Relation between Poaceae pollen concentrations and meteorological factors during 2000–2010 in Timisoara, Romania

This paper presents the results of Poaceae pollen seasons from 2000–2010 in Timisoara, Romania. Airborne Poaceae pollen concentrations was high. An increasing trend in the annual totals was observed. The longest pollen season was recorded in the year 2000. The period in which the Poaceae pollen count exceeded the threshold value of 30 grains/m3 lasted from 9 to 46 days. The present study analyzed the dynamics of pollen seasons in relation to meteorological factors. On the basis of Spearman’s correlation test, the strongest positive correlation was found between the Poaceae pollen counts and temperature; and sunshine hours. Daily average relative humidity, atmospheric pressure and precipitation had a negative effect. A multiple regression analysis was applied to determine how much of the total variance in Poaceae pollen counts can be explained by meteorological parameters. The coefficient of determination ranged from 0.245 to 0.460. Our data illustrate the contrasting effects of temperature, wind, relative humidity and rainfall on the concentration of pollen in the air. The optimum conditions for Poaceae pollen release occur during late spring and early summer. The Poaceae pollen remains one of the major aeroallergens in Timisoara area

Taraxacum officinale (Asteraceae) in the urban environment: seasonal fluctuations of plant traits and their relationship with meteorological factors

Plants can be used as effective bioindicators of the quality of the urban habitat. In this study, physiological traits were examined in plants growing outdoors, in the proximity of a road. All material was collected from robust, well-grown plants. All measurements were performed during the generative phase. Here, the evaluations of some gravimetric parameters (fresh weight, turgid weight, dry weight, water content, ash content) and physiological parameters (initial water content, mineral content, organic content, organic content/mineral content ratio, succulence, mineral deposition in tissues, tissues density, leaf relative water content, specific leaf area) were calculated for Taraxacum officinale from urban unmanaged areas, across the different seasons (winter, spring, summer, fall). One-way analysis of variance (ANOVA) was used to compare these traits in leaves, scapes, and roots. Initial water content and relative water content are good indicators of water status in T. officinale. With regard to succulence, its level was generally considerably lower in roots than in aboveground organs. The mineral content differed significantly among plant organs. For all the parameters analyzed, the most considerable seasonal differences were found in leaves. The Spearman correlations were calculated for the relations between plant traits. Mineral deposition in tissues is the most sensitive parameter, regardless of the organ. The data were subjected to Spearman correlation and linear regression analysis for each physiological parameter and some meteorological factors. The strongest association was generally found with the wind. Variations in the investigated parameters in roots and scapes are more associated with meteorological factors. Taraxacum officinale plants are able to tolerate urban conditions in proximity to a road. Plastic responses to environmental cues make the plant useful in biomonitoring the quality of the urban habitat

O metodă de estimare a indicelui de suplimentare a azotului la plantele de cultură: studiu de caz la grâu

This paper aim was to adapt a physiological parameter which reflects plant growth and productivity for wheat plants in relation with the applied nitrogen dose. This index can be used for various plants due to the fact that can be easy calculated and gives information about the status and requirements of diverse crops. Nitrogen is the most widely used chemical fertilizer and the adjustment of the dose is really important for farmers, who are searching for an optimum cost-benefit ratio. For this study, five experimental N doses were utilized, between 0 and 200 kg/ha. Experimental field was located within Didactic Station of BUASMV Timisoara, Romania. Nitrogen supply index was determined for healthy leaves and mathematical models were developed. The optimum N amount used for this study was 119 kg/ha and the analysis of differences reflected the modifications for doses ranging between 0 and 200 kg/ha.Scopul acestei lucrări a fost de a adapta un parametru fiziologic care reflectă creșterea și productivitatea plantei de grâu în relație cu dozele de azot. Acest indice poate fi folosit pentru numeroase specii de plante deoarece poate fi ușor calculat și oferă informații despre statusul și necesitățile diverselor culturi. Azotul este cel mai mult folosit fertilizator chimic și ajustarea dozei este foarte importantă pentru fermieri, care caută un optim cost-beneficiu. Pentru acest studiu au fost folosite cinci doze experimentale de N, între 0 și 200 kg/ha. Câmpul experimental a fost localizat în Stațiunea Didactică a USAMVB Timișoara, România. Indicele de suplimentare a azotului a fost determinat pentru frunze sănătoase și au fost dezvoltate modele matematice. Cantitatea optimă de N folosită în acest studiu a fost de 119 kg/ha și analiza diferențelor a relevat modificările pentru doze care au variat între 0 și 200 kg/ha