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Bruce W. Wood

Nickel is an often-overlooked plant ( Brown et al., 1987 , 1990 ) and animal ( Welch and Graham, 2005 ) essential micronutrient. Although Ni deficiency in plants severe enough to trigger visual symptoms is relatively rare, compared with other

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Tehryung Kim and Hazel Y. Wetzstein

Zinc deficiency is a widespread nutritional disorder in plants and occurs in both temperate and tropical climates. In spite of its physiological importance, cytological and ultrastructural changes associated with zinc deficiency are lacking, in part because zinc deficiency is difficult to induce. A method was developed to induce zinc deficiency in pecan (Carya illinoinensis (Wangenh.) C. Koch) using hydroponic culture. Zinc deficiency was evaluated in leaves using light and electron microscopy. Zinc deficiency symptoms varied with severity ranging from interveinal mottling, overall chlorosis, necrosis, and marginal curving. Zinc deficient leaves were thinner, and palisade cells were shorter, wider, and had more intercellular spaces than zinc sufficient leaves. Cells in zinc deficient leaves had limited cytoplasmic content and accumulated phenolic compounds in vacuoles. Extensive starch accumulation was observed in chloroplasts. This work represents the first detailed microscopic evaluations of zinc deficiency in leaves, and provides insight on how zinc deficiency affects leaf structure and function.

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Jared Barnes, Brian Whipker, Ingram McCall and Jonathan Frantz

Each essential element taken up by a plant serves to fulfill a specific physiological role, and reduced (nutrient deficiency) or excess (nutrient toxicity) levels of that element often result in unique symptomology that may be used for diagnostic

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Monica Ozores-Hampton

biological nitrogen (N) fixation ( Hochmuth, 2011 ; Nenova, 2006 ). The lack of adequate Fe available for the plant can lead to Fe deficiency ( Broschat and Elliott, 2005 ; Koenig and Kuhns, 2010 ; Walworth, 2013 ). The primary symptom of Fe deficiency is

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Bruce W. Wood

Pecan is a zinc (Zn)-sensitive species possessing a relatively high Zn requirement ( Sparks, 1987 ; Swietlik, 1999 ). Zinc deficiency is a common, and often major, problem in commercial pecan orchards, especially those established on sandy well

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Edward J. Ryder

Three chlorophyll deficiency traits in lettuce (Lactuca sativa) are reported. One, chlorophyll deficient-3 (cd-3), is quite yellow in the seedling stage, and controlled by a single recessive allele. Chlorophyll deficient-4 (cd-4) has sectors of yellow-green and green in the true leaves. It is inherited as a single recessive, and may be allelic to chlorophyll deficient-2 (cd-2). Sickly (si) is stunted, yellow, and partially necrotic, and is also controlled by a single allele. Virescent (vi) is epistatic to cd-4 and the latter is partially lethal. Linkage and additional epistatic relations with previously named chlorophyll deficient genes and other traits are discussed.

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Michael W. Smith, Becky S. Cheary and B. Scott Landgraf

A low leaf Mn concentration was detected in bearing pecan (Carya illinoinensis Wangenh. C. Koch) trees growing in an alluvial soil with an alkaline pH. Trees lacked vigor and leaves were pale in color, but there was no discernible leaf chlorosis or necrosis. Three foliar applications of MnSO4 beginning at budbreak, then twice more at 3-week intervals at rates of 0 to 3.3 kg·ha-1 of Mn increased leaf Mn concentration curvilinearly, and alleviated leaf symptoms. Results indicated that three foliar applications of MnSO4 at 2.15 kg·ha-1 of Mn plus a surfactant were adequate to correct the deficiency.

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Mary E. Dale, Ellen T. Paparozzi and James D. Carr

Cuttings of Euphorbia pulcherrima Willd. ex Klotzsch `Dark Red Annette Hegg' were grown hydroponically in minus S Hoagland's solution modified to supply 0, 1, 2, 4, or 8 mg S/liter for 8 weeks. Nutrient solution changes; visual observations, sampling of tissue, and measurement of electrical conductivity and pH were done every 2 weeks. Deficiency symptoms appeared after 4 weeks of growth in treatments supplying 0 or 1 mg S/liter and occasionally in treatments supplying 2 mg S/liter. Symptoms included reddening of the petiole and main vein of new leaves followed by yellowing of these leaves. Leaf tissue S levels ranged from 700 to 3600 mg S/kg of plant. Deficient levels were identified as <2200 mg S/kg of plant. Suggested critical tissue levels of S would be 2300 to 3000 mg S/kg of plant leaf tissue.

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Chenping Xu and Beiquan Mou

land in the world ( Ruan et al., 2010 ). The response of plants to salinity is complex and involves changes in morphology, physiology, and metabolism. Salinity effects on plants include cellular water deficit, ion toxicity, nutrient deficiencies, and

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Paul Cockson, Josh B. Henry, Ingram McCall and Brian E. Whipker

.5 and 6.0 ( Dole and Wilkins, 2005 ; Hamrick, 2003 ; Kimmins, 1992 ), and high substrate pH induced iron (Fe) deficiencies have been observed by the authors when the substrate pH exceeded 6.5. Growers are also cautioned to avoid excessive levels of