Inter‐ and intrapopulation variation in dormancy of Oryza sativa (weedy red rice) and allelic variation in dormancy‐linked loci

Oryza sativa (weedy red rice), the same species as cultivated rice, is a serious problem in rice production worldwide. Seed dormancy contributes to its persistence. We determined the effect of germination temperature and after‐ripening period on germination capacity (GC) of red rice seeds from Arkansas rice fields in three production zones. We also determined the gene diversity (GD) of dormancy‐linked loci among selected populations. The germination behaviour was evaluated at three temperatures (1°C, 15°C and 35°C) and four after‐ripening periods (0, 30, 60 and 90 days) in two independent experiments. Germination response to temperature and after‐ripening time differed among and within populations in each production zone. Overall, populations from the Delta and Grand Prairie were more dormant than those from White River. Regardless of ecotype or production zone, incubation at 35°C (mean GC = 84–100%) favoured the germination of seeds after‐ripened for 60 days. Germination of these seeds was most variable at suboptimal temperature (15°C), with mean GC ranging from 44 to 97%; at 1°C, none of the seeds germinated. Primary dormancy was released in the majority of populations after 90 days of after‐ripening. Blackhull populations generally had lower mean GC than strawhull populations, regardless of temperature, and required longer after‐ripening time to release dormancy. They also showed a higher inter‐ and intrapopulation variation in germination and after‐ripening than strawhulls and had the highest gene diversity (GD = 0.55–0.58) among test populations. Non‐dormant strawhulls were most distant (D = 0.63) from dormant blackhulls. Ecotype influenced genotypic clustering more than the dormancy trait.     

Approach to the patient in respiratory distress

Respiratory distress is a very common presenting complaint in emergency practice. It is essential that the clinician rapidly determine the underlying cause of the clinical signs using physical examination findings and nonstressful diagnostic tests. Oxygen therapy will often stabilize a patient, allowing for a more complete physical examination and diagnostics, including thoracocentesis, thoracic radiographs, and blood collection for laboratory analysis. The disease processes that cause respiratory distress can be grouped according to anatomic location: the airways, pulmonary parenchyma, pleural space, or thoracic wall. The choice of diagnostic and therapeutic techniques will be dependent on the suspected anatomic origin of disease. Techniques useful in diagnosing airway disorders include oral examination, cervical and thoracic radiographs, fluoroscopy, and bronchoscopy. Therapeutic techniques include intubation and tracheostomy. For parenchymal disease, thoracic radiographs, echocardiography, ultrasound of the thorax, and transtracheal or endotracheal wash can be useful. When the disease process is in the pleural space, thoracocentesis can be both diagnostic and therapeutic. Chest tube placement may be necessary for continuous removal of air or fluid from the pleural space. Monitoring of the respiratory patient can involve serial physical examination, pulse oximetry, and arterial blood gas analysis. It is essential to minimize stress on patients with respiratory distress because decompensation can occur easily, leading to respiratory arrest.     

Genetic relationships of Rhododendron (Ericaceae) in Taiwan based on the sequence of the internal transcribed spacer of ribosomal DNA

Summary

The genetic relationships of 20 Rhododendron species in Taiwan was determined based on the sequence of the internal transcribed spacer (ITS) region of ribosomal DNA. Sequences of the complete ITS region including ITS1, 5.8S rDNA, and ITS2, were obtained by direct sequencing of polymerase chain reaction (PCR)-amplified fragments. Gaultheria itoana was used as an outgroup. Aligned sequences of ITS1 and ITS2 from the 21 taxa resulted in 493 characters. According to the dendrogram, six main clusters were classified among the 20 species of the genus Rhododendron in Taiwan. Rhododendron oldhamii, R. nakaharai, R. taiwanalpinum, R. simsii, R. lasiostylum, R. rubropilosum, R. breviperulatum, R. kanehirai, and R. noriakianum were grouped with R. longiperulatum in cluster I. Rhododendron lamprophyllum was grouped with R. ovatum in cluster II. Rhododendron pseudochrysanthum, R. morri, R. hyperythrum, and R. rubropunctatum were grouped with R. formosanum in cluster III. In addition, R. mariesii, R. ellipticum and R. kawakamii formed three independent clusters. In this study, the findings based on ITS sequences are in agreement with the systematics of Rhododendron.     

小麦条锈菌、叶锈菌和白粉菌混合侵染对病斑扩展的影响

 小麦条锈病、叶锈病和白粉病是小麦主要的叶部病害,它柄在侵染特点、发病规律及危害特性等方面均有许多相似之处。     

Acceleration of post‐mortem changes in Tsaiya duck (Anas platyrhynchos) breast muscle by lactic acid marination

1. The effect of lactic acid marination at 5°C on post mortem changes in breast muscle pectoralis major of spent layer Tsaiya duck was studied.

2. Myofibrils were prepared from 0.1 M and 0.2 M lactic acid marinated muscle and control (non‐marinated samples) sampled at 0, 1, 3, 7 and 14 d post mortem.

3. Changes in myofibril fragmentation index (MFI), myofibrillar proteins and Z‐line structure were examined.

4. Marination of duck breast muscle in lactic acid at 5°C enhanced fragmentation of myofibrils and degradation of myofibrillar proteins and Z‐line structure as compared to control samples.

5. In summary, lactic acid marination at 5°C can accelerate the post mortem degradation of myofibrils in Tsaiya duck breast muscle.     

Vine cuttings as possible initial inoculum sources of Ralstonia solanacearum race 1 biovar 4 on vegetable sweet potato in fields

Ralstonia solanacearum, which consists of five races/biovars, is considered a “species-complex” and is an important phytopathogen that causes wilt disease in more than 200 plant species. R. solanacearum race 1 biovar 4 (R1bv4) has caused yield losses of 30–80 % in the vegetable sweet potato (VSP) in the last decade in Taiwan. To identify the source of the initial inoculum of R1bv4 in VSP fields, soil and cuttings from these fields were examined from 2009 to 2010. The results of the investigation indicated that the population of R1bv4 was generally distributed throughout the natural soil of VSP fields at a density ranging from 1.3?×?10² to 9.5?×?10⁵ cfu/g soil; however, the incidence of bacterial wilt was not significantly associated with the density of the R1bv4 population in soils (R²?=?0.084). In contrast, densities of R1bv4 ranging from 2.3?×?10³ to 5.9?×?10⁵ cfu/g tissue were detected in the vine tissue of asymptomatic plants in the fields. Additional experiments demonstrated that R1bv4-free VSP cuttings without visible symptoms planted in infested soils in the greenhouse setting could carry approximately 3.1?×?10⁵ R1bv4 cfu/g tissue, which suggests the existence of a latent period for R1bv4 in VSP plants. The results of a BIO-PCR analysis showed that R1bv4 was detected in 2.0 to 98.0 % of the VSP cuttings used for propagation in fields; in addition, the percentage of VSP cuttings carrying R1bv4 and the incidence of bacterial wilt in fields were positively correlated (R²?=?0.909). The inoculation experiments conducted in greenhouses and in fields showed that the cutting inoculum (CI) contributed more to the incidence of bacterial wilt in VSP plants than the soil inoculum (SI). In the field experiments conducted in 2010, an incidence of disease of 27.1 to 38.5 % was detected in healthy field cuttings 8 months after transplantation; in contrast, the incidence of disease in field cuttings carrying R1bv4 was 49.0 to 68.8 %. The incidence of disease was significantly lower in healthy cuttings than in cuttings carrying R1bv4 (p?=?0.05).