Effects of exogenous L-arginine on in vitro rooting, chlorophyll, carbohydrate, and proline concentrations in the sweet cherry rootstock M 3 M 14 (Prunus avium L. 3 Prunus mahaleb L.)

The effects of indole-3-butyric acid (IBA) alone and in combination with L-arginine on the morphogenic and biochemical responses in shoot tip explants of the cherry rootstock M 9 M 14 (Prunus avium 9 Prunus mahaleb) were examined. The maximum root number per rooted explant (16), root fresh (FW) and dry (DW) weights, as well as the rooting percentage (100 %) were recorded when 2 mg l-1 IBA (alone) were applied. Including the lowest IBA concentration (0.5 mg l-1) with the lowest and highest L-arginine concentrations (0.5 and 2 mg l-1, respectively) resulted in the greatest root length. The maximum leaf chlorophyll concentration and shoot length of the initial explant were recorded when 0.5 mg l-1 IBA plus 2 mg l-1 L-arginine were applied. In addition,L-arginine in combination with IBA (1 and 2 mg l -1) was found to suppress shoot FW and DW. On the other hand, L-arginine enhanced the promoting effect of IBA on both root length and leaf chlorophyll concentration. The carbohydrate and proline concentrations in leaves were not significantly altered with the application of IBA alone or incombination with L-arginine. On the other hand, the carbohydrate and proline concentrations in roots were decreased with the application of 1 and 2 mg l-1 IBA with L-arginine, resulting in the suppression of the promoting effects of IBA. It is clear from the findings that L-arginine has a direct effect on the in vitro rooting of M 9 M 14 explants, is involved in the function of the photosythetic apparatus, influences leaf chlorophyll content, participates in carbohydrate biosynthesis and metabolism, and is involved in proline accumulation both in leaves and roots.