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Amos Naor

Interrelations between water potential and fruit size, crop load, and stomatal conductance were studied in drip-irrigated `Spadona' pear (Pyrus communis L) grafted on quince C (Cydonia oblonga L.) rootstock and growing in a semi-arid zone. Five irrigation rates were applied in the main fruit growth phase: rates of 0.25, 0.40, 0.60, 0.80, and 1.00 of “Class A” pan evaporation rate. The crop in each irrigation treatment was adjusted to four levels (200 to 1200 fruit per tree) by hand thinning at the beginning of June 1999. The crop was harvested on 1 Aug. 1999, and fruit size was determined by means of a commercial sorting machine. Soil, stem, and leaf water potentials and stomatal conductance were measured during the season. Crop yield was highly correlated with stem and soil water potentials. The highest midday stem water potential was lower than values commonly reported for nonstressed trees, and was accompanied by high soil water potential, indicating that the maximal water absorption rate of the root system under those particular soil conditions was limited. Stomatal conductance was highly correlated with leaf water potential (r 2 = 0.54), but a much better correlation was found with stem water potential (r 2 = 0.80). Stomatal conductance decreased at stem water potentials less than -2.1 MPa. Both stem water potential and stomatal conductance were unaffected by crop load under a wide range of irrigation rates.

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Tongyin Li, Guihong Bi, Richard L. Harkess, Geoffrey C. Denny, and Carolyn Scagel

hydrangea plants in this study on any measurement date. Stomatal conductance. The effects of N rate on g S varied among the four measuring dates ( Fig. 8 ). On 27 Aug., plants fertilized with N from 5 to 20 m m had similar g S , and g S of N

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Bhaskar R. Bondada

used to affix coverslips to the slides. Slides were placed under a compound microscope (Axioskop 2 plus) attached with a digital camera (DXM 1200C), which was used for capturing digital images. Measurement of leaf dimensions and stomatal conductance

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Chenping Xu and Beiquan Mou

this study was to assess the effects of chitosan as a soil amendment on lettuce growth, chlorophyll fluorescence, and gas exchange. Materials and methods Plant materials and experiments . Two trials, each with four replications, were conducted in a

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Emad Bsoul, Rolston St. Hilaire, and Dawn M. VanLeeuwen

, OR). At midday (1130 to 1300 hr ) of the same day, transpiration and stomatal conductance ( g S ) were measured with a steady-state porometer (LI-1600; LI-COR) on the leaf opposite to the one selected for determining Ψ pd . After transpiration and

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Genhua Niu, Denise S. Rodriguez, and Wayne Mackay

decreased ( Björkman et al., 1980 ). However, no relationship was found between leaf water potential and leaf stomatal conductance ( g S ) for oleander ( Gollan et al., 1985 ). Two representative commercial cultivars, Hardy Pink and Hardy Red, and two

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Sung H. Guak, Charles C. Shin, and L. H. Fuchigami

Antitranspirant N-2001 (10%), Great Lakes Chemical Corporation, was applied as a soil drench to `Fuji'/EMLA7' apple plants growing in 15 cm pots in a 25/22±3°C (D/N) greenhouse. After bringing pots to field capacity, chemical application was made and water was withheld thereafter. One hour after chemical application, stomatal conductance of treated and control plants was 0.25 and 0.70 cm/sec, respectively. Stomatal conductance of treated plants was maintained at approximately 0.25 cm/sec throughout the test period (28 days). Stomatal conductance of the control plants decreased to 0.25 cm/sec 13 days after treatment due to desiccation. The stem xylem water potential of the treated and control plants was -2.0 and -5.5 MPa, respectively, 28 days after treatment. The relative water content of leaves of treated plants was 45% greater than controls. The average loss of water via transpiration of treated plants was 32% less than the control plants.

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Ryo Matsuda, Chieri Kubota, M. Lucrecia Alvarez, and Guy A. Cardineau

), transpiration rate, stomatal conductance ( g S ) per unit leaf area, and total soluble protein (TSP) concentration per unit dry weight of young, fully expanded leaves of transgenic tomato grown at conventional (control) or high electrical conductivity (EC); n

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Alexander G. Litvin, Christopher J. Currey, and Lester A. Wilson

the evening. Fig. 3. Photosynthesis ( P n ), stomatal conductance ( g S ), and transpiration ( E ) for basil grown in hydroponic systems under ambient light supplemented with 100 µmol·m −2 ·s –1 of supplemental light from 0600 to 2200 hr provided

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Qiang Liu, Youping Sun, James Altland, and Genhua Niu

, 64 d after the initiation of treatment). Table 2. Plant relative chlorophyll content [soil plant analysis development (SPAD)], chlorophyll fluorescence (F v /F m ), net photosynthesis rate (P n ), stomatal conductance ( g S ), and transpiration rate