Two field experiments were conducted to evaluate the effect of organic (compost 10 m3/fed.) and bio (nitrobein + phosphorein) fertilizers when used with half or full doses of chemical fertilizer in presence of boron foliar spray at 0.0, 50 and 100 ppm on some growth parameters, photosynthetic pigments, minerals and some bioconstituents, endogenous phytohormones and oil yield of dragonhead (Dracocephalum moldavica L.) plants during 2011/2012 and 2012/2013 seasons. Also, interaction effects between boron and the applied fertilizer treatments on growth, chemical composition and oil productivity were studied as well. The results showed that, the applied treatments of fertilizers and boron as well as their combinations significantly increased most growth parameters i.e. plant height, number of branches and leaves/plant, fresh and dry weight of leaves (g)/plant and flowers fresh weight(g)/plant. Also, photosynthetic pigments i.e. chlorophyll a, b and carotenoids, minerals i.e. N, P, K, Fe, Zn and B uptake, and some bioconstituents as total carbohydrates, sugars and free amino acids content in leaves. Also, oil yield in leaves and flowers gave the maximum values when plants treated with organic and bio fertilizers in presence of foliar application with boron at 100 ppm as compared with those of individual application or untreated ones. Moreover, organic and bio fertilizers and in presence of boron at 100 ppm treatments increased endogenous phytohormones i.e. auxin, gibberellin and cytokinin contents, but they decreased abscisic acid values in dragonhead shoots during 2012/2013 season. Furthermore, organic and bio fertilizers and in presence of boron at 100 ppm treatments decreased the activity of antioxidant enzymes i.e. peroxidase, catalase and superoxide dismutase contents in dragonhead leaves during 2012/2013 season.
Thereby, it could be recommended that foliar application with boron at 100 ppm in the presence of half dose of chemical fertilizer+10m3compost/fed.+ bio fertilizer could be used to improve growth and oil productivity of dragonhead plant.
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