…Paula ventures to take you on a plant adventure…

Life signs

For the lack of activity, it might seem that I’ve abandoned my venture… let’s just say that I did lose some of my zeal due to very busy summer months. But, I’m back with renewed passion to share some of my plant-based stories.

Perhaps it would be best to start at the beginning of the summer and progress towards today. It means I need to tell you first of the conference I attended at the end of June in Prague, Czech Republic (the featured photo indicates the beauty of the city, which I visited for the first time). This was the Plant Biology Europe conference organised by EPSO (European Plant Science Organisation) and FESPB (The Federation of European Societies of Plant Biology) and it attracted around 800 participants. In the Macronutrient Section I had (in co-authorship with Philip J. White) a presentation entitled “The importance of cell-type-specific distributions of mineral elements for plant nutrition” with the following abstract:

Plants require seventeen mineral elements and five mineral elements are considered beneficial [1]. Other elements are taken up by plants, when they are phytoavailable in soils. Our knowledge of the distribution of mineral elements between organs (e.g. roots, shoots, leaves, flowers, seeds) has increased considerably over the last century. In addition, we are beginning to discover the distribution of mineral elements between specific cell-types within an organ. It is evident that the concentration of a particular mineral element can differ by an order of magnitude between cell types within an organ. This could be associated with the site of delivery of these mineral elements to the organ, sites of complexation or metabolism of the mineral element, or cell-type-specific uptake, efflux or sequestration processes [2]. Cell-type specific distributions of mineral elements have been documented in leaves of numerous plant species including plants that hyperaccumulate mineral elements [2,3]. However, a comprehensive overview of the cell-type specific distributions of essential, beneficial and toxic elements in plants remains to be undertaken. This talk will attempt to integrate information on cell-type specific distributions of mineral elements in different plant organs and discuss it in the context of the mineral nutrition of higher plants.

This photo was taken just after the talk and I’m in company of a PhD student Patrick Hayes, who works on localisation of mineral elements in plants as well.

Patty and I just after our talks on phosphorus and calcium localisation in plants.

Unfortunately, I cannot share my presentation as it includes too much unpublished data, but I can share few representative slides which show a co-localisation of phosphorus (P) in red, calcium (Ca) in green and potassium (K), magnesium (Mg) and sulphur (S) in leaf cross-sections of different plant species. I mostly focused on the exclusion of P and Ca in different plant species, which prevents the formation of calcium phosphate precipitates.





The conference was wonderful, especially as I also got to meet some of my former colleagues. Particularly I want to mention Prof. Charlotte Poschenrieder and Prof. Juan Barceló (from the Autonomous University of Barcelona,) with whom I spent 3 months in 2006. Also this was a great opportunity to meet with an Erasmus Student I worked with in the lab in Bayreuth, Martina Benáková, who, as a local, gave me an unforgettable night tour of the town. Also I met with some Slovenian researchers and I was updated with the current scientific situation in Slovenia, where, hopefully, I’ll find a job next year when we return to Slovenia.


[1] Conn S, Gillham M (2010) Comparative physiology of elemental distributions in plants. Annals of Botany 105, 1081–1102.

[2] White PJ, Brown PH (2010) Plant nutrition for sustainable development and global health. Annals of Botany 105, 1073–1080.

[3] White PJ, Pongrac P (2016) Heavy metal toxicity in plants. In: Plant Stress Physiology. Shabala S (Ed.) CABI Publishing; in press


Plants on Isle of May

We traveled to Isle of May to see the Atlantic puffins (Fratercula arctica), beautiful birds whose breeding plumage comprises white and black feathers, prominent orange beaks and feet. The island itself was packed with these birds, plus several other species such as guillemots, razorbills, gulls, turns and seals as well.

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The island is home to several salt tolerant plant species and it was an unforgettable vista. Almost the whole island was a covered in carpets of beautiful flowers and I hope I managed to capture it with these photos:

Sea campion (Silene uniflora Roth; Caryophyllaceae).
Sea thrift (Armeria maritima (Mill.) Willd.; Plumbaginaceae).
Sea thrift on the roof of the information centre on the island.
Nettle (Urtica dioica L.; Urticaceae).
A typical image of the island.
Sea campion with docks (Rumex sp.; Polygonaceae).
Sea campion, dock and umbellifers (Apiaceae).
Umbellifers (Apiaceae).
Beautiful cushions of sea campions and the horizon.

The visit to Isle of May is a must for anyone visiting Scotland between April and August, especially if you are on a hunt for an amazing floristic and/ or faunistic experience.


There are only three native conifers in Scotland. These are juniper (Juniperus communis), Scots pine (Pinus sylvestris) and yew (Taxus baccata). Most of other conifers were introduced to Scotland by a Scottish botanist, famous David Douglas. Perhaps most known is a conifer that bears his name, namely Douglas fir (Pseudotsuga menziesii). Its name implies this is a fir, but this is not the case. Firs belong to genus Abies (for example silver fir (Abies alba) which is so very common in my home Slovenia). To amend somewhat for this misleading name, often the name would be written as Douglas-fir. Interestingly, the species epithet in the Latin name,  menziesii, is after Archibald Menties, a Scottish physician and rival naturalist to David Douglas.

Few weeks ago, we visited a place, where the first Douglas fir was planted by David Douglas in Scotland and where the tallest of them (>60 m) still grows. The Hermitage is a beautiful place and worthwhile visiting if you happen to be in Scotland. Here are some glimpses to the experience.

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A colourful invader and a toxic beauty

Whenever I see this plant I stare in wonder. It comes in variety of colours, it smells great and the bunches of its flowers are just beautiful. Rhododendrons, or as its name implies (in Ancient Greek) rose trees, are amazing spring treat for eyes. There are more than 1000 species in the genus, that belongs to Ericaceae family. I remember seeing rhododendron trees in a forest in West Virginia, USA.

Rhododendron in a forest in West Virginia, USA.

It came as a surprise to me, as I was used to see them in gardens and parks in Europe and in our forests we have a very different forest compositions.

On the path I take to work I am accompanied by numerous rhododendrons, which enables me to admire their luxurious colours every day (to be precise 4 times a day as I walk home for lunch). Here are some photos of these rhododendrons:





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Surprisingly, I just recently learned that a particular rhododendron species (Rhododendron ponticum L.) is invasive species in the UK. This means the plant is spreading uncontrollably in woodland areas replacing the natural understory. If you look carefully under this tree, you will see that nothing grows there – it completely destroys any vegetation around. Great number of seeds and suckering roots (meaning they have the ability to propagate, grow whole plants) make them a though pest. In addition, it was shown that its nectar contains grayanotoxin, a substance that, when consumed in a solution, makes honeybees 20-times more likely to die (read the study here: doi:10.1111/1365-2435.12588). This seems a considerable problem to me and it leaves a bitter taste from thereon whenever I see the plant.

Another toxic story involves nothing else but beautiful daffodils (Narcissus poeticus L.).

Daffodils near a local bus stop.

Again, just recently I learned that they are toxic and this was after my friend commented on my home-arranged bouquet of daffodils with: Oh, Paula you’ve treated us with a toxic pleasure. Discussion followed and yes, it is true, daffodils are toxic. As are tulips (Tulipa gesneriana L.), hyacinths (Hyacinthus orientalis L.) and lilies (Lilium sp.) and many other bulbous plants that flower in spring. Their underground bulbs contain toxic substances, most probably to deter a hungry animal in search for nutritious meal in winter time.

Suddenly, labels “do not eat” make sense!

Reaching out and to the light

Last autumn I couldn’t resist and I secretly picked a bouquet of dry barley plants from the field nearby. I’ve been keeping it in the kitchen over the winter and two weeks back it has suddenly become very popular in our house. The reason is that my 5 year old children and their 7 year old friend across the street have started to pay attention to it. At first they realised there are seeds inside the ears and it took them some time to acquire them. Then they wanted to do an experiment with them. The question raised was, how would the seed germinate and how would the plants grow in the darkness when compared to the plants grown in the light. Which will be bigger?

So we had a go and in few days’ time we had a look. First it was clear that the darkness had no effect on the germination. After all, most of the seeds germinate in the darkness of the soils. More surprising was the appearance of the plants that grew in the darkness:

Left: barley seedling grown in the light. Right: barley seedling grown in the darkness.

Seedlings grown in the darkness were taller, weaker and they were not green as the ones that grew in the light, but were pale yellow. It took some thought, but eventually (some of my suggestions to lead them the right way were helpful) they figured it out. These plants try to find the light as soon as possible and thus they grow “taller”. Their pale colour was more perplexing, but I try to explain that plants do not “waste” energy to build something (in this case the chlorophyll) that will be required only when the light is present…

In science we call the phenomenon etiolation and etiolated plants can be seen for example in the shade or even when covered with e.g. leaves. However, new question was raised. What happens if we place these etiolated plants into the sun?

Here is a result:

Left: barley seedling grown in the light. Right: barley seedling placed in the light after 4 days of growth in the darkness, 5 days old.
Left: barley seedling grown in the light, 6 days old. Right: barley seedling placed in the light after 4 days of growth in the darkness, 5 days old.

Kids had great fun doing the experiment and are hungry for more. For now, we planted the barley seedlings into the soil and placed them in the garden. We are carefully monitoring their development and are planning more experiments!

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