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, and promote root growth and viability ( Zhang and Ervin, 2008 ; Zhang et al., 2003 ). However, few studies have reported the effects of SWE-containing material on photosynthesis, NaR activity, and root function of ultradwarf bermudagrass under heat

Open Access

Subjection of intensively managed creeping bentgrass [Agrostis stolonifera L. var. palustris (Huds.). Farw., (syn. Agrostis palustris Huds.)] to supraoptimal soil temperatures is deleterious to root viability and longevity. The ability to estimate viable root length would enable creeping bentgrass managers to more accurately schedule certain management practices. The purpose of this rhizotron study was to develop a model, based on an accumulated degree-day (ADD) method, capable of estimating viable root length density of established `Crenshaw' and `L93' creeping bentgrass maintained under putting green conditions. Viable root length density observations were made biweekly and soil temperature data collected April through September 1997, and January through August 1998 and 1999. Relative viable root length density (RVRLD) is defined as the measured viable root length density divided by the maximum density attained that spring. In both years, maximum annual viable root length density for all plots was reached, on average, by 138 days from the beginning of the year (18 May). Cultivar and year effects were nonsignificant (P = 0.67 and 0.20, respectively). Degree-day heat units were calculated using an array of base temperatures by integral and arithmetical methods. Although the two accumulative methods proved suitable, the model regressing arithmetical degree-day accumulations against the bentgrass RVRLD provided a better fit to the data set. Use of the 10 °C base temperature in the arithmetical ADD calculations provided the following model; RVRLD = 0.98 - [1.30 × 10-4 (ADD)], accounting for 83.8% of the experimental variability (P < 0.0001). As several abiotic/edaphic factors have been shown to significantly influence root growth and viability, development of a widely usable model would include additional factors.

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Abstract

‘Jewel’ sweet potato transplants were held in refrigerated storage at 4.4°, 8.9°, 13.3°, 17.8°, or 26.7°C for 7 or 14 days before planting. Some treatments received a fungicide dip before storage. Maximum plant survivability and root yield were obtained from transplants held for 7 days at 13° to 18°. Ambient storage (26.7°) greatly reduced transplant survivability. Fungicide treatment had no influence on plant stand.

Open Access

Abstract

A modification of the ninhydrin method of evaluating injury was made by expressing the release of ninhydrin-reactive compounds following freezing as a percentage of the potential release. This method eliminates a laborious weighing procedure and also eliminates variability due to differences in endogeneous concentrations of ninhydrin-reactive compounds in roots. The technique correlated well with survival of Pyracantha coccinea Roem. cv. Lalandii Dipp. roots and stems 3 weeks after freezing, and lends itself to studies requiring large numbers of viability determinations using relatively small sample sizes.

Open Access

In Spring 1996, `Meeker' red raspberry root cuttings were planted into a sandy loam soil in 30 cm tall x 27 cm diameter black plastic containers. During Mar. 1997, a second bottomless container was placed over the overwintering canes of half of the plants. The second container was filled with the same sandy loam soil to simulate ridging of the plants. All plants were grown using standard cultural practices on an outdoor, gravel nursery bed. Freeze tolerance of potted whole plants and excised root sections was measured at 5 °C intervals between -5 and -20 °C in a series of laboratory freeze tests conducted during Jan. 1998. Electrolyte leakage data were used to calculate the index of injury for excised roots while whole-plant response to freezing was determined by measuring the subsequent growth of floricane lateral shoots and of primocanes. After 1 month in the greenhouse, results indicated the dry weight of primocanes harvested from plants that were exposed to -20 °C was 56% of the nonfrozen control primocane dry weight. Primocane dry weight from plants exposed to -5, -10 and -15 °C was not different from the controls. Similar results were obtained for the percent of floricanes that were alive and for the dry weight of laterals produced by these floricanes after 3 months in the greenhouse. The whole-plant freeze test results indicated plants at the lowest temperature, -20 °C, were injured but not killed. Root index of injury of single potted plants averaged 5%, 15%, 29%, and 58% at -5, -10, -15, and -20 °C, respectively.

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was recorded every 2 weeks until 8 weeks. We assessed the effect of the medium pH on the viability of the root apex tissue by FDA/PI staining ( Jones and Senft, 1985 ). As the material used for this experiment, we selected rooted shoots among the

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in sweetpotato, assess the potential of root piece planting as a viable alternative to slips, and make recommendations for future research. Overview of root piece research There is a 70-year history of published research relating to propagating

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success of the four identified native shrubs. In addition, the impacts of increasing concentration of rooting hormone and transplanting timing of rooted cuttings were evaluated. Materials and Methods Timing. On three dates in 2012, softwood stem material

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, and also enhance root growth and viability ( Ali et al. 2021 ; Alikaabi et al. 2022; Deolu-Ajayi et al. 2022; Zhang et al. 2022 ). Cytokinins can improve NaR activity and N assimilation ( Sakakibara et al. 2006 ). Recent study showed that the SWE

Open Access

by increasing the capacity for water uptake of roots or reducing water loss from leaves. Previous studies with turfgrass species have shown that extensive root systems and root viability contribute positively to water uptake and thus, plant survival

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