Ethylene production and involvement during the first steps of durum wheat (Triticum durum) anther culture

The role of ethylene in anther culture of durum wheat (Triticum durum Desf. cv. Ardente) was analyzed by testing the effects of 2-chloroethylphosphonic acid (ethrel), silver thiosulfate (Ag+), alpha-aminooxyacetic acid (AOA) and 1-aminocyclopropane-1-carboxylic acid (ACC) on microspore division observed after 21 days of culture and on development of calli estimated at day 45. The use of ethrel and Ag+ indicated a positive effect of ethylene on microspore division, whereas the use of AOA, and to a lesser extent ACC, showed a negative effect. In contrast, the addition of ethrel or Ag+ indicated that ethylene inhibits the development of microspore-derived calli. AOA gave contradictory results. Ethylene production by anthers was about 7 pi anther(-1) h(-1) and decreased during culture, ACC content in the anthers was maximal at day 9, whereas malonyl ACC (MACC) increased sharply from day 0 to day 3 and then decreased. The addition of AOA or ACC to the culture medium decreased or increased, respectively, ethylene production of anthers and the ACC and/or MACC content, but at concentrations higher than those that modified the formation of calli. This formation seems to occur in two successive phases: induction and initiation of microspore division, which was promoted by ethylene, followed by callus development, which was inhibited by ethylene.