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Peitao Lü, Xinmin Huang, Hongmei Li, Jiping Liu, Shenggen He, Daryl C. Joyce, and Zhaoqi Zhang

Termination of vase life for cut flowers is characterized by wilting associated with an imbalance developing between water uptake through xylem conduits in stems and water loss through stomata and other structures on leaves and other organs. To

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Ronald B. Sorensen and Tim L. Jones

Soil depth for water uptake in pecan trees [Carya illinoensis (Wangenh.) C. Koch `Western Schley'] is considered to be <100 cm (3.2 ft) for sites that have high water tables. The objective of this research was to determine the water uptake pattern of pecan trees grown on sites with a deep water table [>30 m (100 ft)] and irrigated at 50 kPa (0.5 bar). Trees (15- to 20-year-old trunks) were transplanted into laser-leveled terraces in 1986. Two terraces (T) were selected and irrigated (1994 and 1995) at 50 kPa (T5) and farmer controlled [T6, weekly at ≈30 kPa (0.3 bar)]. Soil water content was measured on a 1.3 by 1.3 m (4 ft by 4 ft) grid for one tree in each terrace using a neutron probe. In 1994, the average soil depth for water uptake was 75 (2.5 ft) and 62 cm (2.0 ft) for T5 and T6 respectively. In 1995, the average soil depth for water uptake was 150 cm (5 ft) on T5 and 130 cm (4 ft) on T6. The total quantity of water removed below 140 cm (4.6 ft) soil depth was minor (<15%) when compared with the total water removed between 0 and 140 cm depth. T5 showed a deeper (260 cm; 8.5 ft) and wider (3.0 to 5.0 m; 10 to 16 ft) water uptake pattern compared with T6. Thus, pecan trees growing on these coarse soils with a deep water table and irrigated at 50 kPa have an effective root zone of ≈140 to 150 cm (4.6 to 5.0 ft).

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Gretchen B. North and Evan A. Baker

For desert succulents, and for several other plant species, older roots play a more active role in water uptake than is generally acknowledged. We suggest that older roots of most plants can and do take up water, and we discuss in more detail the

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Kristof Vermeulen, Kathy Steppe, Katrien Janssen, Peter Bleyaert, Jan Dekock, Jean-Marie Aerts, Daniel Berckmans, and Raoul Lemeur

an important objective in current horticultural research programs ( Ehret et al., 2001 ). One of the techniques to determine water uptake directly is by using a lysimeter or an electronic balance. This device is commonly used in the scientific

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Donna A. Marshall, James M. Spiers, and Kenneth J. Curry

plants (19.90%). Yet some splits apparently occurred from uptake of water by the roots that is transported to the fruit by the xylem. Susceptibility to splitting in cherries appears to be related to the rate and quantity of water uptake by the fruit

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Andreas Winkler, Stefanie Peschel, Kathleen Kohrs, and Moritz Knoche

assumes the flesh of the berry to be held under compression by an elastically strained skin. Upon water uptake, the pressure in the fruit rises. When the fruit pressure (synonymous with fruit turgor and with flesh turgor) exceeds some critical threshold; i

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M.S. Albahou and J.L. Green

It has been shown that container medium volume affects plant growth and development in conventional production methods. The objective of this study was to investigate the effect of media volume on the growth and yield of the determinate tomato genotype `Pik Red' in the closed, insulated pallet system (CIPS). The CIPS contains media pouches with wicks extended down into a water reservoir. Three root media volumes were investigated: 3, 6, and 9 L (3L, 6L, and 9L). The root media were placed in pouches that varied in diameter but had constant depth. The surface area of the wicks in contact with the bottom of all pouch sizes remained constant at 110 cm2. It was hypothesized that increasing the volume of root media would allow sufficient water replenishment during the dark period to meet the plant's need the next day, and thus allow greater growth and fruit yield. Daily water uptake for each individual plant was measured by the principle of atmospheric pressure and water replacement technique. Media volume had no significant effect on water uptake during early stage of plant growth. After 45 days after planting (DAP), water uptake and plant growth were less in 3L media volume. Water uptake was similar in the 6L and 9L treatments between 45–60 DAP. Total water uptake from day 60 to 125 was greatest in the 9L, intermediate for 6L, and least in the 3L treatments. The water uptake from 1–60 DAP was reflected in the fresh shoot weight, and the water uptake was reflected in the fruit weight. Average fruit sizes and the total fruit weights for the 3L were 67.7% and 60.4% those of the 9L treatment, respectively. The 6L treatment fruit yield and fruit size were intermediate between the 3L and 9L.

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Kelly T. Morgan, Smita Barkataky, Davie Kadyampakeni, Robert Ebel, and Fritz Roka

yields. However, water uptake increased after harvest when irrigation resumed. These observations are in agreement with those of several researchers who reported recovery of sweet orange trees in less than 1 week after resuming irrigation ( Fereres et al

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Ursula K. Schuch, Anita N. Miller, and Leslie H. Fuchigami

Dormant coffee (Coffea arabica L.) flower buds require water stress to stimulate regrowth. A xylem specific watersoluble dye, azosulfamide, was used to quantify the uptake of water by buds after their release from dormancy by withholding water. In non-stressed flower buds, the rate of water uptake was generally slower and variable. In stressed flower buds, the rate of uptake tripled from one day to 3 days after rewatering and preceded the doubling of fresh and dry weight of buds. Free, ester, and amide IAA levels of developing flower buds were measured by GCMS-SIM using an isotope dilution technique with [13C6] IAA as an internal standard. Throughout development, the majority of IAA was present in a conjugated form and the dominant form was amide IAA. The proportions of amide and free IAA changed rapidly after plants were water stressed until day 3, and preceded the doubling of fresh and dry weight. Correlation coefficients of 0.9, 0.7, and 0.7 (p<0.l) were found between auxin content and fresh weight, dry weight, and rate of water uptake, respectively.

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W. J. Carpenter and H. P. Rasmussen

Abstract

The rate of absorption of distilled water by individual ‘Forever Yours’ cut roses was measured in continuous light (720 ft-c) and total darkness. Maximum water uptake in light (1.5 to 3.5 ml/hour) was found 24 to 48 hour (hr) after harvest followed by a gradual decline, while the lower (0.18 to 0.47 ml/hour) uptake in the dark persisted during the 120 hour study. Alternating 12 hour light and dark periods for 120 hours in a second study showed absorption rates change rapidly from light to dark or dark to light exposure. Statistical correlations were made among cut rose morphological parts and the rate of water uptake. Leaf area was found to be the factor most closely associated with water uptake in both light and dark. Anatomical studies revealed overall tissue degradation in rose stems kept in distilled water 5 days.