The effect of salicylic acid and acetylsalicylic acid on red pigment formation in mechanically wounded scales of Hippeastrum x hybr. hort. and on the growth and development of Phoma narcissi
Various organs of <i>Hippeastrum</i> infected by <i>Phoma narcissi</i>, infested with mite, <i>Steneotarsonemus laticeps</i> or mechanically wounded, produce red pigment on the surface of injured tissues. The aim of the present work was to study the effect of salicylic (SA) and acetylsalicylic acids (ASA) (inhibitors of biosynthesis of jasmonates and ethylene) on red pigment formation in wounded scales of bulbs of <i>Hippeastrum</i> and on the mycelium growth of <i>P. narcissi</i> <i>in vivo</i> and <i>in vitro</i>. SA and ASA at a concentration of 1 and 2 mM partially inhibited the formation of red pigment in wounded scales, first of all in first 2 days after treatment. The growth and development of <i>P. narcissi</i> on basal plate and scales of longitudinally cut <i>Hippeastrum</i> bulb treated with SA and ASA (1 and 2 mM) was similar as in control. SA (50 µg·cm<sup>-3</sup>) and ASA (250 µg·cm<sup>-3</sup>) inhibited the mycelium growth of <i>P. narcissi</i> on PDA medium, and concentration of 1000 µg·cm<sup>-3</sup> of both almost totally inhibited the mycelium growth of the pathogen. Inhibitory effect of SA and ASA on the formation of red pigment in wounded scales of Hippeastrum may be caused by lowered biosynthesis and accumulation of jasmonates.