Applying sunflower oil to rapeseed plants reduces water loss.

BACKGROUND: Hydrophobic polymers are used as antitranspirants to block stomata and reduce water loss from plants and thus drought stress, although the use of current commercial products is limited because they are expensive. Plant oils may be much cheaper hydrophobic polymers if they have similar efficacy to commercial antitranspirant products. Two experiments with pot-grown rapeseed plants were conducted to compare sunflower oil with the commercially-available antitranspirant di-1-p-menthene (DPM) for efficacy in reducing water loss, and to test for a linear response to increasing oil concentration. RESULTS: Sunflower oil at the same concentration as DPM (0.5%) was similar in efficacy in reducing the rate of water loss, measured as both rate of weight loss of the plant and rate of stomatal conductance decline. There was a linear response to increasing concentrations of oil, as found in previous research with DPM on rapeseed, with a slower rate of water loss the greater the concentration. CONCLUSION: If other plant oils are equally or more effective in reducing water loss as sunflower oil, there may be potential for plant oils to be used as low-cost antitranspirants to reduce drought damage on large-scale commodity crops, and also by smallholder farmers in low-income countries using locally-produced plant oils. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Rising CO2 from historical concentrations enhances the physiological performance of Brassica napus seedlings under optimal water supply but not under reduced water availability.

The productivity of many important crops is significantly threatened by water shortage, and the elevated atmospheric CO2 can significantly interact with physiological processes and crop responses to drought. We examined the effects of three different CO2 concentrations (historical ~300 ppm, ambient ~400 ppm and elevated ~700 ppm) on physiological traits of oilseed rape (Brassica napus L.) seedlings subjected to well-watered and reduced water availability. Our data show (1) that, as expected, increasing CO2 level positively modulates leaf photosynthetic traits, leaf water-use efficiency and growth under non-stressed conditions, although a pronounced acclimation of photosynthesis to elevated CO2 occurred; (2) that the predicted elevated CO2 concentration does not reduce total evapotranspiration under drought when compared with present (400 ppm) and historical (300 ppm) concentrations because of a larger leaf area that does not buffer transpiration; and (3) that accordingly, the physiological traits analysed decreased similarly under stress for all CO2 concentrations. Our data support the hypothesis that increasing CO2 concentrations may not significantly counteract the negative effect of increasing drought intensity on Brassica napus performance.

Quantifying the impact of exogenous abscisic acid and gibberellins on pre-maturity α-amylase formation in developing wheat grains.

To study the role of abscisic acid (ABA) and gibberellins (GA) in pre-maturity α-amylase (PMA) formation in developing wheat grain, two glasshouse experiments were conducted under controlled conditions in the highly PMA-susceptible genotype Rialto. The first, determined the relative efficacy of applying hormone solutions by injection into the peduncle compared to direct application to the intact grain. The second, examined the effects of each hormone, applied by either method, at mid-grain development on PMA in mature grains. In the first experiment, tritiated ABA ((3)H-ABA) and gibberellic acid ((3)H-GA3) were diluted with unlabelled ABA (100 µM) and GA3 (50 µM), respectively, and applied at mid-grain development using both methods. Spikes were harvested after 24, 48 and 72 h from application, and hormone taken up by grains was determined. After 72 h, the uptake per grain in terms of hormones applied was approximately 13% for ABA and 8% for GA3 when applied onto the grains, and approximately 17% for ABA and 5% for GA3 when applied by injection. In the second experiment, applied ABA reduced, whereas applied GA3 increased α-amylase activity. This confirmed that exogenously applied ABA and GA were absorbed in sufficient amounts to alter grain metabolism and impact on PMA.

Effect of environment and variety on the relationships of wheat grain physical and chemical characteristics with ethanol yield.

BACKGROUND: Following the Renewable Transport Fuel Obligation (RTFO), there is an increasing demand for wheat grain for liquid biofuel in the UK. In order to enhance productivity of the bioethanol industry, good quality wheat must be used. RESULTS: A total of 84 grain samples comprising 14 varieties collected from 11 sites in two harvest years were analysed for a range of grain quality parameters and ethanol yield (EY). The grain quality parameters studied were starch and protein concentration, specific weight, grain density, packing efficiency, thousand-grain weight (TGW), grain length, width, length/width ratio and hardness index. Regression analysis was used to establish the relationships between grain quality parameters and EY. Apart from grain length and density, all grain parameters had significant relationships with EY. In the order of importance, protein concentration, TGW, packing efficiency and specific weight showed good relationships with EY. All other parameters, including starch concentration, showed a poor correlation with EY. EY and the relationship with the grain parameters were affected more by environment than by variety. Some sites gave consistently higher EY than others. When site and variety were considered with TGW and protein, a good prediction of EY could be made (variance accounted for = 87%). CONCLUSION: Combining TGW and protein concentration could be a better indicator of EY than the current practice of specific weight and protein.

Relationships between disease control, green leaf duration, grain quality and the production of alcohol from winter wheat.

BACKGROUND: Since demand for distilling wheat is expected to increase rapidly as a result of the development of the bioethanol industry, efficient production will become of increasing importance. Achieving this will require an understanding of the agronomic factors that influence both grain yield and alcohol yield. Therefore five field experiments using the winter distilling wheat variety Glasgow were conducted over three seasons (2006-2007, 2007-2008 and 2008-2009) to study the relationships between foliar disease and alcohol yield. RESULTS: There was a significant relationship between alcohol yield and the severity of the disease septoria leaf blotch (Septoria tritici), which was present in the experiments from natural infection. Retention of green flag leaf area as affected by disease control following fungicide application was also shown to be important for achieving high alcohol yields. Measurements of grain quality showed that high thousand-grain weight and low grain protein concentration were significantly related to increased alcohol yield. CONCLUSION: The experiments showed the importance of disease management to protect alcohol yields in the distilling wheat crop. Fungicides that provide greater disease control and improved green leaf retention are likely to be beneficial to alcohol yield.

Engineering and design of vehicles for long distance road transport of livestock (ruminants, pigs and poultry).

During road transportation, livestock are subjected to a number of concurrent potential stressors that can increase mortality and morbidity and compromise welfare status and production efficiency. A major concern is the thermal micro-environment within the vehicle with both heat stress and cold stress constituting major problems. It is possible to mitigate the effects of external climatic conditions by improving vehicle design and operation using engineering solutions that match 'on-board' environmental conditions with the biological requirements of the animals. This review describes an investigative approach that targets four elements. These are the thermal conditions on commercial transport vehicles under a range of climatic conditions, the 'thermal comfort zones' or target conditions for different livestock species, the heat and moisture loads upon vehicles that must be dissipated and the thermodynamic characteristics of animal transport vehicles that affect the design of mechanical or active ventilation systems able to function at maximum efficiency under everyday commercial conditions. Results of research around these four elements can provide the sound scientific basis for improved vehicle design and operation and for legislation and codes of practice aimed at optimising animal welfare and productivity in relation to transportation of livestock on journeys of both long and short duration.