LIBRO-CONGRESO-CITRUS

S10
S10O08
Uptake of 44Ca and 15N by young citrus trees
Quiñones A., Martínez-Alcántara B., Alcayde E., and Legaz F.
Instituto Valenciano de Investigaciones Agrarias (IVIA), Citriculture and Vegetal Production, Spain. legaz_fra@gva.es
Calcium is a macroelement involved in numerous physiological processes in plants, such as the division
and growth of cells. Calcium is part of the structure of cell walls and membranes and together with the
magnesium participates in the activation of metabolic enzymes of proteins and carbohydrates. There are
numerous studies on Ca conducted in the plant-soil system, however no information is available on their
absorption and distribution among different organs. In this sense, the use of 44 Ca and 15 N as tracers is a useful
tool since allows to know exhaustively the fate of the element applied in the plant-growing medium system.
Ca absorption by plant roots depends on several factors, among which are the availability of this nutrient in
the culture medium. Therefore, the main objective of this study is to evaluate the response of 7 different 44 Ca
and 15 N concentrations on their uptake and their distribution among different organs in young plants of citrus
grown in sand substrate in a growth chamber. At the end of the labelling period, plants were fractionated
into young developing organs, old leaves, stem, coarse and fibrous roots. Increasing Ca concentration did not
affect significantly the biomass of the different organs. However, significant differences were obtained in 44 Ca
and 15 N uptake. Ca uptake efficiency decreased from 28% to 15% when increasing Ca supplied (0.5 mM to
32 mM), while N uptake efficiency decreased from 49% to 17% (2.5 mM to 70 mM). Whereas Ca was mainly
partitioned to coarse roots, N accumulated in new flush leaves.
S10O09
A new approach to front citrus iron chlorosis: organo-mineral fertilizers from glass-matrix and
organic biomasses
Torrisi B. 1 , Trinchera A. 2 , Allegra M. 3 , Epifani R. 2 , Marcucci A. 2 , Roccuzzo G. 1 , Intrigliolo F. 1 , and Rea E. 2
1 Centro di ricerca per l’Agrumicoltura e le Colture Mediterranee (CRA-ACM), ITALY; 2 Centro di ricerca per lo studio delle Relazioni tra
Pianta e Suolo (CRA-RPS), ITALY; and 3 Centro di ricerca per l’Agrumicoltura e le Colture Mediterranee (CRA-ACM), ITALY.
francesco.intrigliolo@fastwebnet.it
The aim of the present paper was to deepen the agronomical responses of glass-matrix based fertilizers
(GMF), a typology of fertilizer able to release nutrients on the basis of plant-demand, whose nutrient release
increases thanks to the mixing with organic biomasses, such as digested vine vinasse (DVV) and meat-meal
(MM). Laboratory tests and short-term pots trials provided concurring results about the attitude of the mixture
GMF DVV to increase nutrient availability and plant development. In the following stage these mixtures were
tested for their ability to contrast citrus iron chlorosis in calcareous soils, the most complex phenomenon in
citrus orchard and one of major abiotic stresses affecting fruit tree crops in the Mediterranean area. Three
years studies were realized: i) in pots, on ‘Tarocco Scirè’ orange trees [Citrus sinensis] grafted on two different
rootstocks (Carrizo citrange and Swingle citrumelo) and ii) in field, on ‘Tarocco Scirè’ on sour orange rootstock
[C. aurantium], by comparing GMF and its mixtures with DVV and MM application to a synthetic Fe chelate
one. The GMF DVV mixture was able to supply adequately micronutrients, particularly iron, reducing the
chlorosis symptoms, increasing the leaf SPAD index, Fe concentration and decreasing Fe index.
S10O10
Nitrogen and calcium equilibrium on citrus nutrition
Quaggio J.A. 1 , Souza T.R. 1 , Boaretto R.M. 2 , Zambrosi F.C.B. 1 , and Mattos Jr. D. 2
1 Instituto Agronômico (IAC), Center of Soil, Brazil; and 2 Instituto Agronômico (IAC), Center of Citriculture, Brazil.
quaggio@iac.sp.gov.br
Nitrogen (N) and calcium (Ca) are major nutrients in citrus trees and responsible for the ionic equilibrium of
plant cells. Additionally, Ca absorption is directly affected by the form of N supply; e.g. ammonium or nitrate.
Therefore, high yield and fruit quality of citrus depend on balanced application of those, especially under intensive
nutritional program as fertigation. The objective of this study was to evaluate the mineral N and Ca2 absorption
160 - VALENCIA CONFERENCE CENTER, 18th-23rd NOVEMBER 2012