An inexpensive ultrasonic fogging system is presented that aids in the establishment of tissue culture shoots in soil under greenhouse conditions. In addition, ultrasonic fogging may be coupled to CO2 nutrient enhancement via bubbling CO2 into the water reservoirs prior to fogging to improve growth and morphogenesis responses of shoots. A list and cost of items for the system and its assembly is given. Transplanted tissue culture shoots of basil (Ocimum basilicum L.), hosta (Hosta sp.), mint (Mentha sp.), and thyme (Thymus vulgaris L.) were tested with this fogging system with and without CO2 nutrient elevation and compared to the growth of shoots grown under a misting system with and without CO2 nutrient elevation. In all cases, ultrasonic fogging enhanced survival rates, growth (fresh weights) and morphogenesis (axially shoots, leaves and roots) vs. that occurring in the misting system. For example, thyme and mint shoots exhibited 2- and 5-fold increases, respectively, in fresh weights under ultrasonic fogging with CO2 compared to misting systems with CO2. Associated with enhanced survival and morphogenesis was an overall enhancement of shoot and leaf size and overall maturation responses. This is also reflected in enhanced secondary products obtained from shoots grown under ultrasonic fogging compared to shoots grown in misting systems.
Brent Tisserat and Robert Silman
Jerry T. Walker
Twenty herb species were exposed to root-knot nematode under greenhouse conditions. The root systems were examined for root gall development and nematode reproduction as an indication of host suitability. The herbs evaluated were balm (Melissa officinalis L.), basil (Ocimum basilicum L.), catnip (Nepeta cataria L.), chamomile (Matricaria recutita L.), coriander (Coriandrum sativium L.), dill (Anethum graveolens L.), fennel (Foeniculum vulgare Mill.), hyssop (Hyssopus officinalis L.), lavender (Lavandula augustifolia Mill.), oregano (Origanum vulgare L.), peppermint (Mentha ×piperita L.), rocket-salad (Erurca vesicaria L.), rosemary (Rosmarinus officinalis L.), rue (Ruta graveolens L.), sage (Salvia officinalis L.), savory (Satureja hortensis L.), sweet marjoram (Origanum majorana L.), tansy (Tanacetum vulgare L.), thyme (Thymus vulgaris L.), and wormwood (Artemisia absinthium L.). Peppermint, oregano, and marjoram consistently were free of root galls after exposure to initial nematode populations of two or 15 eggs/cm3 of soil medium and were considered resistant. All other herb species developed root galls with accompanying egg masses, classifying them as susceptible or hypersusceptible to root-knot nematode. The highest initial nematode egg density (15 eggs/cm3) significantly decreased dry weights of 14 species. The dry weights of other species were unaffected at these infestation densities after 32- to 42-day exposure.
Diana L. Lange and Arthur C. Camero
Postharvest shelf life (defined by visual quality) of fresh, greenhouse-grown sweet basil (Ocimum basilicum L.) at 5 °C was only 3 to 4 d due to the appearance of chilling injury symptoms. Plants chill-hardened at 10 °C for 4 h daily (2 h at the end of the light period and 2 h at the beginning of the dark period) for 2 d, before harvesting and packaging, had ≈3 d longer postharvest life. Four- to 6-week-old plants were chill-hardened for 1 week at several periods during the day. Chill-hardening at the beginning of the day extended the average shelf life of cuttings from 4- to 5-week-old plants by 1 and 1.5 d, respectively. Shelf life either was decreased or not affected by the other periods of preharvest hardening. More importantly, postharvest chill-hardening of packaged sweet basil for 1 day at 10 °C in darkness before transfer to 5 °C increased average shelf life by 5 d. Good potential exists for postharvest chill-hardening of packaged sweet basil since this method is effective and convenient.
Diana L. Lange and Arthur C. Cameron
The effect of controlled atmospheres (CA) on the development of injury symptoms and storage life of sweet basil (Ocimum basilicum L.) cuttings was assessed. Three-node basil stem cuttings were placed in micro-perforated low-density polyethylene packages and stored in the dark at 20 °C in a continuous stream of nitrogen containing the following percentages of O2/CO2:21/0 (air), 21/5, 21/10, 21/15, 21/20, 21/25, 0.5/0, 0.5/5, 1/0, 1.5/0, 2/0, 1/5, 1.5/5, 1.5/7.5, and 1.5/10. Cuttings stored in an atmosphere of <1% O2 developed dark, water-soaked lesions on young tissue after only 3 days. Fifteen percent or more CO2 caused brown spotting on all tissue. Sweet basil stored in 1.5% O2/0% CO2 had an average shelf life of 45 days compared with 18 days for the air control. None of the CA combinations tested alleviated chilling injury symptoms induced by storage at 5 °C.
Dean A. Kopsell, David E. Kopsell, and Joanne Curran-Celentano
Sweet basil (Ocimum basilicum L.) is a popular culinary herbal crop grown for fresh or dry leaf, essential oil, and seed markets. Recently, basil was shown to rank highest among spices and herbal crops for xanthophyll carotenoids, which are associated with decreased risks of cancer and age-related eye diseases. The research goal for the current study was to characterize the concentrations of nutritionally important carotenoid pigments in popular varieties of basil. Eight cultivars of sweet basil (`Genovese', `Italian Large Leaf', `Nufar', `Red Rubin', `Osmin Purple', `Spicy Bush', `Cinnamon', and `Sweet Thai') were grown in both field and greenhouse environments and evaluated for plant pigments using HPLC methodology. Environmental and cultivar differences were observed for all of the pigments analyzed. `Sweet Thai' accumulated the highest concentrations of lutein, zeaxanthin, and β-carotene carotenoids in the field, while `Osmin Purple' accumulated the highest carotenoid concentrations in the greenhouse. Comparing the two environments, cultivar levels for carotenoid and chlorophyll pigments were higher in the field environment when expressed on both a fresh and dry weight basis. Exceptions were found only for the purple leaf basils (`Osmin Purple' and `Red Rubin'). Positive correlations existed between carotenoid and chlorophyll pigments in both environments. This study demonstrates sweet basil accumulates high levels of nutritionally important carotenoids in both field and greenhouse environments.
J. Pablo Morales-Payan and William M. Stall
Competition partitioning experiments were conducted to determine the extent of shoot and root interference between sweet basil (Ocimum basilicum) and the weeds smooth amaranth (Amaranthushybridus) and livid amaranth (A.lividus). Sweet basil and amaranths were grown for 45 days in plastic 19-L containers filled with fertilized sandy soil. The plants were grown: 1) individually (one plant per container = no interference); 2) one basil plant and one amaranth plant together in the same container (= full interference); 3) one basil plant and one amaranth plant together in the same container, training the shoots apart to avoid canopy contact (= below ground interference); or 4) basil and amaranth grown in different containers set side by side (= above ground interference). Each basil/amaranth treatment was replicated five times and the experiment was conducted twice. The effects of smooth and livid amaranths on basil yield were the same for a given type of interference (full, above ground, below ground). Full interference from amaranth reduced basil shoot yield by about 35%, as compared to the yield of basil with no interference from amaranth. The effects of above-ground and below-ground interference on basil yield were additive, but interference above ground had a greater impact (about 21% basil yield loss) than below ground interference (about 14% basil yield loss). These results show that smooth and livid amaranths may drastically reduce sweet basil shoot yield, and that amaranth interference with sweet basil occurred to a greater extent above ground than below ground.
Hardeep Singh, Bruce Dunn, Mark Payton, and Lynn Brandenberger
Nutrient-film technique (NFT) trials were conducted to quantify the effect of two different water-soluble hydroponic fertilizers (5N–4.8P–21.6K and 5N–5.2P–21.6K) on different cultivars of lettuce (Lactuca sativa), basil (Ocimum basilicum), and swiss chard (Beta vulgaris). Results indicated swiss chard yield was affected only by cultivars, with Fordhook Giant producing the greatest fresh weight across fertilizer treatments. For lettuce production, interaction between fertilizers and cultivars was significant. ‘Mirlo’ and ‘Rubysky’ had greater growth compared with other cultivars in both fertilizers, whereas Dragoon performed well using 5N–4.8P–21.6K, but not 5N–5.2P–21.6K. For basil, dry weight production showed a significant interaction between fertilizers and cultivars. ‘Largeleaf’ produced greater dry weight with 5N–4.8P–21.6K, whereas ‘Lemon’ produced greater dry weight with 5N–5.2P–21.6K. For nutrient concentration of leaves, the concentrations were within the recommended range for lettuce when fertilized with 5N–5.2P–21.6K. Nutrient concentrations varied by nutrient from the recommended range for basil, but there was no significant difference between fertilizers. For swiss chard, the nutrient concentrations were in the recommended range and there was no difference between fertilizers. Therefore, growers may need to use more than one type of fertilizer for different lettuce and basil cultivars for optimum production, whereas swiss chard cultivars can be selected based on yield regardless of fertilizer.
Jonathan M. Frantz and Gregory E. Welbaum
Intensive, deep-batch, hydroponic systems that use float beds (FBs) are used extensively by the tobacco industry to produce transplants. FBs and a modified FB system with separate drying and flooding stages called ebb-and-flood (EF) beds were used to grow 12 diverse horticultural crops to maturity. Beds were filled with 570 L of water with 114 mg·L−1 N and 143 mg·L−1 K or 66 mg·L−1 N and 83 mg·L−1 K in 1994 and 1995, respectively. The EF beds were flooded for 6 hours, then drained for a 6-hour dry stage each 12 hours in 1994, and flooded for 1 hour and dried for 5 hours each 6-hour period in 1995 from May through August. Although both systems were suitable for producing Chinese water spinach (Ipomoea aquatica Forssk.—see footnote in Table 1), vegetable amaranth (Amaranthus tricolor L.), zinnia (Zinnia elegans Jacq.), and sweet basil (Ocimum basilicum L.), the EF system provided greater control over water availability and higher oxygen concentration in the root zone.
Frank Balestri and William R. Graves
The genus Nyssa L. includes several woody species with traits valued by horticulturists, but only black gum (Nyssa sylvatica Marsh.) is prevalent in the nursery trade. A congener, swamp tupelo (Nyssa biflora Walt.), might be a marketable shade tree, but little is known about propagating it from seeds. Because cold, moist stratification overcomes embryo dormancies of black gum, we compared germination of cleaned seeds (surrounding pulp of fruits removed) of swamp tupelo and black gum that were stratified at 5 °C for 0, 14, 28, 42, 56, 70, 84, and 112 days. Seeds of swamp tupelo within intact drupes were also stratified. Across all durations of stratification, 79% of cleaned seeds of swamp tupelo germinated, whereas 11% of seeds within drupes germinated. Germination value of cleaned seeds of swamp tupelo increased from 1.26 to 3.23 as duration of stratification increased. Although cleaned seeds of black gum responded similarly, the benefit of stratification was more pronounced, and the mean germination percentage was lower than for swamp tupelo (66% vs. 79%). In a second experiment, irrigation with low and high concentrations of an extract of fruit pulp of swamp tupelo reduced germination of seeds of basil (Ocimum basilicum L. ‘Superbo’), spinach (Spinacea oleracea L. ‘Bloomsdale’), zinnia (Zinnia ×marylandica Spooner, Stimart, and Boyle ‘Double Zahara Cherry’), and swamp tupelo by 25% to 63% (low concentration) and 40% to 70% (high concentration). Propagators should remove the surrounding pulp from seeds of swamp tupelo and cold stratify them at least for 4 weeks.
Ekaterina A. Jeliazkova, Valtcho D. Jeliazkov, Lyle E. Craker, and Baoshan Xing
Phytoremediation has been suggested as a solution to heavy metal—polluted soils, but the choices of suitable plant species for phytoremediation have been limited. Medicinal and aromatic plants appear to be excellent selections for these plantings, since these plants are grown for economically valuable secondary products (essential oils), not for food or feed. Preliminary research indicates that heavy metals are not accumulated in essential oils, permitting the oil to be used commercially. Productivity of some, but not all aromatic plants was reduced, however, by the heavy metals. The objective of our experiment was to distinguish the mechanism of heavy metal tolerance of plants using germinating seeds of medicinal and aromatic plant species. Seeds from medicinal and aromatic plants were germinated in solutions with selected levels of heavy metals (cadmium at 6 and 10 (μg·L-1; copper at 60 and 150 μg·L-1; lead at 100 and 500 μg·L-1; zinc at 400 and 800 μg·L-1) and in distilled water. Tests on Anethum graveolens L., Carum carvi L., Cuminum cyminum L., Foeniculum vulgare Mill., Pimpinella anisum L., Ocimum basilicum L., and the hyperaccumulator species Brassica juncea L. and Alyssum bertolonii established that different plant species reacted in different ways to the heavy metals. For example, cadmium did not decrease seed germination of Alyssum, O. basilicum, and B. juncea compared with germination in water but did decrease germination of C. cyminum. Lead did not affect germination of A. bertolonii and B. juncea as compared with water but did negatively affect germination of P. anisum, F. vulgare, and C. cyminum. Except for B. juncea, F. vulgare, and C. cyminum, copper had a negative effect on germination. Zinc decreased germination in all tested species except B. juncea.