Drosera glanduligera
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Drosera glanduligera |
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| Coelophylla | ||||||||||||
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| Drosera glanduligera | ||||||||||||
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Drosera glanduligera is the only species of the Coelophylla section from the genus sundew ( Drosera ) withinthe sundew family (Droseraceae). This carnivorous plant is only found in Tasmania and southern Australia .
description
Vegetative characteristics
Drosera glanduligera grows as an annual herbaceous plant with a very short lifespan. The basal leaf rosettes reach a diameter of 3 to 5 centimeters. Stipule buds ("Gemmae") in the center of the leaf rosettes are not formed.
The leaves are divided into a petiole and a leaf blade. The leaf blade is egg to spatulate with a length of 5 to 6 millimeters and a width of 7 to 8 millimeters with a strong indentation in the center.
The stipules have lengths and widths of 2 to 2.5 millimeters, are fringed and fused with the base of the petiole.
Generative characteristics
The flowering period in Australia extends from August to November. The bracts have two or three fringes, each with a 1 to 1.5 millimeter long glue gland. Usually the bracts are missing or they appear individually or in pairs at the base of the inflorescence stem.
The hermaphroditic flowers are radial symmetry and five-fold with a double flower envelope. The inflorescence is imbricate, with one bottom and one top calyx and petal each. The golden-green sepals are egg-shaped with a length of 4 to 4.5 millimeters and a width of 1.5 to 2 millimeters; they are densely covered with glue tentacles and have glandular fringed appendages. The bright orange petals are 4.5 to 5 millimeters wide. The five stamens are 3 to 3.2 millimeters long with white-red stamens. The green ovary is egg-shaped with a diameter and length of 1.3 to 1.5 millimeters. The three orange-colored pens, 0.2 to 0.3 millimeters wide, extend horizontally 1.8 to 2 millimeters at the base, then bend a further 1.8 to 2 millimeters upwards and divide there into four to seven pencil-shaped segments.
The seeds are dark gray, round with concave testa cells in which there are epicuticular wax crystalloids.
Chromosome number
The number of chromosomes is 2n = 22.
Sheet / trap function
Drosera glanduligera has catapulting quick tentacles with a glandless, raised head, which is unique to the genus Drosera . The strongly elongated catapults lie wide on the ground , similar to the signal threads of some spider species . High-speed recordings by the Plant Biomechanics Group at the University of Freiburg showed that touching the catapult heads triggers a very fast bend in the joint zone in the lower third of the petiole after a reaction time of 400 ms. As a result, the prey is thrown from the periphery of the leaf rosette mostly backwards into the sticky center within 75 milliseconds with an acceleration of 7.98 ms −2 . The impact on the considerably shorter glandular glue tentacles standing vertically on the leaf blade triggers the second phase of the two-stage capture process. The prey is transported in 1 to 2 minutes by bending towards the middle of the leaf into an abaxially clearly visible, sack-like depression in the center of the leaf - the so-called digestive trough - where it is broken down by enzymes .
The joint zone of these catapulting quick tentacles is destroyed by bursting due to the high hydraulic pressure during the bend, which is why these catapults only work once. The glue tentacles, which can be moved in all directions, remain fully functional and after a few hours bend back into their original position after the prey has been unloaded in the digestive trough. This means that they are available again for the transport of new prey, which can be delivered by up to 18 catapults on a leaf. This two-stage catching mechanism consisting of a very fast catapult movement in combination with transporting the prey through the glue tentacles in 1 to 2 minutes was called the "catapult glue trap" by scientists at the Albert Ludwig University of Freiburg. The video belonging to the PLOS ONE article (right) with the fruit flies ( Drosophila spec.) Catapulted in 75 ms as prey was selected as the video of the week by the editorial team of Bild der Wissenschaft in 2012 . Other catapult glue traps that snap shut in the range of tenths of a second and work several times were described in 2015 in the Drosera section Bryastrum (dwarf sundew): Drosera microscapa , Drosera occidentalis and Drosera pygmaea .
Due to the catapults, the genus Drosera , whose tentacle movement has so far been classified as slow in the range of seconds, even has a faster trapping mechanism than the related Venus flytrap ( Dionaea muscipula , about 100 ms).
chemistry
Different naphthoquinones are characteristic of some sundew species ( Drosera spec.) And species groups and can therefore be used for chemotaxonomic delimitations and differentiations (Schlauer & Fleischmann 2016). Particularly noticeable parallels between chemistry and systematics can be found in the so-called Australian tribes ("Australian clades"). Thus the dwarf drosera ( Drosera section Bryastrum Planch.) And their close relatives, the Drosera petiolaris group ( Drosera sect. Lasiocephala Planch.) Do not form any naphthoquinones while the "tuber drosera " ( Drosera sections Ergaleium DC., Erythrorhiza (Planch.) Diels.) and Stolonifera (Planch.) DeBuhr) as well as the forked species ( Drosera sect. Phycopsis Planch.) contain plumbagin (= 2-methyljuglone).
Drosera glanduligera ( monotypical Drosera section Coelophylla Planch.), On the other hand, which was previously suspected of being an isolated member of the Drosera section Bryastrum , contains ramentaceon (= 7-methyljuglone). This in turn can be found in some species (eg Drosera aquatica , Drosera hartmeyerorum ) of the spider leg Sundew ( Drosera sect. Arachnopus Planch.), Making them indistinguishable from their relatives in the same section that Plumbagin included (eg Drosera finlaysoniana , Drosera serpens ).
ecology
Drosera glanduligera grows on moist soil in the Australian winter . The plants die completely after the seeds ripen at the beginning of the summer season. They survive the dry season as seeds and germinate as soon as the temperature at the beginning of the winter season falls below 8 to 10 ° C for a few nights on moist soil.
Scientific investigations
A detailed documentation (20 min.) Of the investigations of the catapult glue trap ( Drosera glanduligera ) in the laboratories of the Plant Biomechanics Group at the University of Freiburg in 2012 in collaboration with the Hartmeyer couple and a closing remarks by Thomas Speck , Head of the Botanical Garden and the Plant Biomechanics Group of the University of Freiburg, is available online (see web links).
Occurrence
Drosera glanduligera occurs in southwestern and southeastern Australia and Tasmania. In some locations, Drosera glanduligera is quite common.
Systematics
The first description of Drosera glanduligera was made in 1844 by Johann Georg Christian Lehmann in Novarum et minus Cognitarum Sitrpium Pugillus , 8th 1848 Drosera glanduligera because of their special status by Jules Émile Planchon in the monotypic section Coelophylla Planch. placed within the genus Drosera .
Individual evidence
- ↑ a b data sheet with photos at the International Carnivorous Plant Society . ( Memento of the original from January 29, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Drosera glanduligera at Tropicos.org. In: IPCN Chromosome Reports . Missouri Botanical Garden, St. Louis
- ↑ a b c Simon Poppinga, Siegfried Richard Heinrich Hartmeyer, Robin Seidel, Tom Masselter, Irmgard Hartmeyer, Thomas Speck: Catapulting Tentacles in a Sticky Carnivorous Plant . In: PLOS ONE (Ed.): PLOS ONE . 7 (9): e45735, September 26, 2012, doi : 10.1371 / journal.pone.0045735 .
- ^ Siegfried RH Hartmeyer, Irmgard Hartmeyer: Several pygmy Sundew species catapult-flypaper traps with repetitive function possess, indicating a possible evolutionary change into aquatic snap traps similar to Aldrovanda . In: Carnivorous Plant Newsletter . tape 44 , no. 4 , December 1, 2015, p. 172-184 .
- ^ Jan Schlauer, Andreas Fleischmann: Chemical evidence for hybridity in Drosera (Droseraceae) . In: Biochemical Systematics and Ecology . tape 66 , March 5, 2016.
- ↑ a b c Jan Schlauer, Siegfried RH Hartmeyer, Irmgard Hartmeyer: Unexpected discovery of 7-Methyljuglone (Ramentaceone) in several Australian sundews . In: Carnivorous Plant Newsletter . tape 46 , no. 1 , March 1, 2017.
- ↑ Siegfried RH Hartmeyer, Irmgard Hartmeyer, Tom Masseleter, Robin Seidel, Thomas Speck, Simon Poppinga: Catapults into a deadly trap: The unique prey capture mechanism of Drosera glanduligera. In: Carnivorous Plant Newsletter . tape 42 , no. 1 , 2013, p. 4-14 .
