Kveldssanger

25/09/15. Fact #42. Bit of a different one, but from the same book. Building from the above post of mine on vernalisation, we currently understand that vernalisation does not (at least directly) transfer from parent to seed. For example, if the parent goes through a particular set of environmental conditions, the seed is not pre-natally determined to vernalise in a different manner by default. Now for some context... The term itself was coined by Russian geneticist Trofim Lysenko in the early 20th century. During his research on vernalisation, he fabricated his results in an attempt to prove that vernalisation under favourable conditions would permanently improve genetic stock. Alarmingly (though this no doubt still goes on today within the industry, though to different extremes in different subjects), critics who suggested he was wrong with his results (not knowing they were fabricated) were coerced into silence or shipped off to Siberian labour camps. This crippled the Soviet plant biology 'movement' for a long while, and lead to Western scientists categorically (but incorrectly) dismissing that vernalisation can impact upon offspring - offspring phenotype is influenced by the genes it inherits from its parent(s), and by parental experiences. Source: Karban, R. (2015) Plant Sensing & Communication. USA: The University of Chicago Press.

It is fascinating indeed, though from reading this book it is clear there is much more to be understood. For example, how exactly plants 'perceive' temperature, moisture, etc, is not well-researched. There is no understanding of how plants 'perceive' cold, for example - we know how plants respond to cold, but have no idea how they actually recognise that it is cold, and getting colder or warmer. It's complex, indeed. Plants can even 'remember' how to 'deal' with the cold - 'naive' plants suffer more than 'hardened' plants to cold, for example. One interesting thing this book mentions is that plants can 'remember' they have been through a period of vernalisation (a very cold period) for up to 300 days, assuming the light conditions are wrong for those 299 days before light suddenly becomes 'good enough' for flowering on the 300th day (as cold alone doesn't facilitate flowering - a series of 'conditions' must be met, of which a cold period is just one). After that, they seem to 'forget'. I am sure it is different for each species, however. To add to this point, we also do not know how plants 'know' how long a cold period has gone on for. There is such a long way to go with research that I feel we're just wandering at the threshold of true knowledge.

I do understand where you are coming from. If I am honest, the author of the book has a good way of explaining things. Only a few things thus far have gone 'over my head', so to speak. If I were to paraphrase this: "This localised influx in calcium ions upregulates genes in the 10-30 minute following stimulation, inducing adaptive growth. Particular species, such as Arabidopsis spp., may see at least 2.5% of the entire genome being 'upregulated' following such stimulation. In many other species, it is however likely to be less." I would say: Cellular increases in calcium ions local to the stimulated area induce (through a far more complex series of events) a heightened sensitivity and thereby initiate adaptive growth responses (through the creation and distribution of hormones such as auxin), in the 10-30 minutes following on from initial stimulation. Yes, I am paraphrasing my own parahrase!

Upregulation is used by the author of the book. When I read it I interpreted it as becoming more acutely sensitive. Guess I was partially right, as... ...the definition is quite good here. Oh look, they're talking about nappies there (almost). Hah!

23/09/15. Fact #41. I bet this'll throw you all! I shall quote. "More carefully conducted experiments also suggest that plants use senses other than those that are currently well understood. For example in one study, proximity to a neighbouring plant influenced seed germination and growth of seedlings even when cues associated with light, chemicals, or touch were blocked." Interesting... Sources: Gagliano, M., Renton, M., Duvdevani, N., Timmins, M., & Mancuso, S. (2012) Out of sight but not out of mind: alternative means of communication in plants. PLoS One. 7 (5). e37382. Karban, R. (2015) Plant Sensing & Communication. USA: The University of Chicago Press.

23/09/15. Fact #40. Gravitropism causes shoots to grow against gravity (up) and roots to grow with gravity (down). Simple enough. Though how does the tree 'know' how gravity is impacting its structure? Via statolith cells, found within the interface of the cell wall and plasma membrane (the interface is pretty much the 'control panel' for the plant in terms of response to stimuli). Rich in starch granules, these granules within the cells are subject to gravity and thus apply pressure on the cell's lower side, which 'informs' the interface of the direction of gravity. Strain / stimulus / stretching of the plasma mebrane occurs, calcium ions are accumulated within cells locally (in the roots statoliths are found in the root cap, and in shoots within the endodermal layer), and a "biochemical cascade" (sounds cool) ultimately leads to asymmetrical auxin (growth regulator) distribution and, subsequently, directed growth. Did I say this book was good? Sources: Karban, R. (2015) Plant Sensing & Communication. USA: The University of Chicago Press. Morita, M. T. (2010). Directional gravity sensing in gravitropism. Annual Review of Plant Biology. 61. p705-720.

To add to the above point, the book continues to suggest that recent advances have identified jasmonic acid being implicated in the overall process to touch response. Interestingly, where certain plants studied were unable to 'produce' jasmonic acid, mechanostimulant responses were non-existent. There really is so much to this Plant Sensing & Communication book. It is truly fascinating. Get it if you can! It's good value, for such a comprehensive book.

Interesting addition there! Have you trawled Google Scholar for articles? 23/09/15. Fact #39. Plants can respond to touch, or other form of mechanical stress, and subsequently adapt their form so that their growth is 'optimal'. But how does the plant actually achieve this - what signals are present, and how does the plant interpret that it needs to allocate growth to particular positions in response to mechanical forces? Simply put, the reaction induces a response at the interface of the cell wall and plasma membrane. Within (quite literally) seconds of the interface being 'stressed', simply via mechanical stimulation (the plant's own growth) or via the plasma membrane being strecthed (external forces), the electrical resistance and 'action potential' changes. These processes stimulate ion channels that flow within the plasma membrane, causing positively-charged Ca2 (calcium) ions to move into the cells within the vicinity. This localised influx in calcium ions upregulates genes in the 10-30 minute following stimulation, inducing adaptive growth. Particular species, such as Arabidopsis spp., may see at least 2.5% of the entire genome being 'upregulated' following such stimulation. In many other species, it is however likely to be less. Sources: Braam, J. (2005) In touch: plant responses to mechanical stimuli. New Phytologist. 165 (2). p373-389. Chehab, E., Eich, E., & Braam, J. (2009) Thigmomorphogenesis: a complex plant response to mechano-stimulation. Journal of Experimental Botany. 60 (1). p43-56. Karban, R. (2015) Plant Sensing & Communication. USA: The University of Chicago Press. Lee, D., Polisensky, D., & Braam, J. (2005) Genome‐wide identification of touch‐and darkness‐regulated Arabidopsis genes: a focus on calmodulin‐like and XTH genes. New Phytologist. 165 (2). p429-444. Telewski, F. (2006) A unified hypothesis of mechanoperception in plants. American Journal of Botany. 93 (10). p1466-1476.

22/09/15. Fact #38. Photosynthesis requires both carbon dioxide and water for operations to function. Carbon dioxide is taken up via stomata, which are small openings in the leaf surface (usually on the underside in most abundance, but not always). However, for the leaf to uptake carbon dioxide, water will evaporate via the very same stomata. Guard cells therefore exist, surrounding the cell, to control water loss and carbon dioxide uptake. Such cells, to operate efficiently, rely on numerous 'signals' both internal and external to the plant. One main one is light intensity. Blue light receptors (called phototropins) will respond to light intensity (blue light is utilised by the plant principally to assess light quality and quantity) and, increasing in-tandem with light intensity (to a point!), 'pump' positively-charged hydrogen ions out of the guard cells via the plasma membrane. As these ions move out of the cell, the intra-cellular negative electrical charge facilitates the inflow of positively-charged potassium ions. As these potassium ions are drawn into the cell, water is also brought in via diffusion (water will move across a gradient and into a more 'concentrated' solution - in this case, K+ ions are causing the higher concentration). This water makes the guard cells 'stiff' (or turgid) and keeps them open, thereby facilitating carbon dioxide uptake and water evaporation. Receptors of the guard cells will also respond to internal carbon dioxide levels. Elevated internal levels will cause guard cells to close, and vice versa. This is important, as the guard cells must respond to the needs of the leaf in regards to photosynthesis (interesting fact - respiration 'at dark' leads to high internal levels of carbon dioxide). As the process uses carbon dioxide, the guard cells will therefore continually be opening and closing, providing the needed levels of carbon dioxide, and controlling water loss also through responding to plant and atmospheric water (relative humidity) status. I could go on... Source: Karban, R. (2015) Plant Sensing & Communication. USA: The University of Chicago Press.

Gotta' add this from the same source: Plants mainly absorb red wavelengths. However, as the sun sets (dusk), the ratio of red:far-red wavelengths skews more towards far-red. As a result, plants will temporarily change their sensitivity to far-red light, by means of the Circadian clock, in order to still efficiently photosynthesise.

That is a grand oak! I'm looking to go to the Carpathians in the coming years, though the Bialowezia National Park is also very tempting. I am in the process of reading 'Plant Sensing & Communication', of which I am certain there will be many wonderful facts to share. A very basic one for today, as I'm only on page 11 (!). 21/09/15. Fact #37. Plants detect light when their receptor molecules (chlorophyll, xanthophyll (xantho = yellow), carotenoids, cyanophyll (cyan = blue)) absorb solar electromagnetic radiation (light). Such receptor molecules will only absorb the light if the light wavelength matches the wavelength requires to 'activate' the receptor molecule; otherwise, the molecule will not 'excite' and not 'oscillate' in a higher state. For example, chlorophyll will absorb red wavelengths and reflect green ones. And thus was borne the reason for many different leaf pigmentations! The wider the range of pigments, the more light of different wavelengths that can be used. Source: Karban, R. (2015) Plant Sensing & Communication. USA: The University of Chicago Press. If you want to check out the wavelengths of the different pigments, they can be found online readily. They're in my notes somewhere, but I cannot find them at this moment.

Aye. It's the rate of change, not the change in itself. Trees have always responded to change, as has every other species, though generational turnover in trees is simply not quick enough. Some trees don't produce seed for decades, or require the right conditions to do so (which may require insects, temperature conditions, etc, that are lacking due to the rapid change).

With regards to the Milgram Experiment, I was looking at it from the angle that even though we know nature is struggling, we still continue what we always did (by-and-large) because that is the way the system works. The experiment is somewhat 'allegorical' to my point, though I do feel it stands. One cannot question that nature is struggling - it seems that a mix of peer pressure and, more widely, the system as a whole construct, means change just isn't happening. For instance, how feasible is it for a sudden reduction in the use of petrol and diesel for cars to take place? The 'authority' in this case is 'the system'. On topic of the Milgram Experiment in a literal sense, I would suggest it had a very depressing result. Soil pH change - pollution will acidify (or alkify) soil. The 'expected' pH range is from between 6-5-7.5 (6.8 being 'botanical' neutral, roughly), though of course there is natural variation. However, when we input pollutants, such as fossil fuel emissions, soil acidification via deposition of nitrogen, sulphur, aluminum, and other mineral ions is bad. Aluminum, for example, blocks root nodules, interrupts root-mycorrhizae relationships, and 'leeches' other elements from the soil (calcium, for example, though also iron I do believe). A quick search of Google Scholar will provide many results for aluminum toxicity to plants (and humans! - one of the causes of Alzheimer's, hence the aluminum levels in the air being way above 'safe' is so tragically horrifying). There are many studies on the effect of nitrogen on plants that are already sick, again on Google Scholar (and books, too). Basically, nitrogen encourages plants to use their stored energy for growth. This is all well and good in healthy plants, though when a plant is stressed and has low stored energy, undesirably high levels of soil nitrogen will basically force the plant to allocate its reserves for growth, then leaving it wide open to attack as it now lacks any significant energy reserves. That's the danger is using a nitrogen fertiliser on a sick plant - it won't do it any good, even though the new growth will give the illusion of the plant recovering. With my pollution comment on methane etc, I was speaking more macro-cosmically about how we influence so many things. Methane is a driver in the currently-dubbed 'greenhouse effect' (the sun (CMEs, sun spots, etc) also plays a massive role but that rarely gets covered in depth by the media, but that's another matter entirely). As the climate changes, trees' phenological cycles shift. Compiled with the attrition on trees due to general pollution, fragmentation, and otherwise, the changing phenology is gong to stress the tree - a system cannot cope with so many potentially-overloading factors working against it. I suppose a tree has a 'safety factor' when it comes to its functionality as a system, much like it has a structural safety factor in wind-loading (or other loading) conditions. The damage is likely to be ongoing in places, though that photo as a stand-alone one shows old ribbing callus growth. In some respects one can say the trunk is now fluting as a result. As the woodland is managed, some wounds may be to do with logging operations, I dare say some smaller wounds created by whatever means have lead to frost damage, and the use of the site by humans has also likely had a contribution. If deer are present, they will also initiate damage to trees. I do wonder whether, and this is a pure hypothesis, the fluctuations in annual weather patterns is leading to spontaneous xylem cavitation in trees.

They are very old wounds. Has the forest been managed - mechanical wounds from site clearance, perhaps. Ungulate browsing?

To add (for just a few species): Ornamental cherries - bacterial canker of cherry Planes - anthracnose Willows - anthracnose / rust / aphids Poplars - rust / canker (Xanthomonas) Elm - DED Ash - Chalara / canker Oak - AOD / mildew Horse chestnut - blotch, miner, canker, blight Sweet chestnut - gall wasp So many more...

Yeah saw it the other day - don't watch much TV at all, so when I saw a Stihl advert (one of the only adverts I have actually seen in months...) I was pretty surprised. Nice advert, though somewhat typical in its modus operandi.

I have noticed a lot of poorly trees as well - limes, horse chestnuts, oaks, ash, ornamental cherries, birch, hornbeam, a few field maple. Everything does seem to be struggling. Here's my thoughts: 1. Horrifically poor genetic provenance / pool - when man enters (virgin) forest with timber production in mind, what trees are the first to go? The ones that are best. The best trees are removed. Man ignores the 'naff ones. From the offset, we are altering genetic pools, removing the trees that should be reproducing, and facilitating reproduction of less 'optimal' specimens. At times, man ever clear-fells an area to plant with non-native stock with genetic progeny that would very likely not have 'made it' naturally. We throw the plasticity of forests out of whack, remove the best specimens, fragment, damage, and plant new trees in the wake of the old ones. Coppice woodlands are time-locks due to a lack of natural regeneration - it's all vegetative (layering, suckering, etc). Seed banks are permanently destroyed. We introduce game to forests. Damage is rife, across the entire spectrum of woodland characteristics. Heck, lots of our cherries in woodlands come from jam factory seeds, and our ash stock 'aint much better (thank the rapid planting in the 70s on farmland for that!). Chalara will certainly hit harder than it would if we had actually considered genetic progeny back then with our ash. 2. Man acting as a vector for disease - transport brings over diseases far more rapidly than they would ever be able to naturally succeed (Asian Longhorn Beetle, for example). What would have taken decades takes mere years, and what may never arrive can do. Phytosanitary measures are lacking, despite the good intentions of many, and the lack of desire to limit international and intranational trade and transport will only fuel further issues down the line. Diseases may become pan-mundi, so to speak. All the while, man is planting genetic stock that would not make it through the proper means of species competition and 'survival of the fittest'. Recipe for disaster, no? And we're not even talking about urban areas - genetic stock of our streets is probably shocking. 3. Pollution - soil acidification, salts, aluminium, etc etc etc. Industrial waste. Dumping chemicals in river 'by accident'. Fracking, underground coal gasification, cars, planes, water vapour, CO2, methane... Nitrogen, too much nitrogen on already suffering trees = so very bad. Trees aren't designed for such rapid adverse change. Pulling the carpet out from beneath their feet (roots), no? We never learn as a species. 4. Lack of natural regeneration (woodland and urban) - "I don't like this native oak that is growing in my garden, let me take it out and replace it with a nice japanese maple". trees that are making it naturally are neglected in favour of nursery-bought trees. Want to make a difference? collect local seed, grow that seed, and plant it locally. Not to mention seedling recruitment in woodlands - over-browsing, humans trampling through stuff in the pursuit of experiencing natural beauty (whilst trampling it all down at the same time), disease, pollution, fragmentation. Everything is wrong. It's so bleedin' obvious as well, yet we still harp on about how we can do something about it. Well I don't see that, if I'm honest. Too many people, too little care. We'll be watching the demise from our TV screens, not even bothering to look out the window. Reminds me of the Milgram Experiement, but with our very natural world in the chair instead of another human. Cries of "STOP!" are ignored, even if we recognise we need to stop. /rant. Just my mental notes. Probably little coherency.

For those interested, I heard back from the Forestry Commission (Ken Adams) regarding P. nigra var. betulifolia cultivation. He had some great points, and linked me to his website on the Water Poplar. See here. It's a great read. BLACK POPLARS IN UK

19/09/15. Fact #36. Reproductive growth in plants is driven largely by the environment - light intensity, light duration, temperature, water supply, and other climatic factors will have significant impact upon fruit quality, yield, blossoming, bud dormancy (activation), pollen formation, and more. For this fact, I am going to focus solely on flowers. In the rawest sense, each sequential event (petal opening, anthesis, stigmatic secretion, pollen germination, growth of pollen tubes, maturation of embryo sacs, fusion of polar nuclei, double fertilisation, petal fall, and ovary growth - yes, there are a lot of them!) of the flowering process within plants is regulated by temperature. Where temperatures are low therefore, the process is slowed - this may have an impact upon fruit set. Before flowers can begin to form, the buds must be exposed to the cold (adequate amount of cold varies on the species, though at 7.2 degrees Celsius between 50-1,150 hours may be necessary for different peach cultivars alone), and then be exposed to progressively-increasing temperatures. Of course, this doesn't apply for all species, however. Source: Kozlowski, T. & Pallardy, S. (1997) Chapter 6: Environmental Regulation of Reproductive Growth. In Growth Control in Woody Plants. UK: Academic Press.

18/09/15. Fact #35. Białowieża National Park is one of the very few areas within Europe that still retains an entirely extant ungulate assemblage - European bison, red deer, roe deer, moose, and wild boar, in addition to the wolf and lynx, all roam the forests. At times, livestock have also grazed the forests, though no grazing is present currently. The uniqueness of the National Park, which still retains species otherwise hunted to extinction in other regions, is scientifically intriguing. Białowieża provides for what 'could have been' if other forests were also left to their own devices, and man did not hunt species (sometimes to extinction) or introduce species for a given reason. Białowieża currently has very few forest gaps - less than 5% is open grassland or sedge / reed marsh along the riparian strips. Tree regeneration is a continuous process beneath the canopy of old stands, and also within canopy gaps. The browsing of ungulates, contrary to Vera's view of old forests being a mosaic of open to closed canopy stands, has had little lasting impact upon species composition or stand 'openness'. Seedling recruitment is however impacted by ungulate browsing, as is concluded by studies that have spanned around 70 years. Seedling recruitment of more palatable tree species was of course lower given the ungulate browsing, though the 'landscape of fear' created by the presence of wolf and lynx ultimately altered ungulate browsing habit that in turn was of benefit to seedling recruitment on the whole. Source: Latalowa, M., Zimny, M., Jedrzejewska, B., & Samolijk, T. (2015) Białowieża Primeval Forest: a 2000-year interplay of environmental and cultural forces in Europe’s best preserved temperate woodlandIn Kirby, K. & Watkins, C. (eds.) Europe's Changing Woods and Forests: From Wildwood to Managed Landscapes. UK: CABI.

They are incredible. Their detail is astounding.

Will look to get a fact up tomorrow from one of my books that has a chapter on woodland management and conservation in Białowieża National Park. It's the only (?) forest within Europe that has never been extensively managed, if I recall correctly. It is used as a reference point for 'what could have been' if other forests (and associated ecosystems) were left to manage themselves.

17/09/15. Fact #34. Bit of a different one today as well - a photo and a description. So I was out picking some of the blueberries and apples from the garden, and something caught my eye in the twilight... (Here are all the images in HD (not shrunk to fit here - they're great photos, if I may say so) - Calliteara pudibunda (Pale Tussock) - Album on Imgur) ...a pale tussock (Calliteara pudibunda) caterpillar! So I thought I'd share a bit of info on the species... Turns out they are "fairly common" across England and Wales in terms of distribution and abundance (they seem to have limited spread around the Midlands and from there hardly proceed further north), and the female form is larger than the male at the moth stage - the moth can be identified by the very furry legs that protrude outwards in front of the main body. The species is associated with many small deciduous trees and shrubs (this one I found on a Malus sp.), and was in fact a pest of hop (Humulus lupulus) when it was once grown frequently. I bet beer lovers were furious... ...and don't touch them, as (like many caterpillars) they induce undesirable reactions. Coming into contact with the poisonous hairs or spines may cause skin rashes - or even a hypersensitivity reaction. Sources: An overview of the moth and its habitat. Health issues associate with skin-to-caterpillar contact. Distribution map of the species.

I'll make sure I get pictures of any I come across, then. Both rural and urban.

Sounds interesting. Attached is a retrenching ash. It's not massively old - I suspect the grazing of horses and the farming practices nearby have triggered the retrenchment. https://i.imgur.com/sJfhBRm.jpg I can get plenty more. Just veteran trees, or are you looking for 'pseudo'-veterans too (urban trees reducing mass)? Note the magpie sitting in the top-right of the ash, too. Birds love them. An old oak right by the work depot that is a favourite of crows.