effect of biochar on physiological characteristics of european yew (taxus baccata) seedling in different light intensities

aim: this investigation aims to study the effect of biochar on gas exchange, water relations, and photosynthetic pigments of european yew (taxus baccata) seedling in different light intensities (li). materials and methods: two-year potted seedlings of european yew are placed in forest stands with canopies of closed (15% li), semi-closed (45% li), and open (75% li). in late june 2018, biochar was added to potted soils at the levels of zero, 10, 20, and 30 g.kg-1, and until the end of november, every 3 (or 4) days, 100 ml water was given to each pot. findings: seedling survival at different levels of treatments was 100%. regardless of biochar, the highest photosynthesis, stomatal conductance, intercellular co2 concentration, relative water content, chlorophyll (chl) contents in the closed canopy, and the highest leaf temperature in the open canopy was observed. with increasing biochar concentration, chl b and total chl increased (28-86%, respectively) in the open canopy and decreased (28 and 28%, respectively) in the closed canopy. neither biochar nor li significantly affected electrolyte leakage and carotenoid content. conclusion: although yew seedlings maintained their vegetative quality and health in different li, and the measured variables responded differently to light-biochar combination, it may be best to grow yew in the shade together with biochar. since the effect of biochar becomes more tangible over time, further research in the following years can lead to more accurate findings affected by the combined light-biochar treatment.