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Jackson Teixeira Lobo, Ítalo Herbert Lucena Cavalcante, Augusto Miguel Nascimento Lima, Yuri Alysson Carvalho Vieira, Pedro Igor Rodrigues Modesto, and Jenilton Gomes da Cunha

the effects of biostimulant foliar applications on the nutritional status and fruit production of ‘Kent’ mango cultivated in semiarid conditions. Materials and Methods Plant Material and Growing Conditions. Ten-year-old mango trees cv. Kent ( Mangifera

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Arnon Dag, Ran Erel, Alon Ben-Gal, Isaac Zipori, and Uri Yermiyahu

. Despite the crop's importance, no previous studies have been performed on the effect of olive stock plant nutritional status on propagation rates. In vitro rooting ability depends on many endogenous and exogenous factors such as genetic background

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Alessandro Abruzzese, Ilaria Mignani, and Sergio M. Cocucci

Apple (Malus domestica Borkh.) trees are often affected by a severe June fruit drop, which is often correlated with competition phenomena involving fruit nutrition. This research was initiated to determine if June drop in `Gloster'/M.9 apple could be correlated with a diminished nutrient availability in developing seeds and fruit. During the test period [30 to 62 days after full bloom (AFB)], the fruit that abscised had a diameter similar to that reached by persisting fruit 13 days earlier. Biochemical parameters related to nutritional status of fruit were measured when an abscission peak occurred 38 days AFB. Persisting fruit (control) and abscised fruit were compared along with fruit that abscise 13 days later. The cortex tissue obtained from the two kinds of abscised fruit showed a higher level of soluble reducing sugars and sucrose and a lower content of K+, acid hydrolyzable polysaccharides, and protein compared to the control. Further, the Ca2+ content was higher in abscised fruit than in controls of the same age, whereas there was no difference when fruit of the same size were compared. Total amino acid level was similar in control and abscised fruit at the same age, but there was a lower amino acid level in abscised fruit of the same size. Histological analysis of cortex tissue indicated that abscised fruit have larger cells with less evident nuclei and thinner cell walls than controls. Compared to control fruit, abscised fruit showed the same average number of seeds and a severe inhibition of seed growth; seeds from both kinds of abscised fruit had the same or higher levels of the parameters measured. No positive correlations were observed between fruit abscission and nutrient content of seeds or fruit.

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Nikolaos Koutinas, Thomas Sotiropoulos, Antonios Petridis, Dimitrios Almaliotis, Emmanuil Deligeorgis, Ioannis Therios, and Nikolaos Voulgarakis

several fruit quality attributes and nutritional status of the kiwifruit cultivar Tsechelidis. Materials and Methods The research was conducted in a commercial kiwifruit [ Actinidia deliciosa (A. chev.) C.F. Liang et A.R. Ferguson var. deliciosa

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C.A. Sanchez, M. Wilcox, J.L. Aguiar, and K.S. Mayberry

Twenty field experiments were conducted to evaluate the response of iceberg lettuce (Lactuca sativa L.) to N and evaluate various diagnostic technologies as tools for assessing the N nutritional status of lettuce. Lettuce yields showed a curvilinear response to N in most experiments. Generally, the dry midrib nitrate-N test and the sap nitrate-N test appear to be sensitive indicators of the N nutritional status of lettuce after the folding stage of growth. The chlorophyll meter was not a sensitive indicator of the N nutritional status of lettuce. Preliminary data also show that canopy reflectance, including digital analysis of aerial photographs, is correlated to N nutritional status of lettuce. However, reflectance technologies do not readily distinguish between N deficiencies and other factors (insects, diseases, water stress, etc.) that affect plant biomass and color. Because plant tests do not appear to be sensitive indicators of N nutrition during early growth stages (before folding), a post-thinning (and pre-sidedress) soil nitrate-N test is currently being evaluated.

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F.F. Ahmed, A.M. Akl, F.M. El-Morsy, and M.A. Ragab

Four biofertilizers (active dry yeast, phosphorene, rhizobacterium, and nitrobein) were used to fertilize `Red Roomy' grapevines. Growth and nutritional status of the vines as affected by such fertilizers during 1995 and 1996 were studied. Results showed that fertilizing the vine with all biofertilizers caused a material improvement in shoot length, leaf area, and cane thickness, and effectively enhance the nutritional status of the vines. The favorable effects of such fertilizers were in the following descending order: phosphorene, rhizobacterium, nitrobein, and active dry yeast. A great increase on growth and nutritional status of `Red Roomy' grapevines occurred as a result of supplying the vines with phosphorene or rhizobacterium as good, new biofertilizers.

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Bee Ling Poh, Aparna Gazula, Eric H. Simonne, Francesco Di Gioia, Robert C. Hochmuth, and Michael R. Alligood

fertilizer rates (80% and 60% of the recommended 200 lb/acre N) and IRRs (75% of the target 1000–4000 gal/acre per day) on fresh-market tomato nutritional status and yield. Materials and methods The experimental field located at the North Florida Research and

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Joseph P. Albano*, P. Chris Wilson, and Sandra B. Wilson

Sources of irrigation water in South Florida typically contain high levels of dissolved carbonates and bicarbonates. Repeated application of high alkalinity water can cause substrate-solution pH to rise, thereby altering nutrient availability, and possibly leading to the development of nutrient disorders and a reduction in plant growth. The objectives of the current study were to determine the effects of neutralizing alkalinity of irrigation water on the nutritional status and growth of Thryallis (Galphimia glauca Cav.). Plants were grown in 11.4-L containers in a 5 peat: 4 pine bark: 1sand (v:v:v) mix. Treatments were prepared with water collected from a commercial nursery with inherent calcium carbonate levels in excess of 260 mg·L-1 and pH above 7.3. Treatments consisted of 0% (control), 40%, or 80% alkalinity neutralized with sulfuric acid. At harvest, 51 weeks after initiating treatments, foliar levels of Fe were 28% greater, Mn 55% greater, and Zn 27% greater in the 80% than 0% neutralized alkalinity treatment. Growth indices and leaf greenness averaged over the course of the study were significantly greater in the 40% than in the 0% or 80% alkalinity neutralized treatments. Over the course of the study, leachate pH averaged 7.5, 6.8, and 5.3; and electrical conductivity (EC) averaged 1.4, 1.9, and 2.2 dS·m-1 in the 0%, 40%, and 80% alkalinity neutralized treatments, respectively.

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A.M. Akl, F. Ahmed Faissal, and S. Youssef William

Nutritional status of the vines, berry set, and yield as effected by the application of cycocel at 0.0, 500, 1000, or 1500 ppm and/or using a mixture of Mn, Zn, Cu, and Fe at 0.3% were studied. Cycocel was applied at different periods starting immediately after pruning and ending at 30 days after berry set. Results showed that three sprays of cycocel immediately after pruning, 15 days before first bloom, and at 30 days after berry set, particularly with the application of the four micronutrients together at 0.3%, proved much more effective in increasing the leaf content of total carbohydrates, total N, Zn, Mn, Cu, and Fe as well as berry set, number of clusters, yield and average cluster weight. Spraying Red Roomy vines three times with cycocel at 1000 ppm in combined with Mn + Zn + Cu + Fe at 0.3% gave satisfactory improvement in nutritional status and yield.

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A.M. Akl, A.M. Wassel, F.F. Ahmed, and M.A. Abdel Hady

This study was performed during the 1991, 1992, and 1993 seasons to study the effect of different concentrations and number of sprays urea and/or boric acid on behavior of buds, vegetative growth, and vine nutritional status of Red Roomy grape vines. Two, three, four, or five sprays for both urea at 0.5%, 1.0%, or 1.5% and/or boric acid at 0.1%, 0.2%, 0.3% in addition to the control treatments were applied. A gradual increase was observed in the percentages of burst and fruiting buds, main branch length, leaf area, cane thickness, total chlorophyll, and total carbohydrates in the leaves and considerable depression was observed in the percentages of dormant and vegetative buds. The most pronounced effect on growth and nutritional status was detected on vines sprayed four times with urea at 1.0% plus boric acid at 0 2% during the growing season.