The Potential of Nitrate Accumulation in Plants and the Effects of Nitrate on Human Health

Abstract

Plants take nitrogen (N) from the soil through their roots throughout their life cycle. The amount and uptake form of nitrogen, an essential nutrient, significantly influence plant growth and their interactions with the environment. In soil, N is present in inorganic forms such as nitrate (NO3−) and ammonium (NH4+), but can also be found in organic forms such as urea, free amino acids and short peptides. Nitrate (NO3−) is a very important form of nitrogen for all plants due to its role in plant nutrition and physiology. Leafy vegetables have a very important place in the human diet, but they are a food group that contributes greatly to nitrate (NO3−) uptake by living organisms. Exogenous nitrate concentrations are among the most important factors influencing NO3− accumulation in plants. Leafy vegetables can accumulate high amounts of nitrates if nitrogen fertilisation is excessive. Nitrate-containing foods consumed by humans can pose serious health risks. This review focuses on nitrate assimilation and transport in plants, nutritional, environmental and physiological factors affecting nitrate accumulation, the contribution of vegetables to nitrate uptake in humans, and the harmful and beneficial effects of nitrate on human health.

Keywords

• Nitrate assimilation and transport
• Nitrate toxicity
• Nİtrate reductase
• Leafy vegetables
• Human health

Bitkilerde Nitrat Birikim Potansiyeli ve Nitratın İnsan Sağlığı Üzerindeki Etkileri

Öz

Bitkiler tüm yaşam döngüleri boyunca kökleri aracılığıyla topraktan azot (N) alırlar. Temel bir besin elementi olan azotun miktarı ve alınma formu, bitki büyümesini ve onun çevresiyle olan etkileşimlerini önemli ölçüde etkiler. Toprakta N; nitrat (NO3−) ve amonyum (NH4+) gibi inorganik formlarda bulunmakla birlikte üre, serbest amino asitler ve kısa peptidlerden oluşan organik formlarda da bulunabilmektedir. Nitrat (NO3−), bitki beslenmesindeki ve fizyolojisindeki rolü nedeniyle tüm bitkiler için çok önemli bir azot formudur. Yapraklı sebzeler insanların beslenmesinde çok önemli bir yer tutmakla birlikte canlıların nitrat (NO3−) alımına yüksek seviyelerde katkı sağlayan bir besin grubunu da oluşturmaktadır. Nitratın eksojen konsantrasyonları, bitkilerde NO3− birikimini etkileyen en önemli faktörler arasındadır. Azotlu gübrenin aşırı uygulanması durumunda yapraklı sebzeler yüksek düzeyde nitrat biriktirebilir. İnsanlar tarafından tüketilen nitrat bakımından zengin besinler ciddi sağlık tehlikeleri oluşturabilir. Bu derleme çalışması, bitkilerde nitrat asimilasyonu ve taşınımı, nitrat birikimini etkileyen besinsel, çevresel ve fizyolojik faktörler, insanların diyetle nitrat alımına sebzelerin katkısı ve nitratın insan sağlığı üzerindeki zararlı ve faydalı etkileri üzerine odaklanmaktadır.

Anahtar Kelimeler

• Nitrat asimilasyonu ve taşınımı
• nitrat toksisitesi
• nitrat redüktaz
• yapraklı sebzeler
• insan sağlığı

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