All organisms are fitted for the habitat in which they live. Some are sufficiently flexible in their requirements that they can withstand small shifts in their environment. Others are so well fitted that they cannot withstand habitat change and will eventually fail. The extent of seasonal changes varies with latitude. Plants in temperate and sub-arctic are fitted for changing weather patterns from hot and dry to cold and wet as the calendar moves from summer into winter. Deciduous plants start growing in spring with varying degrees of rapidity and move through flowering and fruiting in summer and early autumn. Finally, some produce a magnificent display of autumn colour, but all senesce and shut down with the return of winter. Evergreen plants frequently inhabit the higher latitudes and retain their foliage. This is an energy conservation measure as they can respond more quickly when winter ends and growth restarts.
Plants respond to seasonal change by sensing alterations in daylength, spectral composition and most importantly temperature. It is known as acclimatisation (acclimation in the American literature). Falling temperatures are the most potent triggers in preparation for winter dormancy. Cold and ultimately freezing weather will seriously damage plant growth where acclimatisation has not been completed. Without preparation freezing ruptures cell membranes in leaves and stems disrupting their normal functions. These effects are measurable and used as means of quantifying plant hardiness. Membrane leakiness correlates with increased ionic concentrations when damaged leaves are placed in water and the resultant pC measured. Changes in chlorophyll fluorescent indicated damaged photosynthetic apparatus and measurable. Similarly, in some species bonding in lipid molecules alters and can be traced by mass spectroscopy. Understanding these processes and their ultimate goal which is protective dormancy underpins more accurate understanding of the natural world. It also provides information useful for breeding cold tolerant crops and garden plants.
Cold Damaged Plant
The rapidity of climate change is such that the protective mechanisms of plants and other organisms cannot respond with sufficient speed. Autumn in cool temperate regions, for example, is now extending as an increasingly warm period. This means that plants are not receiving the triggers necessary for acclimatisation in preparation for severe cold. Buds are commencing growth earlier in spring and now frequently are badly damaged by short bursts of deep cold. These buds cannot be replaced and as a consequence deciduous trees and shrubs in particular are losing capacities for survival.
This tobacco (Nicotiana tabacum) relative was first planted in the SCIence Garden in the summer of 2018. It was grown from seed by Peter Grimbly, SCI Horticulture Group member. Although normally grown as an annual, some of the SCIence Garden plants have proven to be perennial. It is also gently self-seeding across the garden. It is native to the south and southeast of Brazil and the northeast of Argentina but both the species and many cultivars of it are now grown ornamentally across Europe. Flower colour is normally white, but variants with lime green and pink through to darker red flowers are available.
Like many Nicotiana this species has an attractive floral scent in the evening and through the night. The major component of the scent is 1.8-cineole. This constituent has been shown to be a chemical synapomorphy for the particular section of the genus Nicotiana that this species sits within (Raguso et al, Phytochemistry 67 (2006) 1931-1942). A synapomorphy is a shared derived character – one that all descendants and the shared single ancestor will have.
This ornamentally and olfactorily attractive plant was chosen for the SCIence Garden to represent two other (arguably less attractive) Nicotiana species.
Firstly, Nicotiana benthamiana, a tobacco species from northern Western Australia. It is widely used as a model organism in research and also for the “pharming” of monoclonal antibodies and other recombinant proteins.
In a very topical example of this technology, the North American biopharmaceutical company Medicago is currently undertaking Phase 1 clinical trials of a Covid-19 vaccine produced using their plant-based transient expression and manufacturing technology.
Secondly, Nicotiana tabacum, the cultivated tobacco which contains nicotine. This alkaloid is a potent insecticide and tobacco was formerly widely used as a pesticide.
This vivid extract from William Dallimore’s memoirs of working at Royal Botanic Gardens, Kew illustrate how tobacco was used in the late Victorian era.
“Real tobacco was used at Kew for fumigating plant houses. It was a very mixed lot that had been confiscated by excise officers, and it was said that it had been treated in some way to make it unfit for ordinary use before being issued to Kew. With the men working in the house ten men were employed on the job. After the first hour the atmosphere became unpleasant and after 1 ½ hours the first casualties occurred, some of the young gardeners had to leave the house. At the conclusion there were only the two labourers the stoker and one young gardener to leave the house, I was still about but very unhappy. Each man employed at the work, with the exception of the foreman, received one shilling extra on his week’s pay.“
After a second such fumigation event it was reported that there was a great reduction in insect pests, particularly of mealy bug and thrips, with a “good deal of mealy bug” falling to the ground dead.
Health and safety protocols have improved since the Victorian era, but the effectiveness of nicotine as an insecticide remains. From the 1980’s through the 1990’s a range of neo-nicotinoid plant protection agents were developed, with structures based on nicotine. Although extremely effective, these substances have also been shown to be harmful to beneficial insects and honey bees. Concerns over these adverse effects have led to the withdrawal of approval of outdoor use in the EU.
Imidacloprid – the first neo-nicotinoid developed
In early 2020, the European commission decided not to renew the European license for the use of Thiacloprid in plant protection, making it the fourth neo-nicotinoid excluded for use in Europe.
Where the next generation of pest control agents will come from is of vital importance to the horticulture and agriculture industries in the UK and beyond and the presence of these plants in the garden serves to highlight this.
Soil is a very precious asset whether it be in your garden or an allotment. Soil has physical and chemical properties that support its biological life. Like any asset understanding its properties is fundamental for its effective use and conservation.
Soils will contain, depending on their origin four constituents: sand, clay, silt and organic matter. Mineral soils, those derived by the weathering of rocks contain varying proportions of all four. But their organic matter content will be less than 5 percent. Above that figure and the soil is classed as organic and is derived from the deposition of decaying plants under very wet conditions forming bogs.
Essentially this anaerobic deposition produces peat which if drained yields highly fertile soils such as the Fenlands of East Anglia. Peat’s disadvantage is oxidation, steadily the organic matter breaks down, releases carbon dioxide and is lost revealing the subsoil which is probably a layer of clay.
Cracked clay soil
Mineral soils with a high sand content are free draining, warm quickly in spring and are ‘light’ land. This latter term originates from the small number of horses required for their cultivation. Consequently, sandy soils encourage early spring growth and the first crops. Their disadvantage is limited water retention and hence crops need regular watering in warm weather.
Clay soils are water retentive to the extent that they will become waterlogged during rainy periods. They are ‘heavy’ soils meaning that large teams of horses were required for their cultivation. These soils produce main season crops, especially those which are deeply rooting such as maize. But in dry weather they crack open rupturing root systems and reducing yields.
Silt soils contain very fine particles and may have originated in geological time by sedimentation in lakes and river systems. They can be highly fertile and are particularly useful for high quality field vegetable and salad crops. Because of their preponderance of fine particles silt soils ‘cap’ easily in dry weather. The sealed surface is not easily penetrated by germinating seedlings causing erratic and patchy emergence.
Soil finger test
Soil composition can be determined by two very simple tests. A finger test will identify the relative content of sand, clay and silt. Roll a small sample of moist soil between your thumb and fingers and feel the sharpness of sand particles and the relative slipperiness of clay or the very fine almost imperceptible particles of silt. For a floatation test, place a small soil sample onto the top of a jam jar filled with water. Over 24 to 48 hours the particles will sediment with the heavier sand forming the lower layer with clay and silt deposited on top. Organic matter will float on the surface of the water.
Soil floatation test
The Industrial Decarbonisation Challenge (IDC) is funded by UK government through the Industrial Strategy Challenge Fund. One aim is to enable the deployment of low-carbon technology, at scale, by the mid-2020’s . This challenge supports the Industrial Clusters Mission which seeks to establish one net-zero industrial cluster by 2040 and at-least one low-carbon cluster by 2030 . This latest SCI Energy Group blog provides an overview of Phase 1 winners from this challenge and briefly highlights several on-going initiatives across some of the UK’s industrial clusters.
Phase 1 Winners
In April 2020, the winners for the first phase of two IDC competitions were announced. These were the ‘Deployment Competition’ and the ‘Roadmap Competition’; see Figure 1 .
Figure 1 - Winners of Phase 1 Industrial Decarbonisation Challenge Competitions.
Net-Zero Teesside is a carbon capture, utilisation and storage (CCUS) project. One aim is to decarbonise numerous carbon-intensive businesses by as early as 2030. Every year, up to 6 million tonnes of CO2 emissions are expected to be captured. Thiswill be stored in the southern North Sea which has more than 1,000Mt of storage capacity. The project could create 5,500 jobs during construction and could provide up to £450m in annual gross benefit for the Teesside region during the construction phase .
For further information on this project, click here.
Figure 2 – Industrial Skyscape of Teesside Chemical Plants
In 2019, Drax Group, Equinor and National Grid signed a Memorandum of Understanding (MoU) which committed them to work together to explore the opportunities for a zero-carbon cluster in the Humber. As part of this initiative, carbon capture technology is under development at the Drax Power Station’s bioenergy carbon capture and storage (BECCS) pilot. This could be scaled up to create the world’s first carbon negative power-station. This initiative also envisages a hydrogen demonstrator project, at the Drax site, which could be running by the mid-2020s. An outline of the project timeline is shown in Figure 3 .
For further information on this project, click here.
Figure 3 - Overview of Timeline for Net-Zero Humber Project
The HyNet project envisions hydrogen production and CCS technologies. In this project, CO2 will be captured from a hydrogen production plant as well as additional industrial emitters in the region. This will be transported, via pipeline, to the Liverpool Bay gas fields for long-term storage . In the short term, a hydrogen production plant has been proposed to be built on Essar’s Stanlow refinery. The Front-End Engineering Design (FEED) is expected to be completed by March 2021 and the plant could be operational by mid-2024. The CCS infrastructure is expected to follow a similar timeframe .
For further information on the status of this project, click here.
Project Acorn has successfully obtained the first UK CO2 appraisal and storage licence from the Oil and Gas Authority. Like others, this project enlists CCS and hydrogen production. A repurposed pipeline will be utilised to transport industrial CO2 emissions from the Grangemouth industrial cluster to St. Fergus for offshore storage, at rates of 2 million tonnes per year. Furthermore, the hydrogen production plant, to be located at St. Fergus, is expected to blend up to 2% volume hydrogen into the National Transmission System . A final investment decision (FID) for this project is expected in 2021. It has the potential to be operating by 2024 .
For further information on this project, click here.
Figure 4 - Emissions from Petrochemical Plant at Grangemouth
SCI Energy Group October Conference
The chemistry of carbon dioxide and its role in decarbonisation is a key topic of interest for SCI Energy Group. In October, we will be running a conference concerned with this topic. Further details can be found here.
Single plant cells have amazing capacities for regenerating into entire plants. This property is known as ‘totipotency’ discovered in the 1920s. Linking this with increasing understanding of growth control by plant hormones resulted in the development of the sterile, in vitro, culture. Tiny groups of cells, explants, are cut from the rapidly growing tips of shoots in controlled environments and washed in sterilising agents. These are cultured sterile jars containing a layer of agar supplemented with nutrients and hormones.
Green plantlets growing on sterile agar
The process is known as ‘tissue culture’ or micropropagation. As the cells divide and multiply, they are transferred through a series of sterile conditions which encourage root formation.
Roots growing from newly developing plantlets
Ultimately numerous new whole plants are generated. At that point they are removed from sterile conditions and weaned by planting into clean compost in high humidity environments. High humidity is essential as these transplants lack the protective coating of leaf and stem waxes which prevent desiccation. Ultimately when fully weaned the plants are grown under normal nursery conditions into saleable products.
Why bother with this processes which requires expensive facilities and highly skilled staff? A prime advantage is that micropropagated plants have genotypes very closely similar to those of the original parent, essentially they are clones. As a result vast numbers of progeny can be generated from a few parents preserving their characteristics. That is particularly important as a means of bulking-up newly bred varieties of many ornamental and fruit producing plants which otherwise would be reproduced vegetatively from cuttings or by grafting and budding onto rootstocks. Micropropagation is therefore a means for safeguarding the intellectual property of plant breeding companies.
Explants cut from parent plants before culturing can be heat-treated as a means of removing virus infections. The resultant end-products of rooted plants are therefore disease-free or more accurately disease-tested. These plants are usually more vigorous and produce bigger yields of flowers and fruit. Orchids are one of the crops where the impact of micropropagation is most obvious in florists’ shops and supermarkets.
Orchids have benefitted greatly from micropropagation
Large numbers of highly attractive orchids are now readily available. Previously orchids were very expensive and available in sparse numbers.
The world is not perfect and there are disadvantages with micropropagation. Because the progeny are genetically similar they are uniformly susceptible to pests and pathogens. Crops of clonal plants can be and have been rapidly devasted by existing and new strains of insects and diseases to which they have no resistance.
Elderflowers are in full bloom this month, both in hedgerows as well as gardens across the country. Whether they are the wild Sambucus nigra or a cultivated variety with green or black leaves they are all beautiful and useful plants.
The black leaved cultivar growing in the SCIence Garden has pink blooms, whereas the wild species has white flowers. It was purchased as ‘Black Beauty’, but is also sold as ‘Gerda’.
Sambucus nigra f. porphyrophylla ‘Black Beauty’ growing in the SCIence Garden
This cultivar, along with ‘Black Lace’ (Eva) was developed by Ken Tobutt and Jacqui Prevette at the Horticulture Research International research station at East Malling in Kent and released for sale in the horticulture trade in 2000. The leaves stay a dark purple throughout the year and the flowers have a good fragrance.
The shrub will tolerate hard pruning so is useful for smaller spaces and provides a long season of interest. The plant is also a forager’s delight, both in early summer (for the flowers) and in the autumn (for the berries).
Most commonly one may think of elderflower cordial, or perhaps even elderflower champagne, but an excellent alternative to the rose flavoured traditional “Turkish Delight” can be made - https://www.rivercottage.net/recipes/elderflower-delight. I can highly recommend it!
The chemistry of the elderflower aroma is complex. Analyses such as that in the reference below* have identified many different terpene and terpenoid components including nerol oxide, hotrienol and nonanal.
* Olfactory and Quantitative Analysis of Aroma Compounds in Elder Flower (Sambucus nigra L.) Drink Processed from Five Cultivars. Ulla Jørgensen, Merete Hansen, Lars P. Christensen, Karina Jensen, and Karl Kaack. Journal of Agricultural and Food Chemistry 2000 48 (6), 2376-2383. DOI: 10.1021/jf000005f
Some plants such as lettuce require cool conditions for germination (<10 oC), a condition known as thermo-dormancy. This reflects the evolution of the wild parent species in cooler environments and growth cycles limited by higher summer temperatures. Transforming live but dormant seed into new healthy self-sufficient plants requires care and planning. The conditions in which seed is stored before use greatly affect the vigour and quality of plants post-germination. Seed which is stored too long or in unsuitable environments deteriorates resulting in unthrifty seedlings.
Seed is either sown directly into soil or into compost designed especially as an aid for germination. These composts contain carefully balanced nutrient formulae which provide larger proportions of potassium and phosphorus compounds which promote rooting and shoot growth. The amounts of nitrogen needed at and immediately post-germination are limited. Excess nitrogen immediately post-germination will cause over-rapid growth which is susceptible to pest and pathogen damage.
Minor nutrients will also be included in composts which ensures the establishment of efficient metabolic activities free from deficiency disorders. Composts require pH values at ~ 7.0 for the majority of seedlings unless they are of calicifuge (unsuited for calcareous soils) species where lime requirement is limited and the compost pH will be formulated at 6.0. Additionally, the pC will be carefully tuned ensuring correctly balanced ionic content avoiding root burning disorders. Finally, the compost should be water retentive but offering a rooting environment with at least 50 percent of the pore spaces filled with air. Active root respiration is essential while at the same time water is needed as the carrier for nutrient ions.
Seedlings encountering beneficial environments delivering suitable temperatures will germinate into healthy and productive plants.
Some plants such as lettuce require cool conditions for germination (<10 oC), a condition known as thermo-dormancy. This reflects the evolution of the wild parent species in cooler environments and growth cycles limited by higher summer temperatures.
Careful husbandry under protection such as in greenhouses provides plants which can be successfully transplanted into the garden. The soil receiving these should be carefully cultivated, providing an open crumb structure which permits swift and easy rooting into the new environment. It is essential that in the establishment phase plants are free from water stress. Measures which avoid predation from birds such as pigeons may also be required.
Netting or the placing of cotton threads above plants helps as a protection measure. Weeds must be removed otherwise competition will reduce crop growth and encourage pests and diseases, particularly slug browsing. Finally, the gardener will be rewarded for his/her work with a fruitful and enjoyable crop!
Another month starts in the SCIence Garden with no visitors to appreciate the burgeoning growth of fresh new leaves and spring flowers, but that doesn’t mean we should forget about it!
Hopefully in our absence the Laburnum tree in the garden, Laburnum x watereri ‘Vossii’ will be flowering beautifully, its long racemes of golden yellow flowers looking stunning in the spring sunshine!
Laburnum x watereri ‘Vossii’ in the SCIence Garden
This particular cultivar originated in the late 19th century in the Netherlands, selected from the hybrid species which itself is a cross between Laburnum alpinum and L. anagyroides. This hybrid species was named for the Waterers nursery in Knaphill, Surrey and was formally named in a German publication of 1893 (Handbuch der Laubholzkunde, Berlin 3:673 (1893)
The laburnum tree is found very commonly in gardens in the UK, and is noticeable at this time of year for its long chains of golden yellow flowers. However, the beautiful flowers hide a dark side to this plant. The seeds (and indeed all parts) of the tree are poisonous to humans and many animals. They are poisonous due to the presence of a very toxic alkaloid called cytisine (not to be confused with cytosine, a component of DNA). Cytisine has a similar structure to nicotine (another plant natural product), and has similar pharmacological effects. It has been used as a smoking cessation therapy, as has varenicline, which has a structure based on that of cytisine. These molecules are partial agonists at the nicotinic receptor (compared to nicotine which is a full agonist) and reduce the cravings and “pleasurable” effects associated with nicotine.
Cytisine is found in several other plants in the legume family, including Thermopsis lanceolata, which also looks stunning in early summer and Baptisia species, also growing in the SCIence Garden and flowering later in the year.
In 2018 there were 9.6 million deaths from cancer and 33% of these were linked to exposure to tobacco smoke.* Since the link between smoking and lung cancer was established in 1950, the market for smoking cessation therapies has increased enormously. In 2018 it was worth over 18 billion dollars annually worldwide and is projected to increase to 64 billion dollars by 2026.** Staggering! Varenicline, sold under the brand names Champix and Chantix, is one of the most significant smoking cessation therapies apart from nicotine replacement products.
If you see a laburnum tree whilst out on your daily allowed exercise this month, have a thought for its use as a smoking cessation therapy!
* Data from the Cancer Research UK website https://www.cancerresearchuk.org/health-professional/cancer-statistics/worldwide-cancer#heading-Zero accessed May 2020.
Seed is one of Nature’s tiny miracles upon which the human race relies for its food and pleasure.
Each grain contains the genetic information for growth, development, flowering and fruiting for the preponderant plant life living on this planet. And when provided with adequate oxygen, moisture, warmth, light, physical support and nutrients germination will result in a new generation of a species. These vary from tiny short-lived alpines to the monumental redwood trees growing for centuries on the Pacific west coast of America.
Humankind has tamed and selected a few plant species for food and decorative purposes.
Seed head of beetroot, the seeds are in clusters.
Seed of these, especially food plants, is an internationally traded commodity. Strict criteria governed by legal treaties apply for the quality and health of agricultural and many horticultural seeds. This ensures that resultant crops are true to type and capable of producing high grade products as claimed by the companies who sell the seed.
Companies involved in the seed industry place considerable emphasis on ensuring that their products are capable of growing into profitable crops for farmers and growers. Parental seed crops are grown in isolation from farm crops thereby avoiding the potential for genetic cross-contamination. With some very high value seed the parent plants may be grown under protection and pollinated by hand.
Samples of seed are tested under laboratory conditions by qualified seed analysts. Quality tests identify levels of physical contamination, damage which may have resulted in harvesting and cleaning the seed and the proportion of capable of satisfactory germination. There may also be molecular tests which can identify trueness to type. Identifying the healthiness of seed is especially important. The seed coat can carry fungal and bacterial spores which could result in diseased crops. Similarly, some pathogens, including viruses, may be carried internally within seed.
Septoria apicola – seed borne pathogen causing late blight of celery
Pests, especially insects, find seed attractive food sources and may be carried with it. Careful analytical testing will identify the presence of these problems in batches of seed.
The capabilities of seed for producing vigorous plants is particularly important with very high value vegetable and salad crops. Vigour testing is a refined analytical process which tracks the uniformity and speed of germination supplemented with chemical tests determining the robustness of plant cells. Producers rely on the quality, uniformity and maturity rates of crops such as lettuce, green broccoli or cauliflower so they meet the strict delivery schedules set by supermarkets. Financial penalties are imposed for failures in the supply chain.
Biology’s seemingly inert tiny seed grains are essential ingredients of humankind’s existence!
March in the SCIence Garden
Narcissus was the classical Greek name of a beautiful youth who became so entranced with his own reflection that he killed himself and all that was left was a flower – a Narcissus. The word is possibly derived from an ancient Iranian language. But the floral narcissi are not so self-obsessed. As a member of the Amaryllidaceae, a family known for containing biologically active alkaloids, it is no surprise to learn that they contain a potent medicinal agent.
Narcissus (and in particular this cultivar) are an excellent source of galanthamine, a drug more commonly associated with snowdrops (Galanthus spp.). Galanthamine is currently recommended for the treatment of moderate Alzheimer’s disease by the National Institute of Health and Clinical Excellence (NICE) but is very effective in earlier stages of the disease too.
Today, part of the commercial supply of this molecule comes from chemical synthesis, itself an amazing chemical achievement due to the structural complexity of the molecule, and partly from the natural product isolated from different sources across the globe. In China, Lycoris radiata is grown as a crop, in Bulgaria, Leucojum aestivum is farmed and in the UK the humble daffodil, Narcissus ‘Carlton’ is the provider.
Narcissus ‘Carlton’ growing on large scale
Agroceutical Products, was established in 2012 to commercialise the research of Trevor Walker and colleagues who developed a cost effective, reliable and scalable method for producing galanthamine by extraction from Narcissus. They discovered the “Black Mountains Effect” – the increased production of galanthamine in the narcissus when they are grown under stress conditions at 1,200 feet. With support from Innovate UK and other organisations, the process is still being developed. Whilst not a full scale commercial production process just yet, the work is ongoing. As well as providing a supply of the much needed drug, this company may be showing the Welsh farming community how to secure additional income from their land. They continue to look for partners who have suitable land over 1000 ft in elevation.
The estimated global patient population for Alzheimer’s in 2010 was 30 million. It is expected to reach 120 million by 2050. The global market for Alzheimer’s disease drugs for 2019 was US$ 2870 million.
Transferring plants between countries was a profitable source for novel commercial and garden plants until quite recently.
Potato crop: Geoff Dixon
Potatoes and tomatoes are classic examples arriving in Europe from South America during the 16th century. Substantial numbers of new plants fuelled empire expansion founding new industries such as rubber and coffee. One of the earliest functions of European botanic gardens was finding potentially valuable new crops for colonial businesses. At home selecting orchids and other exotics from imported plants brought fame and fortune for head gardeners managing the large 19th century estates such as Chatsworth. Commercially seed merchants selected by eye and feel new and improved vegetables, fruit and flowers.
The rediscovery of Mendel’s laws of inheritance brought systematic science and formalised breeding new crops and garden plants. Analysing the effects of transferring physical, chemical and biological characters identified gene numbers and their functions.
Colour range in Gladioli: Geoff Dixon
As a result, varieties with improved colourfulness, fruitfulness, yield and pest and pathogen tolerance fill seedsmen’s catalogues. Breeding increased food supplies and added colour into the gardens springing up in suburban areas as affluence increased.
Greater plant reliability and uniformity arrived with the discovery of F1 hybrids.
Hybrid Sunflowers: Geoff Dixon
Selected parental lines each with very desirable characters such as fruit colour are in-breed for several generations. Then they are crossed bringing an explosion of vigour, uniformity and reliability (known as heterosis). Saving seed from the hybrid lines does not however, perpetuate these characters; new generations come only from remaking the original cross. That is a major boon for the breeder as competitors cannot pirate their intellectual property.
Knowledge at the molecular level has unravelled still further gene structure and functioning. Tagging or marking specific genes with known properties shortens the breeding cycle adding reliability and accuracy for the breeder. Simplifying the volume of genetic material used in crosses by halving the number of chromosomes involved adds further precision and control (known as haploidisation).
Opportunities for breeding new plants increases many-fold when advantageous genes are transferred between species. Recent developments of gene-editing where tailored enzymes very precisely snip out unwanted characters and insert advantageous ones is now offering huge opportunities as a non-transgenic technology. Breeding science makes possible mitigation of climate change, reducing for example the impact of soil degradation brought about by flooding.
Flood degraded land: Geoff Dixon
Growing in just about the most challenging of locations in the SCIence Garden are a small group of Helleborus niger. They are planted in a very dry and shady location underneath a large tree sized Escallonia and although they struggled to establish when they were first planted (in May 2017) they are now flowering and growing well.
This plant was first featured as a Horticulture Group Medicinal Plant of the Month in December 2011 and as it is now in the SCIence garden I thought a reprise was in order.
Helleborus is a genus of 15 species of evergreen perennials in the buttercup family, Ranunculaceae. In common with most members of the family, the flowers are radially symmetric, bisexual and have numerous stamen.
Helleborus is the Latin name for the lent hellebore, and niger means black – referring in this species to the roots.
This species is native to the Alps and Appenines. Helleborus niger has pure white flowers, with the showy white parts being sepals (the calyx) and the petals (corolla) reduced to nectaries. As with other hellebores, the sepals persist long after the nectaries (petals) have dropped.
All members of the Ranunculaceae contain ranunculin, an unstable glucoside, which when the plant is wounded is enzymatically broken down into glucose and protoanemonin. This unsaturated lactone is toxic to both humans and animals, causing skin irritation and nausea, vomiting, dizziness and worse if ingested.
Protoanemonin dimerises to form anemonin when it comes into contact with air and this is then hydrolysed, with a concomitant ring-opening to give a non-toxic dicarboxylic acid.
Many hellebores have been found to contain hellebrin, a cardiac glycoside. The early chemical literature suggests that this species also contains the substance but later studies did not find it suggesting that either mis-identified or adulterated material was used in the early studies.
It is reported to contain many other specialized metabolites including steroidal saponins.
This plant has long been used in traditional medicine – in European, Ayurvedic and Unani systems and recent research has been aimed at elucidating what constituents are responsible for the medicinal benefit.
Extract of black hellebore is used sometimes in Germany as an adjuvant treatment for some types of tumour.
A recent paper* reports the results of a safety and efficacy investigation. The Helleborus niger extract tested was shown to exhibit neither genotoxic nor haemolytic effects but it was shown to have anti-angiogenetic effects on human umbilical vein endothelial cells (HUVEC), anti-proliferative effects and migration-inhibiting properties on tumour cells thus supporting its use in cancer treatment.
* Felenda, J.E., Turek, C., Mörbt, N. et al. Preclinical evaluation of safety and potential of black hellebore extracts for cancer treatment. BMC Complement Altern Med 19, 105 (2019) doi:10.1186/s12906-019-2517-5
Aldrin, Armstrong and Collins, Apollo 11’s brave astronauts were the first humans with the privilege of viewing Earth from another celestial body. These men uniquely wondered “what makes Earth special?” Certainly, within our Solar System, planet Earth is very special. Its environment has permitted the evolution of a panoply of life.
Green plants containing the pigment, chlorophyll either in the oceans as algae or on land as a multitude of trees, shrubs and herbs harvest energy from sunshine. Using a series of chemical reactions, known as photosynthesis, light energy is harvested and attached onto compounds containing phosphorus.
Captured energy then drives a series of reactions in which atmospheric carbon dioxide and water are combined forming simple sugars while releasing oxygen. These sugars are used further by plants in the manufacture of larger carbohydrates, amino acids and proteins, oils and fats.
The release of oxygen during photosynthesis forms the basis of life’s second vital process, respiration. Almost all plants and animals utilise oxygen in this energy releasing process during which sugars are broken down.
Released energy then drives all subsequent growth, development and reproduction. These body-building processes in plants are reliant on the transfer of the products of photosynthesis from a point of manufacture, the source, to the place of use, a sink.
Leaves and shoots are the principle sources of energy harvesting while flowers and fruits are major sinks with high levels of respiration.
Figure 1: Photosynthesis vs respiration, drawn by James Hadley
Transfer between sources and sinks occurs in a central system of pipes, the vascular system, using water as the carrier. Water is obtained by land plants from the soils in which they grow. Without water there would be no transfer and subsequent growth. Earth’s environment is built around a ‘water-cycle’ supplying the land and oceans with rain or snow and recycles water back into the atmosphere in a sustainable manner.
Early in Earth’s evolution, very primitive marine organisms initiated photosynthetic processes, capturing sunlight’s energy. As a result, in our atmosphere oxygen became a major component. That encouraged the development of the vast array of land plants which utilise rain water as the key element in their transport systems.
Subsequently, plants formed the diets of all animals either by direct consumption as herbivores or at second-hand as carnivores. As a result, evolution produced balanced ecosystems and humanity has inherited what those astronauts saw, “the Green Planet”.
Earth will only retain this status if humanity individually and collectively defeats our biggest challenge – climate change. Burning rain forests in South America, Africa and Arctic tundra will disbalance these ecosystems and quicken climate change.
Controlling when and how vigorously plants flower is a major discovery in horticultural science. Its use has spawned vast industries worldwide supplying flowers and potted plants out-of-season. The control mechanism was uncovered by two American physiologists in the 1920s. Temperate plants inhabit zones where seasonal daylength varies between extending light periods in spring and decreasing ones in autumn.
Those environmental changes result in plants which flower in long-days and those which flower in short-days. ‘Photoperiodism’ was coined as the term describing these events. Extensive subsequent research demonstrated that it is the period of darkness which is crucially important. Short-day plants flower when darkness exceeds a crucial minimum, usually about 12 hours which is typical of autumn. Long-day plants flower when the dark period is shorter than the crucial minimum.
Irises are long day flowers. Image: Geoffery R Dixon
A third group of plants usually coming from tropical zones are day-neutral; flowering is unaffected by day-length. Long-day plants include clover, hollyhock, iris, lettuce, spinach and radish. Gardeners will be familiar with the way lettuce and radish “bolt” in early summer. Short-day plants include: chrysanthemum, goldenrod, poinsettia, soybean and many annual weed species. Day-neutral types include peas, runner and green beans, sweet corn (maize) and sunflower.
Immense research efforts identified a plant pigment, phytochrome as the trigger molecule. This exists in two states, active and inactive and they are converted by receiving red or far-red wavelengths of light.
Sunflowers are day neutral flowers. Image: Geoffery R Dixon
In short-day plants, for example, the active form suppresses flowering but decays into the inactive form with increasing periods of darkness. But a brief flash of light restores the active form and stops flowering. That knowledge underpins businesses supplying cut-flowered chrysanthemums and potted-plants and supplies of poinsettias for Christmas markets. Identifying precise demands of individual cultivars of these crops means that growers can schedule production volumes gearing very precisely for peak markets.
Providing the appropriate photoperiods requires very substantial capital investment. Consequently, there has been a century-long quest for the ‘Holy Grail of Flowering’, a molecule which when sprayed onto crops initiates the flowering process.
Chrysanthemums are short day flowers. Image: Geoffery R Dixon
In 2006 the hormone, florigen, was finally identified and characterised. Biochemists and molecular biologists are now working furiously looking for pathways by which it can be used effectively and provide more efficient flower production in a wider range of species.
2019 has been declared by UNESCO as the Year of the Periodic Table. To celebrate, we are releasing a series of blogs about our favourite elements and their importance to the chemical industry. Today’s blog is about the various uses of nitrogen.
Nitrogen – an imperative part of DNA
The polymer that makes up the genetic code of is a sequence of nitrogen bases laid out on a backbone of sugar and phosphate molecules and blended into a double helix.
The nitrogen bases are translated into proteins and enzymes which regulate most our system’s biochemical reactions.
RDX is a nitrogen explosive. This means its explosive properties are primarily caused by the presence of many nitrogen–nitrogen bonds, which are extremely unstable, especially as nitrogen atoms want to come together to produce nitrogen gas due to the triple bond.
Ultimately, the more nitrogen–nitrogen bonds a molecule has, the more explosive it is. RDX is normally combined with other chemicals to make it less sensitive or less likely to explode.
One of the most powerful explosive chemicals is PETN, containing nitro groups and nitroglycerin in dynamite. Despite its powerful explosions, the chemical rarely will detonate alone. PETN was used frequently during World War II, whereby PETN was used to create exploding bridgewire detonators, using electric currents for detonations.
Among the least stable explosives is aziroazide azide, with 14 unstable nitrogen bonds, most of them bonded into unstable nitrogen–nitrogen bonds. Touching or handling this chemical can cause it to detonate, making it one of the most dangerous non-nuclear chemicals.
Nitrogen and plants
Nitrogen plays a significant role for plants to keep healthy. Plants usually contain 3-4% nitrogen in their above-ground tissues. Nitrogen is a major component of chlorophyll which plants use to capture sunlight energy to produce sugars, and a major component of amino acids, which are the building blocks of life.
Overall, nitrogen is a significant component to DNA, a key nutrient to plants, and the uses of nitrogen in everyday life span across various chemical industries including the production of fertilisers and explosives.
Tracking pollen can help scientists better understand pollinator behaviour.
Pollination and pollination services are key for productive farming. In fact, many farms actively manage pollination, bringing in bees or planting effective field margins.
Fluorescent quantum dots on a bee show the distribution of the marked pollen. Image: Corneile Minnaar
Despite the importance of pollination, for many years research has been limited as there is no efficient way to study pollen distribution or track individual pollen grains.
Scientists at the university have developed an innovative method to track pollen using quantum dots.
Tracking pollen with quantum dots. Source: Stellenbosch University
Quantum dots are nanocrystals that emit bright fluorescent light when exposed to UV light. The quantum dots were equipped with lipophilic (fat-loving) ligands to allow them to stick to the fatty outer layer of pollen grains. The fluorescent colour of the quantum dots can then be used to track any pollen they have adhered to.
At the SCI HQ in Belgrave Square, London, we have curated a beautiful garden filled with plants that represent our technical and regional interest groups. Each of these plants has a scientific significance. On World Wildlife Day, we take a look at how some of our plants are doing in March.
Cyclamen hederifolium - the ivy-leaved cyclamen. Image: SCI
Cyclamen hederifolium is included in the SCIence garden to represent the horticulture group. This beautiful pink flower has a mutualistic relationship with ants, in which the ants carry the seeds far away, ensuring no competition between young plants and the original.
Dichroa febrifuga - a hydrangea with anti-malarial properties. Image: SCI
Not yet flowering, D. febrifuga is a traditional Chinese herbal medicine that is used for treatment of malaria. It contains the alkaloids febrifugine and isofebrifugine which are thought to be responsible for it’s anti-malaria properties.
Fatsia japonica - the paper plant. Image: SCI
F. japonica is also known as the glossy-leaved paper plant and is native to Japan, southern Korea and Taiwan. This plant represents our materials group.
Rosmarinus officinalis aka rosemary - a herb with many uses from culinary to chemical. Image: SCI
Rosemary is a common herb that originates in the Mediterranean. It has many uses, including as a herb for cooking and fragrance. One of it’s more scientific uses is as a supply of lucrative useful phytochemicals such as camphor and rosemarinic acid.
Prunus mume ‘Beni-chidori’ - a Chinese ornamental flower. Image: SCI
The Prunus mume tree is a beautiful ornamental tree that has significance in East Asian culture. It has a wide variety of applications, from medicinal to beverages, and can been seen in many pieces of art. This plant is in the SCIence garden to represent our Chinese Group UK.
Pieris japonica - the Dwarf-Lilly-of-the-Valley-Shrub. Image: SCI
The Pieris japonica ree has Asian origins, and represents our Agrisciences group. The leaves contain diterpenoids which inhibit the activity of feeding pests, such as insects.
Pulmonaria ‘Blue Ensign’ - lungwort. Image: SCI
The lungwort has been used since the Middle Ages as a medicinal herb to treat chest or lung diseases. It is an example of the use of the doctrine of signatures - where doctors believed that if a plant resembled a body, it could be used to treat illness in that body part.
Euphorbia amygdaloides - the wood spruce. Image:SCI
Euphorbia amygdaloides is planted to represent our Materials Chemistry group. It has a waxy feel, and has potential to be used as an alternative to latex.
Erysimum ‘Bowles Mauve’ - a flowering plant in the cabbage family. Image: SCI
The Erysimum ‘Bowles Mauve’ is a member of the cabbage family (Brassicaceae). This plant was used to make the first synthetic dye, Mauvine, when SCI founding member William Perkin discovered in in 1858.
Plants generate their energy from sunlight via photosynthesis, however many crops have a photosynthetic glitch, which costs them a significant amount of energy that could be used for growth. This glitch has been shortened using careful engineering by researchers from the University of Illinois and US Department of Agriculture’s Agricultural Research Service, to generate plants with a 40% increase in productivity in real-world conditions.
Tobacco seedlings. Image: Claire Benjamin/RIPE project
During photosynthesis, carbon dioxide (CO2) and water are converted into sugars by the enzyme Rubisco, which is fuelled by energy from sunlight. Rubisco is the planets most abundant protein, but its efficiency has resulted in an oxygen-rich atmosphere, and it cannot reliably distinguish between CO2 and oxygen (O2). Approximately 20% of the time, O2 is grabbed by Rubisco instead of CO2, and then converted into a compound which is toxic to plants. This compound can be recycled through a process known as photorespiration.
The research team. Image: Claire Benjamin/RIPE project
In this study, alternate routes for the process have been engineered, allowing the plant to save resources better utilised for growth. The scientists generated three alternate routes using different sets of promoters and genes, which were then stress tested in 1,700 individual plants to find the best performers.
Combatting malnutrition in all its forms – overweight and obesity as well as undernutrition and micronutrient deficiencies – is a global problem.
The European Academies Science Advisory Council (EASAC) recently published a report calling for urgent action on food and nutrition security: this action will need to include consideration of the options for changing European diets to mitigate climate change, conferring co-benefits for health.
The European Commission estimates 51.6% of the EU’s population is overweight. Image: Tony Alter/Flickr
EASAC brings together EU member states’ national science academies with the aim of offering evidence-based advice to European policy makers. EASAC provides a means for the collective voice of European science to be heard and its recent report is part of a global project led by the InterAcademy Partnership (IAP).
The analysis and recommendations for Europe are accompanied by parallel activities focusing on Africa, Asia and the Americas. The IAP report will be published later in 2018.
EASAC recommendations will incorporate global challenges and needs, not just those in Europe. Image: Pixabay
In the EASAC report we emphasise that research and innovation are central to finding solutions. We recommend being more ambitious in identifying and using scientific opportunities: How can the current evidence base shape understanding of both supply- and demand-side challenges? And how should the research agenda be defined, including basic research, to fill knowledge gaps?
Climate change will have negative impacts on food systems, necessitating the introduction of climate-smart agriculture such as the adoption of plant breeding innovations to cope with drought.
Climate-Smart Agriculture in Action. Video: Farming First
Agriculture and current diets also contribute significantly to climate change. Mitigating this contribution depends on land-sparing and agronomic management practices together with efforts to influence consumer behaviours associated with excessive greenhouse gas emissions from agriculture, including the over-consumption of calories and meat.
Among the core findings in our report is that food consumption will need to change to improve consumer health. It is important to explore individual responsiveness to nutrition and the links to health, and to consider the particular needs of vulnerable groups.
High meat production has been linked to increasing carbon emissions. Image: Pixabay
As part of the changes to food consumption patterns, a decrease in the consumption of animal protein could be important for both health and the environment but, globally, more research is needed to clarify these relationships and to measure sustainability related to consumption of healthy diets. We also call for policy makers to introduce incentives for affordable nutrition.
Agriculture has significant impacts on the environment. We call for the revamp of the Common Agricultural Policy to focus on innovation rather than subsidies, in order to play a key role in European competitiveness and the bioeconomy.
Alternatives to traditional forms of animal protein include food from the oceans, laboratory-grown meat and insects. Research is needed to understand and inform consumer attitudes to innovative food and diets.
Also, research objectives for the next generation of biofuels should include examining the potential of cellulosic raw materials. Further ahead, energy research must continue to explore how to engineer systems with improved photosynthesis.
Biofuels are derived from common crops, including wheat, corn and sugar. Image: Public Domain Pictures
Europe should not stall on opportunities for innovation coming within range. Breakthroughs in genome editing and other genetic research are crucial to the future of agriculture. European policy makers must capitalise on these scientific advances.
For improved plant and animal breeding, it is important to protect and characterise wild gene pools and to continue sequencing and functional assessment to unveil the potential of genetic resources. Precision agriculture offers many opportunities to improve productivity with reduced environmental impact. Large data sets are vital to support innovation and prepare for risk and uncertainty.
Open-source automated precision farming | Rory Aronson | TEDxUCLA. Video: TEDx Talks
Underpinning all our recommendations is the recognition that research and innovation must be better integrated, across disciplines and the public and private sectors, in order to better understand the interfaces between health, nutrition, food and other ecosystem services.
EASAC emphasises that efforts to increase food systems’ efficiency should not focus on increasing agricultural productivity by ignoring environmental costs.
On average, 10% of all crop production is lost annually to drought and extreme heat, with the situation getting worse year on year. Heat stress happens over short-time periods, but drought happens over longer timescales and is linked to drier soils. Maize and wheat are especially hard hit, with yields falling by up to 50% if drought hits.
On the High Plains, the largest US wheat-growing region, drought is a possibility every season. ‘Drought stress can be a key concern, especially in dry lands, but even in irrigated areas we can’t expect the same levels of water in future and farmers face restrictions,’ says Chris Souder at Monsanto.
So, this is not simply a developing world problem. Pedram Rowhani, University of Sussex, UK, found cereals in more technically developed agricultural systems of North America, Europe, and Australia suffered most from droughts. Yield losses due to drought were 19.9% in the US compared to almost no effect in Latin America.
Crop breeders in the past paid a great deal of attention to yield, but not enough to resilience to extreme events such as drought, Rowhani says, but this is changing. Growers increasingly want built-in drought resilience and plant scientists are looking for novel solutions. New, unconventional approaches based on novel insights from basic science might be necessary.
Hundreds of genes and proteins are involved in the complex trait of drought resistance. Plants avoid drought stress by shortening their life cycle with accelerated flowering, or cut down water loss by closing leaf pores called stomata. One approach by breeders is to target specific traits by crossing individual plants that perform best under drought conditions.
Stomata are found of the underside of leaves and are used for gas exchange. Image: Pixabay
‘About 97% of plant water loss occurs through the stomata. If you want to regulate the amount of water a plant uses, regulate the stomata,’ says Julie Gray, University of Sheffield, UK. Gray has been genetically tweaking wheat, barley, and rice plants so they have fewer of these pores.
She believes rising CO2 levels in the atmosphere means that they do not suffer from less carbon dioxide from opening their stomata. ‘CO2 levels have gone up 40% over the last 200 years. It’s quite possible they are producing more stomata than they need,’ says Gray.
Power plant in Tihange, Belgium. CO2emissions continue to increase. Image: Hullie@Wikimedia Commons
Gray reports that plants grown at 450ppm CO2 with reduced stomatal density, but increased stomatal size, had larger biomass and increased growth tolerance when water was limited. ‘Plants can operate with perhaps half as many stomata before you see significant effects on photosynthesis, so you can definitely reduce water loss this way,’ says Gray.
Root of the issue
At the other end of the plant plumbing system are roots. Susannah Tringe, Joint Genome Institute, UK, is seeking microbes that can gift stress-tolerance to their plant hosts. ‘The microbes associated with plants are likely to be just as important for plant growth and health as the microbiome of humans,’ says Tringe.
Though a lot of work has focused on finding the ‘magic microbe,’ Tringe believes whole communities will be necessary in real field conditions, whereas a single strain could be out-muscled by competitors.
Regular bouts of drought are leading to famine in developing countries. Video: Food and Agriculture Organization of the United Nations
Sugar and drought
‘Drought is probably the most widespread abiotic stress that limits food production worldwide. There is always need to improve drought tolerance,’ says Matthew Paul, Rothamsted Research Institute, UK.
‘Sucrose is produced in photosynthesis,’ Paul explains. ‘During drought conditions, plants will withhold sucrose from the grain, as a survival mechanism’. This can terminate reproductive structures and abort seed formation, even if drought is short-lived, greatly compromising yield.
A plant scientist studying rice plants. Image: IRRI Photos@Flickr
Rothamsted researchers have looked at modifying plants so sugar keeps flowing. ‘If you can get more sugar going to where you want it […] then this could improve yields and yield resilience,’ enthuses Paul. Field studies show that GM maize improved yields from 31 to 123% under severe drought, when compared with non-transgenic maize plants.