Agrochemiczne metody biofortyfikacji marchwi (Daucus carota L.) w jod - nowe perspektywy jodowania żywności
AbstractIodine is a micronutrient essential for the proper development and functioning of human and animal organism. It is estimated that from 30 to 38% of total human population live in an area with endemic deficiency of iodine. In numerous countries program of iodine prophylaxis is based primarily on salt iodization. The efficiency of this method of iodine supplementation relies mostly on the level of salt consumption and the loss of salt during its storage and processing. I-laving taken into consideration social effects of excessive salt consumption being a major problem in many countries, World Health Organisation recommends to substantially reduce the level of NaC1 intake. This proposition brings about a serious risk of diminished effectiveness of current model of iodine prophylaxis. In such a case this institution indicates the need for developing other ways of iodine introduction into human diet. It seems important that, despite the mandatory salt iodization and high level of its consumption, the worst situation is noted in Europe, where approximately 59.9% of children and 56.9% of adults consume diet with inadequate daily intake of this element. iodine is not considered a nutrient for plants. The main cause of endemic deficiency of iodine is believed to be the low total content of this clement (or its bivavailable forms) in soils resulting in low soil-to-plant distribution and, as a consequence, low transfer of iodine into the food chain. Plant biofortification (enrichment) with iodine, particularly with respect to vegetables, is considered an alternative (to salt iodization) method of introducing iodine into human diet. Despite the fact that iodine was discovered over 200 years ago, numerous aspects of its influence on soil environment and higher plants have not yet been sufficiently diagnosed. There is still need to conduct thorough studies evaluating the influence of iodine both for the environment and crop plants prior to the implementation of iodine biofortification methods into agricultural and horticultural practice. In-depth analysis of these issues, together with wide aspects of iodine biogeochemistiy, was discussed in a theoretical part of the work. The aim of the study presented in the experimental part was to determine the influence of different soil fertilization (various doses and chemical forms of iodine were used) and foliar application of iodine on yield, efficiency of iodine biofortification and storage capacity of carrot 'Kazan F1' storage roots. In the years 2008-2010 two independent experiments with carrot cultivation were conducted followed by four-month storage of harvested roots. In the experiment no. 1 seven combinations with different soil and foliar application of iodine were distinguished including: 1) control (without soil or foliar application of iodine), combinations with pre-sowing soil fertilization with iodine in the dose of: 2) 0.5, 3) 1.0, and 4) 2.0 kg I • ha-1 as well as four-time foliar spraying with iodine solution in the concentration of: 5) 0.0005%, 6) 0.005% and 7) 0.05% - the following amounts of iodine were applied to plants: 0.02, 0.2 and 10 kg I • ha-', respectively using 1000 dm3 of work solution per 1 ha. In the experiment no. 2 seven combinations with different soil fertilization with iodine and nitrogen was applied in the studies including: 1) control - without N and I fertilization, 2) KI fertilization without N application, 3) KI01 fertilization without N application, 4) KI+Ca(N01)2 fertilization, 5) K1034-Ca(NO3)2 fertilization, 6) KI+(NI-11)2SO4 fertilization, 7) K101+ (NH4)2SO4 fertilization. Iodine as KI and KI03 was applied pre-sowing in a dose of 2 kg I • ha-1. Nitrogen fertilization in the form of NH4N01 (in experiment no. 1), Ca(NO3)2 and (NI-14)2SO4 (in experiment no. 2) was performed pre-sowing and as a top dressing with 100 kg N • ha-1. Soil application of iodine (also together with nitrogen fertilization) as well as foliar spraying with this element generally had no influence on the yield of carrot leaves and storage roots. The exception was the decrease in total yield of storage roots and total biological yield of plants treated with iodine and ammonium sulphate (experiment no. 2) - particularly when using K103 (rather than KI). Various synergistic and antagonistic interactions noted in particular combinations with respect to plant nutrition with macro- and micronutrients had no direct effect on carrot yield. A comparable level of iodine biofortification of roots after foliar application of K103 when compared to soil fertilization with KI (in all doses - experiment no. 1) provided indirect evidence for phloem transport of iodine from leaves to roots in carrot. In experiment no. 2 the efficiency of iodine biofortification was similar for all combinations with different nitrogen fertilization and soil application of two chemical forms of iodine: I- and I03-. Application of 2.0 kg I • ha-1 KI together with soil fertilization with NH4NO3 (experiment no. 1) improved iodine accumulation in roots to a greater extent than introduction of the same amount of KI and KTO.3 with Ca(NO3)1 and (NH4)2SO4 in the experiment no. 2. Iodine content in carrots after storage decreased if was expressed per dry weight while increased when was calculated per fresh weight of roots. The rate of weight loss of stored carrot roots was positively correlated with applied dose of iodine — particularly through foliar spraying of KIOA. Due to a relatively substantial loss of root weight and noted iodine content (per dry weight) after storage, foliar application of Kl03 in a dose of 2.0 kg I • ha I can become a recommended method of iodine biofortification of carrot for fresh consumption and/or processing directly after harvest. In the ease of carrot cultivation for storage purposes a more appropriate method of its enrichment with iodine would he soil application of KI or KI03 in a dose of 2.0 kg I. ha-1— without or with simultaneous N fertilization applied as NH4NO3 rather than Ca(NO3)2 and (NH4)2SO4. On the basis of the obtained results it was estimated that the consumption of a 100 g portion of fresh carrot biofortified with iodine may cover 4.2-10.7% and 5.0-11.8% of the recommended daily intake for this element, respectively for carrots consumed directly after harvest or after four-month storage. In both experiments an increase of soil redox potential (Eh) was noted for all tested combinations with soil or foliar application of iodine when compared to the control. Analysis of iodine content in soil conducted in 0.03 mol acetic acid extracts did not reveal a significant variation between combinations.
|Other language title versions||Agrochemical methods of iodine biofortification of carrot (Daucus carota L.) — a new perspective of iodine rich food|
|Publisher||Uniwersytet Rolniczy im. Hugona Kołłątaja w Krakowie, MNiSW |
|Publishing place (Publisher address)||Kraków|
|Book series /Journal (in case of Journal special issue)||Zeszyty Naukowe Uniwersytetu Rolniczego im. Hugona Kołłątaja w Krakowie. Rozprawy, ISSN 1899-3486, (0 pkt)|
|Publication size in sheets||6.8|
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