The goal of this study was to expedite galax seed germination in vitro. Galax seeds were collected from Yancey County, N.C., at an elevation of about 1100 m. Aseptic cultures were established using the tiny rust-colored seeds. In vitro seed germination was achieved under different pH conditions (4.2, 5.0, and 5.8). Seeds cultured in the medium with pH 4.2 tended to germinate early with a better rate than those cultured with a higher pH of 5.0 or 5.8 at the very beginning. Gradually, seeds from media with pH 5.0 and 5.8 caught up in germination. Eventually, seeds from all pH treatments produced a very similar germination rate. Attempts to use the matted and scaly rhizomes and very tender new growth as explant materials to establish aseptic cultures were not successful, due to severe contamination. However, our observations suggested that the very tender new growth could be a good source of explants once the optimum sterilization time is established.
Guochen Yang, Carl Niedziela, and Zhongge (Cindy) Lu
Xiuli Shen, Guochen Yang, and Zhongge (Cindy) Lu
To overcome the limitations of traditional propagation, this research was initiated to develop an alternative means for efficient production of Alexandrian laurel (Danae racemosa L. Moench). An in vitro propagation protocol has been developed for Danae racemosa L. Moench using seeds as a source of material for culture initiation. Seedlings were produced after seeds were cultured for 3 month on MS () medium. Shoot multiplication occurred on MS medium with or without 6-benzylaminopurine (BAP) with 100% multiplication percentage. However, shoot number was significantly increased from an average of 2.8 to more than six with the addition of 5 or 25 μM BAP. Among two indole-3-butyric acid (IBA) treatments tested for rooting of seedlings, incorporation of 5 μM IBA in MS medium significantly increased rooting percentage to 86.4% compared with 71.2% without IBA. The greatest number of roots (three) was produced by 5-minute IBA pulse. However, both IBA treatments significantly reduced root length. The longest root (12.8 mm) was observed on MS medium without any IBA treatment and the shortest (6.1 mm) was produced by IBA pulse. In vitro-propagated plantlets grew well after transfer to a substrate of peat and pine bark (1:1) in the greenhouse. No morphological variation was observed.
Guochen Yang, Zhongge (Cindy) Lu, and Carl E. Niedziela Jr.
This research was initiated to study different culture media and plant growth regulators for their influences on callus initiation and production, with a research goal of developing an efficient in vitro callus regeneration protocol for guava (Psidium guajava L.). Guava is an important tropical fruit species that is rich in vitamins and vitamin precursors, minerals, organic acids, and pectins. Seventy-nine phytochemicals provide guava with many unique properties and actions, including anti-microbial, astringent, bactericidal, cicatrizant, emmenagogue, hypoglycemic, laxative, nutritive, and spasmolytic. Different concentrations of various plant growth regulators (PGR), such as 6-benzyladenine (BA), kinetin, or 2,4-dichlorophenoxyacetic acid (2,4-D), and naphthaleneacetic acid (NAA) were added to basic Murashige and Skoog (MS) and woody plant medium (WPM) and tested for their influences. Differences in callus initiation and morphology were noticed between MS and WPM, and among PGR concentration treatments.
Julia Charlotte Robinson, Guochen Yang, Sanjun Gu, and Zhongge (Cindy) Lu
Black cohosh (Actaea racemosa L.), a medicinal herb commonly used in herbal supplements for the treatment of various ailments, is a perennial herb that grows naturally under shade conditions in temperate forest regions. This project studied the growth and rhizome yield of Black cohosh under shade conditions of 0%, 40%, 60%, and 80% in a high tunnel (9.1 m wide × 29.3 m long) on the North Carolina Agricultural and Technical University Farm. Seed rhizomes were planted in raised beds incorporated with 9070 kg/acre compost and preplant fertilizer on 29 May 2016. There was one row per bed, with in-row spacing at 45.7 cm, and one drip line per bed for irrigation. Fertigation was done weekly through the drip tapes with Multi-K 13–0–46 (27.2 kg N/acre) during the growing season. Beds were mulched after sprouting. Growth data of fully mature plants were collected on canopy width and length, total number of stems per plant, stem diameter, and length/height; and rhizome fresh and dry weight. Data were analyzed at the 0.05 level of significance. Plant canopy, stem diameter, and length/height were significantly greater in 40% shade (average, 504.7 × 472.6 mm, 3.7 mm, and 135.9 mm, respectively) than in other shade conditions, with the smallest sizes in 0% shade (average, 255.8 × 255.7 mm, 2.1 mm, and 95.4 mm, respectively). There were no significant differences between the 60% and 80% shade conditions in plant canopy, stem diameter, and length/height. However, the total number of stems per plant (4.9) in 0% shade was significantly more than those in other shade conditions, with the least of stems per plant (2.9) in 80% shade. Rhizome fresh and dry weight per plant were the greatest (164.6 and 48.1 g, respectively) in 40% shade, and the least (77.8 and 22.5 g, respectively) in 0% shade. The results indicate that optimum growing conditions for Black cohosh was in 40% shade with a Daily light integral (DLI) between 15 and 0 mol/m2/day, and a day- and nighttime temperature difference between 8.3 and 2.7 °C.