This paper reports the results of observations of the abundance of population Succisa pratensis Moench, as well as temporal and spatial variabilities of chosen traits such as the number of rosettes, number of leaves per rosette, number and height of flowering stems, number of flower heads per generative stem and number of seeds per fruit. Investigations were conducted in the years 2009−2013, in six patches of Molinietum caeruleae with different dominant species, unmanaged from 10 to 22 years. On the basis of studies performed, the state of populations and chances for maintenance in the colonised site were evaluated.
The field experiment focused on three high-inulin vegetable crops: chicory (Cichorium intybus L. var. sativum Bisch), black salsify (Scorzonera hispanica L.) and common salsify (Tragopogon porrifolius L.), and took into account two cultivation methods (flat soil and ridges) and a phacelia (Phacelia tanacetifolia L.) intercrop, the biomass of which was mixed with the soil during pre-winter ploughing. Cultivation without an intercrop served as the control. The studies aimed at evaluating the influence of ridge cultivation using a phacelia intercrop on the species composition and population of vegetable weeds as compared to traditional flat-soil cultivation with no intercrop. In total, 24 taxa in the primary and 31 taxa in the secondary weed populations (mostly characteristic for vegetable crops) were recorded in high-inulin species plantations. Monocarpic species such as Senecio vulgaris, Chenopodium album and Lamium amplexicaule dominated in the spring, while Stellaria media, Capsella bursa-pastoris and Urtica urens were most numerous at the end of the vegetation period. Applying phacelia as the intercrop and ploughing its biomass before winter significantly reduced the primary weed population for all of the cultivated crop species as compared to the no-intercrop cultivations. Phacelia grown as the intercrop reduced the occurrence of Senecio vulgaris, while favouring the development of Lamium amplexicaule. The cultivation system affected the primary weed infestation of vegetables, whereas it had no impact on the level of secondary weed infestation. At the beginning of the vegetation periods, fewer weeds grew in ridges than in the flat soil system. The crop species had no effect on the primary weed infestation, while it influenced weed numbers in the secondary. The lowest number of weeds was recorded in the secondary weed infestation of chicory, the well-developed leaf rosettes of which efficiently eliminated most of the weeds.
Native populations of endemic, rare and threatened Limonium species (L. meyeri, L. bulgaricum, L. latifolium, L. vulgare, L. asterotrichum and L. gmelinii) in Bulgaria were monitored and found seriously declined. To preserve these wild genotypes, an approach involving in vitro propagation of explants isolated from immature inflorescence stems was applied at the Institute of Ornamental Plants, Sofia. The rooted plantlets produced were acclimated and grown outdoors under an optimized cultivation regime, which resulted in the establishment of an ex situ plantation. Plant performance ex situ (determined by leaf rosette diameter, plant height and the number of flower stems) was substantially improved and the variation in the biometric indices was found remarkably lower than in natural environment. The developmental stages of ex situ plants appeared with a delay in relation to their onset in the native environment, but occurred synchronously within each species. Analysis of germination of seeds harvested from ex situ and in situ grown plants showed species-specific behaviour, but in general, seed vitality remained relatively low in laboratory conditions, in the soil and in vitro. In order to assess the potential for protecting the native Limonium species from uncontrolled harvesting, the possibility for the production of cut flowers in ex situ conditions was studied. High yield of cut flowers from ex situ plants in comparison with the potential yield from the wild plants and extended vase life in comparison with commercially produced Limonium sinuatum were obtained. The results demonstrated that the applied micropropagation and agrotechnique for protected cultivation are reliable tools for ex situ conservation of the endangered Limonium genotypes in the Bulgarian flora. In addition to its advantage as a rescue measure, the developed system was shown to be suitable for obtaining cut flowers of competitive market quality.
Modifications in growing techniques can affect the yield and nutritional quality of various cultivated plants. Among them, the use of biostimulants is environmental friendly method of stimulating crop productivity, stress resistance, and affecting yield or chemical composition of the plants. The aim of the investigation was determining of the effect of biostimulant treatment on yield and its quality of carrot grown for summer harvest. The experiment was carried out in 2009-2011 in the experimental station of the University of Agriculture in Krakow, south Poland. Two experimental factors were taken into consideration: (1) cultivar: Nandrin F1 and Napoli F1 (2) dose of Aminoplant (foliar application): 1.5 and 3.0 dm3∙ha-1 and control (without Aminoplant). Total and marketable yield, root length, its diameter, leaf mass and leaf : root mass ratio were assessed. The dry matter, soluble sugar, carotenoids and nitrate ions contents were analyzed as main determinants of carrot nutritional quality.
Aminoplant influenced not only carrot productivity, but mainly chemical composition of the roots. The present results also suggest that carrot reaction to biostimulant treatment was depended on a cultivar more than on environmental conditions in particular growing seasons. The significant effect of Aminoplant in a dose of 1.5 dm3∙ha-1 on the yield of roots and leaf rosette mass of ‘Nandrin F1’ appeared only in the first year of the experiment. Spraying with Aminoplant in a dose of 3.0 dm3∙ha-1 significantly increased the soluble sugars content in carrot roots of both cultivars but only in 2011. Dry matter content was also affected by biostimulant treatment mainly for ‘Napoli F1’, which showed the lowest dry matter content when sprayed with Aminoplant in a dose of 1.5 dm3∙ha-1. In 2010 control plants contained the greater amount of carotenoids, while in next year roots of plants treated with Aminoplant in a dose of 3.0 dm3∙ha-1 had more these compounds. The significant effect of Aminoplant on nitrates content in carrot roots was observed but were not repeatable in the experimental years, so different climatic conditions modified carrot reaction on biostimulant spraying.
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