Nutritional Efficiency and Morphophysiological Aspects With Growth in the ‘Okinawa Roxo’ Peach Rootstock

The aim of this study was to evaluate the efficiency of nutrient uptake, accumulation, distribution and use, and its relationship with growth variables, chlorophyll content, and root and shoot dry-weight partitioning in the 'Okinawa Roxo' peach rootstock, submitted to different nutrient solutions and substrates. The experimental design was completely randomised, with four treatments and five replications. The treatments were T1: Ns1 = Souza et al. nutrient solution (2011), applied to a sand substrate; T2: Ns2 = Hoagland and Arnon (1950), applied to a sand substrate; T3: Commercial Substrate + H2O; and T4: Control, Sand + H2O. Ninety days after transplanting (DAT), morphological, physiological and nutritional parameters were determined in the 'Okinawa Roxo' rootstock, together with the correlation between nitrogen concentration and nitrogen balance index, and the chlorophyll content and index. The greatest zinc content was detected in the shoots of the 'Okinawa Roxo' plants, at more than 80% of the accumulated total. Treatments T1 and T2 (nutrient solutions Ns1 and Ns2 respectively) made it possible to obtain 'Okinawa Roxo' plants with the best morphophysiological characteristics, being ready for grafting three months after transplanting in a greenhouse. The use of the Ns1 nutrient solution resulted in greater efficiency in the uptake and use of the nutrients nitrogen (N), potassium (K) and iron (Fe). The N and Total Chlorophyll concentrations in the leaves of the red-leaved peach tree can be estimated indirectly with a chlorophyll meter, and are an accurate indication of the nutritional status of the plant in relation to nitrogen content.