Rough lemon seedlings [Citrus limon (L)] were hydroponically-cultured in complete Shive's nutrient solution (+K) or in Shive's nutrient solution with potassium omitted (-K) for a period of eight months. Fresh and dry weight of whole -K plants were reduced 4-fold (P<0.01). Nitrogen metabolism was monitored during this period in young, fully expanded leaves. Results showed that leaves of -K plants accumulated 2.5-fold more NH3-NH4 + than +K plants (P<0.01) and exhibited a concomitant increase in both activity of the de novo arginine biosynthetic pathway (2.5-fold) and free-arginine concentration (3.5-fold; P<0.001). Leaf proline content of -K plants increased 1.6-fold (P<0.05), while putrescine content increased 10-fold. Arginine decarboxylase activity was accelerated in -K plants.
Yusheng Zheng and Carol J. Lovatt
S. Singh, B.K. Ray, S. Bhattacharyya, and P.C. Deka
Multiple shoots were obtained from shoot tips (2 to 3 mm) derived from mature plants (5 to 6 years old) of Citrus reticulata Blanco cv. Khasi mandarin and C. limon Burm.f. cv. Assam lemon when cultured on Murashige and Skoog (MS) medium, supplemented with (mg·liter-1) 1.0 BAP, 0.5 kinetin, and 0.5 NAA. Root induction was observed when 7-week-old single shoots (≈ 2 cm long) of both Citrus species were cultured on MS medium supplemented with (mg·liter-1) 0.25 BAP, 0.5 NAA, and 0.5 IBA. These plantlets were successfully established in the soil. Chemical names used: naphthalene acetic acid (NAA), indole 3-butyric acid (IBA), and benzylamino purine (BAP).
Z.N. Deng, A. Gentile, F. Domina, E. Nicolosi, and E. Tribulato
Protoplasts isolated from an embryogenic callus line of `Femminello siracusano' lemon [Citrus limon (L.) Burm. f.] were incubated with 0.5 μm toxin of Phoma tracheiphila (Petri) Kanc. et Ghik., the pathogen of the mal secco disease, which seriously damages most commercial lemon cultivars. Two toxin-tolerant cell lines were obtained, and plants were regenerated from each line. The selected protoclones were tested for their tolerance by exposing callus and protoplasts to the toxin and detecting chitinase (a pathogenesis-related protein) among the intra- and extracellular proteins extracted from leaves of regenerated plants and suspension culture, respectively. The tolerance of the protoclones in these tests was equivalent to the tolerant lemon cultivar Monachello, and they were substantially more tolerant than their mother cultivar Femminello siracusano.
Aydin Uzun, Osman Gulsen, Gucer Kafa, and Ubeyit Seday
Lemon [ Citrus limon (L.) Burm. f.] cultivar improvement is important to consumers as well as the citrus industry. Alata Horticultural Research Institute, Mersin, Turkey, announces four new lemon cultivars obtained by budwood irradiation. Three
Chris A. Martin, Jean C. Stutz, Bruce A. Kimball, Sherwood B. Idso, and David H. Akey
Growth and topological indices of `Eureka' lemon were measured after 6 months in well-watered and well-fertilized conditions and factorial combinations of moderate (29/21C day/night) or high (42/32C day/night) temperatures and ambient (350 to 380 μmol·mol) or elevated (constant 680 μmol·mol-1) CO2. In high temperatures, plants were smaller and had higher levels of leaf chlorophyll a than in moderate temperatures. Moreover, plants in high temperatures and elevated CO2 had about 15 % higher levels of leaf chlorophyll a than those in high temperatures and ambient CO2. In high temperatures, plant growth in elevated CO2 was about 87% more than in ambient CO2. Thus, high CO2 reduced the negative effect of high temperature on shoot growth. In moderate temperatures, plant growth in elevated CO2 was only about 21% more than in ambient CO2. Irrespective of temperature treatments, shoot branch architecture in elevated CO2 was more hierarchical than those in ambient CO2. Specific shoot extension, a topological measure of branch frequency, was not affected by elevated CO2 in moderate temperatures, but was increased by elevated CO2 enrichment in high temperatures-an indication of decreased branch frequency and increased apical dominance. In moderate temperatures, plants in elevated CO2 had fibrous root branch patterns that were less hierarchical than at ambient CO2. The lengths of exterior and interior fibrous roots between branch points and the length of second-degree adventitious lateral branches were increased >50% by high temperatures compared with moderate temperatures. Root length between branch points was not affected by CO2 levels.
David A. Francko, Kenneth G. Wilson, Qingshun Q. Li, and Maria A. Equiza
( Citrus limon ), miniature rose ( Rosa chinensis minima ), azalea ( Rhododendron indicum ‘Formosa’), and wax begonia ( Begonia spp.). Azaleas were sampled from specimens in the first author's home landscape (late winter fertilization with a 10N–4.4P–6.6K
Mirko Siragusa, Fabio De Pasquale, Loredana Abbate, Letizia Martorana, and Nicasio Tusa
, G. Bianco, M. 2004 Inter-simple sequence repeat markers and flow cytometry for the characterization of closely related Citrus limon germplasm Biotechnol. Lett. 26 1296 1299 Coletta Filho, H.D. Machado
Pinchas Spiegel-Roy, Aliza Vardi, Yosef Yaniv, Luba Fanberstein, Avraham Elhanati, and Nir Carmi
Two lemon (Citrus × limon L. Burm. F.) cultivars, Eureka and Villafranca, were subjected to a mutation-inducing process, which led to the production of seedless mutants in both cultivars. This mutation-inducing process did not affect many other lemon traits.
Vicente Gimeno, James P. Syvertsen, Inma Simon, Vicente Martinez, Jose M. Camara-Zapata, Manuel Nieves, and Francisco Garcia-Sanchez
flooding of ‘Verna’ lemon trees on SO rootstock relative to trees that were interstocked with two different orange varieties. Materials and Methods Trees and growth condition. Two-year-old ‘Verna’ lemon trees [ Citrus limon (L.) Burm.] grafted on SO ( C
Brent Tisserat, Danny Jones, and Paul D. Galletta
Nutrient medium can be sterilized using a household-type microwave oven. The required microwave treatment time was influenced by the oven's microwave power intensity (70 to 700 W), vessel type, volume of medium employed, and the presence of energy sink water reservoirs (ESWR). Growth rates of strawberry (Fragaria vesca L.) shootlets, lemon [Citrus limon (L.) Burm. f.] fruit halves, or carrot (Daucus carota L.) callus cultured on either microwaved or autoclaved media were similar. Microwaving and autoclaving appeared to reduce GA3 activity compared with medium containing filter sterilized GA3. Chemical name used: gibberellic acid (GA3).