Differential tolerance to iron deficiency of citrus rootstocks grown in nutrient solution

• Published in: Scientia horticulturae 2005-03, Vol.104 (1), p.25-36
• Main Authors: Pestana, Maribela, Varennes, Amarilis de, Abadía, Javier, Faria, Eugénio Araújo
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Biomass allocation; calcareous soils; calcium carbonate; chlorophyll; Chlorophyll fluorescence; chlorosis; Citrus; citrus fruits; Citrus sp; dry matter content; fluorescence; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; iron; length; Lime-induced chlorosis; Mineral composition; nutrient content; nutrient deficiencies; nutrient solutions; plant nutrition; Poncirus; Rootstocks; shoots; SPAD; Vegetative propagation. Micropropagation; Vegetative propagation. Sowing and planting. Harvesting
• ISSN: 0304-4238; 1879-1018
• DOI: 10.1016/j.scienta.2004.07.007

We studied the effects of Fe deficiency on physiological parameters of citrus rootstocks grown in nutrient solution. Three 4-week old rootstocks (‘Troyer’ citrange – Citrus sinensis (L.) Osb. × Poncirus trifoliata (L.) Raf., Citrus taiwanica Tan. and Shim., and ‘Swingle’ citrumelo – Poncirus trifoliata (L.) Raf. × Citrus paradisi Macf.) were grown in nutrient solutions with 0, 5, 10, 15 and 20 μmol Fe dm −3. Calcium carbonate (1 g dm −3) was added to all solutions to mimic the natural conditions in calcareous soils. For each rootstock, shoot length, number of leaves, and root and shoot dry weights were measured at the end of experiment. Chlorophyll concentration was estimated using a portable SPAD-502 meter calibrated for each rootstock. The amount of nutrients (P, K, Mg, Ca, Fe, Zn, Mn, and Cu) was determined in shoots. Chlorophyll fluorescence parameters ( F 0: basal fluorescence; F m: maximum fluorescence; F v = F m − F 0: variable fluorescence) were measured with a portable fluorimeter. ‘Troyer’ citrange rootstock was the most tolerant to Fe deficiency. These plants grew more and accumulated more chlorophyll and nutrients than the others in the presence of low levels of Fe (10 μmol Fe dm −3). ‘Swingle’ citrumelo plants needed 20 μmol Fe dm −3 in the nutrient solution to secure adequate growth. ‘Taiwanica’ orange rootstock had an intermediate behaviour, but could be distinguished from ‘Troyer’ citrange based on fluorescence parameters, since there was a variation in the basal fluorescence in the former, whereas in ‘Troyer’ citrange the basal fluorescence was not affected by the supply of Fe.