Sucrose homeostasis: Mechanisms and opportunity in crop yield improvement

Sugar homeostasis is a critical feature of biological systems. In humans, raised and dysregulated blood sugar is a serious health issue. In plants, directed changes in sucrose homeostasis and allocation represent opportunities in crop improvement. Plant tissue sucrose varies more than blood glucose and is found at higher concentrations (cytosol and phloem ca. 100 mM v 3.9–6.9 mM for blood glucose). Tissue sucrose varies with developmental stage and environment, but cytosol and phloem exhibit tight sucrose control. Sucrose homeostasis is a consequence of the integration of photosynthesis, synthesis of storage end products such as starch, transport of sucrose to sinks and sink metabolism. Trehalose 6-phosphate (T6P)-SnRK1 and TOR play central, still emerging roles in regulating and coordinating these processes. Overall, tissue sucrose levels are more strongly related to growth than to photosynthesis. As a key sucrose signal,T6P regulates sucrose levels, transport and metabolic pathways to coordinate source and sink at a whole plant level. Emerging evidence shows that T6P interacts with meristems. With careful targeting, T6P manipulation through exploiting natural variation, chemical intervention and genetic modification is delivering benefits for crop yields. Regulation of cereal grain set, filling and retention may be the most strategically important aspect of sucrose allocation and homeostasis for food security

A wave packet Golden Rule treatment of vibrational predissociation

The time-dependent wave packet technique is applied to the Golden Rule treatment of vibrational predissociation. The wave packet at time zero is taken as the product of the quasibound wave function and the coupling inducing predissociation. The rate for vibrational predissociation can then be obtained by Fourier transform into the energy domain of the time-dependent wave packet autocorrelation function. The method has been applied to a model triatomic van der Waals molecule. It is shown that when the bound-state components of the wave packet are projected out, the time-dependent version of the Golden Rule approximation provides an alternative efficient technique to treat intramolecular decay. © 1991 American Institute of Physics.Peer Reviewe

Assessing the impact of climate change on sweet potato in Uganda

Sweet potato is a mainstay of household food security and a major source of vitamin A across sub-Saharan Africa, and particularly in Uganda. Understanding how climate change is likely to impact on sweet potato would be useful for policymakers in Uganda making decisions to improve food security and increase resilience to climate shocks. However, sweet potato is an under-researched crop and the impacts of climate change have not been systematically analysed. The Sweet Potato Catalyst Project aims to assess the impacts of climate change on sweet potato in Uganda and develop ways for local stakeholders to access and assess this information to strengthen governance. This policy briefing note provides an overview of the research, the approach being taken and anticipated outcomes that will feed into the UNFCCC Koronovia Joint Work on Agriculture

Sweet potato production in Uganda in a changing climate: what is the role for fertilisers

This policy brief for the Ugandan Government covers the use of manure and inorganic fertilisers in sweet potato production, including how fertiliser use in sweet potato production can contribute to boosting yields, livelihood resilience, improving diets and fighting malnutrition in Uganda in the face of climate change

Effect of bending on the predissociation dynamics of N2O+

In this paper we introduce a modified version of the infinite-order sudden approximation (IOSA) for rotational and bending degrees of freedom, together. © 1983.Peer Reviewe

A theoretical investigation on the spectrum of the Ar trimer for high rotational excitations

Abstract: A detailed study of the rovibrational spectrum of the Ar trimer is performed by means of an exact hyperspherical coordinate (HC) method and a variational approach based on distributed Gaussian functions (DGFs) to describe the interparticle distances. The good agreement observed between the energy levels obtained with both procedures for high values of the total angular momentum (J=15 and 20) reveals the quality of the DGF method to describe the rotation of the title system. Rotational constants for the lowest bound states, obtained as averages for each vibrational state, have been obtained and compared to previous results. A detailed analysis of density probability functions obtained by means of the HC approach for rovibrational states at J=0 and 20 shows close similitudes thus supporting the vibration-rotation separation adopted within the DGF scheme for the Ar(3) system