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"Smillie, Ian"
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Overproduction of Abscisic Acid in Tomato Increases Transpiration Efficiency and Root Hydraulic Conductivity and Influences Leaf Expansion
Overexpression of genes that respond to drought stress is a seemingly attractive approach for improving drought resistance in crops. However, the consequences for both water-use efficiency and productivity must be considered if agronomic utility is sought. Here, we characterize two tomato (Solarium lycopersicum) lines (sp12 and sp5) that overexpress a gene encoding 9-cisepoxycarotenoid dioxygenase, the enzyme that catalyzes a key rate-limiting step in abscisic acid (ABA) biosynthesis. Both lines contained more ABA than the wild type, with sp5 accumulating more than sp12. Both had higher transpiration efficiency because of their lower stomatal conductance, as demonstrated by increases in δ¹³C and δ¹ɸO, and also by gravimetric and gas-exchange methods. They also had greater root hydraulic conductivity. Under well-watered glasshouse conditions, mature sp5 plants were found to have a shoot biomass equal to the wild type despite their lower assimilation rate per unit leaf area. These plants also had longer petioles, larger leaf area, increased specific leaf area, and reduced leaf epinasty. When exposed to root-zone water deficits, line sp12 showed an increase in xylem ABA concentration and a reduction in stomatal conductance to the same final levels as the wild type, but from a different basal level. Indeed, the main difference between the high ABA plants and the wild type was their performance under well- watered conditions: the former conserved soil water by limiting maximum stomatal conductance per unit leaf area, but also, at least in the case of sp5, developed a canopy more suited to light interception, maximizing assimilation per plant, possibly due to improved turgor or suppression of epinasty.
Journal Article
Enhanced thylakoid photoprotection can increase yield and canopy radiation use efficiency in rice
High sunlight can raise plant growth rates but can potentially cause cellular damage. The likelihood of deleterious effects is lowered by a sophisticated set of photoprotective mechanisms, one of the most important being the controlled dissipation of energy from chlorophyll within photosystem II (PSII) measured as non-photochemical quenching (NPQ). Although ubiquitous, the role of NPQ in plant productivity remains uncertain because it momentarily reduces the quantum efficiency of photosynthesis. Here we used plants overexpressing the gene encoding a central regulator of NPQ, the protein PsbS, within a major crop species (rice) to assess the effect of photoprotection at the whole canopy scale. We accounted for canopy light interception, to our knowledge for the first time in this context. We show that in comparison to wild-type plants,
psbS
overexpressors increased canopy radiation use efficiency and grain yield in fluctuating light, demonstrating that photoprotective mechanisms should be altered to improve rice crop productivity.
Stella Hubbart et al. show that over-expression of the photoprotective protein gene
psbS
leads to enhanced canopy-level radiation use efficiency and grain yield in rice. The results demonstrate that alterations to photoprotection and light-harvesting processes could be used to improve yield in rice crops.
Journal Article
The retirement project of George Stuart Atkins: development radio in the time of cybernetics
For years after its start-up in 1979, Farm Radio International (FRI) sent radio scripts and other material to broadcasters in more than 100 developing countries, believing it reached as many as 100 million people. By 2000, however, its unidirectional scattershot approach was being questioned by both communication specialists and its principal donor. Following a four-year struggle to reorganise its mission, programmes, and funding, FRI found new purpose, a new donor, and solid evidence of impact. The viewpoint offers lessons in management, communications for development, donor infatuation with \"The Next Big Thing\", the difference between information and knowledge, and how people learn.
Journal Article
Stylohyoid Complex Syndrome Associated With Unilateral Vocal Cord Palsy: A Case Report
Eagle's syndrome is a rare cause of cervicofacial pain and is due to abnormalities in the stylohyoid process, stylohyoid ligament or lesser cornu of the hyoid bone. Generally, patients affected by Eagle's syndrome present with pain in the lateral or upper neck, angle of the mandible, submandibular space and throat (exacerbated by head movements and/or mastication); foreign body sensation; headache and referred otalgia. A 66-year old gentleman presented with a 36-month history of recurrent pain localising mainly to the right angle of the mandible and radiating to the submandibular triangle. No pathological changes were noted on multiple ultrasound scans. Flexible nasendoscopy revealed a right vocal cord palsy. Initially, the CT scan revealed an abnormality in the stylohyoid complex, and the patient was managed conservatively. Subsequent three-dimensional CT scan noted significant worsening of the abnormality in the stylohyoid complex. Due to progressive nature of the patient's symptoms and progression of stylohyoid complex calcification noted on imaging, the patient was listed for surgery. He underwent partial styloidectomy and vocal cord injection for cord paralysis secondary to impingement on the vagal nerve by the stylohyoid complex. The patient recovered well and denies any ongoing stylalgia. Various cases of Eagle's syndrome have been managed successfully in a conservative manner. However, the authors of this case report suggest that patients with Eagle's syndrome should be monitored closely. A delay in surgical intervention can lead to complications such as complete ossification of the stylohyoid complex and impingement on surrounding structures. This, in turn, increases intra-operative complexity.
Journal Article
Patronage or partnership
Much has been written about the need to build local capacities in emergency and postemergency situations. Many relief programs, however, remain characterized by externality: in their funding, accountabilities, approach to management, and dependence upon expatriate staff. Reality often flies in the face of stated policy and good intentions. In reality, strengthening local capacity is easier said than done, and there are real tradeoffs between outsiders doing something right now in the midst of an emergency, on the one hand, and building longer term local skills, on the other.
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