to our future generations. Let’s all stop waiting for someone else to solve our problems, and be the change ourselves.

Word count: 499

References:

IPCC (2013) Climate change: the physical science basis. Working group contribution to the fifth assessment report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge, UK and New York, USA.
Thuiller, W. (2007) Biodiversity: climate change and the ecologist.Nature,448(7153), pp.550-552.
Hansen, J., Sato, M., Ruedy, R., Lo, K., Lea, D.W. and Medina-Elizade, M. (2015) Global temperature change. Proceedings of the National Academy of Sciences, 103(39), pp.14288-14293.
Oktyabrskiy, V.P. (2016) A new opinion of the greenhouse effect.St. Petersburg Polytechnical University Journal: Physics and Mathematics,2(2), pp.124-126.
Brown, I., Thompson, D., Bardgett, R., Berry, P., Crute, I., Morison, J., Morecroft, M., Pinnegar, J., Reeder, T., and Topp, K. (2016) UK Climate Change Risk Assessment Evidence Report: Chapter 3, Natural Environment and Natural Assets. Report prepared for the Adaptation Sub-Committee of the Committee on Climate Change, London.
Gray, R. (2015) Our scorched Earth in 2100: Nasa maps reveal how climate change will cause temperatures to soar. [online] Available at: http://www.dailymail.co.uk/sciencetech/article-3125113/Earth-2100-Nasa-maps-reveal-world-need-adapt-rising-temperatures-caused-climate-change.html [Accessed 20 March 2017].
Naithani, S. (2016) Plants and global climate change: A need for sustainable agriculture. Current Plant Biology,6(2), p.1.
Worland, J. (2015) The weird effect climate change will have on plant growth. [Blog]Time. Available at: http://time.com/3916200/climate-change-plant-growth/ [Accessed 6 Mar. 2017].
Smith, S.D., Huxman, T.E., Zitzer, S.F., Charlet, T.N., Housman, D.C., Coleman, J.S., Fenstermaker, L.K., Seemann, J.R. and Nowak, R.S., (2000) Elevated CO₂ increases productivity and invasive species success in an arid ecosystem.Nature,408(6808), pp.79-82.
Walther, G.R., Post, E., Convey, P., Menzel, A., Parmesan, C., Beebee, T.J., Fromentin, J.M., Hoegh-Guldberg, O. and Bairlein, F., (2002) Ecological responses to recent climate change.Nature,416(6879), pp.389-395.

Read more:

http://journal.frontiersin.org/article/10.3389/fpls.2016.01123/full

http://www.open.edu/openlearncreate/mod/oucontent/view.php?id=22627&printable=1

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How can plants cope with rising temperatures?

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