Eva Hanáčková

Regulation of the phenolic profile of berries can increase their antioxidant activity.

The changes of the antioxidant activities (AOA), antiradical activities (ARA), low-density lipoprotein (LDL) oxidation, and total contents of phenolics, anthocyanins, flavonols, hydroxybenzoic acids, and hydroxycinnamic acids in black currant and black chokeberry, after treatment with ornithine decarboxylase inhibitor, a polyamine inhibitor (O-phosphoethanolamine, KF), and a phenol biosynthesis stimulator (carboxymethyl chitin glucan, CCHG), were analyzed spectrophotometrically. Gallic acid, hydroxycinnamic acids, and selected flavonol contents was analyzed by RP-HPLC. Both regulators increased the AOA measured as inhibition of peroxidation (IP) in black chokeberry, 1.71-fold after treatment with KF(1) and 1.74-fold after treatment with CCHG. In black currant IP was elevated after CCHG application only in lower dose (CCHG(1) 63.36% vs control 53.23%). In black chokeberry the total phenolics content was elevated 1.49-fold after KF(1) application and 1.31-fold after CCHG(2) application. The regulators had the lower effect on the phenolic accumulation in black currant. There was a strong relationship between the total phenolics in the both crops and anthocyanins, hydroxybenzoic acids, and hydroxycinnamic acids contents, respectively. Both regulators significantly changed the ratio of conjugated (rutin) to free (quercetin) flavonol mainly in black chokeberry. The antioxidant activities compared using LDL in vitro oxidation assay were increased more expressively after treatment with KF(2) in both crops.

IMPACT OF VERMICOMPOST EXTRACT APPLICATION INTO SOIL AND ON PLANT LEAVES ON MAIZE PHYTOMASS FORMATION

Nowadays in scientific literature many opposing data are presented of the impacts of vermicompost extract on the quantity and quality of crop production. Therefore, the principal objective of two independent experiments was to study the effects of vermiextracts, which were applied before maize sowing into soil and during the growing season on the maize leaves, on its phytomass formation. The first, field experiment consisted of 9 variants. Variant 1 was the control one without the extract application. We studied the effect of the rising doses (90, 130, 170, 210 dm3·ha-1) of vermi-extract applied into soil before the maize sowing in the variants E1, E2, E3, E4. In the variants E1+E, E2+E, E3+E, E4+E along with the rising doses of vermi-extract was also applied the uniform dose of vermi-extract (40 dm3·ha-1) at the growth stage BBCH 15. The second, pot experiment was pursued in the vegetation cage and comprised 3 variants: variant 1 was the control, in the variants 2 and 3 the foliar application of vermi-extract was used. The vermi-extract was applied once (growth stage BBCH 12) in the variant 2 and in the variant 3 it was used twice (at growth stages BBCH 12 and BBCH 16). The achieved results show that the vermi-extract applied in the presowing period increased the yield of maize grains if the application doses were 130–170 dm3·ha-1. The positive or negative impact of the foliar application by vermi-extract on the yield of maize grains depended on the period of application and the grown cultivar. In order to increase the starch content in grains it was more suitable to carry out the presowing vermi-extract application than during the growing season. The presowing application and the foliar application of vermi-extract tended to decrease the nitrogen content in grain. The foliar application of vermi-extract had the positive impact on the plant height and stalk thickness of the maize plants only in short term. The information obtained from the first half of maize growing season related to the plant height and stalk thickness was not the appropriate indicator for the assessment of maize grain yields.

THE INFLUENCE OF SOIL CULTIVATION AND FERTILIZATION ON THE YIELD AND PROTEIN CONTENT IN SEEDS OF COMMON PEA (PISUM SATIVUM L.)

Abstract The aim of this study is to assess the effect of different soil tillage in the interaction with fertilization and the use of post-harvest residues on yield and protein content in pea seeds, variety Dunaj. The field experiment was established in years 2009–2011 on Experimental Base of the Slovak University of Agriculture in Dolná Malanta. There were evaluated based upon three soil tillage methods (B1 – conventional tillage, B2 – reduced tillage, B3 – minimal tillage) and three treatments of fertilization (0 – unfertilized control, MF – balance fertilization by mineral fertilizers based on soil analysis and planned pea yield (3 t/ha), PHR – balance fertilization by mineral fertilizers + incorporation of post-harvest residues). Significantly higher seed yield was achieved at reduced tillage (3.28 t/ha) than conventional (3.12 t/ha) and minimized tillage (3.08 t/ha); however, most significantly, higher protein content in average of treatments was determined in conventional tillage (23.38%). Most significantly, negative linear correlation (r = −0.948⊕⊕⊕) was determined between the yield and crude protein content in pea seeds. Fertilized treatments reached highly significant higher yields of common pea than unfertilized control. Compared with the control, average yield was higher by 10.3% – 15.1%. Significantly higher crude protein contents by 0.86% (PHR) and 1.27% (MF) were reached on unfertilized treatments than on fertilized one. The highest content of crude protein (24.14%) and the highest production of it per hectare (759 kg/ha) were determined in treatment with post harvest residues ploughed into soil. Over an average of 3 years, the highest profit (163.87 €/ha) and return (30.7%) was achieved from the pea grown using fertilizing treatments (FM and PHR) at minimal soil tillage and systematic use of mineral fertilizers.