during two recent trips to tasmania, i had the opportunity to discover the beauty of the island and its amazing wildlife. while the australian and tasmanian fauna generally receives much attention, the plant life here is not less extraordinary.
with this post, i’m using the opportunity to briefly introduce some trees and other woody plant species i encountered on the island. while some of these species also occur in a wider range in australia, some others represent the species’ last/only occurrence in the world, and a few of them date back to the supercontinent gondwana and a time before even the age of dinosaurs. tragically, most of these old species are very vulnerable to bushfires, and a large area was struck by widespread bushfires in january 2016.
it’s been rather quiet in the blog lately, so i thought i’d share a peek into what we’ve been up to at work:
Hydraulic vulnerability analysis using X-ray microCT
One of the major points of critique for hydraulic measurements of xylem vulnerability and embolism is that they are destructive measurements. In contrast, non-invasive imaging has made it possible to observe xylem function and the spread of embolism in living, intact plants without destructive sampling and associated artefacts.
In collaboration with Iain Young and Richard Flavel at the University of New England, Armidale, we recently scanned the stems of young Eucalyptus trees at high resolution using X-ray Micro Computed Tomography (microCT) to visualize the loss of hydraulic function at increasing levels of drought. [more...]
not too long ago, we came across a small patch of squirting cucumbers (ecballium elaterium) in spain, and wanted to see their rather spectacular mode of seed propagation in action:
using hygroballochory, the species can expel its seeds into distances of up to 12 meters.
footage was recorded with a gopro hero 3 black at 120 fps, 720p. clips are in real-time, 4x slow motion, and (last sequence) 8x slow motion (i.e.15 fps), respectively.
the tiny plant below is a stone plant seedling (aizoaceae), growing in the harsh conditions of the “knersvlakte” quartz gravel landscape in north-eastern south africa. the seedling has only formed its first pair of cotyledons, which are already completely covered in epidermal bladder cells:
bladder cells are modified trichomes (hair-like structures) common in the stone plant family (aizoaceae), which are used to remove salt from the plant system.
to give you a better sense of scale, here’s the same view plus my index finger tip: [more...]
stellate parenchyma is a form of aeration tissue (aerenchyma) in plants, which helps with internal air circulation in plants. the tissue is typical of aquatic and wetland plants, and consists of cells with large intercellular spaces that allow air supply to underwater plant parts.
due to the very narrow depth of field at high magnification, the picture is actually a focus stack of 22 combined layers. to get a feeling for the three-dimensional structure of this anatomical section, check out the animation below: [more...]
the common smoothcap moss (atrichum undulatum) features transversely undulate leaves, but its most prominent feature are the long, distinctly beaked capsules that are borne on 3 cm long, reddish setae.
the species is also called catherine’s moss in english, and wellenblättriges katharinenmoos in german.
species details via Farbatlas Flechten und Moose (Wirth, Düll)
in april, we went on a short botanical spring-excursion to slovenia. led by bozo frajman, we experienced a short glimpse of the slovenian culture, cuisine and – of course – the flora.
main stops were made in:
- vaska skupnost lukovec, where, besides plants, we also found some interesting animals
- podpec at the edge of the karst plateau, with the extremely rare moehringia tommasinii, which is known only from 6 locations along the karst edge in slovenia, croatia and italy
- the lovely coast town of piran (slovenia owns 46.6 km of the adriatic coastline, that’s about 2 cm per citizen ;) )
- ljubljana, the friendly slovenian capital
- pot v pekel (the “road to hell”), one of the locations where the carniolian primrose (primula carniolica) is growing.