The seeds of most Australian acacias have pronounced physical dormancy (PY). While fire and hot water (HW) treatments cause the lens to ‘pop’ almost instantaneously, for many Acacia species the increase in germination percentage can be gradual. If PY is broken instantly by HW treatment, why is germination often an extended process? Control and HW treatments were performed on seeds of 48 species of Acacia. Seeds were placed on a moist substrate and imbibition was assessed by frequently weighing individual seeds. In the two soft-seeded species all control seeds were fully imbibed within 6–24 h, while in hard-seeded species very few control seeds imbibed over several weeks. In 10 species over 50% of the HW-treated seeds imbibed within 30 h, but mostly the percentage of imbibed seeds gradually increased over several weeks. Some seeds in a replicate would imbibe early, while others would remain unimbibed for many days or weeks then, remarkably, become fully imbibed in less than 24 h. While HW treatment broke PY almost instantaneously, it appeared that in many Acacia species some other part of the testa slowed water from reaching the embryo. This process of having staggered imbibition may be a way of ensuring not all seeds in a population germinate after small rain events. Thus it appears the lens acts as a ‘fire gauge’ while some other part of the seed coat acts as a ‘rain gauge’.

Seeking to improve the wear resistance of the Ti6Al4V (Ti64) alloy for biomedical applications, carbon nanotubes (CNTs) and calcium phosphate (CaP) ceramics were added to Ti64 powder and successfully 3D-printed using a commercial laser engineered net shaping (LENS™) system. It was hypothesized that CNTs would allow for in situ carbide formation during laser processing, resulting in increased surface hardness. It was also hypothesized that CaPs would allow for protective tribofilm formation during wear, reducing material loss from wear-induced damage. Scanning electron microscopy images reveal defect-free microstructures with fine carbides evenly distributed, while X-ray diffraction confirms the presence of carbides without additional unwanted intermetallic phases. Vickers microhardness shows an increase in surface hardness in coatings containing both CNTs and CaPs. In vitro tribological studies found reduced coefficient of friction, reduced wear rates, and reduced metal ion-release concentrations in coatings containing both CNTs and CaPs. This study demonstrates the efficacy of CNTs and CaPs to improve wear resistance of Ti64 for potential applications in articulating surfaces of load-bearing implants.

Les traitements utilisant des rayons X de basse énergie continuent à être réalisés maisen faible nombre. Le praticien se trouve en général près du patient pour maintenirl’appareil et expose donc ses yeux. Avec la modification envisagée de la limite maximaled’exposition du cristallin, des mesures ont été jugées nécessaires pour mieux en connaîtrel’exposition. Pour cela une simulation des traitements a été réalisée. Pour la dose d’untraitement superficiel de 42 Gy, l’exposition du cristallin derrière des verres radioatténuateurs se situe entre 130 et 43 μSv pour des distances entre 40 et 60 cm. Pourl’intra cavitaire les valeurs obtenues sont vingt fois plus faibles. L’atténuation par lesverres est supérieure à 90 %. Le port des lunettes avec verres radio atténuateurs permetde minimiser la dose au cristallin de façon significative. L’application de la nouvellelimite maximale n’aura pas d’impact sur le nombre de traitements.

Structural studies in seeds with physical dormancy (PY) are important to better understand its causes and release when subjected to treatments for dormancy breaking. The aims of this study were to (1) characterize the PY break; (2) examine the role of different seed structures in water uptake; and (3) identify the water gap in Senna multijuga seeds. Imbibition patterns of dormant and non-dormant (subjected to dormancy breaking treatments) seeds and the morphological changes during dormancy breaking and germination were evaluated. To identify the water gap, the micropyle and lens were blocked separately, and the water absorption by seed parts was determined. Structural characteristics of the seed coat were also examined. Immersion in water at 80°C was efficient in breaking seed dormancy and imbibition occurred first at the hilar region, through the lens. Water was not absorbed through the micropyle or the extra-hilar region. S. multijuga seeds have a testa with a linearly aligned micropyle, hilum and lens. The seed coat consisted of a cuticle, macrosclereids, one (hilar region) or two (extra-hilar region) layer(s) of osteosclereids and parenchyma cell layers. The lens has typical parenchyma cells underneath it and two fragile regions comprised of shorter macrosclereids. Heat treatment stimulated the lens region, resulting in the opening of fragile regions at the lens, allowing water to enter the seeds. It is concluded that short-term exposure to a hot water treatment is sufficient for the formation of a water gap in S. multijuga seeds, and only the lens acts in the imbibition process.

This study analysed the anatomical structure of the seed coats, identified the location of water uptake and evaluated the effects of alternating temperatures and heat treatment on the breaking of physical dormancy of two species of Fabaceae (Caesalpinioideae), Cassia leptophylla and Senna macranthera, from the Atlantic forest of Brazil. The seed coats of both species consisted of a cuticle (extra-hilar region) or remaining funicle region (hilar region), subcuticular layer, palisade layer with lignin, osteosclereids, sclerified parenchyma and white cells. The palisade layer was formed by elongated macrosclereids with a light line of callose. In thermally scarified seeds of C. leptophylla, water entered through the micropylar canal, and in S. macranthera the water entered through the lens. Alternating temperatures that ranged from 15 to 30°C did not break physical dormancy of either species; however, exposure to 50°C broke seed hardcoatedness, allowing the entrance of water in both species.

Physical dormancy refers to seeds that are water impermeable. Within the Fabaceae, the structure associated with the breaking of dormancy is usually the lens. This study verified the role of the lens in physical dormancy of seeds of Schizolobium parahyba, a gap species of Fabaceae from the Atlantic Forest of Brazil. The lens in S. parahyba seeds appeared as a subtle depression near the hilum and opposite the micropyle. After treatment of the seeds with hot water, the lens detached from the coat. Blocking water from contacting the lens inhibited water absorption in hot-water-treated seeds. High constant (30°C) and alternating (20/30°C) temperatures promoted the breaking of physical dormancy and germination in non-scarified seeds. Maximum percentage of germination occurred earlier for seeds incubated at 20/30°C than for those incubated at 30°C. Seeds with a blocked lens did not germinate at alternating or high temperatures. This study suggests that alternating temperatures are probably the cause of physical dormancy break of seeds of S. parahyba in gaps in the forest.

Faba bean (Vicia faba L.) was used as the rootstock for lentil scions to test the feasibility of using in vivo inter-generic grafting techniques as a substitute for root induction and as a tool in lentil genetic improvement. An accession of each of the six wild Lens species was used as the scion in grafts to faba bean breeding line FB50-9 rootstock. Successful grafts were obtained for all species with survival of grafts to seed maturity between 70.7 and 87.7% except for Lens orientalis PI 72735 with 55.3% survival. Days to flower remained the same after grafting, except for scions of L. nigricans PI 72560 and L. orientalis PI 72735 which had a lag phase of 9 and 7 d, respectively. For all six wild species, seed diameter and seed weight were not significantly different between non-grafted controls and scions grafted onto faba bean rootstocks. This simple approach opens the possibility of using in vivo grafting techniques to rescue inter-specific hybrids of lentil. The technique has potential as a useful tool in lentil breeding, as a means of improving seed multiplication rate of rare genetic resources of wild lentil and as a way to reduce the costs of germplasm multiplication of wild lentil species.

Although many studies have been conducted on seeds with a water-impermeable seed or fruit coat (physical dormancy), the primary site of water entry into these seeds after dormancy-breaking treatments is still controversial. Thus, the role of lens, hilum, micropyle and extrahilar regions in water uptake of seeds treated to break physical dormancy was examined in Vigna oblongifolia and Sesbania sesban (Fabaceae) following pretreatment with sulphuric acid and hot water. Morphology of seed surfaces in treated versus non-treated seeds of both species was examined with scanning electron microscopy. Most seeds of V. oblongifolia first cracked in the hilum when pretreated with sulphuric acid, but they cracked in both the hilum and extrahilar regions when pretreated with hot water. However, in S. sesban seeds, a crack formed only in the lens following either acid scarification or hot-water treatments, and the seeds imbibed water only through the lens. These results indicate that the primary site of water entry into seeds following physical dormancy break can vary with species and treatments. Slow, early imbibition via the hilum, and subsequent rapid imbibition via the lens, may not be detected unless seeds are monitored for several days. Time allowed for imbibition studies may, at least in part, explain various interpretations about the role of the lens in physical dormancy reported in the literature.

The distribution of preganglionic motoneurons supplying the ciliary ganglion in the cat was defined both qualitatively and quantitatively. These cells were retrogradely labeled directly, following injections of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) into the ciliary ganglion, or were transsynaptically labeled following injections of WGA into the vitreous chamber. Almost half of the cells are distributed rostral to the oculomotor nucleus, both in and lateral to the anteromedian nucleus. Of the remaining preganglionic motoneurons, roughly 20% of the total are located dorsal to the oculomotor nucleus. Strikingly few of these neurons are actually found within the Edinger-Westphal nucleus proper. Instead, the majority are found in the adjacent supraoculomotor area or along the midline between the two somatic nuclei. An additional population, roughly 30% of the total, is located ventral to the oculomotor nucleus. This study also provides evidence for a functional subdivision of this preganglionic population. Pupil-related preganglionic motoneurons were transsynaptically labeled by injecting WGA into the anterior chamber, while lens-related preganglionic motoneurons were transsynaptically labeled by injecting WGA into the ciliary muscle. The results suggest that the pupil-related preganglionic motoneurons, that is, those controlling the iris sphincter pupillae muscle, are located rostrally, in and lateral to the anteromedian nucleus. In contrast, lens-related preganglionic motoneurons, that is, those controlling the ciliary muscle are particularly prevalent caudally, both dorsal and ventral to the oculomotor nucleus. Thus, the cat intraocular muscle preganglionic innervation is spatially organized with respect to function, despite the dispersed nature of its distribution.