Category: seeds

Sowing Victoria

Posted on by andy.winfield

By Nicola Temple

A photo taken a couple of years ago – I
have a grasp on my son as he leans
over into the tropical pool to get a
good look. Victoria cruziana is in flower
as is the lotus above us.
Photo credit: Shelby Temple

For me, one of the highlights at the University of Bristol Botanic Garden is the giant waterlily (Victoria cruziana) that lives in the pond in the tropical glass house. Its enormous leaves, which can reach 2 metres in diameter, are studded with spines on the underside and always provide ample wow factor for visiting children (my own included).  

The plant is found in slow moving waterways in Brazil, Argentina, Paraguay and Bolivia – in places such as the Pantanal. Its pollination story is an interesting one in that it is pollinated by a beetle (Cyclocephata castaneal). Its white flowers give off a strong scent that attracts the beetles in the evening. The flower then closes around the beetles, trapping them in the flower overnight. The flower produces heat (thermogenesis), raising the temperature as much as 9oC above the ambient temperature outside, which means the beetles can maintain a high level of activity without using as much energy. It’s a thermal reward and the plant benefits as the active beetles will pollinate the flower. The pollinated flower opens the next evening, revealing a new light pink colouration to its petals. The beetles flee the flower and make their way to the next unpollinated flower.

Of course, this species of beetle isn’t found in the Botanic Garden, which makes pollination a bit more challenging. However, there are other insects in the Garden that have filled this niche and the plants have set seed over the last few years. However, this is the first year that staff at the Botanic Garden have tried to sow this seed and, so far, things are going well!
The seeds of Victoria cruziana are kept wet.
Photo credit: Andy Winfield

Replicating the natural environment

In its natural environment, the seeds from Victoria cruziana would be buried in the sediments, stirred up perhaps by grazing capybara and swirling river currents. It wouldn’t be until the high water levels following the rainy season had receded that the water temperature and the amount of light penetrating to the sediments beneath would be sufficient to prompt germination.

In the Botanic Garden, botanical horticulturist, Andy Winfield, first primed the seeds by scratching the tough seed coat with secateurs. The seeds were then sown into topsoil and covered with a layer of horticultural grit. The pots with the sown seeds were then placed in a container of water to a level about 10 cm depth above the seed. This replicates the approximate water depth in the natural environment. The water is heated to a temperature of between 30oC and 32oC; this is critical to start the germination process.

Andy scores the seeds with secateurs
before sowing.
Photo credit: Nicola Rathbone

Victoria cruziana grows around the edges of water bodies and in wetland areas where there is no forest canopy. In order to replicate the amount of daily sun it would be receiving in the tropics and sub-tropics, grow lights on a 12h on/12h off cycle were hung above the pots. Then the whole contraption was covered in plastic film to reduce evaporation and maintain humidity.

Andy had read that germination time is generally about 2-3 weeks in this type of scenario, but within a few days he noticed that the seeds were starting to send out roots and when I visited a week after sowing, the hypocotyledonous stems were clearly emerging from the seeds and shooting upwards toward the surface of the water. 

Preparing to plant Victoria out

At the moment, the water temperature in the pool in the tropical glasshouse is only about 14oC, far too chilly for Victoria. In the coming weeks, however, these plants are

likely to grow quite quickly. Andy and the rest of the team at the Garden will pot them on several

times, gradually reducing their water temperature. At the same time, Bristol temperatures will be increasing and the tropical glasshouse will start getting warmer, as will the pool. By the time the Victoria plants have a few decent leaves, the temperatures between the tropical pool and the plants will have become similar enough that Victoria can be put into the planters in the pond.

The annual light intensity here in Bristol is considerably less than Victoria cruziana would receive in South America. However, the long summer days here mean that during those months more solar radiation is received here in a single day than in tropical South America. This helps Victoria cruziana flourish in the Botanic Garden tropical pool over the summer and it will be worth a visit to see it in flower. See the series of photos below taken the day the seeds were sown.

Andy prepares the loamy mix for sowing.
Photo credit: Nicola Rathbone

The seeds are sown into a loamy mix.
Photo credit: Nicola Rathbone

The soil is covered with a horticultural grit.
Photo credit: Nicola Rathbone

The seeds are sown and are ready for immersion
in a nice warm bath.
Photo credit: Andy Winfield
The pots immersed in the warm bath.
Photo credit: Nicola Temple
Only one week after sowing, the embryonic stem
has emerged and is stretching for the surface.
Photo credit: Nicola Temple

Sources:

Seymour, R.S. and Matthews, P.G.D. 2006. The role of thermogenesis in the pollination biology of the Amazon waterlily 
     Victoria amazonica. Annals of Botany 98(6): 1129-35.

The Svalbard Global Seed Vault: a safe haven for seed

Posted on by andy.winfield

By Helen Roberts

Svalbard is a group of Norwegian islands located in the high Arctic and only 1,300 km from the North Pole. It is breathtakingly beautiful. The landscape is stark, unforgiving and wholly memorable. I visited these islands more than 16 years ago as part of a 6-week science expedition – I was part of a botanical group looking at the exceptionally low-growing Arctic Willow. 
Memories of that place are still strong today. Its beauty and sense of isolation is unique. The humdrum of everyday life is simply stripped away here. You are left with the landscape, weather and incredible flora and fauna. Although life became simple, the vastness of the place was exhilarating and I felt totally and utterly free. 
The stark landscape of Svalbard
Photo credit: Paul Williams [via Flickr CC BY-NC 2.0]

The Arctic is an ideal refuge for seeds

Within this unforgiving landscape, nestled deep within a mountainside, is a seed bank of global importance. It holds 12,000 years of agricultural history and contains the world’s largest collection of crop diversity. 
The Global Seed Vault is the brainchild of renowned scientist Cary Fowler, a former executive director of the Global Crop Diversity Trust. It started as a simple idea back in the 1980s in the spirit of global collaboration, and finally came to fruition in 2008 when the building was completed. However, building the collection within is ongoing.
Svalbard Global Seed Vault
Photo credit: Amber Case [via Flickr CC BY-NC 2.0]
The facility currently holds about 850,000 different varieties of seed and acts as the back up for seed banks across the globe. This is a collection that is vastly important for food security and the safeguarding of crop diversity. Those 850,000 packets of seed represent more than 5,000 species and nearly half of the world’s most important food crops, from cereal and rice to unique varieties of legumes. The seed deposits come from over 60 different institutions and represent nearly every country in the world. 
The chosen location of the global seed vault is an interesting story. It needed to be located somewhere safe from both potential natural disasters and human conflict. Svalbard itself is a safe place to store seed both in terms of physical and social factors. Svalbard’s remoteness ensures an extra layer of security, while its geological stability and location, 130m above sea level, means the vault would be safe even in the worst-case scenario of sea-level rise. The storage facility is buried 150m deep into the side of a mountain where there is no radiation and where humidity levels remain low. The mountain also acts as a natural freezer, reducing the facility’s reliance on mechanical refrigeration. The local infrastructure on Svalbard is also very good despite its remoteness – Svalbard is serviced by regular scheduled flights.
Svalbard itself is also politically very stable and military activity is prohibited in the region under the terms of the Treaty of Svalbard of 1920. The local government is highly competent and Norway has long been recognised as a key country in the international efforts to conserve Plant Genetic Resources for Food and Agriculture (PGRFA). 

Building and running the vault

The Global Seed Vault is built to store up to 4.5 million different varieties of seed. Constructed to be highly functional, the rectangular edifice emerging from the side of the mountain is stark but architecturally beautiful. The structure is energy efficient; insulated by the mountainside, it maintains an ambient temperature of -7°C and therefore only needs a further temperature drop to -18°C to reach the recognised standard temperature for the storage of viable seed. 
The vault was built and paid for by the Norwegian government to provide a service to the world community. The structure took 12 months to build and cost NOK 50 million (approximately £4.6 million). The facility runs as a partnership between the Government of Norway, the Nordic Genetic Resource Centre (NordGen) and the Global Crop Diversity Trust. Operations regarding the vault are administered and controlled by an international advisory council of experts representing the Food and Agriculture Organization of the United Nations (FAO), national gene banks, the Consultative Group on Agricultural Research (CGIAR) and the Governing Body of the International Treaty on Plant Genetic Resources for Food and Agriculture (ITPGRFA). 

Inside the building

Some people are lucky enough to visit the seed vault on the rare occasions that you can gain access inside. I had to see the interior of the facility via a virtual tour. 
The front entrance is understated, although to gain access you have to go through half a dozen locked doors, each requiring a different key. Although, security appears minimal, it’s not. The facility is under constant surveillance by Staatsbygg, the government of Norway’s property manager and developer;  security cameras and sensors are located throughout the building. There is some natural security, of course, as the roaming polar bears outside outnumber the human population of Svalbard. 
From the entrance lobby, a 150m long tunnel extends into the mountain before reaching the three main storage chambers. At the moment, only one storage chamber is in use, in time the others will be filled as more seed varieties are deposited. 
Seed is only deposited three times a year and this is the only time when the vault is opened. 

Making a deposit

The metal shelves inside the Global Seed Vault.
Photo credit: Dag Terje Filip Endresen
[via Flickr CC BY-NC 2.0]
On arrival to Svalbard, seed lots are x-rayed and taken to the vault by NordGen staff members. The seed boxes containing the seed, which have been carefully placed in 3-ply aluminium packages, are then wheeled by trolley to the main storage chamber within the vault. Each package will contain on average 500 seeds. 
The seed lots are placed on simple metal shelving and are assigned bar codes to allow easy retrieval. They are catalogued using an information system called the Seed Portal of The Svalbard Seed Vault. This allows depositors to submit seed inventories and the general public to look at basic information about the seed that is stored within. Storage is free to depositors and they control access to the deposits. It is an International Black Box system, which ensures that only the depositor can access the raw seed and open the boxes. 

The most recent seed deposits

Last year, the first tree seeds were deposited from Norway and Finland. In February, pine and spruce seed was taken to the vault for storage from the Norwegian Forest Seed Center and the Finnish gene reserves forests of Lappträsk and Puolango, and Filpula and Lovisa. This deposit provides a back-up in the event that global climate change, forest management techniques and other factors, such as pests and disease begin to compromise the genetic diversity of these forests. It is a method of conserving the existing genetic resources and enabling long-term monitoring of the genetic variation within these forests, including any changes that occur because of tree breeding. This long-term tree seed project involves the countries of Finland, Denmark, Sweden, Iceland and Norway. 
The last deposit of seed was on 26th May 2016, with deposits from Germany, Thailand, New Zealand and the World Vegetable Center in Taiwan. Germany placed over 6,000 accessions into the vault of a number of different crop varieties, New Zealand deposited a number of varieties of sheep food including rye grass and white clover, Thailand deposited some 20 samples of very special chilli peppers and the World Vegetable Center deposited 1,200 seed lots from a number of different nations. 

Our agricultural future

The importance of this seed vault is apparent; it ensures the survival of the world’s most important crop species. Some seed varieties within the depths of this safe haven can survive for up to 4,000 years. In terms of food security, that is long term planning for human agriculture. 

Helen Roberts is a trained landscape architect with a background in plant sciences. She is a probationary member of the Garden Media Guild and a regular contributor to the University of Bristol Botanic Garden blog.


References:

Doomsday Vault Opened for Syrian Seeds: 
What is NordGen?:
Croptrust: 
Forest seed destined for Svalbard:
Forest tree seeds arrive at Svalbard’s ‘Doomsday vault’:
Arctic seed vault ‘key to future global crops’:
Storing the World’s Seeds in a Frozen Mountainside:
From sheep food to chili peppers – seed deposit at Arctic Vault takes the world one step closer to future food security: 
In the vault: David Osit:
Svaalbard Global Seed Vault:

Seed sowing at the Botanic Garden

Posted on by andy.winfield

By Helen Roberts

Last month I met up with Penny Harms, Glasshouse Co-ordinator at the University of Bristol Botanic Garden to explore the many different plants they grow from seed. At the end of May the garden staff were nearing the end of a mammoth seed sowing frenzy in preparation for the summer ahead, but Penny explained that seed is continuously sown throughout the year depending on a particular plant’s germination requirements. 
We entered the glasshouses via the potting house, which contains a whole range of pots, growing media and tools for propagation. There are different shaped tampers for firming down compost, and numerous dibbers and widgers to gently prick out seedlings. The growing substrate typically used for most seed germinated at the Botanic Garden is a neutral peat-free compost composed mainly of composted bark, coir and composted green material. 
Penny explained the finer details of the growing media used, “This compost can be altered by sieving out larger chunks for those seeds that require a finer grade tilth, such as poppy species. Fine and medium grades can be produced depending on the particular size of the sieve pores with perlite often added to help with drainage and aeration.”

Some seeds need constant warmer temperatures

Seed sowing occurs in a number of places within the gardens. Some seed needs a dose of warmth to get germination underway and are sown in propagators in the glasshouses to ensure a stable warm temperature of about 22°C. Others can be directly sown into prepared soil and include many of the ballast seed garden species like Calendula officinalis and Amaranthus caudatus, which form a display in the gardens. Those species destined for the grain barge are grown under glass and have recently been ferried across to the barge and planted. I spied seedlings destined to make the watery journey including Avena sativa (oats) and Eruca sativa (rocket). 
Some of the Amaranthus caudatus Helen has grown from seed
at home. Photo credit: Helen Roberts.
Back in the warmth of the propagation glasshouses, Penny pointed to a number of seedlings planted at the start of April including the beautiful but very poisonous half-hardy annual Ricinus communis var. gibsonii, otherwise known as the castor oil plant. This species is grown for its dark red metallic foliage and is planted out in the hot border once all risk of frost is past. A dark purple bronze variety of this species, equally as lovely, is ‘New Zealand Purple’. 
Penny explained how to grow Ricinus communis, “The species is easy to germinate from seed, but does require a temperature of 20-25°C, so it is best grown in a propagator case in a cool greenhouse where the temperature can be kept stable. Once big enough, it is carefully pricked out and hardened off to then be planted out in June.”
Growing steadily under cover of glass are a number of seedlings destined for the hot border that act as effective border fillers. They include the lovely canary creeper, Tropaeolum peregrinum, a half-hardy annual climber with pale green stems, leaves and yellow flowers, and Tropaeolum majus ‘Black Velvet’, another half-hardy annual with beautiful almost black flowers. Other climbers sown in the glasshouses are the common but wonderfully scented varieties of Lathyrus odoratus (sweet peas). The sunny yellow flowers of Tithonia rotundifolia ‘Yellow Torch’ and Helianthus ‘Mongolian Giant’ currently growing in the glasshouses are also useful border fillers. The latter species is a giant that grows up to four metres high, making it a favourite amongst children. More delicate looking blooms also need the warmth of the glasshouses for germination, such as Digitalis lanata (Woolley Foxglove), which has woolly spikes of fawn coloured flowers with a pearlized lower lip. 

Some seed is worth the wait

Some seed germinates very quickly if conditions are right – sometimes within a week – but other seed can be extremely difficult and requires a great deal of molly-coddling in order to get germination success. Penny carefully pointed to a seedling of Cardiocrinum giganteum var. yunnanense, the Giant Yunnan Lily, which as an adult is a beast of a plant and can grow up to 2.5 metres with huge fragrant nodding creamy inflorescences. This species is normally propagated from either seed or by bulbs and can take as long as 4 to 5 years before it flowers. It is a monocarpic species that will die after it flowers leaving offsets, which will then become subsequent plants. This is certainly a species for a patient gardener; it takes a long time to flower but it also takes a considerable time to germinate as Penny emphasised.
Blooms of the Cardiocrinum giganteum var yunnanense
– the Giant Yunnan Lily.
Photo credit: Col Ford and Natasha de Vere
[via Flicr CC licence 2.0]
“This species can be tricky to germinate,” explained Penny, “This one has taken over a year to germinate so it is quite special.”
This is a species that appeals partly due to the fantastic inflorescences, but it has freaky (and rather scary) looking seedpods that resemble vegetative heads with fangs. In my opinion, the lengthy germination and time to flowering is worth the wait. 
Tropical and subtropical plants that only survive as mature specimens in the glasshouses can be even trickier to propagate by seed. The seed from Passiflora, a large genus of mostly vines needs to be sown quickly when fresh as dried seed takes much longer to germinate. The subtropical vines of the Aristolochia species, aptly named Dutchman’s pipe, require similar treatment. Species grown at the gardens are A. labiata and A. trilobata, and have beautiful ornate blooms of about 15cm. A. labiata flowers resemble the mottling and coloration of a rooster’s comb. Although tropical and sub tropical species can be a bit trickier to grow up from seed, most species can be sown throughout the year. 
Some species do not need the cosseting of warmth and will happily germinate outside although some seedlings, like borecole (kale), are protected with wire mesh to prevent bird damage particularly from pigeons. Species that have germinated and are growing happily outside at the Garden include the mixed colours of Salvia viridus, more commonly known as the Clary Sage. This produces small spires of lovely flowering bracts loved by pollinators. These are intended for the Mediterranean beds along with the tall spires of Echium italicum, the Pale Bugloss, a beautiful pyramidal plant belonging to the Borage family and Viola arborescens, a pretty violet with large lavender coloured flowers. 
Other plants need to be sown at different times of the year and some species have enough flexibility in this that you can sow depending on when you want a plant to flower in the subsequent year. For most gardeners, autumn and spring sowing are the busy sowing months. At the Botanic Garden, for example the open faced flowers of Papaver somniferum, (Opium Poppy), are sown in the autumn.
“These poppies are treated differently to other poppy species,” said Penny, “in that they have been sown in September and will be good strong plants by the time they are planted out the following year, producing flowers earlier than if seed had been sown in the spring.”

Helen Roberts is a trained landscape architect with a background in plant sciences. She is a probationary member of the Garden Media Guild and a regular contributor to the University of Bristol Botanic Garden blog.