Effect of asparagine, cysteine, citrulline, and glutamine on in vitro rooting and biochemical constituents in cherry rootstocks

Effects of four amino acids, L-asparagine, L-cysteine, L-citrulline, and L-glutamine in different concentrations (0, 0.5, 1, and 2 mg dm-3) combined with 2 mg dm-3 indole-3-butyric acid, on in vitro rooting and biochemical constituents of cherry rootstocks CAB-6P (Prunus cerasus L.) and Gisela 6 (P. canescens × P. cerasus) were investigated. In CAB-6P, root number and root fresh mass (FM) were maximum at 0.5 mg dm-3 cysteine. All amino acids reduced root length in CAB-6P and root number as well as root FM in Gisela 6. In Gisela 6, 0.5 mg dm-3 asparagine or 2 mg dm-3 glutamine reduced root length. In CAB-6P, 100 % rooting was achieved in the control and with 1 and 2 mg dm-3 cysteine or 1 mg dm-3 citrulline. In Gisela 6, the rooting percentage was maximum (76.92 %) with 0.5 mg dm-3 asparagine. Callus FM in CAB-6P was the greatest at 1 mg dm-3 and in Gisela 6 at 2 mg dm-3 citrulline. Callusing was 100 % in the majority of treatments for CAB-6P and 92.31 % for Gisela 6 with 0.5 or 2 mg dm-3 citrulline. Cysteine, citrulline, and glutamine diminished chlorophyll content in Gisela 6 whereas in CAB-6P all four amino acids hardly affected it. Carotenoid and porphyrin content in CAB-6P was decreased due to asparagine (0.5 or 1 mg dm-3). Porphyrin content in CAB-6P was also reduced by adding 0.5 or 1 mg dm-3 cysteine or 2 mg dm-3 citrulline. In Gisela 6, all amino acids decreased carotenoid and porphyrin content. In CAB-6P, all treatments except 0.5 mg dm-3 glutamine or 2 mg dm-3 asparagine increased leaf sucrose content. In roots, both sucrose and proline content were increased only at 1 mg dm-3 cysteine whereas in leaves only 0.5 mg dm-3 asparagine caused a 3-fold increase in proline content. A decrease in root proline in CAB-6P was observed due to asparagine, citrulline, or glutamine. In Gisela 6, decreased leaf sucrose and proline content was recorded at 2 mg dm-3 cysteine. All amino acids did not alter root sugar content remarkably whereas root proline content was raised by adding 0.5 mg dm-3 glutamine or 1 mg dm-3 cysteine.