Search Results

You are looking at 1 - 10 of 113 items for :

  • "Citrus limon" x
Clear All

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.

Free access

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).

Free access

Abstract

Sprays of ammonium ethyl carbamoyl-phosphonoate (Krenite), applied to the tops of mature Lisbon lemon trees [Citrus limon (L). Burml.] resulted in significant inhibition of re-growth for over 3 years. One spray increased yield over the control trees (hand topped annually), while 2 sprays reduced yield. The sprays did not effect the N concentration in the leaves.

Open Access

Abstract

Sprays of a plant growth regulator ammonium ethyl carbamoylphosphonoate (Krenite), applied to top regrowth of mature Lisbon lemon trees [Citrus limon (L.) Burmann] resulted in significant inhibition of growth for over 1 year. At concentrations above 0.2% there was excessive foliar and small branch damage.

Open Access

Abstract

Lemons (Citrus limon (L.) Burm. f.) were stored for up to 27 weeks at 10°C in air and in an atmosphere of 3 to 5% O2 and 0.1 to 0.2% CO2, with and without an ethylene absorbent. Mold incidence was high in controlled atmosphere (CA) storage where ethylene accumulated, but removal of ethylene reduced its development. CA storage improved retention of green color in lemons.

Open Access

Abstract

‘Bearss’ lemons (Citrus limon Burm f.) stored 21 days at 1°C and held 14 days at 21° sustained 15% chilling injury (Cl) compared to 1% after 10° storage and 21° holding period. Decay, predominantly caused by Penicillium digitatum Sacc., was negligible during storage at either 1° or 10°, but developed during the holding period at 21°. After storage at 1° or 10° plus 2 weeks at 21°, decay averaged 7.4% and 0.7%, respectively. Fruit size, method of curing, and presence of oleocellosis were not related to Cl or decay development.

Open Access
Author:

Abstract

Film wrapping or holding for 3 days at 21°C reduced chilling injury (CI) and decay of ‘Bearss’ lemons (Citrus limon Burm. f.) stored at 1° for 21 days plus 14 days at 21°. Prestorage treatments of 40% CO2 for 3 days at 21° or dips in 2%, 10%, or 20% vegetable oils were not effective in reducing CI or decay during a similar storage and holding period. The use of 10 μl·liter−1 ethylene to degreen lemons significantly increased CI and decay compared to degreening without ethylene, especially when lemons were stored at 1°.

Open Access

Abstract

Mature green lemon (Citrus limon Burm.) fruits are degreened commercially with ethylene to enhance yellow color development and improve marketing quality. This treatment often results in the development of a peel disorder called red blotch, a superficial reddish-brown discoloration, which may cover most of the fruit peel. We found that degreening at 30°C, instead of the recommended temperature of 25°, eliminated the disorder. Similarly, a predegreening treatment of dipping the fruit in the antioxidant ethoxyquin (“Stop Scald”) prevented red blotch development. The high temperature and the antioxidant may act on oxidative enzyme systems, which are apparently causative factors of the disorder.

Open Access

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.

Free access

Abstract

Leaves of cold-acclimated lemon [Citrus limon (L.) Burm. f.], grapefruit (C. paradisi Macf.), orange [C. sinensis (L.) Osbeck], and mandarin (C. unshiu Marc.) trees ranged in cold hardiness from −4 to −11°C. No significant differences in water content (g H2O/g dry weight) or melting point depression were observed. Plots of liquid water content during freezing (g H2O/g dry weight) vs. temperature were similar for the 4 citrus species. The tissues apparently deviated from ideal freezing behavior because less ice was formed. The reduced ice formation could not be accounted for by osmotic effects. Negative pressure potential developed during freezing is hypothesized to play a role in tissue water potential in frozen systems. It was concluded that hardier Citrus leaves survive freezing of a larger fraction of their tissue water.

Open Access