John T.A. Proctor

Understory light and root ginsenosides in forest-grown Panax quinquefolius

The objective of this study was to determine the relationship between light levels in the understory of a broadleaf forest and the content of six ginsenosides (Rg(1), Re, Rb(1), Rc, Rb(2,) and Rd) in 1- and 2-year-old American ginseng (Panax quinquefolius L.) roots. Our results revealed that ginsenoside contents in 1- and 2 year-old roots collected in September were significantly related to direct and total light levels, and duration of sunflecks. At this time, the effect of light levels accounted for up to 48 and 62% of the variation in ginsenoside contents of 1- and 2-year-old American ginseng roots. Also, red (R) and far red (FR) light, and the R:FR ratio significantly affected Rd, Rc, and Rg(1) contents in 2-year-old roots, accounting for up to 40% of the variation in ginsenoside contents.

Effect of simulated sulfuric acid rain on apple tree foliage, nutrient content, yield and fruit quality

Abstract Simulated sulfuric acid rain (pH 1.5, 2.0, 3.0, 4.0) or a control rain (pH 5.6) was sprayed on limbs of mature trees of McIntosh, Rhode Island Greening, Delicious and Golden Delicious apple. At pH 3.0 and below, values which rarely occur, lesions appeared on leaves. These lesions were small and barely visible at pH 3.0, but increased in size and were bifacially necrotic at pH 1.5. Leaves of Golden Delicious were the most sensitive to acid rains. Brown necrotic and red lesions developed on petals at pH 1.5 and 2.0 with some injury at pH 3.0 and these injured petals fell prematurely. Fruit set of Golden Delicious was 10.6% and was not influenced by acid rain sprays. Fruits were injured by acid rain sprays of pH 3.0 and less. At pH 1.5 and 2.0 sunken necrotic areas of 5 mm diameter were common while at pH 3.0 only small black, corky elevated spots appeared. Cork production was stimulated in the sunken necrotic areas. Fruit weight, size, firmness, soluble solids and starch content of Delicious, Rhode Island Greening and Golden Delicious were not affected by acid rains. Russeting of Rhode Island Greening and Golden Delicious was not influenced by acid rains. The N concentration of leaves was reduced by rains of low pH but levels of K + , Ca 2+ , Mg 2+ were unaffected. Injury to McIntosh foliage stimulated premature ripening and drop of fruit in late August. Yield was not related to leaf injury except possibly with McIntosh, nor was it related to flower injury when data for one growing season were considered. Data from the third year would suggest manifestation of cumulative injury effects in the two previous years.

Ginsenoside Content of North American Ginseng (Panax quinquefolius L. Araliaceae) in Relation to Plant Development and Growing Locations

North American ginseng (Panax quinquefolius L.) was analysed for total ginsenosides and ten major ginsenosides (R0, Rb1, Rb2, Rc, Rd, Re, Rf, Rg1, pseudoginsenoside F11, and gypenoside XVII), and variations in ginsenoside content with age of plant (over a four-year-period) and geographic location (Ontario versus British Columbia) were investigated. In the roots the total ginsenoside content increased with age up to 58-100 mgㆍg.1 dry weights in the fourth year, but in leaves it remained constant over time. Roots and leaves, moreover, had different proportions of individual ginsenosides. The most abundant ginsenosides were Rb1 (56 mgㆍg.1 for Ontario; 37 mgㆍg.1 for British Columbia) and Re (21 mgㆍg.1 for Ontario; 15 mgㆍg.1 for British Columbia) in roots, and Rd (28-38 mgㆍg.1), Re (20-25 mgㆍg.1), and Rb2 (13-19 mgㆍg.1) in leaves. Measurable quantities of Rf were found in leaves (0.4-1.8 mgㆍg.1) but not in roots or stems. Our results show that ginsenoside profiles in general, and Rf in particular, could be used for chemical fingerprinting to distinguish the different parts of the ginseng plant, and that ginseng leaves could be valuable sources of the ginsenosides Rd, Re, and Rb2.

Characterization of North American Ginseng Rust-Spot and the Effects of Ethephon

Rust-spot on North American ginseng roots (Panax quinquefolius L.) is considered a physiological, not a pathological disorder. Ginseng rust-spot starts as an orange spot on the surface of the root and may spread forming a sunken, round to irregular lesion, ~5 mm in diameter. Pieces of root, ~7 mm in length and containing a rust-spotted lesion, were embedded in agar and sectioned using a vibratome. These sections and hand sections, cut with a two-sided razor blade, were examined using fluorescence microscopy. The 4-5 cell layers of the periderm were destroyed in the area of the lesion and orange substances were deposited in and around the lesion. Sections stained with vanillin-HCl and viewed using bright field microscopy confirmed that the orange substances were phenolic compounds. Scanning electron microscopy showed that the periderm had pulled away from the root, or was completely destroyed, in the area of the lesion. The smooth surface of the lesion indicates the deposition of phenolic compounds in surrounding cells as a wound response. Roots sprayed or dipped in ethephon (1500 mgㆍL.1) developed rust-spots, more so at 21±2oC than at 3±0.2℃. Roots held at 21±2℃ were yellowish and developed white cell proliferations. Comparable control roots also developed rust-spots likely due to the high undecomposed organic matter content of the incubation soilless mix.

Extended Stratification of North American Ginseng Seed

The North American ginseng (Panax quinquefolius L.) seed crop varies from year to year. The ability to hold stratified seed for a year would ensure continuity of seed supply and no interruption in production cycles. Seed drying and rehydration protocols at room temperature (21±2℃) were developed. These protocols and seed storage at 4±1℃ and 35%, or variable, relative humidity (RH) allowed the holding of stratified seed for one year and then establishment of the following five treatments in field plots: Trt.1 : dried 2005 stratified seed (seed harvested Fall 2004) held at 4℃ and at variable humidity ; Trt.2 : 2006 stratified seed planted directly into the field; Trt.3 : 2005 stratified seed dried in October 2005 and held at 4℃ and 35% RH ; Trt.4 : 2005 stratified seed held in moist sand from October to December 2005 at room temperature (21±2℃) and then in December dried and held at 4℃ and 35% RH; Trt.5 : 2005 stratified seed held in moist sand from October to December 2005 at room temperature and then in December dried and held at-12℃. Seedling emergence was best in Trts. 2 and 4 with 67.3 and 65.1% respectively which is similar to the industry expected rate of 68% after regular stratification. Seedling growth was similar in Trts. 2 and 4 with root dry weights of 172 and 159 ㎎ respectively in mid-August. Therefore, if holding stratified seed in August/September for one year is desired, the seed can be placed in moist sand until December and then dried and stored at 4℃ and 35% RH. These seed can be planted in the following August/September and will germinate and grow in the following year to give an acceptable crop.

SEASONAL CHANGES IN NET CARBON DIOXIDE EXCHANGE RATES OF AUTUMN BLISS, A PRIMOCANE-FRUITING RED RASPBERRY (RUBUS IDAEUS L.)

Seasonal changes in leaf net carbon exchange rate (NCER), stomatal conductance (gs), and intercellular CO2 (ci) were determined for 2-yr-old potted Autumn Bliss (Rubus idaeus L.) plants grown under field conditions. NCER varied inconsistently between leaves which subtended fruiting lateral branches (laterals) and those that did not. In leaves with fruiting laterals, it was lower on three dates, similar on three other dates and once greater than in leaves without fruiting laterals. Evidence of nonstomatal inhibition of photosynthesis was also apparent as leaf NCER and gs fluctuated during the season while ci remained relatively constant. The leaf chlorophyll content increased when fruiting laterals were present, but this did not produce a consistently higher leaf NCER. The SPAD-501 meter provided a rapid and accurate, nondestructive estimate of leaf chlorophyll content for Autumn Bliss red raspberry leaves. Under uniform environmental conditions, all healthy, fully expanded leaves along the primocane had t...

Source-Sink Relations in North American Ginseng Seedlings as Influenced by Leaflet Removal

Seedlings of North American ginseng (Panax quinquefolius L.) were grown to full canopy establishment and then leaflet or leaf removal at different times applied to determine the effects on plant growth and performance. Leaf removal at 47, 57, 69 and 78 days after seeding resulted in 82.1, 59.8, 41.3 and 29.8% reduction, respectively, in root dry matter (economic yield) ; this indicates that leaf removal during the early root growth period causes greatest reduction in root yield. Removal of 1, 2, and 3 leaflets at 42, 52, 62 and 70 days from seeding reduced root weight at harvest (80 days from seeding) linearly, particularly at earlier removal dates. The perennating bud formed on all roots and was not influenced by treatment. This would suggest that if leaf loss occurs after canopy establishment the plant will re-grow the next year after the obligatory dormancy period.

Low-Temperature Storage of Immature (Green) North American Ginseng Seed for Fall Planting

Freshly harvested, immature (green) seeds of North American ginseng (Panax quinquefolius L.) were stratified for up to 3 years in plastic pails in controlled environment rooms at 5±1℃ for 9 months and then 21± 2℃ for 3 months (Trt. 1, regular stratification), or continuously at -2±0.2℃ (Trt. 2), or continuously at 3±0.2℃ (Trt.3). During stratification at -2 and 3℃ embryos did not grow. On seeding in the field embryos grew rapidly and resultant seedlings were comparable to those from regularly stratified seed. Seedling emergence rate was acceptable at the industry expected rate of 68% after one year of storage, but not after two years storage when it declined to 17.5%. Seed rot was so severe in year 3 that no planting was carried out. Seedling and second year growth were similar at the three stratification temperatures; most importantly, root dry weight (economic yield) was similar. Low-temperature storage of freshly-harvested North American ginseng seed is an acceptable method for short-term retention of propagating material.

In Vitro Flower Abscission Induction in North American Ginseng

In vitro studies using detached inflorescences with peduncles were conducted to investigate flower abscission agents in North American ginseng (Panax qulnquefolius L.). Of the nine compounds studied only three, ammonium thiosulphate (ATS), abscisic acid (ABA) and ethephon induced abscission. Anilazine, benzyladenine, carbaryl, gibberellic acid, napthaleneacetic acid and thidiazuron did not induce abscission. ATS dip treatments did not induce abscission but the spray treatments induced 60.5% abscission at 1500 ㎎·L-¹ and 33.1 % at 3000 ㎎·L-¹. Severe chlorophyll loss occurred on all inflorescences treated with ATS. Both ABA dip treatments and a 250 μmol·L-¹ spray treatment caused abscission (40%) without adverse effects, and timing of ABA application was important. Because ABA was only significant in the dip treatments, ABA may not be a practical option for field use on ginseng. Ethephon sprays induced more abscission as the season progressed and as the concentration increased. As the dip concentrations of ethephon increased, the abscission rate decreased and the health of the inflorescences declined. The 1500 ㎎·L-¹ spray of ethephon gave consistent abscission results over the growing season with little phytotoxicity. Treatment with the competitive ethylene inhibitor 1-methylcy-clopropene (1-MCP) suggested that flower abscission was due to the liberation of ethylene from the breakdown of ethephon.

Carbohydrate and Ginsenoside Changes in Ginseng Roots Grown in the Bay of Plenty, New Zealand

Ginseng is traditionally cultivated worldwide in cold continental climates. It is now also being cultivated in maritime environments such as New Zealandis. This paper reports a number of growth and quality parameters for plants grown under those conditions over two growing seasons and the intervening winter dormant period. While shoot biomass peaked mid-summer, in contrast, root biomass peaked late autumn/early winter. Starch, sucrose, fructose, glucose and inositol were detected in the roots. Starch concentrations were highest in early autumn (mean 470 mg/g-¹dry weight) and lowest in mid spring (218 mg/g-¹dry weight). Sucrose concentrations were low during early summer until late autumn but increased rapidly with the onset of winter and peaked during mid spring (168 mg/g-¹dry weight). Fructose and glucose concentrations were similar and peaked in late spring (5.3 and 6.2 mg/g-¹dry weight). Inositol concentrations peaked in mid summer (1.7 mg/g- dry weight). Starch/sugar ratios were high during summer and autumn and low during winter and spring. Ginsenoside concentrations and profiles showed that the six major ginsenosides, Rg1, Re, Rb1, Rc, Rb2 and Rd, were present, but Rf was absent. Concentrations did not vary with sampling date. The most abundant ginsenosides were Re (15.9 to 17.5 mg/g-¹dry weight) and Rb1 (10.7 to 18.1 mg/g-¹dry weight). Combined, they accounted for > 75% of total ginsenoside concentrations. Limited taste tests indicated that highest root quality occurred during late autumn, after the shoots had senesced. However, quality could not be related to plant chemistry.