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The effects of trellising on absorption of photosynthetically active radiation (PAR, 400- to 700-nm wavelength) by foliage and fruits, on fruit composition, and yield were studied in 1988 under semi-arid conditions using field-grown Vitis vinifera L. `Petite Sirah' grapevines in a mature vineyard. A vertical inclination was obtained by attaching shoots to a vertically arranged three-wire trellis; 60° shoot inclination from horizontal was obtained by attaching shoots to a “V-type” Tatura trellis; a standard two-wire trellis (control) was used in which shoots attached to the upper wire were permitted to orient downward to the vineyard floor. PAR absorption by foliage during mid-morning to mid-afternoon periods was highest in the standard trellis and lowest in the Tatura trellis. PAR available for absorption by fruits was lowest in the standard trellis and highest in the Tatura trellis. Analysis of fruit composition at harvest revealed that total dissolved solids (°Brix) was significantly higher for berries from the Tatura trellis than for the vertical trellis or the control. The Tatura trellis resulted in the highest alcohol content of wine. Per-vine yields did not differ significantly among the three trellis systems.
Abstract
‘Sumter’ cucumber (Cucumis sativus L.) plants were grown in the vegetative state with nutritionally sufficient solution followed by a 2-week period with Mn deficiency (no Mn), sufficiency (0.1 mg Mn/liter), or toxicity (10 mg Mn/liter). Beginning 34 days after germination, or about 2 weeks before imposition of Mn deficiency and toxicity treatments, plants were harvested every 3 days. With Mn deficiency and toxicity, rates of accumulation of dry weight (DW), fresh weight (FW), N, P, and K were lower than with Mn sufficiency. In contrast, rates of accumulation for Cu, Fe, and Zn were generally higher with Mn deficiency, compared to these fluxes in Mn-sufficient plants. Anomalously high accumulation rates for DW, FW, Cu, and Mn were estimated for the 3-day period following the beginning of the toxic Mn treatment.