Water relations and irrigation requirements of onion (Allium Cepa L.): a review of yield and quality impacts

The results of international research on the water relations and irrigation needs of onions have been synthesized in an attempt to link fundamental studies on crop physiology to irrigation practices, and consequent impacts on crop yield, quality and storage. Following a brief introduction on its origins and centres of production, a synthesis of research on crop development including plant water relations, crop water requirements, yield response to water, irrigation systems and scheduling are presented. Most of the evidence stems from research conducted in arid and semi-arid regions notably the USA, India, Spain and Turkey. The findings confirm that onion seasonal water requirements are highly variable depending on agroclimate, location and season, as are the crop coefficients (Kc) which range from 0.4 to 0.7 (initial stage), 0.85 to 1.05 (middle development) and 0.6 to 0.75 (final stage). Seasonal irrigation needs are reported to vary from 225 to 1040 mm to produce between 10 and 77 t ha-1. The most sensitive stages for water stress are at emergence, transplanting and bulb formation. Final crop quality can also be affected by water excess. Water stress at specific stages can negatively impact on quality leading to reduced size and multi-centred bulbs. In recent years, pressure on water resources, retailer demands for quality assurance and rising production costs have meant that onion irrigation has switched from traditional low efficiency (furrow) methods to more efficient advanced (sprinkler and drip) technologies. For scheduling, optimal soil water potential thresholds for triggering irrigation were found to be between -17 kPa and -27 kPa for drip and furrow irrigation. Research is underway to maximize water use efficiency in onions, but the deficit irrigation regimes being tested under experimental conditions have yet to be adopted commercially

Fluoxetine Exerts Age-Dependent Effects on Behavior and Amygdala Neuroplasticity in the Rat

The selective serotonin reuptake inhibitor (SSRI) Prozac® (fluoxetine) is the only registered antidepressant to treat depression in children and adolescents. Yet, while the safety of SSRIs has been well established in adults, serotonin exerts neurotrophic actions in the developing brain and thereby may have harmful effects in adolescents. Here we treated adolescent and adult rats chronically with fluoxetine (12 mg/kg) at postnatal day (PND) 25 to 46 and from PND 67 to 88, respectively, and tested the animals 7–14 days after the last injection when (nor)fluoxetine in blood plasma had been washed out, as determined by HPLC. Plasma (nor)fluoxetine levels were also measured 5 hrs after the last fluoxetine injection, and matched clinical levels. Adolescent rats displayed increased behavioral despair in the forced swim test, which was not seen in adult fluoxetine treated rats. In addition, beneficial effects of fluoxetine on wakefulness as measured by electroencephalography in adults was not seen in adolescent rats, and age-dependent effects on the acoustic startle response and prepulse inhibition were observed. On the other hand, adolescent rats showed resilience to the anorexic effects of fluoxetine. Exploratory behavior in the open field test was not affected by fluoxetine treatment, but anxiety levels in the elevated plus maze test were increased in both adolescent and adult fluoxetine treated rats. Finally, in the amygdala, but not the dorsal raphe nucleus and medial prefrontal cortex, the number of PSA-NCAM (marker for synaptic remodeling) immunoreactive neurons was increased in adolescent rats, and decreased in adult rats, as a consequence of chronic fluoxetine treatment. No fluoxetine-induced changes in 5-HT1A receptor immunoreactivity were observed. In conclusion, we show that fluoxetine exerts both harmful and beneficial age-dependent effects on depressive behavior, body weight and wakefulness, which may relate, in part, to differential fluoxetine-induced neuroplasticity in the amygdala

The effect of hot water treatment and type of unit packaging on durability of fresh-cut pepper during short storage

The aim of the study was to assess the effect of the hot water treatment on storage ability of yellow fruit fresh-cut pepper ‘Sunny F1’. The usefulness of unit packaging of fresh-cut red fruit pepper ‘Yecla F1’ was also evaluated. The post-harvest hot water treatment of temperature 45-55 °C improved the hardness of fresh cut pepper ‘Sunny F1’. The best quality in cold storage and subsequent shelf life (18-20 °C) maintained pepper treated by water with temperature of 55 °C for 12 seconds. The storage temperature influenced significantly the quality of fresh-cut pepper. Pepper maintained better quality at a temperature of 3 °C and 5 °C than at 8 °C. Comparing the unit packaging for fresh-cut pepper ‘Yecla F1’, distinctly better quality after 6 days of storage at 8 °C was found for pepper on polystyrene foam trays wrapped in stretchy film and in bags with microperforation (PET/PE and PET) than in polyethylene bags with perforation (6 holes ø 0.04 cm)

The influence of nano-silver, nano-copper and hydrogen peroxide on vegetable pathogens

Silver nanoparticles used in concentration 100 ppm inhibited S. sclerotiorum development on fresh cut carrot. The best results were obtained for nano-silver with diameter 8 nm (when the spraying was done twice: before and after fungus inoculation). Nano-copper and mixture of nano-silver and nano-copper did not affect the disease development. It was found that none of used nanopar-ticles (nano-silver, nano-copper, and mixture of nano-silver and nano-copper) inhibited B. cinerea mycelium growth on fresh cut cabbage and fresh cut onion. Huwa-San TR50 appeared to be effective against S. sclerotiorum if the pathogen inoculation was done after two and three days of vegetable spraying. Huwa-San did not influence on B. cinerea growth on cabbage and onion