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D. M. Glenn and W. V. Welker

The effect of ground covers on water uptake was studied using peach trees grown in a 4-part split root system. In 1992, one section of the root system was in bare soil and 3 sections were in combination with `K-31' tall fescue. In 1993, K-31 was eliminated in 2 additional sections, leaving 1 section in combination with `K-31'. When grass transpiration was suppressed by covering the K-31, tree water uptake/cm of root length was greater in the presence of grass compared to bare soil under well watered conditions. These data indicate that peach trees compensate for interspecific competition by increasing root hydraulic conductivity.

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J. N. Sacalis

Abstract

Effects of a mixed bed ion exchange resin column on vascular blockage and vase life were studied in cut roses (Rosa hybrida L. cv. Red American beauty) by measuring blockage rates in excised stem sections and by determining water uptake, fresh weight retention, and longevity of cut roses held in distilled water. The ion exchange column inhibited vascular blockage in excised stem segments. Water uptake and retention of fresh weight of cut roses were enhanced significantly by the ion exchange column treatment, and early wilting, known as “bent neck” was inhibited.

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Dave Llewellyn, Katherine Schiestel, and Youbin Zheng

). There were no treatment effects for any of the cultivars for water uptake during the first 7 d postharvest. Specific leaf area. There were no treatment effects on SLA for any of the cultivars ( Table 2 ). Leaf, growing substrate, and air temperatures

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James D. Oster, D.E. Stottlmyer, and M.L. Arpaia

, averaging ≈2 dS·m −1 , considering the different experimental conditions under which they were obtained. An ECe of ≈2 dS·m −1 could be a salinity level that limits water uptake ( Bernstein and Francois, 1973 ) by Mexican seedling rootstocks. If this is

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Juan Carlos Melgar, Arnold W. Schumann, and James P. Syvertsen

-holding capacities ( Koo, 1980 ). Water-saving irrigation techniques and fertilizer strategies can be used to improve efficiency of water uptake in grapevines ( Vitis vinifera L.) and peach trees [ Prunus persica (L.) Batsch] ( Chalmers et al., 1981 ; Dry et al

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Manuel G. Astacio and Marc W. van Iersel

, lasting only a few hours after ABA treatment. It is possible that ABA temporarily increases water uptake through its impact on aquaporins and then limits it by causing morphological changes to the roots (i.e., suberization) as a means of protecting the

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Michael Knee, Peg McMahon, and Glenn Carey

An undergraduate class in postharvest physiology observed a number of factors in the senescence of cut roses, which had been studied separately in the literature. They assessed the relative importance of the factors in determining vase life. `Samantha' roses were held at 20C in distilled water or a floral preservative. Ethylene treatment caused petal distortion and premature senescence. Floral preservatives stimulated ethylene production, although vase life was extended relative to flowers in water. Higher sugar contents and respiration were maintained in preservative than in water. Water uptake by roses was almost constant, but stem resistance to water flow increased faster in water than in preservative. In the 2nd week of vase life, transpiration exceeded water uptake, particularly for roses in water. As much of this water was lost through leaves as through the flower. The results suggest that a complex interaction of several factors determines vase life.

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R. H. Young, H. K. Wutscher, and L. G. Albrigo

Abstract

Orange trees (Citrus sinensis (L.) Osb.) with early-stage (sectored) and moderate blight were evaluated for zinc accumulation and water translocation characteristics. Zinc accumulated at above-normal levels in the outer 2 cm of trunk wood, but water uptake was at below-normal levels in the inner 2 to 6 cm of trunk wood of moderately blighted trees. Water-flux density of roots was not correlated with zinc accumulation. In trees with early stages of blight, zinc accumulated at above-normal levels in the healthy-appearing sides of the trunks, as well as in the blighted sides, but the water uptake in the healthy-appearing sides was similar to that in the trunks of healthy trees. Evidence suggested that the blight effect on abnormal zinc metabolism developed prior to the dysfunction of water translocation.

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N. Zieslin, H. C. Kohl Jr., A. M. Kofranek, and A. H. Halevy

Abstract

Flowers of different cultivars of rose (Rosa hybrida L.) vary in their sensitivity to bent-neck after cutting with ‘Cara Mia’ the most sensitive, and ‘Samantha’ the most resistant of the cultivars tested. Bent-neck is influenced by several factors: water loss by leaves, differences in water uptake ability of the stem, and the ability of the bloom to absorb water from other plant organs on the flower shoot.

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John W. White and Mark D. Shaw

Abstract

An instrument that actuates an irrigation system in response to a weight loss from a pot-soil-plant system, is described. The instrument utilizes the principle that the pot-soil-plant system can act as an integrator of all factors influencing water uptake and loss. The instrument is essentially a scale which continuously weighs the pot-soil-plant system placed upon it. Provisions are included in the design to compensate for gains in weight as the plant grows.