Cornus Stolonifera Michx Research Articles

The Adaptive Ability of Cornus Stolonifera Michx. ´Kelseyi´ in Changing Environment

Abstract Water represents one of the limiting environmental factors having impact on all the processes in plants. Water stress is considered as the most significant cause of photosynthesis defects. Measuring fluorescence of chlorophyll a is one of the methods revealing defects in the photosynthetic aparatus. The examination has been carried out on the plants Cornus stolonifera Michx. ´KELSEYI´ cultivated in two different irrigation regimes (a regime with 40% substrate saturation and a controlling regime with 60% substrate saturation). We have used a fluorometer HANSATECH FMS 1 to measure modulated fluorescence of chlorophyll a. A three-week period of measurement was set between June and August during two years of experiments (2011 and 2012). The selected chlorophyll fluorescence parameters Fv /Fm - maximum quantum efficiency of PSII; ΦPSII - effective quantum yield of PSII; Rfd - chlorophyll fluorescence decrease ratio and NPQ - non-photochemical chlorophyll fluorescence quenching, proved to be insensitive to given water deficit. Cornus stolonifera Michx. ´KELSEY´ appears to be a woody plant capable of water efficiency.

Response of red‐osier dogwood (Cornus stolonifera) seedlings to sodium sulphate salinity: effects of supplemental calcium

A greenhouse study was designed to test the effects of sodium sulphate (Na2SO4) on red‐osier dogwood (Cornus stolonifera Michx) seedlings in the presence and absence of additional calcium (Ca2+). Changes in growth parameters, ion and carbohydrate accumulation and cell wall composition were examined. Calcium alleviated the effect of Na2SO4 on shoot height; however, it did not affect the reduction in shoot and root dry weights. An increased level of sodium (Na+) in roots of plant exposed to Na2SO4 was recorded in the presence of supplemental Ca2+ whereas there was no change in potassium (K+) and Ca2+ levels. In shoots of seedlings treated with Na2SO4, the addition of Ca2+ did not affect Na+, K+ and Ca2+ levels. The amount of soluble carbohydrates was increased in leaves of seedlings treated with Na2SO4 both in the absence and presence of supplemental Ca2+. The decrease in cell wall material in response to salt stress was alleviated by Ca2+ in stem tissues although Ca2+ did not alter the changes in hemicellulose and cellulose. Sugar composition of pectins and hemicellulose were modified in stems and leaves by Na2SO4 and/or Ca2+. The results of this study showed that calcium was able to alleviate the effects of salt stress on shoot height and cell wall content of red‐osier dogwood stems. Furthermore, changes occurred in cell wall composition of red osier seedlings treated with Na2SO4.

Effects of NaCl on water relations and cell wall elasticity and composition of red-osier dogwood (Cornus stolonifera) seedlings.

Red-osier dogwood (Cornus stolonifera Michx, Syn. Cornus sericea), a species relatively well adapted to moderately saline conditions compared with other boreal species, was used to test the effects of NaCl on plant water relations, cell wall elasticity, and cell wall composition of seedlings. Three month-old seedlings were treated hydroponically with 0, 25, and 50 mm NaCl for 21 days. The osmotic potential at full turgor, osmotic potential at turgor loss, pressure potential at full turgor, and relative water content at turgor loss of red-osier dogwood shoot tissue were not significantly affected by the NaCl treatments. Cell wall elasticity of the shoot tissues did not change following NaCl treatments, suggesting that elastic adjustment did not play a role in the adaptation mechanism. Hemicellulose content of the cell wall increased in salt treated seedlings. The primary sugar found in the cell wall hemicellulose fraction was xylose. In the pectin fraction arabinose and galacturonic acid were the main sugars. Sodium chloride stress did not alter the sugar composition of the hemicellulose fraction; however, NaCl did increase the amount of rhamnose in the pectin fraction. The results of this study suggest that at moderate salinity red-osier dogwood does not make any osmotic or elastic adjustments in the shoot tissue, but some changes in the cell wall composition do occur. These changes could contribute to the decrease in growth recorded in red-osier dogwood during NaCl stress.

Metabolic inhibition of root water flow in red-osier dogwood (Cornus stolonifera) seedlings.

The short-term effects of sodium azide (NaN(3)) on water flow in red-osier dogwood (Cornus stolonifera Michx.) seedlings were examined in excised roots at a constant pressure of 0.3 MPa. NaN(3) significantly decreased root water flow rates (Q(v)). It also induced a significant reduction in root respiration and reduced stomatal conductance to a greater extent in intact seedlings than in excised shoots. Apoplastic flow of water increased with the NaN(3)-induced decreases in Q(v). Mercuric chloride (HgCl(2)) was also used to characterize the water flow responses and respiration of dogwood roots. Similarly to NaN(3), 0.1 and 0.3 mM HgCl(2) decreased root respiration rates and Q(v). The lower, 0.05 mM HgCl(2) treatment, reduced Q(v), but had no significant effect on root oxygen uptake. The reduction of Q(v) in HgCl(2)-treated plants was only partly reversed by 50 mM mercaptoethanol. The mercurial inhibition of Q(v) suggested the presence of Hg-sensitive water channels in dogwood roots. The results indicate that root-absorbed NaN(3) metabolically inhibited water channel activities in roots and in shoots and resulted in stomatal closure. It is suggested that the inhibition of respiration that occurs in plants stressed with environmental factors such as flooding, cold soils, and drought may be responsible for the closure of water channels in root cells and inhibition of root water flow.

Effects of consolidated tailings water on red-osier dogwood ( Cornus stolonifera Michx) seedlings

As part of their tailings management, the oil sand industries plan on producing consolidated (composite) tailings (CT), in which an inorganic coagulant aid (gypsum) is added to create a non-segregating deposit. The water associated with this treatment contains potentially phytotoxic levels of sodium, sulfate, chloride, boron, aluminum, fluoride and strontium. Since CT water is expected to saturate deposits in the reclamation areas, it may affect successful reclamation of these sites. Red-osier dogwood ( Cornus stolonifera Michx) was demonstrated to be relatively salt resistant and to have high potential for the reclamation of mining areas. In the present study, we used red-osier dogwood to examine the effects of CT water on the accumulation of ions within plant tissue, growth, gas exchange, water potentials and chlorophyll concentration. CT water reduced shoot lengths and dry weights in treated plants. The roots of treated plants accumulated higher concentrations of sodium and chloride than did shoots. The accumulation of sodium and chloride was accompanied by an increase in magnesium and calcium and a decrease in potassium in the roots, while the levels of potassium increased in the leaves. CT water altered gas exchange and water potentials in seedlings, and resulted in a decrease in chlorophyll's a and b. The results suggest that the mechanisms of salt resistance in red-osier dogwood seedlings involve the restriction of sodium transport from roots to shoots.

Effects of NaCl and Na2SO4 on red-osier dogwood (Cornus stolonifera Michx) seedlings

Sodium chloride and sodium sulfate are commonly present in extraction tailings waters produced as a result of surface mining and affect plants on reclaimed areas. Red-osier dogwood (Cornus stolonifera Michx) seedlings were demonstrated to be relatively resistant to these high salinity oil sands tailings waters. The objectives of this study were to compare the effects of Na2SO4 and NaCl, on growth, tissue ion content, water relations and gas exchange in red-osier dogwood (Cornus stolonifera Michx) seedlings. In the present study, red-osier dogwood seedlings were grown in aerated half-strength modified Hoagland's mineral solution containing 0, 25, 50 or 100 mM of NaCl or Na2SO4. After four weeks of treatment, plant dry weights decreased and the amount of Na+ in plant tissues increased with increasing salt concentration. Na+ tissue content was higher in plants treated with NaCl than Na2SO4 and it was greater in roots than shoots. However, Cl− concentration in the NaCl treated plants was higher in shoots than in roots. The decrease in stomatal conductance and photosynthetic rates observed in presence of salts is likely to contribute to the growth reduction. Our results suggest that red-osier dogwood is able to control the transport of Na+ from roots to shoots when external concentrations are 50 mM or less.

Germination, growth and gas exchange of selected boreal forest seedlings in soil containing oil sands tailings

Greenhouse experiments were conducted to determine the effects of soil enriched in fine tailings (FT), produced by the oil sands extraction, on germination, seedling growth and physiology of several plant species of the boreal forest. The germination of seeds was initially delayed by 15% FT in dogwood ( Cornus stolonifera Michx) and jack pine ( Pinus banksiana Lamb) but not in white spruce [ Picea glauca (Moench) Voss]. In the second set of experiments we showed that all dogwood seedlings survived 6 months of treatment with 15% FT while the survival rates of raspberry, jack pine and white spruce seedlings were reduced to 44, 55 and 94%, respectively. FT reduced root and shoot dry weights in raspberry seedlings and the number of lateral shoots in jack pine and white spruce seedlings. In raspberry and jack pine seedlings, reductions of gas exchange were recorded. The results of our study suggest that the modifications of soil chemistry, texture and structure by FT may all contribute to the observed phytotoxic effects.

Responses of Boreal Plants to High Salinity Oil Sands Tailings Water

AbstractIn the extraction of bitumen from oil sands ore, large volumes of railings water (CT water) containing elevated levels of Na, sulfate, bicarbonate and chloride are produced. High salinity process waters will probably affect terrestrial reclamation options. The present study tested the impact of tailings waters on boreal forest species including aspen (Populus tremuloides Michx.), buffalo berry [Sheperdia canadensis (L.) Nutt], northwest hybrid poplar (Populus deltoides × Populus balsamifera), dogwood (Cornus stolonifera Michx.), jack pine (Pinus banksiana Lamb.), and white spruce [Picea glauca (Moench) Voss]. Seedlings were grown in solution culture containing mineral nutrients and different dilutions of CT water, with and without supplemental salts (Na2SO4 and NaCl). After 4 wk of treatment, dogwood, hybrid poplar, and buffalo berry showed relatively high resistance to saline CT waters. Conifer seedlings developed leaf necrosis in all treatments, while aspen seedlings rapidly lost their foliage and produced new leaves. In comparison to the controls, elevated Na levels were measured in plant tissue of all species grown in CT water. However, some differences between species were observed, with jack pine seedlings showing much higher Na content than aspen, dogwood, or hybrid poplar. In hybrid poplar, the accumulation of Na was accompanied by a significant reduction in K, Mg, Ca, and P. Buffalo berry, aspen, jack pine, and white spruce showed elevated levels of S after growth in the sulfate‐enriched CT waters. High tissue Na content did not induce leaf injury in dogwood, hybrid poplar and buffalo berry, suggesting possible Na resistance.

Factors affecting red-osier dogwood seed germination

Seeds from 55 populations of native Alberta red-osier dogwood (Cornus stolonifera Michx.) were collected over 2 years (1984 and 1985) to determine the range of variability for seed germination and the effect of ecoregion and moisture conditions in the collection sites on this trait. Each year the unscarified seeds were stored at 3 °C for 30 days, stratified at 3 °C for an additional 30 days and then incubated on an 8 h light: 16 h dark cycle at a temperature of 25:10 °C (light:dark) for germination. A wide range of germination percentages was observed among populations collected in any 1 year. However, the variability was not due to the ecoregion or moisture condition of the collection site. Germination percentage of populations collected in 1984 and 1985 formed five and seven groups, respectively. A study involving eight sites that were common to 1984, 1985, and 1986 revealed a significant effect of population on seed germination. This population effect was not obscured by the combined effects of year, precipitation, temperature, and seed size. The year effect was significant only when population was used as a covariate. Precipitation during seed formation significantly influenced germination performance even after adjustments were made for population and year. Seed germination in red-osier dogwood appears to be influenced by the population from which the seeds are collected and by yearly environmental fluctuations. Therefore, germination studies in this species must include seeds from diverse populations collected over several years. Key words: red-osier dogwood, Cornus stolonifera Michx., germination, population, environment.

Individual Variation in Fruit Choice by American Robins (Turdus migratorius)

A13STRACT.--I tested American Robins (Turdus migratorius) for individual differences in fruit consumption and preference when offered six trials of a three-way choice of white mulberry (red variety; Morus alba L.), Bella honeysuckle (Lonicera x bella), and red-osier dogwood (Cornus stolonifera Michx.) fruits. Fruit choice was examined secondarily in relation to indices of fruit quality (fruit mass, percent water, refractive index, trial date, source plant) and in relation to age, sex, and individual morphometric variation of the birds. Pooling all trials and all birds, mulberry was eaten significantly more than either honeysuckle or dogwood. Although adults differed from juveniles in body mass at capture and in relative bill dimensions, fruit choice did not vary in relation to age or sex. Also, juveniles were not more variable than adults in fruit choice. However, individual birds differed significantly in fruit choice (15 preferred mulberry, 2 preferred dogwood, 0 preferred honeysuckle), and 15 individuals were consistent in fruit choice from trial-to-trial. Indices of fruit quality changed over the course of the study. For each of the three fruit species, some variables were significantly different among individual plants, over time, or both. Some fruit-quality variables explained small but significant amounts of variation in fruit consumption (numbers of fruits eaten) and preference (number of fruit A eaten/[(number of fruit B eaten) + (number of fruit C eaten)]. Robins preferred fruits from mulberry trees that had fruits of relatively lower mass and higher refractive index. After I controlled for effects of fruit quality, trial date, and source plant in multiple regression analyses, residual consumption and preference scores still differed significantly among individuals. Residuals for mulberry and dogwood were negatively correlated, which implies a trade-off in consumption of these two fruits. Individual differences in body mass, but not in bill or wing dimensions, explained significant amounts of the variation in residual mulberry consumption and in mulberry and dogwood preference. Heavier robins tended to prefer and eat more mulberries, the largest fruit, whereas lighter robins preferred dogwood fruits, which were the smallest. Dietary diversity correlated positively with wing length. Received 26 December 1990, accepted 8 June 1991.

Freezing Stress Response in Woody Tissues Observed Using Low-Temperature Scanning Electron Microscopy and Freeze Substitution Techniques

The objective of the current research was to examine the response of woody plant tissues to freezing stress by using scanning electron microscopy (SEM). Nonsupercooling species red osier dogwood (Cornus stolonifera Michx.), weeping willow (Salix babylonica L.), and corkscrew willow (Salix matsudana Koidz. f. tortuosa Rehd.) survived freezing stress as low as -60 degrees C. Cell collapse of ray parenchyma cells of these species was expected but did not occur. It was concluded that ray parenchyma cells of these species do not fit into either the supercooling or extracellular freezing classifications. Tissues from flowering dogwood (Cornus florida L.), apple (Malus domestica Borkh. cv "Starking III"), red oak (Quercus rubra L.), scarlet oak (Quercus coccinea Muench.), and red ash (Fraxinus pennsylvanica Marsh) were confirmed as supercooling species, and did not survive exposures below -40 degrees C. Ray parenchyma cells of these species did not collapse in response to freezing stress, as was expected. Cell collapse along the margins of voids were observed in bark of all seven species. Voids were the result of extracellular ice crystals formed in the bark during exposure to freezing stress. Tissues prepared by freeze substitution techniques were found to be adequately preserved when compared to those prepared by conventional fixation and low temperature SEM techniques. A freezing protocol for imposing freezing stress at temperatures lower than experienced naturally in the area where the study was conducted was developed that produced responses comparable to those observed in specimens collected in the field during natural freezing events.

VEGETATIVE MATURITY OF Amelanchier alnifolia Nutt. COMPARED TO RED-OSIER DOGWOOD AND RESCUE CRABAPPLE

Onset of vegetative maturity and its relationship to cold acclimation was studied in the saskatoon berry (Amelanchier alnifolia Nutt.). Red-osier dogwood (Cornus stolonifera Michx.) and Rescue crabapple (Malus domestica × baccata) were also included in the study for comparison. The onset of vegetative maturity was on 29 May 1985. This was 2 mo earlier than the onset of vegetative maturity in dogwood or Rescue crabapple. Shoots of saskatoon berry subjected to cool temperatures (4 °C) for a 2-wk interval after the onset of vegetative maturity induced cold acclimation from −10 °C to −25 °C, whereas shoots collected prior to the date of vegetative maturity were unable to acclimate. Daylength had no effect on cold acclimation.Key words: Amelanchier alnifolia, dogwood, crabapple, cold acclimation, frost hardiness, saskatoon berry

Twig weight–diameter relationships for selected browse species on the Duck Mountain Forest Reserve, Manitoba

Estimates of twig weight from twig diameter of 10 plant species browsed by moose (Alcesalces L.), elk (Cervuselaphus L.), and white-tailed deer (Odocoileusvirginianus Zimmerman) were obtained from one site along the edge of the Duck Mountain Forest Reserve, Manitoba. Seasonal variation in the twig weight–diameter relationships was great, as shown by differences in the correlation coefficient for the seasons. The highest correlations occurred in midwinter. Collection of twigs during their dormancy in winter or during their period of growth cessation in late summer produced the highest correlations between twig weight and twig diameter. In addition, red osier dogwood (Cornusstolonifera Michx.) was collected at three other sites and revealed that between-site differences in twig weight predicted from mean diameter were less than 20% for all test sites.

Matacil insecticide spraying, pollinator mortality, and plant fecundity in New Brunswick forests

Exposure-cage trials in spruce–fir forest near Doaktown, N.B., Canada, showed that Matacil aminocarb insecticide, applied for control of spruce budworm, increased mortality rates of several types of solitary bees and syrphid flies, although previous studies had found no effect on bumblebees. Of two plant species predominantly pollinated by the sensitive pollinator taxa, one (Maianthemum canadense Desf.) showed significantly reduced fecundity in sprayed areas. The other (Cornus stolonifera Michx.) tended toward reduced fecundity in sprayed areas, although this trend was obscured by great within-treatment variability. Cornus canadensis L., which is visited by bumblebees as well as by the smaller, Matacil-susceptible insects, showed no reduction of fecundity in sprayed areas. This study generally supports the practicality of assessing plant risk a priori by considering (i) the breeding system, (ii) the flowering phenology, (iii) the effective pollinators, and (iv) the known susceptibility of the pollinators to the spray agent in use.

Modeling Cold Hardiness of Red-osier Dogwood

Abstract Effects of temperature on cold acclimation and deacclimation of red-osier dogwood (Cornus sericea L. syn. Cornus stolonifera Michx.) plants were determined at different stages of plant development. Results were used to develop models for predicting stem hardiness. Acclimation and deacclimation rates were related to temperature and plant developmental stage (expressed as degree growth stage, °GS). Decreasing temperature promoted increasing acclimation. Maximum acclimation rates in the temperature range of 5° to 20°C occurred at maximum rest (270°GS). During the decreasing rest phase (270 to 315°GS), deacclimation occurred at temperatures from 7° to 20°C. At earlier stages of development (315° and 335°GS) during the quiescent phase (315 to 360°GS), 5°C was the only temperature that promoted hardiness, whereas at a later stage (341°GS) all temperatures tested caused deacclimation. The models, using bihourly temperatures and accumulating °GS, predicted hardiness within an average deviation of 4.7°C.

Changes in Frost Hardiness of Stem Cortical Tissues of Cornus stolonifera Michx. after Recovery from Water Stress

Moderate water stress increases frost hardiness in many woody plants but little attention has been given to changes in hardiness after recovery from water stress. Tests were carried out to examine how much water stress-induced frost hardiness remained when plants were rewatered under different day length regimes. Red osier dogwood plants (Cornus stolonifera Michx.) were water-stressed at normal growing temperatures in long day (LD) or short day (SD) conditions, exposed to 6 nights of freezing temperatures, and then returned to normal growing conditions with full water supply. Water-stressed plants gained an additional 8 to 10 C of hardiness. The amount of freeze-induced hardiness in both stressed and control plants was not significant (approximately 2 C) and was not affected by photoperiod. When plants were kept in or transferred to LD, they lost nearly all of their water stress-induced hardiness within 7 days after rewatering. Water-stressed plants in SD lost the least amount of hardiness (5 C) when rewatered. In dogwood, water stress is an effective way to increase hardiness temporarily, but the photoperiod has a large effect on the retention of the acquired hardiness.

VARIABILITY ASSOCIATED WITH LEAF WATER POTENTIAL IN RED-OSIER DOGWOOD IN FIELD AND GROWTH CHAMBER ENVIRONMENTS

Sources of variability associated with pressure chamber measurements of leaf water potential (Pleaf) made on a single clone of red-osier dogwood, Cornus sericea L. (Cornus stolonifera Michx.), were assessed by the nested analysis of variance method in both growth chamber and field environments. Variation among plants was significant in the field, but not in the growth chambers. Sampling from different branches on the same plant had no effect on Pleaf, but the point of insertion or node from which a leaf was taken significantly affected Pleaf. In the field environment a stress gradient was associated with node position with leaves from upper nodes under more stress than those from lower nodes. Under growth chamber conditions, there was no consistent stress gradient. Diurnal variability in Pleaf followed daily atmospheric demand in well-watered dogwood plants.

Environmental and Seasonal Factors Affecting the Frost-induced Stage of Cold Acclimation in Cornus stolonifera Michx

Stem tissues of red-osier dogwood (Cornus stolonifera Michx.) acclimated from -3 C to -40 or -50 C in 8 to 10 weeks under a short photoperiod (9 hours) and controlled temperature conditions. During the summer months plants did not acclimate as well as at other times. The sequence of day/night temperature regimes which induced maximum acclimation was 20/15 C for 5 to 6 weeks; 15/5 C for 2 to 3 weeks; 15/5 C plus 1 hour of frost per day for 1 week. The duration of exposure to each temperature regime influenced the rate and intensity of frost-induced acclimation. Less than 5 weeks of warm temperature preconditioning at 20/15 C reduced subsequent frost-induced acclimation. The inductive influence of frost on cold acclimation was additive over 5 days of repeated exposure, but its effects after the first exposure(s) were not immediate-requiring 1 to 4 days of 15/5 C following the frost treatments for the expression of the frost-induced acclimation to be manifest. There was a 75% increase in rRNA following 3 days of frost exposure and plants in an O(2)-free atmosphere during frost exposure failed to acclimate. The results suggest that seasonal acclimation behavior was due to endogenous rhythms rather than developmental stage, and that the frost-induced phase of acclimation involves aerobic metabolic processes.

Freezing of Water in Red-Osier Dogwood Stems in Relation to Cold Hardiness

Studies of stem water in red-osier dogwood (Cornus stolonifera Michx.) using nuclear magnetic resonance spectroscopy indicated that most freezing occurs at temperatures above -30 C in cold-hardy and tender stems. Hardy and tender stems had about the same amount of unfrozen water at -40 C (0.28 gram of water per gram dry weight). When hardy stems were slowly cooled below -20 C, the temperature below which little additional freezing occurs, they survived direct immersion in liquid N(2) (-196 C). Fully hardy samples not slowly precooled to at least -15 C did not survive direct immersion in liquid N(2). The results support the hypothesis that cooling rate is an unimportant factor in tissue survival at and below temperatures where there is little freezable water.

Xylem Water Potential and Electrical Impedance Ratios as Measures of Vegetative Maturity in Red-osier Dogwood (Cornus stolonifera Michx.)1

Abstract Xylem water potential (XWP) and electrical impedance ratios were used to determine the time of vegetative maturity in red-osier dogwood (Cornus stolonifera Michx.) grown under 2 temperature and a short-day dormancy inducing regime in growth chambers and a lathhouse under natural conditions. The decline in XWP correlated with the development of vegetative maturity as measured by tip dieback after defoliation. Under growth chamber conditions, average XWP values reached a minimum at the time of vegetative maturity. In all cases, however, variability within samples was so large as to preclude the use of XWP as an accurate, reliable index of vegetative maturity. A change in electrical impedance ratios at and after vegetative maturity caused the impedance meter to go “off scale.” Compared with XWP values, changes in electrical impedance ratios were more consistent and show promise in predicting vegetative maturity.