László Huzsvai

Systematic Measurement Methods for the Determination of the SPAD Values of Maize (Zea mays L.) Canopy and Potato (Solanum tuberosum L.)

Based on Soil Plant Analysis Development (SPAD) values, nitrogen (N) deficiency, nutrient need, and the effect of fertilizer treatments on crop conditions can be quickly estimated, but the method of SPAD measurement significantly affects the accuracy of estimation. In field experiments near Debrecen, Hungary, we measured the reliability and accuracy of SPAD measurements in maize and potato populations using a Minolta SPAD-502 meter (Minolta, Tokyo, Japan). The aim of our study was to determine which SPAD measurement methods are capable of detecting small differences in the SPAD values. During the examination of maize ear leaves, we determined the distribution of SPAD values along the leaf blade and then identified single- and multipoint measurement methods. By comparing the results of the measurement methods we established that the single-point-based measurements are less suitable for the determination of the average SPAD value of the leaf blade than the multipoint-based measurements. Also, we showed that the increase in the number of measurement points does not influence the accuracy of the measurement in the case of systematic measurement methods based on the distribution of SPAD values. Thus we recommend five-point measurements to obtain the average SPAD values of the ear leaves: the tip of the leaf blade and at one quarter and one half of the leaf blade from the base on both the right and left sides. From the measurements conducted in potato, we showed that the SPAD values change at every foliar level and that the measurements carried out on the middle foliar level provide the closest correlation with the average SPAD values of the leaf canopy. Based on these results, we recommend making measurements at different foliar levels or on the middle foliar level to determine the average SPAD value of the potato leaf canopy.

Effect of molybdenum treatment on molybdenum concentration and nitrate reduction in maize seedlings

Since 1940 molybdenum has been known as an essential trace element in plant nutrition and physiology. It has a central role in nitrogen metabolism, and its deficiency leads to nitrate accumulation in plants. In this study, we cultivated maize seedlings (Zea mays L. cv. Norma SC) in nutrient solution and soil (rhizoboxes) to investigate the effect of molybdenum treatment on the absorption of molybdenum, sulfur and iron. These elements have been previously shown to play important roles in nitrate reduction, because they are necessary for the function of the nitrate reductase enzyme. We also investigated the relationship between molybdenum treatments and different nitrogen forms in maize. Molybdenum treatments were 0, 0.96, 9.6 and 96 μg kg(-1) in the nutrition solution experiments, and 0, 30, 90, 270 mg kg(-1) in the rhizobox experiments. On the basis of our results, the increased Mo level produced higher plant available Mo concentration in nutrient solution and in soil, which resulted increased concentration of Mo in shoots and roots of maize seedlings. In addition it was observed that maize seedlings accumulated more molybdenum in their roots than in their shoots at all treatments. In contrast, molybdenum treatments did not affect significantly either iron or sulfur concentrations in the plant, even if these elements (Mo, S and Fe) play alike important roles in nitrogen metabolism. Furthermore, the physiological molybdenum level (1× Mo = 0.01 μM) reduced NO3-N and enhanced the NH4-N concentrations in seedlings, suggesting that nitrate reduction was more intense under a well-balanced molybdenum supply.

Modeling of plant adaptation to climatic drought induced water deficit

Soil moisture flux to root surface is considered the main determining factor of the transpiration intensity of plants. This assumption is valid not only in optimal plant physiological conditions without any physical barrier for the evaporation from the leaves, but in climatic drought as well, when high usable soil water amount cannot supply the evapo-transpiration intensity of plant. A new algorithm we built up describing the plant adaptation in climatic drought when stoma’s closure and reduction of plant’s potential evapo-transpiration (PET) starts. The adaptation algorithm of Doorenbos et al. (1978) is developed further defining that soil moisture content initiating the stomata’s closure. The critical soil moisture content is varying according to the PET, and drought tolerance of plant. If soil moisture content is less than the critical one, the plant evapo-transpiration (ET) can be highly different in the drought tolerance plant groups. The new drought tolerance algorithm is applied to maize field plots on chernozem soil of the experimental station of the Debrecen University, in East Hungary. Simulated soil water storages are compared to measured ones of a field plot treatment in five consecutive years. The soil moisture content profiles are measured with a BR-150 capacitance probe (Andrén et al. 1991). Differences between measured and simulated soil water storages are not significant in 2003. Simulations indicate low soil water storages in autumn of 2006, and in the first half of 2007 predicting the low maize production realized in 2007. The new plant adaptation algorithm can be used for a climate and soil moisture content sensitive irrigation control as well. The maize production is an illustrative biohydrological example of water flow through the soil-plant-atmosphere continuum.

Plasma progesterone, metabolic hormones and beta-hydroxybutyrate in Holstein-Friesian cows after superovulation

Metabolic hormones [insulin, leptin, insulin-like growth factor-I (IGF-I), thyroxine (T4) and triiodothyronine (T3)], progesterone (P4) and beta-hydroxybutyrate (BHB) serum concentrations were evaluated and their effect on the superovulation results of donor cows was investigated in a semi-arid environment. Body weight, body condition score (BCS) and lactation stage were also included in the analysis. Twenty-three Holstein-Friesian cows were superovulated with 600 IU FSHp following the routine procedure and flushed on day 7 in a Multiple Ovulation and Embryo Transfer Centre in the semi-arid area of Brazil. The corpora lutea (CL) were counted and blood samples were collected for assays. All of the hormones investigated and BHB serum concentrations were within the physiological ranges. There was a positive correlation between hormones, except between BHB and all the others. The leptin level was influenced by feeding status, as indicated by the BCS. Insulin, T4, T3 and BHB levels were affected by milking status. Dry cows had higher levels of all hormones except BHB. An optimum level of leptin resulted in the highest number of CL, while the linear increase of P4, T4 and IGF significantly increased the number of CL.

The productive lifetime of sows on two farms from the aspect of reasons for culling

Abstract The aim of this study was to compare the characteristics of the productive lifetime (PLT) of sows kept on two farms, from the aspect of reasons for culling. The study was based on data from animals from two breeding farms in Hungary, using the data of 3493 crossbred Dutch Large White and Dutch Landrace sows (DLW × DL) between their first farrowing until the time of culling (2006 and 2012). For six years, the annual culling rate for both farms averaged 45%. The most frequent reasons for removal on both farms were reproductive problems (40%, 51%), leg problems (29%, 23%) and mortality (19%, 15%). There was a significant difference between the distributions of reasons for culling on the two farms (χ2=41.7, P≤0.001). The distributions of reasons for culling differed in three periods of sow breeding (Farm A: χ2=264.7, P≤0.001; Farm B: χ2=511.1, P≤0.001). The percentage of main removal reasons decreased, whereas the frequency of culling due to age increased. Using survival analysis (Kaplan-Meier method and Cox proportional hazard model), significant differences were identified between the PLT of sows culled due to reproductive problems (P≤0.001), leg problems (P≤0.001) and old age (P≤0.001). Reproductive problems (HR: 1.34, P≤0.001) and leg problems (HR: 1.39, P≤0.001) were higher and culling due to old age (HR: 0.44, P≤0.001) was lower on Farm A compared to Farm B. There were no significant differences between the two farms in terms of mortality (HR: 0.99, P=0.923). Overall, the results can be useful for breeders of crossbred (DLW × DL) sow populations in more accurately defining their culling systems.

Növekvő molibdén-koncentráció hatása a különböző nitrogénformákra, valamint a molibdén nitrátasszimilációban betöltött szerepe@@@The effect of increasing molybdenum concentration on different nitrogen forms and the role of molybdenum in nitrate assimilation

Osszefoglalas A novenyek nitrogen asszimilacioja bonyolult biokemiai folyamatok osszessegen keresztul valosul meg. Novenyeink a nitrogent a talajbol tobb formaban vehetik fel. A felvett formatol fuggetlenul valamennyi forma ammoniumma alakul, hogy a noveny hasznositani tudja. Celkitűzesunk volt, hogy laboratoriumi korulmenyek kozott vizsgaljuk, hogyan hat a novekvő koncentracioju molibdenellatas a kulonboző nitrogen-formakra, valamint hogyan befolyasolja a nitratasszimilacio folyamatat. Kiserleti novenykent egy ketszikű (napraforgo, Helianthus annuus L. cv Arena PR) novenyt valasztottunk, melynel kulon vizsgaltuk a hajtas es a gyoker molibden koncentraciojat. Kiserletunkkel igazoltuk, hogy a nitratasszimilacio egyik lenyeges mozzanatanak, a nitratredukcionak a zavartalan lejatszodasahoz a molibden nelkulozhetetlen. A megfelelő molibdenellatas a nitrat-reduktaz enzim aktivitasat noveli, igy elkerulhetjuk, hogy a nitrat karos mennyisegben halmozodjon fel novenyeinkben. A molibdenellatas es a nitratredukcio ...

A molibdénellátás hatása kukorica csíranövényekre@@@The effect of molybdenum supply on maize seedlings

Osszefoglalas A molibden alapvető nyomelem a novenyi tapanyagellatasban. Novenyelettani jelentő seget 1940-ben bizonyitottak be. A noveny nitrogen anyagcserejeben van fontos szerepe, hianyaban nitrat felhalmozodas tapasztalhato. Kutatomunkank celja kettős volt: Kiserleteink soran egyreszt arra a kerdesre kerestuk a valaszt, hogyan valtozik a kukorica (Zea mays L. cv Norma SC) csiranoveny Mo, Fe es S koncentracioja novekvő kon centracioju Mo-kezelesek soran. Azert tartottuk fontosnak e harom elem koncentraciojanak nyomon koveteset, mert a nitratredukcioban, a nitrat-reduktaz műkodeseben ezek az elemek kiemelt szerepet toltenek be. Masreszt kiserleteinkkel laboratoriumi korulmenyek kozott kivantuk igazolni, hogy szoros osszefugges van a molibdenellatas es nitratredukcio kozott: a novenyek fiziologiai molibden szuksegletet biztositva, csokkenteni tudjuk nitrat tartalmukat. Kiserleteink az alabbi ket tipusba sorolhatok: rizoboxos- es tapoldatos kiserletek. Rizoboxos kiserleteinkben harom kulonboző koncentraci...