Interest in the health benefits of vegetables prompted an investigation of the levels of carotenoids in commercial varieties and UA breeding lines of spinach. Plant carotenoids perform a critical function as antioxidants, providing protection against a variety of reactive oxygen species generated primarily during photosynthesis. When ingested by humans, these compounds maintain their antioxidant activities and are receiving considerable attention in relation to multiple health benefits, including cancer prevention. While the best-known and most-studied carotenoid is beta-carotene, other carotenoids are now receiving attention due to their higher antioxidant activity compared to beta-carotene. Most dark-green leafy vegetables, such as spinach and kale, are relatively high in carotenoids, especially lutein. In this study, significant differences in average content of both lutein and beta-carotene were found between genetic lines of spinach. Some lines exhibited considerable variation between plants, while others were highly uniform. There was a very high correlation (r2 = 0.96) between lutein content and betacarotene content. The significant difference between spinach lines suggests that improvement of general carotenoid antioxidants and lutein could be obtained through a breeding program.
The fine fescues are generally considered to be acid-tolerant compared to many other cool-season turfgrasses. However, there is a lack of documentation on aluminum tolerance of fine fescues at both the species and cultivar levels. A total of 58 genotypes belonging to five species or sub-species were screened under greenhouse conditions using solution culture, sand culture, and acid Tatum subsoil. This soil had 69% exchangeable Al and a pH of 4.4. An Al concentration of 640 μM and a pH 4.0 were used in solution screening and sand screening. Differences in Al tolerance were identified at both species and cultivar levels based on relative growth. The genotypes with endophyte infection generally exhibited greater Al tolerance than endophyte-free genotypes. The results indicate that fine fescues vary in Al tolerance and there is potential to improve Al tolerance with breeding and to refine management recommendations for fine fescues regarding soil pH.
A method for measuring soil water potential in field soils was adapted for use in turfgrass soils. The system uses tensiometers installed flush with the soil surface and permits a measuring depth as shallow as 2.5 to 5.0 cm. Water potential within a tensiometer was measured with a portable pressure transducer. Linear relationships between water potential measured with mercury manometers or vacuum gauge-equipped tensiometers and the pressure transducer were obtained (r2 = 0.99 and 0.97, respectively). The system accurately measures soil water potential of turfgrass soils, while permitting routine cultural practices to be performed.
Take-all patch, caused by Gaeumannomyces graminis (Sacc.) Arx. & D. Olivier var. avenae (E.M. Turner) Dennis (Gga), is a disease of creeping bentgrass (Agrostis stolonifera Huds.), which most often is associated with golf courses. Synthesis of ligneous and phenolic compounds by plants requires adequate Mn+2 and Cu+2 nutrition and may be a factor in disease resistance. An experiment was conducted on a creeping bentgrass fairway naturally infested with Gga to determine if foliar applications of Mn+2 (1.02 and 2.04 kg·ha–1 per application) and Cu+2 (0.68 kg·ha–1 per application) would reduce take-all severity. Prior to initiating treatments, soil pH was 6.4 and Mehlich-3 extractable Mn+2 and Cu+2 were 5 mg·kg–1 and 1.7 mg·kg–1, respectively. Manganese and copper sulfate treatments were initiated in July 1995 and foliarly applied every 4 weeks through 1997 with the exception of December, January, and February. Disease incidence was decreased from 20% on untreated turf to 5% with the high rate of MnSO4. For both years, turf treated with the high rate of Mn+2 had less disease than turf receiving the low rate of Mn+2. The application of CuSO4, however, did not influence disease development.