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Abstract

Nodes from mature tissue of Paulownia tomentosa Steud. were cultured on a modified Murashige-Skoog (MS) medium containing BAP and NAA. Axillary buds elongated most rapidly from nodes of greenhouse-grown trees on a medium containing 1.0 mg BAP/liter and 0.1 mg NAA/liter. After 7 days on this medium, the elongated shoots were transferred to media containing IBA (0.5–1.0 mg/liter) or the shoots were quick-dipped (15 sec) in the K-salt of IBA (KIBA, 500–1000 ppm) and rooted under mist in the greenhouse. The shoots rooted in 7–10 days and were easily transplanted to 6 packs (6-celled plastic flat) for continued development. This propagation scheme provides a method for the rapid multiplication of plants from mature tissue Paulownia in a very short period of time (14–17 days). Chemical names used: 1-naphthaleneacetic acid (NAA); benzylaminopurine (BAP); 1H-indole-3-butanoic acid (IBA).

Open Access
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The effects of high concentrations of Cl-, K+, Mg2+, and Ca2+ of the simulated waste water on the growth of turfgrass species and partitioning of these mineral element concentrations in the turfgrass-soil system have been studied. This is a two year project and the waste treatment was started in the first week of October 1993. The waste water contains 17.89 mM of K+, 97.5 mM of Ca2+, 78.1 mM of Mg2+, and 389.17 mM of Cl-. Kentucky bluegrass, perennial ryegrass, tall fescue, bermudagrass, and zoysiagrass have been irrigated with 1/5, 1/10, and 1/20 times concentration of the waste water and mowed weekly at 5 cm high. The preliminary results showed that there was no detectable growth inhibition of turfgrass by the three waste water concentrations. Waste water irrigation significantly increased the uptake of the mineral elements by the turfgrass. Significant reduction of the mineral element concentrations in the leach by the turfgrass system only found under the conditions of low concentration waste irrigation. However, the seasonal growth pattern of the turfgrass species may have significant influence on the partitioning of the element concentrations in the turfgrass-soil system and their concentrations in the leach. This prediction will be detected by the future studies.

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Abstract

Anatomical studies of terminal, leafy stem cuttings of red raspberries after 5 weeks under mist indicated that the structures of stems immediately below the oldest leaf, as well as at 2 to 3 cm above the base of the cuttings of 2 hybrid selections ‘MR 158’ and ‘MR 480’ were basically the same. Besides the normal vascular cambium, an anomalous cambial region was differentiated at the inner face of the cortex. Both of these cambia induced secondary stem thickening. The lack of emergence of roots through the large callus masses might be attributed to the compactness of the callus tissue in which the primordia are embedded. Adventitious roots arose from parenchyma cells in various locations in these stem cuttings.

Open Access

This research tests the hypothesis that decreasing lateral spacing from 45 to 35 feet in solid-set sprinkler systems increases the uniformity of irrigation water distribution and improves water and N fertilizer use efficiencies. Three different spacings between sprinkler laterals (35', 40', and 45') were set up in three blocks in a 60-acre commercial carrot field in Western Kern County in California's San Joaquin Valley. Determinations of irrigation water distribution uniformity, yields, crop water use, plant growth, and nitrate leaching were made. Mean sprinkler distribution uniformities (DU) were found to be 80.6%, 78.1%, and 86% for the 35-, 40-, and 45-ft spacings, respectively. Total carrot yield and quality did not differ significantly among the three spacings, corroborating the finding that irrigation uniformities were similar among the treatments. Although the three lateral spacings evaluated in this initial experiment did not result in major differences in irrigation uniformity, total yields, or quality, the findings of this initial stage of our research are significant. They point to the need for new assessments of currently used protocols for evaluating sprinkler irrigation management of water and nitrogen fertilizer if they can be confirmed by repeated trials in coming years.

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Summer decline of annual bluegrass (Poa annua L.) putting greens is a major concern of golf course superintendents. Low soil water infiltration rates and high concentrations of salts in the root zone are contributing factors. This study was conducted to determine the effects of summer cultivation treatments on field infiltration rates of water, soil salinity, oxygen diffusion rates (ODR), bulk density, total and air-filled porosity, and root weight density. This research was conducted during two summer seasons (1996 and 1997) on a practice putting green located at Industry Hills Golf Courses, City of Industry, Calif. The green was constructed to U.S. Golf Association (USGA) specifications in 1978. Cultivation treatments consisted of: 1-3) water injection cultivation (WIC) applied with a Toro HydroJect every 21 d (raised position), and every 14 or 21 d (lowered position); 4) solid tine cultivation (STC) applied every 14 d; and 5) no cultivation (check). Results showed WIC and STC significantly increased field infiltration rates of water and lowered overall soil electrical conductivity of the extract (ECe) at depths of 2.5 to 7.5 cm and 7.5 to 15.0 cm in the root zone. The effects of WIC, raised position, did not differ significantly from those of STC, but infiltration rates of water were greater on all rating dates. Cultivation treatments had no significant effects on overall soil ODR, bulk density, and porosity or on overall root weight density.

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High concentration of boron (B) and selenium (Se) found in the environment may be detrimental to the sustainability of agriculture in regions of the western USA. Boron and Se uptake by wild mustard (Brassica juncea (L Czern & Coss.) and tall fescue (Festuca arundinacea Schreb. L.) was investigated under greenhouse conditions in thermic typic torriorthent soils containing naturally high levels of B and Se. The design structure was a randomized complete block with six 18-L plots per treatment, three blocks, and two treatments. After plants were harvested and separated into shoots and roots, tissues were analyzed for total tissue B and Se, and soils from each pot were analyzed for residual B and Se. The highest concentrations of B were recovered in shoots from wild mustard and roots from tall fescue. Tissue Se concentrations were generally similar in both plant species. Post-harvest soil B and Se concentrations were significantly lowered irrespective of the plant species and of the harvest. The effectiveness of using wild mustard and tall fescue for B and Se soil reclamation will be discussed.

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Scarification treatments (a control, a 10-minute vacuum, or a 1.5-minute ultrasound), different media (modified Norstog and Van Waes) and growth regulators [benzyladenine (BA) at 0, 1, 1.5, or 2 mg·L-1 and 6-(r,r-dimethylallylamino)-purine riboside (2iPR) at 0, 1, 1.5 or 2 mg·L-1] were used in combination to increase seed germination of Cypripedium calceolus var. parviflorum. Seeds treated with ultrasound had higher germination (58.0%) than those treated with vacuum (27.4%) or controls (19.2%). Germination rates increased with 2iPR level and reached a maximum between 1.5 and 2 mg·L-1. Seeds on Van Waes medium, which were not transferred to fresh medium after germination, had a severe browning problem causing many protocorms to die. Those on Norstog medium continued to grow into seedlings with less browning. Germination rates of Calopogon tuberosus × Calopogon `Adventure' and Liparis liliifolia were determined on the different media and growth regulator treatments. Multiple shoots of Calopogon developed from single seeds on media containing growth regulators. Flower buds formed in vitro on Calopogon in media containing 1 mg·L-1 or higher BA 5 months after germination. L. Iiliifolia seeds in Norstog medium had a higher proportion of germination than those in Van Waes medium.

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Turfgrass managers are using reclaimed water as an irrigation resource because of the decreasing availability and increasing cost of fresh water. Much attention, thereby, has been drawn to select salinity-tolerant turfgrass cultivars. An experiment was conducted to evaluate the relative salinity tolerance of 10 common bermudagrasses (Cynodon dactylon) under a controlled environment in a randomized complete block design with six replications. ‘SeaStar’ seashore paspalum (Paspalum vaginatum) was included in this study as a salinity-tolerant standard. All entries were tested under four salinity levels (1.5, 15, 30, and 45 dS·m−1) consecutively using subirrigation systems. The relative salinity tolerance among entries was determined by various parameters, including the normalized difference vegetation index (NDVI), percentage green cover determined by digital image analysis (DIA), leaf firing (LF), turf quality (TQ), shoot vertical growth (VG), and dark green color index (DGCI). Results indicated that salinity tolerance varied among entries. Except LF, all parameters decreased as the salinity levels of the irrigation water increased. ‘Princess 77’ and ‘Yukon’ provided the highest level of performance among the common bermudagrass entries at the 30 dS·m−1 salinity level. At 45 dS·m−1, the percent green cover as measured using DIA varied from 4.97% to 16.11% among common bermudagrasses, where ‘SeaStar’ with a DIA of 22.92% was higher than all the common bermudagrass entries. The parameters LF, TQ, NDVI, DGCI, VG, and DIA were all correlated with one another. Leaf firing had the highest correlation with other parameters, which defined its value as a relative salinity tolerance measurement for common bermudagrass development and selection.

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Bermudagrass (Cynodon sp.) is one of the most commonly used warm-season turfgrasses in the southern areas and transition zone of the United States. Due to the increasing demand for water resources and periodic drought, it is important to improve the drought resistance of bermudagrass for water savings and persistence under drought stress. This study was conducted to determine whether experimental bermudagrass genotypes have improved drought resistance compared with the standard cultivars Tifway and Riley’s Super Sport (Celebration®) at Stillwater, OK. The trials were designed as randomized complete blocks with four replications in Expt. I and three replications in Expt. II. In each experiment, genotypes were subjected to progressive acute drought conditions using polyethylene waterproof tarps to exclude precipitation over a period of at least 72 d. Bermudagrass entries were evaluated for turfgrass quality, leaf firing, normalized difference vegetation index, and live green cover at least once each week during the dry-down. Substantial drought response variations were found in this study, and all parameters were positively and highly correlated. A turf performance index (TPI) was assembled based on the number of times an entry ranked in the top statistical group across all testing parameters on each date. ‘DT-1’ (TifTuf®) and OSU1221 had the top TPI in both experiments. Most of bermudagrass experimental genotypes had equal or greater TPI than the standard Tifway, showing improved drought resistance through breeding effects. The identification of superior drought resistance experimental genotypes provided useful information to breeders on cultivar release.

Open Access

Optimal water management is essential in irrigated agricultural regions to sustain productivity, conserve water resources and protect groundwater quality. The southern San Joaquin Valley (SJV) of California is a major irrigated production region in which solid set sprinkler systems are commonly used to grow such crops as carrots (Daucus carota L.), potatoes (Solanum tuberosum L.), garlic (Allium sativum L.) and onions (Allium cepa L.) in predominantly sandy soils. Water and fertilizer use efficiencies are important concerns in this region. In 1996 and 1997, we evaluated the effects of three sprinkler spacings [32.2, 38.6 and 45 ft (9.8, 11.8 and 13.7 m)] and irrigation uniformity within these spacings on carrot yield, quality and nitrogen content. Applied water and soil nitrate and ammonium contents were monitored at four locations within each sprinkler lateral spacing throughout both seasons. Neither sprinkler spacing nor location within a given sprinkler spacing affected carrot production or quality. Distributions of soil nitrate and ammonium resulting from the different sprinkler spacings were also not correlated with carrot yields. These results suggest that any of the three spacings can be used for high carrot quality and productivity.

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