Zinc deficiency is widespread in agronomic soils and can be considered as one of the main micronutrient deficiencies affecting the production of fruit tree species. The effects of Zn deficiency in the rootstock GF 677 (Prunus dulcis × Prunus persica) have been studied. Control (+Zn; 2.4 µM ZnSO4) and Zn deficient (-Zn; 0 µM Zn) plants were grown for 21 days in hydroponics in a growth chamber, using half-Hoagland nutrient solution (pH 5.5). Leaf chlorophyll was monitored daily with a SPAD device. Root and shoot (old, developed, young and apical leaves) tissues were sampled at 7, 14 and 21 days after the treatment onset. Metal micronutrients were determined by AAS in all tissues, leaf photosynthetic pigments (chlorophylls and carotenoids) were analysed by HPLC-UV-VIS, the activity of the Zn-dependent enzyme carbonic anhydrase (CA) activity was measured in young leaf extracts, and root metabolomic analysis was carried out by 1H-NMR. Major effects were observed in roots, young leaves and apical leaves. Chlorosis was observed from day 7 in young leaves of -Zn plants. Zinc concentrations decreased with time in -Zn plants in all tissues tested, and changes in roots were more rapid and intense than in other tissues. The CA activity and photosynthetic pigment concentrations in young leaves decreased with time in -Zn plants. Twelve of the 25 metabolites detected by 1H-NMR in roots were affected at 7, 14 or 21 days by the -Zn treatment. At day 21, changes observed included a 1.2-fold increase in the amino-acid arginine, 22-25% decreases in the amino-acids glutamate and glycine, and decreases in the carboxylate citrate (43%) and the disaccharides sucrose (38%) and trehalose (14%). Zinc deficiency also led to a 1.2-fold increase in the concentration of the alkaloid trigonelline (Trg).

Supported by Grant PID2020-115856RB-100 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”, and the Aragón Government (GroupA09-20R). J.L.C.-G. was supported by a pre-doctoral Mexican CONACYT scholarship (288000/471811).

8 Pags.- 7 Tabls. Proceedings IX International Symposium on Mineral Nutrition of Fruit Crops,

Peer reviewed