Tag Archives: lettuce

xxx M. Amirouche, L. Zella and D. Smadhi
Influence of nitrogen fertilization on lettuce yields (Lactuca sativa L.) using the 15N isotope label
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Influence of nitrogen fertilization on lettuce yields (Lactuca sativa L.) using the 15N isotope label

M. Amirouche¹*, L. Zella² and D. Smadhi³

¹National High School, Department of Rural Engineering, El–Harrach, DZ16004 Algiers, Algeria
²University of Saad Dahlab, Faculty of Nature and life sciences, Department of biotechnology, Ouled Yaïch, DZ09000 Blida, Algeria
³Division of Bioclimatology and Agricultural Hydraulic, National Institute for Agricultural Research, El–Harrach, DZ16004 Algiers, Algeria
*Correspondence: mawhoub.amirouche@gmail.com

Abstract:

Nitrogen fertilization plays an important role in the growth of market gardening and the improvement of yields. Its efficiency of use is imperative for the preservation of the agricultural environment. An experiment is carried out over three consecutive years (2014/2015), (2015/2016) and (2016/2017), in a sub humid climate. The methodology adopted focuses on the variation of optimal nitrogen doses and their effects on the evolution of lettuce cultivation (Lactuca sativa L.), which has a socio-economic impact. The approach takes into account the isotopic marking technique, 15N. The experimental device adopted is of the complete random block type, with four (04) levels: 0 (control), 60, 120 and 180 kg N ha-1 with four (04) repetitions. These levels are used to diagnose the effect of different doses on biomass (dry matter) and yield. It has been shown those doses between 0 and 120 kg N ha-1 increase significantly (p < 0.05), yields and dry matter with values of 18.32, 45.49 to 57.93 t ha-1 and 4.32, 5.52 to 9.77 t ha-1, respectively. The rate of 120 kg N ha-1, is shown statistically, as the efficient rate to cover the nitrogen needs of lettuce. This efficiency reaches 74.48%. Beyond that, nitrogen is not valorized by the crop. These results contribute to the realization of a technical reference system for lettuce cultivation, for an efficient use of nitrogen.

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1249–1260 V. Alle, U. Kondratovics, A. Osvalde and M. Vikmane
Differences in cadmium accumulation and induced changes in root anatomical structures in plants used for food
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Differences in cadmium accumulation and induced changes in root anatomical structures in plants used for food

V. Alle¹*, U. Kondratovics¹, A. Osvalde² and M. Vikmane¹

¹University of Latvia, Faculty of Biology, Department of Plant Physiology, St. Jelgavas 1, LV-1004 Riga, Latvia
²University of Latvia, Institute of Biology, Laboratory of Plant Mineral Nutrition, St. Miera 3, LV-2169 Salaspils, Latvia
*Correspondence: vita.alle@lu.lv

Abstract:

 A rapid urbanization passes all over the world thus the effect of chemicals, including heavy metals, increases on plants. Heavy metal pollution poses a serious hazard to humans’ health, and it uptake into plants is the primary way through which it can enter the food chain. The goal of this study was to investigate the impact of cadmium (Cd) contamination on plant growth responces, Cd uptake, and changes in the root anatomical structures as species-specific reaction to Cd stress. The vegetation experiment was carried out with monocotyledon Hordeum vulgare L. and dicotyledonous Lactuca sativa L. The plants were grown in quartz sand under controlled optimal growth conditions. Changes in the root structure and Cd accumulation were studied at five levels of Cd added as Cd(NO3)2 4 H2O solution in substrate. The level of Cd in the air-dry plant material was estimated by an atomic absorption spectrometer. To identify structural changes in the plant roots which were caused by Cd accumulation cross sections were cut using microtome and stained with Astra Blue/Safranin for observations using a light microscope. Barley and lettuce growth and development were significantly influenced by increasing the amount of Cd in substrate. There were differences in the ability to accumulate Cd in above-ground plant parts depending on a model object. Substrate contamination with Cd caused significant changes in the root anatomical structures. The obtained results confirmed significance of anatomical and physiological studies to reveal species-specific plant response to Cd stress to avoid heavy metal entrance in the food.

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39–48 M. Järvan and P. Põldma
Content of plant nutrients in vegetables depending on various lime materials used for neutralising bog peat
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Content of plant nutrients in vegetables depending on various lime materials used for neutralising bog peat

M. Järvan¹ and P. Põldma²

¹Department of Field Crops, Estonian Research Institute of Agriculture, Teaduse 13, 75501 Saku, Estonia; e-mail: malle.jarvan@mail.ee
²Department of Horticulture, Estonian Agricultural University, Kreutzwaldi 64, 51014 Tartu, Estonia; e-mail: ppoldma@eau.ee

Abstract:

The trials were performed in the years 1998–2000 in Saku (59°18’N, 24º39’E) in greenhouse conditions. The aim was to establish how lime materials used for the neutralisation of bog peat acidity (oil shale ash, clinker dust, limestone meal, dolomite meal and their mixtures), which changed significantly the contents of available Ca, K and Mg in the peat substrata, affect the mineral composition of vegetable leaves (lettuce, cucumber, tomato, paprika) and the mutual relationships between elements (K, Ca, Mg, P). In the case of all vegetables, a strong Ca and Mg antagonism occurred. The Mg content of plants was very sensitive to the Ca:Mg ratio in the lime material used for peat neutralisation. In the case of limestone meal, the tomato plants contained Mg 0.18–0.24% and cucumber plants 0.36–0.40%; in the case of dolomite meal, 0.66–0.71% and 0.78–0.90, respectively. The Ca and K contents of vegetables were somewhat less affected by the difference of lime materials than the Mg content. Abundant Mg in lime material increased P content in plants, a synergism between Mg and P occurred.
Lettuce grown on substrata neutralised with mixtures of limestone and dolomite meal contained less nitrates than that grown on substrata with clinker dust and oil shale ash. Too high K content in the substrate neutralised with clinker dust had a negative effect on the carotene content of lettuce.

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