Winter Color Research Articles

Xanthophyll cycle pigment and antioxidant profiles of winter-red (anthocyanic) and winter-green (acyanic) angiosperm evergreen species

Leaves of many angiosperm evergreen species change colour from green to red during winter, corresponding with the synthesis of anthocyanin pigments. The ecophysiological function of winter colour change (if any), and why it occurs in some species and not others, are not yet understood. It was hypothesized that anthocyanins play a compensatory photoprotective role in species with limited capacity for energy dissipation. Seasonal xanthophyll pigment content, chlorophyll fluorescence, leaf nitrogen, and low molecular weight antioxidants (LMWA) of five winter-red and five winter-green angiosperm evergreen species were compared. Our results showed no difference in seasonal xanthophyll pigment content (V+A+Z g(-1) leaf dry mass) or LMWA between winter-red and winter-green species, indicating red-leafed species are not deficient in their capacity for non-photochemical energy dissipation via these mechanisms. Winter-red and winter-green species also did not differ in percentage leaf nitrogen, corroborating previous studies showing no difference in seasonal photosynthesis under saturating irradiance. Consistent with a photoprotective function of anthocyanin, winter-red species had significantly lower xanthophyll content per unit chlorophyll and less sustained photoinhibition than winter-green species (i.e. higher pre-dawn F(v)/F(m) and a lower proportion of de-epoxidized xanthophylls retained overnight). Red-leafed species also maintained a higher maximum quantum yield efficiency of PSII at midday (F'(v)/F'(m)) during winter, and showed characteristics of shade acclimation (positive correlation between anthocyanin and chlorophyll content, and negative correlation with chlorophyll a/b). These results suggest that the capacity for photon energy dissipation (photochemical and non-photochemical) is not limited in red-leafed species, and that anthocyanins more likely function as an alternative photoprotective strategy to increased VAZ/Chl during winter.

Overseeding Florida Lawns for Winter Color

Revised! ENH14, a 4-page illustrated fact sheet by L.E. Trenholm and J. Bryan Unruh, describes this practice used to provide green winter turf color for Florida lawns — selecting rye grasses, seedbed preparation, maintenance, and transitioning back to permanent grass. Published by UF Department of Environmental Horticulture, December 2010.

Persistence of Overseeded Cool-Season Grasses in Bermudagrass Turf

Cool-season grass species are commonly overseeded into bermudagrass turf for winter color. When the overseeded grass persists beyond the spring; however, it becomes a weed. The ability of perennial ryegrass, Italian (annual) ryegrass, intermediate ryegrass, and hybrid bluegrass to persist in bermudagrass one year after seeding was determined. Perennial ryegrass, intermediate ryegrass, and Italian ryegrass produced acceptable ground cover in the spring after fall seeding. Hybrid bluegrass did not establish well, resulting in unacceptable cover. Perennial ryegrass generally persisted the most one year after seeding, either because of summer survival of plants or because of new germination the following fall. Plant counts one year after seeding were greater in the higher seeding rate treatment compared to the lower seeding treatment rate of perennial ryegrass, suggesting new germination had occurred. Plant counts one year after seeding plots with intermediate ryegrass or Italian ryegrass were attributed primarily to latent germination and not summer survival. Applications of foramsulfuron generally did not prevent overseeded species stand one year after seeding, supporting the conclusion of new germination. Although quality is less with intermediate ryegrass compared to perennial ryegrass, it transitions out easier than perennial ryegrass, resulting in fewer surviving plants one year later.

An Analysis on the Color Trend of Street Fashion in Dalian, China(paper no. 2) - Focused on 2010 Winter, Compare with the Chinese Traditional Color Preference -

The purpose of this research is to analyze the effect of the traditional color sentiment on the contemporary clothing color by researching the street fashion of 2010 Winter season of Dalian in China, in view of the clothing color of women in their 20-30 years of age, along with traditional Chinese color. This is the 2nd paper following the paper no. 1, focusing on 2010 Summer season, so the research method is same as the paper no. 1. As a result, Black and deep tone PB color most frequently appeared. The vivid and strong tone of R, YR, Y color showed high frequency of clothing colors. This results illustrate that the clothing color choices of Chinese women was affected by Chinese traditional color sentiment rather than the international color trend. Characteristically, in winter season, frequency of R and Y color categories were higher than in summer season, specially in the top and accessories color, those colors showed higher frequency than the other colors. These were the important points in dealing with winter color trend, so that the fashion company and brands should take it an important points when they are planning winter clothing colors. The achromatic colors show the high frequency in both seasons. The bottom color shows high incidence of Black and deep tone of PB color categories as in the previous researches. That means consistent color trend existed in Dalian city, however it does not seem to have its origin from traditional Chinese color preferences. This kinds of regional and seasonal research might contribute to finding the basic informations about the design and marketing strategies to launch into the Chinese fashion market.

Association between winter anthocyanin production and drought stress in angiosperm evergreen species.

Leaves of many evergreen angiosperm species turn red under high light during winter due to the production of anthocyanin pigments, while leaves of other species remain green. There is currently no explanation for why some evergreen species exhibit winter reddening while others do not. Conditions associated with low leaf water potentials (Ψ) have been shown to induce reddening in many plant species. Because evergreen species differ in susceptibility to water stress during winter, it is hypothesized that species which undergo winter colour change correspond with those that experience/tolerate the most severe daily declines in leaf Ψ during winter. Six angiosperm evergreen species which synthesize anthocyanin in leaves under high light during winter and five species which do not were studied. Field Ψ, pressure/volume curves, and gas exchange measurements were derived in summer (before leaf colour change had occurred) and winter. Consistent with the hypothesis, red-leafed species as a group had significantly lower midday Ψ in winter than green-leafed species, but not during the summer when all the leaves were green. However, some red-leafed species showed midday declines similar to those of green-leafed species, suggesting that low Ψ alone may not induce reddening. Pressure–volume curves also provided some evidence of acclimation to more negative water potentials by red-leafed species during winter (e.g. greater osmotic adjustment and cell wall hardening on average). However, much overlap in these physiological parameters was observed as well between red and green-leafed species, and some of the least drought-acclimated species were red-leafed. No difference was observed in transpiration (E) during winter between red and green-leaved species. When data were combined, only three of the six red-leafed species examined appeared physiologically acclimated to prolonged drought stress, compared to one of the five green-leafed species. This suggests that drought stress alone is not sufficient to explain winter reddening in evergreen angiosperms.

Genetic Diversity of the Japanese Marten (Martes melampus) and Its Implications for the Conservation Unit

Molecular phylogenetic analyses of combined mitochondrial DNA sequences (2814 bp; cytochrome b gene, displacement loop region, and NADH dehydrogenase subunit 2 gene) identified nine groups among 49 individual Japanese martens, Martes melampus, collected from several areas in Japan. The grouping was not correlated with winter coat color, but was consistent with geography. In particular, the monophyly of 29 Tsushima martens, M. m. tsuensis, was supported by strong clade support and topological tests. Haplotype and nucleotide diversities were much lower for the Tsushima population than for any population on the Japanese main islands. In addition, analyses of heterozygosity in nuclear growth hormone receptor gene sequences (654 bp) showed genetic homogeneity for the Tsushima population. This evidence supports the view that the Tsushima marten's long history of isolation on small islands is responsible for its genetic distinctiveness and uniformity, validating the Tsushima population as an evolutionarily significant unit.

Diversity and Relatedness of Common Carpetgrass Germplasm

Common carpetgrass (Axonopus fissifolius Raddi) is a stoloniferous, sod‐forming species used sparingly as a turfgrass. No information is available regarding the relationships between germplasm accessions of this species. Accordingly, the initial objective of this study was to evaluate the relatedness of common carpetgrass germplasm for morphological and turfgrass performance traits. This was accomplished using principal component and cluster analysis. Resulting principal components were separated into related traits that influenced plant architecture, aesthetic appeal, and inflorescence characteristics. The secondary objective was to identify if collection location impacted genotype performance. This was completed by arranging genotypes into groups on the basis of their geographic origin within the collection area and subsequently analyzing the groups to determine if collection location impacted growth and performance. Differences were found for winter color, establishment, and seedhead density between the SE group and other groups (SW, NE, and NW) which were not different from each other. Groups refer to regions; specifically, SE represents south of 31° N latitude and east of 86° W longitude, SW represents south of 31° N latitude and west of 86° W longitude, NE represents north of 31° N latitude and east of 86° W longitude, and NW represents north of 31° N latitude and west of 86° W longitude.

Overseeding Florida Lawns for Winter Color

Revised! ENH-14, a 3-page illustrated directory by L.E. Trenholm and J. Bryan Unruh, describes this practice used to provide green winter turf color for Florida lawns — selecting ryegrasses, timing, seedbed preparation, dethatching, seeding, watering, maintenance, and reestablishing permanent grass. Published by the UF Department of Environmental Horticulture, November 2007.

Walory użytkowe odmian gazonowych Festuca ovina wysiewanych w siewie czystym i mieszankach na trawnikach ozdobnych

In this paper we showed the results of 4-years’ experiments on the usefulness of some cultivars and mixtures of grasses for decorative lawns in the Mazurian Lakeland conditions. The following characteristics were estimated in 9º scale: winter hardiness, turf compactness, colour, leaf fineness and general aspect of lawns. Amond the studied cultivars of Festuca ovina the best features for pure sowing were founo for cultivars ‘Witra’, both designed in the Department of Grassland Sciences and Nieznanice 'Klomb'.

225 Growth and Aesthetic Evaluations of Container- and Field-grown Atlantic White Cedar, Chamaecyparis thyoides (L.) B.S.P.

Fifty-four taxa of Atlantic white cedar [Chamaecyparis thyoides (L.) B.S.P.] were assembled and maintained. A protocol for propagation of Atlantic white cedar was established. Plants were grown in containers and in a replicated field plot. Height and width data were recorded from container- and field-grown plants and all taxa were evaluated for growth habit, growth rate, and summer and winter color. Color descriptions of foliage are provided based on the Royal Horticultural Society colour chart. Exceptional taxa were identified based on needle color, texture, growth habit, and growth rate. Superior green forms include Dirr Seedlings 1 and 2, `Emily', `Rachel', and `Okefenokee'. The superior variegated form is `Webb Gold'. Superior blue forms include `Blue Sport', `Glauca Pendula', and `Twombly Blue', and superior slow-growing forms include `Andelyensis', `Meth Dwarf', `Red Star', and `Heatherbun'. These taxa are recommended to growers, landscapers, and gardeners for production and use.

Hardiness and Aesthetic Quality of Boxwood Cultivars as Affected by Landscape Exposure

Five cultivars of boxwood (Buxus microphylla)—'Winter Gem', B. microphylla var. japonica `Green Beauty', `Green Velvet', `Green Mountain' and `Glencoe'—were planted in twelve different exposures at Manhattan and Wichita, Kan., representing USDA hardiness zones 5 and 6 respectively. The 1995–96 winter was one of great extremes. Lows of –25°C for Manhattan and -23°C for Wichita were recorded, along with sharp 24-hour temperature drops of 31–32°C in January and March. Differences in cultivar performance were noted between the sites. At the Wichita site best winter color was exhibited by `Green Velvet' and `Glencoe', whereas `Green Mountain' sustained some bronzing of foliage due to winter sun. At Manhattan only `Glencoe' in protected locations exhibited good winter color. All other surviving cultivars showed considerable bronzing. In addition, `Green Beauty' was severely damaged at Manhattan, sustaining bark splitting due to low temperatures, although most plants survived at Wichita. Shaded locations on north, northeast and northwest produced best plant quality of all cultivars; whereas, the poorest plant performance occurred on south and southeast exposures.

Behavioural response and winter survival of mated and unmated diapausing females of the Tetranychus atlanticus-urticae complex (Acari, Tetranychidae)

Behavioural responses were studied in mated and unmated females of a Dutch strain of the spider mite Tetranychus urticae which were destined to enter diapause. Observations were confined to the period between acquirement of the winter coloration by the females (a few days after the last moult) and their entering of artificial hibernation sites offered to the mites on the host leaves. Unmated females were found to stay longer on the leaf surface than mated females; they entered the hibernation sites significantly later than mated females. The delay in the search for hibernation sites shown by unmated females may be seen as a behavioural adaptation to enhance the chance of being fertilized before hibernation. Winter survival of mated and unmated diapausing females of the same strain of mites was studied both in the laboratory at a constant temperature of 2±1°C and outdoors under natural climatic conditions in Amsterdam during the winter of 1990–1991. Survival was high under both conditions for mated as well as unmated females; no significant differences in survival were found between both types of female. Observations on post-diapause females of Tetranychus atlanticus (a mite belonging to the T. urticae complex) sampled from strawberry fields near Moscow in spring, showed that at most 10% of the females of this natural spider mite population were unmated. Both mated and unmated females had survived winter temperatures of -28 to -30°C.

MICROPROPAGATION OF PACHYSANDRA PROCUMBENS

Pachysandra procumbens, the Allegheny pachysandra, is very rare to rare throughout most of its native range. Winter color, growth habit and ease of maintenance all recommend this perennial as an alternative ground cover for shady habitats. Development of micropropagation protocols may allow for its mass distribution. Non-wild collected shoots were disinfested using conventional procedures and were cultured and maintained in an MS based stock medium. Shoots proliferated equally well on an MS, a modified MS or a DKW based medium. Shoots had significantly more swelled buds when cultured in medium gelled with Gelrite or in liquid medium on membrane rafts compared to vermiculite. Microcuttings with or without a basal node rooted equally well. Microcuttings with or without an apical bud rooted equally well; however, microcuttings with an apical bud produced significantly longer roots.

Seasonal regulation of dormancy in Chrysopa carnea (Neuroptera)

In Ithaca, New York, diapause incidence in Chrysopa carnea exceeds 50 per cent among adults emerging between 31 August and 3 September. Apparently, decreasing late summer day lengths, which exceed the stationary critical photoperiod in the laboratory, act on the sensitive stages and induce diapause. Full diapause intensity occurs about 2 weeks after adult emergence; complete winter coloration appears approximately 2 weeks later. Photoperiodic stimili in combination with the geographic strain largely determine diapause depth. Decreasing autumn day lengths decelerate diapause development and maintain diapause until the winter solstice. Subsequently, short day lengths and cold temperatures slow diapause development. In nature, neither long days, increasing day lengths, nor chilling hasten diapause termination. Diapause duration is largely determined by the interaction between inducing photoperiod, maintaining photoperiodic and thermal stimuli, and geographic strain. In Ithaca, diapause ends (all response to photoperiod ceases) between 22 January and 12 March. After diapause ends, the animals retain their diapause characteristics until temperatures exceed 4°C. Post-diapause reproductive development in females requires approximately 100 heat units above 4°C; however, below 8°C mating and oviposition are absent. Although the winter coloration remains, mating occurs within 1 day after transfer from 4 to 24°C. Temperature determines the rate at which the green summer colour returns.

Effects of Various Nitrogen Sources, Timing, and Rates on Quality and Growth Rate of Cool‐Season Turfgrasses1

AbstractFertilizer applications to cool‐season turfgrasses usually consist of treatments in spring, summer, and early fall. Two field studies were designed to compare various fertilizers at different timing and rate schedules on several cool‐season grasses alone and in mixed stands. A 10‐2.6‐3.3 (30% org. N) fertilizer was used at .5, 1.0, and 1.5 kg/ARE in single and split treatments in May, August, September and late November. Ammonium nitrate (AN) and ureaformaldehyde (UF) were compared at equal rates on ‘Merion’ Kentucky bluegrass (Poa pratensis L.). A total of 1.5 kg/ARE was applied in split treatments during the same months as stated above. Turf quality ratings were taken for three seasons, and bi‐weekly clipping weights, for two full growing seasons.Growth and color responses were correlated with fertilization rates in the first study, but at all three rates, fall and late fall treatments resulted in more uniform turf quality and less clipping weights than with comparable spring and summer fertilization. Calculated CV values were consistently lower for both parameters. Grasses maintained better winter color and greened up earlier in spring. Results with AN in the second study were similar, while UF treatments failed to produce satisfactory turf at the tested rate. Fall and late fall AN applications regularly maintained acceptable turf within acceptable clipping limits.

The annual cycle in the Djungarian Hamster Phodopus sungorus Pallas

Seasonal variations in several functions were observed in a strain of Phodopus s. sungorus bred and kept in the laboratory at Erling-Andechs (47° 58'N, 11° 11'E) under natural illumination: 1. During their first winter most hamsters changed into a whitish winter coat (Figs. 2, 5, and 14). The change in fur coloration is described (Fig. 1). In most animals molt into the winter coat started in October or November, and was completed in December. Molt into the summer coat started in January or February, and was completed in March or early April. Hamsters kept at outdoor temperatures started molt into winter pelt earlier, and finished molt into summer pelt later, than animals kept indoors (Figs. 3 and 4). Winter coloration was more extreme in animals kept at outdoor temperatures. 2. Molt into the winter coat was induced in summer by exposing hamsters to short photoperiods (Fig. 6). However, these animals spontaneously changed back into summer fur while remaining under short-day conditions. 3. The animals had a marked annual cycle in body weight with maximum weight in July and August, and minimum weight in December and January, while they were in winter pelage (Figs. 7 and 8). 4. Reproduction was observed only between February and November (Fig. 9). Young were born within 18 days (2 cases) or 19 days (27 cases) after the breeding pairs were established. Mean litter size was 5 (range 1-9) (Fig. 10). Average litter size was smaller in the first litter of a ♀ than in the second, but was smaller again in subsequent litters (Fig. 11). 5. Growth curves of young hamsters were compared with data from the literature (Fig. 12). In the mean ♂ ♂ were heavier than ♀ ♀ (Table 1). 6. The majority of ♂ ♂ showed testis involution during the first winter. The weight of winter testes was about 1/9th that of summer testes (Fig. 13). The cauda epididymidis contained no spermatozoa in winter animals, and many in summer animals. 7. Daily torpor was observed in many animals, but only during the winter, and only in those animals that had changed into winter coloration. Body temperature dropped to about 20°C in hamsters kept at 6°C ambient temperature. 8. More than 10% of the animals remained in summer colour during the first winter (Figs. 2, 3, and 14). In these animals, testicular state and body weight corresponded to those of summer animals (Fig. 15), and torpor was not observed. 9. During their second winter, only a small percentage of animals changed into the winter coat, and even in these animals winter coloration was poorly expressed (Fig. 2). Testicular regression was also rare in the second winter, and less marked than in first-year animals (Fig. 16). The two individual testes in an animal often differed considerably in size and activity.-Reproduction almost ceased after the hamsters had lived through their second winter. 10. Phodopus has a midventral sebaceous gland, which is much larger in ♂ ♂ than in ♀ ♀. An annual cycle in its activity was indicated, but was not studied quantitatively. A discussion of the observations is presented which includes aspects of the situation in free-living populations.-The annual cycles of all the individual functions observed in the laboratory (body weight, testis activity, reproduction, colour change, torpidity) were strictly synchronized with each other, which suggests that these functions are regulated by a single complex of coupled factors, or even by one single factor, within the organism. The annual cycle was influenced by photoperiod, but it was not exclusively caused by external factors and their changes; an internal component of the annual cycle has to be potulated.

Adult diapause in Chrysopa carnea: Photoperiodic control of duration and colour

Diapause was induced in two ways and the duration of reproductive diapause in Chrysopa carnea was then measured in each case under conditions which maintained diapause (LD 12 : 12) and conditions which terminated diapause (LD 16 : 8). A relatively short reproductive diapause resulted in all animals when the insects were reared and maintained in a constant LD 12 : 12 photoperiod. This régime also produced a pale winter colour—waxy-green or waxy-yellow. A more enduring diapause ensued in animals reared, or reared and maintained, under LD 16 : 8 prior to being transferred to LS 12 : 12 and most of these animals achieved a darker winter hue—waxy-green with dark reddish-brown dorsal markings or waxy-brown with darker reddish-brown on the dorsum. Thus, the two indices—duration of diapause and change in colour—revealed that transfer from one stationary photoperiod to another (LD 16 : 8 to LD 12 : 12) may have produced a more intense diapause, i.e. a greater suppression of physiological processes, than that elicited by a constant LD 12 : 12 lighting regimen. A high proportion of the experimental animals entered diapause and there was no apparent relationship between the percentage response and the intensity of the diapause evoked by the different conditions. Newly emerged adults ceased ovipositing under LD 12 : 12 and entered diapause more quickly than did reproductively active adults put under the same conditions. Both the pupa and the adult perceive a change in photoperiod.

Overseeding Florida Lawns for Winter Color

Overseeding is the practice of using a temporary grass that is seeded into the permanent lawn to provide winter color. While this practice is common on golf courses, athletic fields, and high-profile landscape areas, the principles also apply to homeowners who wish to have a green lawn year-round. It is important to remember,however, that this also entails year-round lawn maintenance. This document is ENH14, one of a series of the Environmental Horticulture Department, Florida Cooperative Extension Service, Institute of Food andAgricultural Sciences, University of Florida. Original publication date August 22, 2001. Revised September 2001.

Greenkeeping Research

THE report of the Board of Greenkeeping Research for 1937 (from the Board's Research Station, St. Ives, Bingley, Yorks. 2s. July 1938) shows an increasing amount of advisory work and original investigation at the St. Ives Research Station and at other centres. The Station lives within its income, but research work cannot be greatly extended with the present financial arrangements, as advisory work makes the first claim upon revenue. More advisory work was, moreover, accomplished in 1937 than in any previous year. The volume of research papers does not appear to reflect this policy, however, and a general account of work in progress will be found in the report, and also in a paper by the Station's director, Mr. R. B. Dawson (J. Roy. Hort. Soc., 63, 8 ; August 1938). A promising line of investigation concerns the use of potassium permanganate on lawns, to destroy moss and expel earthworms ; further developments will be awaited with interest. Supplies of seed of St. Ives creeping red fescue, the first of a series of improved strains of lawn grasses, are now available to greenkeepers. This strain has greater leafiness and density of growth than the existing varieties ; it has good winter colour, and reasonable resistance to fungal disease. Successful courses of instruction in the science and practice of greenkeeping have been prosecuted at the Station, and practical demonstration has been greatly improved by the establishment of a permanent exhibition of implements for the treatment of lawns.

Color and Primeness in Variable Mammals

THE phenomenon of seasonal color change commonly seen in northern animals became of particular interest to the writer when it was found that primeness in all fur-bearing animals, save the albino, was solely dependent upon a blanching process of the hair-roots and entirely independent of dermal thickness or pigmentation. Subsequent investigation showed that the depigmentation process did not cease at the level of the epidermis, but that it was continued out into the proximal portion of the hair-shaft to a variable extent in different fur-bearing animals. The latter fact suggested the idea that the blanching of the jack-rabbit and Arctic white fox might merely be the outward evidence of an exaggerated state of this same physiological process. Examination of the literature gave a very wide range of opinion as to the cause and nature of the seasonal change of color in these mammals. One interpretation of the process is that expressed by Allen (1894), Anthony (1928), Seaton (1928), Nelson (1918), and Pennant (1784), who with one accord state that the autumnal change of color in variable mammals (Lepus americanus) is due to a shedding of the pigmented summer fur and the growth of a white (albinotic) winter coat. On the other hand, Richardson (1829), Hadwen (1929), Merriam (1884) and Welch (1869) suggest that the change is not due to a shedding of the summer pelage, but that the existing coat lengthens and undergoes a blanching process, thus providing the winter coloration. Both sides, with the exception of Hadwen and Merriam, apparently agree as to the manner in which the reversion to summer dress takes place, namely, that the