Some laboratory germination responses of the seeds of river red gum, Eucalyptus camaldulensis Dehn. Syn. Eucalyptus rostrata Schlecht

1958 ◽  
Vol 6 (2) ◽  
pp. 129 ◽  
Author(s):  
RJ Grose ◽  
WJ Zimmer
Keyword(s):  
Constant Temperature ◽  
Environmental Conditions ◽  
Eucalyptus Camaldulensis ◽  
Special Technique ◽  
Optimum Conditions ◽  
Light Requirements ◽  
Petri Dishes ◽  
River Red Gum

A method for sampling from bulked eucalypt seed for germination tests, and a special technique for testing germination of these seeds in Petri dishes are described. The seeds of Eucalyptus camaldulensis Dehn. will germinate both at constant and at alternating temperatures. They germinate best at a constant temperature of about 95°F. The seeds require light for satisfactory germination. The light requirements of all seed-lots tested were satisfied by 8 hours of light daily at a constant temperature of 95°F. Light requirements are least at temperatures close to 95°F. There is an interaction between light and temperature and the requirement for light is reduced as the temperature is increased. Stratification also reduces the requirement for light in germination. Thirty-one different lots of seeds have been studied. It has been shown that no relationship exists between environmental conditions of the locality of collection and optimum conditions for germination.

scholarly journals Ecophysiological, morphological, and biochemical traits of free-living Diplosphaera chodatii (Trebouxiophyceae) reveal adaptation to harsh environmental conditions

PROTOPLASMA ◽  
2021 ◽  
Author(s):  
Cynthia Medwed ◽  
Andreas Holzinger ◽  
Stefanie Hofer ◽  
Anja Hartmann ◽  
Dirk Michalik ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Botanical Garden ◽  
Tree Bark ◽  
Photon Flux ◽  
Low Light ◽  
Transmission Electron ◽  
Light Requirements ◽  
Adaptive Mechanisms ◽  
Terrestrial Habitats ◽  
Excellent Preservation

AbstractSingle-celled green algae within the Trebouxiophyceae (Chlorophyta) are typical components of terrestrial habitats, which often exhibit harsh environmental conditions for these microorganisms. This study provides a detailed overview of the ecophysiological, biochemical, and ultrastructural traits of an alga living on tree bark. The alga was isolated from a cypress tree in the Botanical Garden of Innsbruck (Austria) and identified by morphology and molecular phylogeny as Diplosphaera chodatii. Transmission electron microscopy after high-pressure freezing (HPF) showed an excellent preservation of the ultrastructure. The cell wall was bilayered with a smooth inner layer and an outer layer of polysaccharides with a fuzzy hair-like appearance that could possibly act as cell-cell adhesion mechanism and hence as a structural precursor supporting biofilm formation together with the mucilage observed occasionally. The photosynthetic-irradiance curves of D. chodatii indicated low light requirements without photoinhibition at high photon flux densities (1580 μmol photons m−2 s−1) supported by growth rate measurements. D. chodatii showed a high desiccation tolerance, as 85% of its initial value was recovered after controlled desiccation at a relative humidity of ~10%. The alga contained the low molecular weight carbohydrates sucrose and sorbitol, which probably act as protective compounds against desiccation. In addition, a new but chemically not elucidated mycosporine-like amino acid was detected with a molecular mass of 332 g mol−1 and an absorption maximum of 324 nm. The presented data provide various traits which contribute to a better understanding of the adaptive mechanisms of D. chodatii to terrestrial habitats.

Predator and prey detection in two species of water bear (Tardigrada)

2019 ◽  
Vol 188 (3) ◽  
pp. 860-864 ◽  
Author(s):  
Harry A Meyer ◽  
Hannah E Larsen ◽  
Nézira O Akobi ◽  
Garret Broussard
Keyword(s):  
Environmental Conditions ◽  
The Other ◽  
Physical Contact ◽  
Nutrient Agar ◽  
Control Treatment ◽  
Prey Detection ◽  
Potential Prey ◽  
Predator Prey ◽  
Petri Dishes

Abstract Tardigrade behavioural studies have focused on responses to abiotic environmental conditions. Predator–prey interactions have received some attention, but not how predators and prey might detect one another. Here, we investigate whether a predatory tardigrade species is attracted to, and a potential prey tardigrade avoids, areas previously occupied by the other. In our experiments, Milnesium lagniappe was the predator and Macrobiotus acadianus the prey. Petri dishes with non-nutrient agar were used as experimental arenas. In one treatment, we allowed Macrobiotus to roam over half of the agar for 20 h, while leaving the other half free of Macrobiotus. We then removed the prey and introduced the predator. In the control treatment, no prey were added. Results indicated that Milnesium individuals were significantly concentrated in the area previously occupied by Macrobiotus, whereas no such concentration was evident when Macrobiotus had not been present. A similar protocol was used to test whether Macrobiotus avoided areas previously occupied by the predator. As expected, Macrobiotus were significantly concentrated in the area never occupied by Milnesium, unlike the control treatment. These results suggest that both species can detect the other without physical contact and react accordingly. Given that the experiments were conducted in darkness, detection is probably olfactory.

scholarly journals A Computer Vision System for the Automatic Classification of Five Varieties of Tree Leaf Images

Computers ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 6 ◽  
Author(s):  
Sajad Sabzi ◽  
Razieh Pourdarbani ◽  
Juan Ignacio Arribas
Keyword(s):  
Neural Network ◽  
Vision System ◽  
Eucalyptus Camaldulensis ◽  
Prunus Armeniaca ◽  
Malus Pumila ◽  
Computer Vision System ◽  
Cydonia Oblonga ◽  
River Red Gum ◽  
Hybrid Artificial Neural Network

A computer vision system for automatic recognition and classification of five varieties of plant leaves under controlled laboratory imaging conditions, comprising: 1–Cydonia oblonga (quince), 2–Eucalyptus camaldulensis dehn (river red gum), 3–Malus pumila (apple), 4–Pistacia atlantica (mt. Atlas mastic tree) and 5–Prunus armeniaca (apricot), is proposed. 516 tree leaves images were taken and 285 features computed from each object including shape features, color features, texture features based on the gray level co-occurrence matrix, texture descriptors based on histogram and moment invariants. Seven discriminant features were selected and input for classification purposes using three classifiers: hybrid artificial neural network–ant bee colony (ANN–ABC), hybrid artificial neural network–biogeography based optimization (ANN–BBO) and Fisher linear discriminant analysis (LDA). Mean correct classification rates (CCR), resulted in 94.04%, 89.23%, and 93.99%, for hybrid ANN–ABC; hybrid ANN–BBO; and LDA classifiers, respectively. Best classifier mean area under curve (AUC), mean sensitivity, and mean specificity, were computed for the five tree varieties under study, resulting in: 1–Cydonia oblonga (quince) 0.991 (ANN–ABC), 95.89% (ANN–ABC), 95.91% (ANN–ABC); 2–Eucalyptus camaldulensis dehn (river red gum) 1.00 (LDA), 100% (LDA), 100% (LDA); 3–Malus pumila (apple) 0.996 (LDA), 96.63% (LDA), 94.99% (LDA); 4–Pistacia atlantica (mt. Atlas mastic tree) 0.979 (LDA), 91.71% (LDA), 82.57% (LDA); and 5–Prunus armeniaca (apricot) 0.994 (LDA), 88.67% (LDA), 94.65% (LDA), respectively.

Litter Fall and Leaf Decomposition in a River Red Gum (Eucalyptus camaldulensis) Swamp

1983 ◽  
Vol 31 (3) ◽  
pp. 307 ◽  
Author(s):  
SV Briggs ◽  
MT Maher
Keyword(s):  
New South ◽  
Eucalyptus Camaldulensis ◽  
Leaf Decomposition ◽  
Leaf Fall ◽  
Litter Fall ◽  
Nutrient Input ◽  
South Wales ◽  
Flood Period ◽  
Important Food Source ◽  
River Red Gum

Litter fall and leaf decomposition rates were measured in Murrumbidgil Swamp, a river red gum (Eucalyptus camaldulensis) swamp near Booligal, New South Wales. Total litter fall, excluding large branches, was about the same as in other eucalypt and overseas hardwood forests (369-580 g m-2 year-1), but the proportion of leaf fall (21-29%) was lower. Litter fall was greater after the swamp dried out following a prolonged period of flooding than during the flood period. Ionic concentrations in the leaf litter were higher than in other eucalypts, but accessions were similar because leaf fall was lower in the red gum forest. The order of nutrient input was Ca > N > Mg ≈ Na ≈ K > S > P > Fe. Decomposition of red gum leaves submerged in the swamp was rapid at first (up to 19.2% loss in weight in 24 h) and then slowed down. The half life of the leaves decomposing over 4 months was 80 days. It is suggested that E. camaldulensis litter may provide an important food source for detritivorous invertebrates and hence for waterfowl in red gum swamps.

Restoration of Catchment Water Balance: Responses of Clonal River Red Gum (Eucalyptus camaldulensis) to Waterlogging

1997 ◽  
Vol 5 (2) ◽  
pp. 101-108 ◽  
Author(s):  
Kandia Akilan ◽  
John K. Marshall ◽  
Anne L. Morgan ◽  
Richard C. C. Farrell ◽  
David T. Bell
Keyword(s):  
Water Balance ◽  
Eucalyptus Camaldulensis ◽  
River Red Gum

scholarly journals Bioassay, Effect of Field-Aged Residue Degradation of Basillus Thuringiensis, 1994

1995 ◽  
Vol 20 (1) ◽  
pp. 351-351 ◽  
Author(s):  
J. F. Brunner ◽  
M. D. Doerr ◽  
L. O. Smith
Keyword(s):  
Constant Temperature ◽  
Petri Dish ◽  
Larval Survival ◽  
Apple Orchard ◽  
Food Storage ◽  
Storage Container ◽  
Tree Fruit ◽  
Petri Dishes ◽  
Extension Center ◽  
Neonate Larvae

Abstract Using a leaf-disk bioassay, B. thuringiensis products were evaluated for residue effects on PLR and OBLR neonate larvae. The test was conducted in an apple orchard at the Tree Fruit Research and Extension Center. The trees were 15-yr-old spur type ‘Red Delicious’ on dwarfing roots. The treatments were applied on 22 Sep at the recommended rate with a handgun sprayer at 300 psi to the point of drip, simulating a dilute spray of approximately 400 gal/acre. Each treatment was replicated three times with one tree in each. Ten leaves were collected from the interior canopy of each tree at 1, 4, 6 and 8 DAT. Two punches (2.3 cm diameter) were taken from each leaf. Four punches were placed in a petri dish (Falcon 1006, 50 × 9 mm), keeping the leaves from each replication separate. Petri dishes were chosen randomly, and five 1- to 2-d-old leafroller larvae were placed on the leaves. Five petri dishes were prepared for each tree and each leafroller species (75 larvae per treatment). The petri dishes were placed inside a food storage container and kept at 20°C constant temperature and a photoperiod of 16:8 (L:D) h. Petri dishes were examined after 7 d and larval survival recorded.

scholarly journals The Fracture Toughness of PVC / GRP Sandwich Systems in Marine Environment

2008 ◽  
Vol 17 (1) ◽  
pp. 096369350801700 ◽  
Author(s):  
Cemal Koçhan ◽  
Gökdeniz Neşer ◽  
Çiçek Özes
Keyword(s):  
Fracture Toughness ◽  
Constant Temperature ◽  
Marine Environment ◽  
Environmental Conditions ◽  
Sandwich Beam ◽  
Core Material ◽  
Mode I ◽  
Foam Core ◽  
Marine Environmental

The aim of this study is to investigate experimentally the fracture toughness of sandwich systems with the PVC foam core in marine environment with a Mode-I Cracked Sandwich Beam (CSB) test arrangement. Five CSB specimens at each condition were tested. To get the values under marine environment, one set of specimen was conditioned in a 5% solution of NaCl for a 120 h period at a constant temperature of 50°C. It has been found that the fracture toughness of the PVC foam core material slightly increases under marine environmental conditions. It can be concluded that under the conditions in this study the system with the PVC core was largely unaffected by the immersion process.

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