rooting efficiency of Carrizo citrange microshoots produced from cultures initiated from nodal explants. Carrizo citrange is a main citrus rootstock widely used in important citrus-producing areas such as Spain and California, where ≈90% of the new
Almudena Montoliu, Aurelio Gómez-Cadenas and Rosa M. Pérez-Clemente
Maria Luiza De Oliveira, James G. Thomson and Ed Stover
from juvenile ‘Carrizo’ citrange and mature ‘Washington Navel’ orange nodal segments. ‘Washington Navel’ orange is one of the most important fresh-fruit oranges in the United States ( Boriss, 2006 ), and its mature tissue is generally considered
Francisco García-Sánchez and James P. Syvertsen
, 2004 ). There is a marked effect of citrus rootstocks on the uptake and transport of Cl – and/or Na + . For example, the rootstock Cleopatra mandarin has a good capacity to exclude Cl – , whereas Carrizo citrange is considered to be a Cl – accumulator
Francisco García-Sánchez and J.P. Syvertsen
Three-month-old citrus rootstock seedlings of the Cl- excluder Cleopatra mandarin (Citrus reticulata Blanco) and the Cl- accumulator Carrizo citrange [C. sinensis (L.) Osb. × Poncirus trifoliata L.] were fertilized with nutrient solution with or without additional 50 mm NaCl and grown at either ambient CO2 (360 μL·L-1) or elevated CO2 (700 μL·L-1) in similar controlled environment greenhouses for 8 weeks. Elevated CO2 increased plant growth, shoot/root ratio, leaf dry weight per area, net assimilation of CO2, chlorophyll, and water-use efficiency but decreased transpiration rate. Elevated CO2 decreased leaf Ca2+ and N concentration in non-salinized Cleopatra. Salinity increased leaf Cl- and Na+ in both genotypes. Carrizo had higher concentrations of Cl-but lower Na+ in leaves than Cleopatra. Salinity decreased plant growth, shoot/root ratio, net gas exchange, water use, and root Ca+2 but increased root N in both genotypes regardless of CO2 level. Neither salinity nor elevated CO2 affected leaf chlorophyll fluorescence (Fv/Fm). Carrizo had higher Fv/Fm, leaf gas exchange, chlorophyll, N, and Ca2+ than Cleopatra. Salinity-induced decreases in leaf osmotic potential increased leaf turgor especially at elevated CO2. The increase in leaf growth at elevated CO2 was greater in salinized than in nonsalinized Carrizo but was similar in Cleopatra seedlings regardless of salt treatment. In addition, salinity decreased water-use efficiency more at elevated CO2 than at ambient CO2 in Cleopatra but not in Carrizo. Elevated CO2 also decreased leaf Cl- and Na+ in Carrizo but tended to increase both ions in Cleopatra leaves. Based on leaf growth, water-use efficiency and salt ion accumulation, elevated CO2 increased salinity tolerance in the relatively salt-sensitive Carrizo more than in the salt-tolerant Cleopatra. In salinized seedlings of both genotypes, Cl- and Na+ concentration changes in response to eCO2 in leaves vs. roots were generally in opposite directions. Thus, the modifications of citrus seedling responses to salinity by the higher growth and lower transpiration at elevated CO2 were not only species dependent, but also involved whole plant growth and allocations of Na+ and Cl-.
Jim Syvertsen and Francisco Garcia-Sanchez
Two-month-old citrus rootstock seedlings of Cleopatra mandarin (CM) and Carrizo citrange (CC) were fertilized with nutrient solution, with or without additional 50 mM NaCl, and grown under either ambient CO2 (aCO2, 360 ppm) or elevated CO2 (eCO2, 720 ppm) for 8 weeks. Elevated CO2 increased plant growth, shoot: root ratio, net assimilation of CO2, leaf chlorophyll, and water use efficiency (WUE), but decreased plant water use. Salinity decreased growth, shoot: root ratio, net gas exchange and water use. Neither salinity nor eCO2 affected leaf chlorophyll fluorescence (Fv/Fm), but CC had higher Fv/Fm, leaf gas exchange, chlorophyll, N and Ca than CM. Although salinity increased leaf Cl and Na in both genotypes, CC had higher leaf Cl, but lower Na than CM. Salinity-induced decreases in leaf osmotic potential increased leaf turgor, especially at eCO2. There were no interacting effects of eCO2 and salinity on plant growth, but salinity decreased WUE more at eCO2 than at aCO2 in CM; but not in CC. Elevated CO2 decreased leaf Cl and Na in CC, but tended to increase both ions in CM leaves. Patterns of Cl and Na responses in roots generally were in opposite direction to their respective responses in leaves. Thus, the modifications of citrus seedling responses to salinity by higher growth and lower water use at eCO2 were not only species dependent, but also involved whole plant allocations of Na and Cl.
M. Carmen González-Mas, M. José Llosa, Antonio Quijano and M. Angeles Forner-Giner
, citrus-growing success depends on availability of suitable rootstock that is tolerant of low Fe. Trifoliate orange [ Poncirus trifoliata (L.) Raf.], sweet orange [ C. sinensis (L.) Osb.], and Carrizo citrange ( C. sinensis × P. trifoliata ) are all
Concetta Licciardello, Biagio Torrisi, Maria Allegra, Fabiola Sciacca, Giancarlo Roccuzzo, Francesco Intrigliolo, Giuseppe Reforgiato Recupero, Paola Tononi, Massimo Delledonne and Vera Muccilli
Carrizo citrange is considered tolerant, and sour orange ( Citrus aurantium ), various mandarins ( Citrus reticulata , Citrus nobilis ), Rangpur lime ( Citrus limonia ), and rough lemon ( Citrus jambhiri ) are considered very tolerant ( Hamze et al., 1986
William S. Castle, James C. Baldwin, Ronald P. Muraro and Ramon Littell
consecutive seasons when the trees were 16 and 17 years old. Samples of 400 kg of fruit were differentially harvested in March by combining fruit from four replicates of trees on Carrizo citrange, Cleopatra mandarin, rough lemon, sour orange, or Swingle
Thomas A. Obreza and Robert E. Rouse
The growth response of young `Hamlin' orange (Citrus sinensis L. Osbeck) on Carrizo citrange (C. sinensis × Poncirus trifoliatu L. Raf.) trees to N-P-K fertilizer rates under field conditions in southwestern Florida was studied to determine the minimum fertilizer required to bring trees into maximum early production. The highest 8N-1.8P-6.6K fertilizer rate was 2.72,5.45, and 8.17 kg/tree in 1989,1990, and 1991, respectively. Additional fertilizer treatments equaled 50%, 25%, or 13% of the maximum rate. Fertilizer sources contained either all water-soluble N (applied more frequently) or 40% to 50% controlled-release N (applied less frequently), and they did not affect fruit yield or quality. The response of trunk cross-sectional area, tree canopy volume, and fruit yield to fertilizer rate was described by a linear plateau model. The model predicted a fruit yield of 22.6 kg/tree at the estimated critical fertilizer rate of 48% of maximum. Fruit yield at the 50% maximum rate averaged 21.2 kg/tree. As fertilizer rate increased, total soluble solids concentration (TSS) in juice and the TSS: acid ratio decreased, but weight per fruit and TSS per tree increased. A fruit yield >21 kg/31-month-old tree indicated vigorous growth.
Kim D. Bowman
treatments were applied to trees of ‘Earlygold’ sweet orange ( Citrus sinensis ) budded onto Carrizo citrange ( C. sinensis × Poncirus trifoliata ) rootstock in June 2002 as described in the previous report ( Bowman, 2005 ). The treatments were: 1) none; 2