Interspecific variations of photochemical properties in a xerotherm grassland community

In this work the role of xanthophyll cycle an d its relation to the photosynthetic activity in the dominant species of a semiarid sandy grassland community (Potentillo-Festucetum pseudovinae) were studied during the stressful summer period . The total amount of xanthophyll cycle pigments (violaxanthin, anteraxanthin, zeaxanthin) related to total chlorophyll content (VAZ pool) showed considerable interspecific alterations and it was 2-3 times larger in the summer period than in spring. The changes in the xanthophyll cycle , the potential (FyFm) and actual photochemical efficiency (AF/Fm) of PSII, as well as, the results of parallel measurements on their daily dynamics show that zeaxanthin has a major role in the photoinhibition in the photosynthetic apparatus during the summer stress on sandy grassland species. In July, the decrease s of F/F m was accompanied with increases of NPQ at the 100-120% extentt depending on the species

Variation in ecophysiological traits of dominant species in open and closed stands of a semiarid sandy grassland

Under the continental climate of the Carpathian Basin, semiarid grasslands represent one of the widespread vegetation types. Due to overgrazing and other disturbances, most of the semiarid grasslands in Hungary are the mosaics of more or less degraded patches. Our work has focused on the variations in the ecophysiological traits of the common dominant species in a moderately degraded (vegetation cover 70%) and a strongly degraded stand (vegetation cover 27%) of Potentillo-Festucetum pseudovinae community. As a result of low soil moisture content, species experienced significantly higher leaf water saturation deficit in the open stand. Carotenoid pool was larger for all the species in the strongly degraded stand. The protective xanthophyll cycle pool was also higher in the strongly degraded stand, and reached 30–33% of the total carotenoid content. The potential photochemical efficiency (Fv/Fm) was lower for monocot species. There was a decrease in the Fv/Fm values at noon, which was larger in the strongly degraded stand

Study of yellow rust infection on various winter wheat genotypes

Winter wheat (Triticum aestivum L.) is our most important cereal. During its production several pathogens can infect the population. In our two-year study susceptibility of 9 winter wheat genotypes against the pathogen Pucciniastriiformis var. striiformis was investigated by three different nitrogen supply levels on a humous sandy soil type. Percentage frequency of yellow rust infection was lower in case of the genotypes Hystar, Mv. Csárdás, Mv. Magdaléna than in case of HK1307, 1304KV, Antonius or Hywin. Based on our results it can be stated that in the crop year 2016 the highest susceptibility towards the pathogen yellow rust was observed for the winter wheat variety GK Csillag. No consequent effect of nitrogen active substance treatments on yellow rust infection could be stated, different applied nitrogen dosages did not affect the infection rate of different genotypes to a statistically verifiable extent

A növényi nitrogén-hasznosítás elemei és kihívásai

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Effect of selenite and selenate uptake by maize plants on specific leaf area

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Role of selenite and selenate uptake by maize plants in chlorophyll A and B content

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