The influence of a wide range of CO2 levels on the growth, morphogenesis, and secondary metabolite production in vitro was evaluated. Shoots of thyme (Thymus vulgaris L.) and a spearmint–peppermint cross (Mentha spicata × Mentha piperita) were grown on MS medium with and without 3% sucrose under 350, 1500, 3000, 10,000, and 30,000 μL CO2/L for 8 weeks. Dichloromethane extracts from leafs were analyzed using GC-MS techniques. Prominent peaks were identified by comparison with known standards. Highest growth (i.e., fresh weight) and morphogenesis responses (i.e., leafs, shoots and roots) were obtained when shoots were grown under 10,000 μL CO2/L regardless of whether or not sucrose was included in the medium. Ultra-high CO2 concentrations (3000 μL CO2/L) stimulated secondary metabolite production regardless of whether or not the medium contained sucrose. However, the combination of certain ultra-high CO2 levels (e.g., 3000 to 10,000 μL CO2/L) and the presence of sucrose in the medium resulted in shoots producing the highest levels of secondary metabolites. These results suggest that in vitro photosynthesis, which is stimulated by ultrahigh CO2 levels, may enhance secondary metabolite production.
Brent Tisserat and Steven Vaughn
Eric B. Brennan
Many important herbs [e.g., mint (Mentha sp.), thyme (Thymus sp.)], underused and nutritious vegetables [e.g., purslane (Portulaca oleracea), amaranth (Amaranthus tricolor)], and important biological control plants [e.g., sweet alyssum (Lobularia maritima)] have small seeds (≤ 1.5-mm long) that are difficult to plant with raw (i.e., nonpelleted) seed using existing seeders. A novel tool known as the slide hammer (SH) seeder was developed for the precise seeding of raw seeds of small-seeded plants. The SH seeder is a jab-type planter made primarily from electrical conduit tubing and other materials that are inexpensive and readily available in a hardware store or on the Internet. The interchangeable seed hopper is made from a plastic snap cap vial that has one or more holes of varying diameter depending on the desired seeding rate and seed size. Seed forms a “bridge” above the hole in the vial until they are dislodged from the force of the SH that discharges seeds to fall to the soil. Detailed plans are provided for how to make and use the SH seeder. The fabrication time is 2 to 4 hours with a material cost of ≈$32. I determined the seed vial hole specifications for the precise seeding of a variety of small-seeded plants, including chives (Allium schoenoprasum), chinese chives (Allium tuberosum), basil (Ocimum basilicum), grain amaranth (Amaranthus sp.), sweet alyssum, purslane, creeping thyme (Thymus serpyllum), and spearmint (Mentha spicata) that ranged in size from ≈200 to 11,000 seeds per gram. The diameter of the hole that was suitable for discharging the seed from the vial was always larger than the average seed length, and the ratio of hole diameter to seed length ranged from 1.07 to 1.62. Seeding rate uniformity evaluations were conducted for these species using vials with one vs. two holes and showed that the seeding rate was higher by an average of 58% to 173% from a vial with two holes compared with one hole. For most plant species evaluated, the SH seeder was able to dispense as few as one to three seeds consistently. Seed discharge increased somewhat with increasing SH weight for all species evaluated. The SH seeder can be useful for interplanting sweet alyssum as an insectary plant for aphid (Aphidoidea) control between existing plants of organic lettuce (Lactuca sativa), and for intercropping cultivars of purslane as a novel vegetable in between transplanted organic broccoli (Brassica oleracea Italica group) plants. This novel seeding tool has many potential uses for direct, hand seeding in vegetable and herb production systems and in weed research trials. The seeder could be automated and made with a variety of alternative materials.
D.D. Treadwell, G.J. Hochmuth, R.C. Hochmuth, E.H. Simonne, S.A. Sargent, L.L. Davis, W.L. Laughlin, and A. Berry
Greenhouse experiments were conducted in 2005 and 2006 near Live Oak, FL, to develop fertilization programs for fresh-cut ‘Nufar’ basil (Ocimum basilicum) and spearmint (Mentha spicata) in troughs with soilless media using inputs compliant with the U.S. Department of Agriculture's National Organic Program (NOP). Four NOP-compliant fertilizer treatments were evaluated in comparison with a conventional control. Treatments and their analyses in nitrogen (N), phosphorus (P), and potassium (K) contents are as follows: conventional hydroponic nutrient solution [HNS (150 ppm N, 50 ppm P, and 200 ppm K)], granular poultry (GP) litter (4N–0.9P–2.5K), granular composite [GC (4N–0.9P–3.3K)], granular meal [GM (8N–2.2P–4.1K)], and GM plus a sidedress application of 5N–0.9P–1.7K fish emulsion (GM + FE). Electrical conductivity (EC) of the media, fresh petiole sap nitrate (NO3-N) and K concentrations, dried whole leaf NO3-N, P, and K concentrations, and yield and postharvest quality of harvested herbs were evaluated in response to the treatments. Basil yield was similar with HNS (340 g/plant) and GP (325 g/plant) in 2005 and greatest with HNS (417 g/plant) in 2006. Spearmint yield was similar with all treatments in 2005. In 2006, spearmint yields were similar with the HNS and GP yields (172 and 189 g/plant, respectively) and greater than the yields with the remaining treatments. In both years and crops, media EC values were generally greater with the GC than with the GP, GM, and GM + FE treatments but not in all cases and ranged from 1.77 to 0.55 dS·m−1 during the experiments. Furthermore, HNS media EC values were consistently equal to or lower than the GP media EC values except with EC measurements on 106 days after transplanting in both crops in 2005. Petiole NO3-N and K results were variable among crops and years, but provided valuable insight into the EC and yield data. We expected EC, petiole NO3-N, and petiole K to be consistently higher with HNS than with organic treatments, but they were not, indicating a reasonable synchrony of nutrient availability and crop demand among the organic treatments. The postharvest quality of both basil and spearmint was excellent with all treatments with few exceptions.
Theocharis Chatzistathis, Ioannis Therios, and Dimitrios Alifragis
constitute a detoxification mechanism to olive trees, protecting the above-ground part of the tree from Mn toxicity. Under Mn excess/toxicity conditions also, other plant species such as Mentha spicata , Citrus sp., Pseudoaccacia sp., Juglans regia
Hsing-Ying Chung, Ming-Yih Chang, Chia-Chyi Wu, and Wei Fang
increase the concentration of rosmarinic acid in spearmint [ Mentha spicata ( Fletcher et al., 2010 )]. However, this series of studies lacked a quantitative assessment of the energy consumption of electric light sources used for crop production; therefore
Muqiu Zhao, Huaibao Zhao, Qianjin Du, and Yunfeng Shi
), and mint ( Mentha spicata ) are important sources of natural inhibitors ( Abbasi and Manzoor, 2013 ; Kiran and Patra, 2003 ; Opoku et al., 2014 ). A wide variety of tropical medicinal plants that are traditionally used to cure diseases, or to
Khalid M. Elhindi, Yaser Hassan Dewir, Abdul-Wasea Asrar, Eslam Abdel-Salam, Ahmed Sharaf El-Din, and Mohamed Ali
knowledge, Kumar et al. (2014) investigated seed germination of C. sativum using 2,4-dichlorophenozyacetic acid (2,4-D) and GA 3 . The effect of different PGRs including 2,4-D, ethephon, GA 3 , and NAA on seed germination of Mentha arvensis ( Mentha
Susan L.F. Meyer, Dilip K. Lakshman, Inga A. Zasada, Bryan T. Vinyard, and David J. Chitwood
.S. Riseman, A. 2005 Insecticidal activity of selected monoterpenoids and rosemary oil to Agriotes obscurus (Coleoptera: Elateridae) J. Econ. Entomol. 98 1560 1565 Walker, J.T. Melin, J.B. 1996 Mentha × piperita, Mentha spicata and effects of their
( Thymus vulgaris ), sage ( Salvia officinalis ), rosemary ( Rosmarinus officinalis ), peppermint ( Mentha piperita ), and spearmint ( Mentha spicata ). Bioactivities were compared, and potential interactive/synergistic effects of different herb