THE EFFECT OF FERTILIZATION REGIME ON Scolymus hispanicus PLANT GROWTH
In the present study, different fertilization regimes were evaluated aiming to establish cultivation protocols for the commercial cultivation of the species. Seven fertilization treatments varying in amounts of N:P:K (namely, 100:100:100; 200:100:100; 200:200:200; 300:100:100; 300:200:200; 300:300:300 ppm on N:P:K and control where no fertilizers were added) were applied via nutrient solution feeding in pot-grown golden thistle plants. The growth parameters tested included the measurement of number of leaves, the fresh and dry weight of leaves, SPAD index, leaf area and specific leaf area, while net photosynthesis (Pn) at different light intensities (PAR:0-1300 µmol·s-1·m-2) was also recorded. Pn did not differ among the tested fertilization regimes, while a gradual increase was observed with increasing light intensity. Regarding the growth parameters, the highest number of leaves was recorded for the 300:100:100 treatment, while the highest fresh weigh and lowest dry weigh of leaves was observed in the treatment of 300:200:200. Moreover, a negative effect on fresh weight of leaves was observed in the case of 300:300:300 treatment. The highest leaf area was recorded in 300:100:100 and 100:100:100 treatments, whereas specific leaf area increased at 300:100:100 and 300:200:200 treatments being significantly different only from the control treatment. Similarly, no significant differences were observed in SPAD index between the fertilization treatments, whereas the control treatment recorded the lowest overall value. In conclusion, the application of fertilizers on S. hispanicus had positive effects on plant growth and visual appearance, especially the 300:200:200 treatment where increasing trends of fresh yield were recorded.