28 Feb 2019
Citrus Rootstock

The effect of chloride on four different citrus rootstocks

N. J.J. Combrink, N. Labuschagne, R. O. Barnard & J. M. Kotzé
South African Journal of Plant and Soil

Most of the world’s citrus is irrigated (Furr & Ream, 1969) and salt accumulation often results from use of poor quality irrigation water and inadequate soil drainage (Bernstein, 1975; Backlund & Hoppes, 1984). Citrus is generally considered to be a salt sensitive plant (Bernstein, 1969; Furr & Ream, 1969; Kirkpatrick & Bitters, 1969) although a wide range of salt . tolerance exists among citrus rootstocks (Cooper, 1961; Embleton, Labanauskas & Bitters, 1962; Peynado & Roger, 1962). Most rootstocks are adversely affected by salinity levels at which conductivity of the satl.l,rated soil extract (ECe) is about 250 – 300 mS m-I (Bernstein, 1975),. ‘It has been reported that heavy losses in production can occur even in the absence of visible toxicity symptoms such as leaf burn (Harding, Pratt & Jones, 1958; Pearson & Huberty, 1959; Peynado & Roger, 1962; Shalhevet, Yaron & Horowicz, 1974).

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28 Feb 2019
Chloride-stressed Citrus

Polyamines in Chloride-stressed Citrus Plants: Alleviation of Stress by Nitrate Supplementation via Irrigation Water

Yoel Bar, Akiva Apelbaum, Uzi Kafkafi, and Raphael Goren
The Kennedy–Leigh Centre for Horticultural Research
The Hebrew University of Jerusalem, Rehovot 76100, Israel

A study was conducted to elucidate the effects of chloride in the irrigation water on growth and development of two citrus rootstocks. ‘Cleopatra’ mandarin (Citrus reshni Hort. ex Tan) is salt tolerant and ‘Troyer’ citrange (Poncirus´Citrus sinensis) is salt sensitive. Increasing chloride from 2 to 48 mM in the irrigation water resulted in increased leaf chloride levels, more severe damage of the leaves, and reduced branch growth. High chloride in the irrigation water also caused increased putrescine (PUT) and decreased spermine (SPM) contents of the leaves.

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28 Feb 2019
Boron and Chlorine for Citrus Trees

Boron (B) and Chlorine (Cl) for Citrus Trees

Mongi Zekri and Tom Obreza
IFAS Extension, University of Florida

To maintain a viable citrus industry, Florida growers must consistently and economically produce large, high-quality fruit crops year after year. Efficiently producing maximum yields of high-quality fruit is difficult without understanding soil and nutrient requirements of bearing citrus trees.

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