Water stress is one of the most important problems that limit the cultivation ofcrops in arid and semi-arid regions of Iran. In this study, the effect of putrescine wasstudied on one-year-old seedlings of both Carrizo citrange (Citrus sinensis Osb. ×Poncirus trifoliate Raf.) and Volkameriana (Citrus volkameriana) grown in containers,under water stress. A factorial experiment based on a completely randomized designwas set up using putrescine at three concentrations of 0, 1, and 2 mM on seedlingsunder 0.3 field capacity. Results showed that foliar application of putrescine increasedroot and shoot growth and total plant biomass in both seedling rootstocks. Putrescinesignificantly reduced the root diameter, which was due to an increased percentage offine roots. Moreover, the application of putrescine significantly increased the relativewater content, proline, and soluble sugars content, but reduced the electrolyte leakage.Although the growth rate and total plant biomass had been decreased under waterstress, putrescine application limited the downward effects of water stress in bothmentioned seedlings. (3) (PDF) Biochemical and morphological response of Carrizo citrange and Volkameriana rootstocks to putrescine and water stress.
