Quality traits and mineral profile of carrot ‘Dordogne’ as affected by foliar applications of silicon

Carrot (Daucus carota L.) represents the world's main root crop. Its fleshy taproot is very common in western diets, being consumed as fresh vegetable or in form of processed products. Because of its composition and high per capita consumption, carrot is a valuable dietary source of carotenoids, polyphenols and minerals, thus further improving its chemical traits might properly address the growing world demand for nutrient-dense foods. Moreover, despite the fact that fresh carrots can usually be stored for long time in controlled environment (6-8 months at approximate to 0 degrees C), not as much can be attained for 'early' carrots produced in southern Italy, because of leaves presence, which promotes transpiration and senescence. A promising strategy might be the preharvest foliar application of silicon (Si), which is reported to modulate plant metabolism and to strengthen the plant tissues, also improving the product tolerance to postharvest storage conditions. Silicon has also gained interest because of its biofortification activity. Beside its beneficial role on human health, Si can improve the nutraceutical traits of plant products by enhancing the uptake of minerals, as well as the synthesis of specialized metabolites such as ascorbic acid, carotenoids and phenolics. The aim of this study was to investigate the effects of Si foliar sprays on carrot morphological and compositional traits, along with its postharvest behaviour also in relation to the leaf presence. Silicon improved leaf dry matter and photosynthetic pigments contents. Treated roots showed higher dry matter content, and an overall improved mineral profile. Moreover, Si attenuated weight loss and carotenoids degradation during 7 days of storage at 12 degrees C.