Published in Scientific Papers. Series B, Horticulture, Vol. LXVIII, Issue 1
Written by Doina CLAPA, Ana-Maria RADOMIR, Adrian George PETICILĂ, Adelina DUMITRAȘ, Monica HÂRŢA
Hypericum calycinum L. is a species of the genus Hypericum with pharmaceutical, ornamental, and landscape potential. To assess the salt and drought tolerance stress, in vitro cultures grown on media supplemented with different concentrations of NaCl (0; 10; 30; 50; 100 mM) and PEG 6000 (0; 10; 20; 30; 50 g/l) were used. After six weeks of in vitro culture under salinity and drought stress conditions, the following parameters were evaluated: viability, number of shoots, shoot length, rooting percentage, number of roots, root length, fresh weight, dry weight, water content, stress tolerance index (STI), and McKinney index (MKI). The viability of initial explants was higher under low salt stress (100% under 10 mM NaCl) compared to low drought stress (80% under 10 g/l PEG 6000). Drought stress caused a decrease in shoot height under all concentrations of PEG 6000, while the longest shoots (4.38 ± 0.22 cm) were obtained on the culture medium supplemented with 10 mM NaCl. The rooting percentage was 0% using concentrations of 30, 50, and 100 mM NaCl and 20, 30, and 50 g/l PEG. Our results showed that H. calycinum had a higher sensitivity to drought stress compared to salt stress.
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