Descurainia Research Articles

MOISTURE-DEPENDENT PHYSICAL PROPERTIES OF MEDICAL TINY SEEDS: PART A: FLIXWEED (DESCURAINIA SOPHIA L.)

Knowledge of agricultural seeds’ physical properties has significant importance for machinery and processing equipment design. Physical properties of flixweed (Descur ainia sophia L.) seeds were determined as a function of moisture content. Several properties were studied in the moisture range from 5.28 to 17.53% dry basis. Also, probability distribution of seeds’ principal dimensions were modeled by Gamma, Generalized Extreme Value, Lognormal, and Weibull functions. With increasing moisture content from 5.28 to 17.53%, properties including; length, width, thickness, geometric and arithmetic mean diameter, sphericity, specific surface area, volume, and projected area showed no specific trend. In contrast, the surface area increased from 6×10-7 to 1×10-6 m2. The bulk and particle density decreased from 696.61 to 542.51 kg·m-3, and 1217.50 to 1189.02 kg·m-3, respectively. The porosity increased from 42.78 to 54.37%. The maximum external static angle of friction belonged to wood at all moisture content levels, followed by the iron and galvanized surfaces. At all moisture levels, the emptying angle of repose was more than the filling one.

Host plants as reservoirs of the main oil-producing cabbage crops pests in the eastern forest-steppe of Ukraine

Considering the geographical position of Ukraine, which is Such biotic factor as the vegetation distribution, which is the forage base for most insects, influences their spreading greatly. This connection is strongly expressed among the harmful herbivorous insects. The presence and distribution of the plants which are cultivated or used by humans and on which the insects are fed is certainly the first and basic condition for the emergence of a zone or a breeding ground of harmfulness. The presence of the most preferred by the insects fodder plants often leads to the formation of a zone or a center of the greatest damage (in the presence of other favorable conditions for the existence and reproduction of the pest). In the course of the researches concerning the identification of the host plants as reservoirs of the main oil producing cabbage crops pests which have been conducted in 2011–2014 in the communities (meadows, roadsides of highways and field perimeters) of the Kharkiv district of the Kharkiv region it has been found out the host plants as reservoirs for the dominant pests of the oil producing cabbage crops were dandelion, caustic buttercup, field mustard, hedge mustard, tansy mustard, yellow rocket and field shepherd’s purse. The largest number of species of the host plants as reservoirs was found on the roadsides of highways and along the field perimeters (6 species) and on the meadows (2 species).The cruciferous fleas, rape blossom beetles and cruciferous bugs visited such crops as field mustard, hedge mustard and yellow rocket most often. Field shepherd’s purse was the least significant among the identified host plants as reservoirs. Only a small amount of the cabbage fleas fed on this crop. This fact can be explained by the small white flowers that do not attract the rape blossom beetles and rose chafers as well as by a ground flat leaf rosette, which is always covered with dust and prevents the fleas and bugs from feeding.

First Report of Downy Mildew Caused by Hyaloperonospora sisymbrii-sophiae on Flixweed (Descurainia sophia) in China

Flixweed (tansy mustard) has been used in Chinese medicine since the Han Dynasty (ca. AD 200) (Jiangsu New Medical College, 2000), and it is widely cultivated in China due to its medicinal values. However, downy mildew caused by Hyaloperonospora sisymbrii-sophiae is a major constraint to flixweed’s cultivation (Zhou Songdong et al., 2001). This disease produces large portions of well-defined yellow spots on the leaf. The corresponding lower surface of the leaf displays typical white downy growth symptoms, and the pathogen infects the leaf, stem, pedicel, flowers, and pods. During November 2012, flixweed seedlings were observed with characteristics of downy mildew symptoms in the fields of the Shangqiu region of Henan Province, China. On the upper leaves, the lesions were first seen as irregular, less discrete yellowish spots. Over time, a white mildew layer developed on lower leaves. The infection resulted in chlorosis to the entirely necrotic leaves with white mildew on both the upper and lower surfaces....

Growth Stage Affects Response of Selected Weed Species to Flaming

Propane flaming could be an alternative tool for PRE control or suppression of early-emerging weeds in organic and conventional crops. The objective of this study was to test the tolerance of selected early-season weeds to broadcast flaming in no-till systems. Four winter annuals (tansy mustard, henbit, cutleaf evening primrose, and field pennycress), one summer annual (common lambsquarters), and one perennial (dandelion) species were included in the study. Except for dandelion, the response to propane flaming was evaluated at two growth stages. Flaming treatments were applied using an all-terrain-vehicle-mounted flamer moving 4.8 km h−1, and propane pressure was adjusted to deliver doses of 0 (nonflamed control), 22, 34, 48, 67, and 90 kg ha−1. The response of each species to propane doses was described by log-logistic models based on visual ratings of weed control and dry matter reduction. Response to broadcast flaming varied among species and growth stages. Common lambsquarters, tansy mustard, and henbit were more susceptible to flaming than cutleaf evening primrose, field pennycress, and dandelion. On the basis of visual ratings, propane doses between 54 and 62 kg ha−1 effectively controlled (90% control) common lambsquarters at the early growth stage (five-leaf), tansy mustard at both growth stages (nine-leaf and flowering), and henbit (flowering). However, a higher propane dose (> 80 kg ha−1) was necessary to obtain 90% control of common lambsquarters in later growth stage (11-leaf) and early growth stage of henbit (nine-leaf). Cutleaf evening primrose, field pennycress, and dandelion exhibited higher levels of tolerance to broadcast flaming. A 90% control of these species was not achieved even with the highest propane dose (90 kg ha−1) utilized in the study. Results of this study indicate that a single application of broadcast flaming can be an effective tool for controlling tansy mustard, henbit, and common lambsquarters and temporary suppression of cutleaf evening primrose, field pennycress, and dandelion.

LIVESTOCK ACTIVITY AND CHIHUAHUAN DESERT ANNUAL-PLANT COMMUNITIES: BOUNDARY ANALYSIS OF DISTURBANCE GRADIENTS

The impact of domestic livestock on soil properties and perennial vegetation is greatest close to water points and generally decreases exponentially with distance from water. We hypothesized that the impact of livestock on annual-plant communities would be similar to that on perennial vegetation. We used multivariate analysis and semivariograms to locate boundaries and to determine the number and width of different annual-plant zones (referred as biotic zones) on long-term livestock disturbance gradients in the northern Chihuahuan Desert, New Mexico. We estimated abundance of annuals in 0.5-m2 quadrats placed at 30-m intervals on 10 livestock disturbance gradients originating at water points. Tansy mustard, Descurainia pinnata, was abundant in severely disturbed areas and also in areas that are known to have high soil nitrogen content. Amaranthus palmeri was abundant in half of the transects in the zones nearest the water points. The relationships of annual-plant abundance and species richness with distance from water points and with perennial-plant cover were not significant (R2 < 0.1). The number of boundaries and sizes of zones varied with distance from water points, with seasons, and with duration of grazing. The first biotic zone (most severely impacted by cattle) ranged from 75 to 795 m radius for winter–spring annuals and from 165 to 1065 m radius for the summer annuals. Variability in the number and size of biotic zones along grazing gradients was spatially correlated with the frequency and intensity of disturbance, with landscape position, and with patchiness of soil features. There were fewer and larger zones of summer annuals than of winter–spring annuals. Boundary analysis of livestock disturbance gradients provided a method with replication for assessing the impact of long-term livestock grazing on annual-plant communities. Livestock create nutrient-rich patches near water points by mixing dung with soil by hoof action. These nutrient-rich patches support species of annuals that are rare or absent in areas where soils are subjected to low-intensity disturbance.

Sulfate uptake by salinity‐tolerant plant species

Abstract High soluble‐sulfate (SO4) concentrations affect water quality, soil chemistry, plant sulfur (S) levels, and possibly ruminant‐animal health. The objective of this greenhouse pot study was to determine the potential for accumulating high levels of S by tansy mustard (Descurainia pinnata (Walt.) Britton), kochia (Kochia scoparia L. Schrad.), yellow sweet clover (Melilotus officinalis L.), slender wheatgrass (Elymus trachycaulus (Link) Gould ex Shinners), and sunflower (Helianthus annuus L.). Plants were grown on both a Brinegar (fine‐loamy Ultic Argixeroll) and Portneuf (coarse silty Durixerollic Calciorthid) soil. Each species received five‐SO4 levels. The saturation extract electrical conductivity (EC) of the cropped soils ranged from 6 to 16 dS/m, while the soluble SO4 varied from 16 to 200 mmolc/kg soil. Soil solutions were saturated or very nearly saturated with respect to gypsum at the conclusion of each study. Plant dry matter yield, except of grass growing on the non‐calcareous soil, was not reduced by SO4 treatment nor by the sulfate‐induced decrease in mole fraction of calcium (Ca)/(sum cations) to values less than 0.10 for kochia and grass. Sulfur concentration in the plants ranged from 2.5 mg/g in grass to 10 mg/g in mustard and for each species was linearly related to the SO4 treatment and soil‐SO4 activity. Plant SO4‐S values ranged from 70 μg/g in the grass to nearly 900 μg/g in mustard. Total nitrogen (N): organic S was 4.4, 7.5, 11.4, 16.5, and 5.8 for mustard, kochia, clover, grass, and sunflower, respectively. It was concluded that these species could accumulate high levels of S in the above ground tissue.

Recently Recognized Cultivated and Encouraged Plants Among the Hohokam

The anomalous geographic distribution of agave and cholla cactus remains in archaeological sites points to cultivation. Cholla pollen is ubiquitous in hamlets distant from its probable sources. Five plants have undergone morphologic change indicative of domestication: little barley (Hordeum pusillum), Mexican crucilo (Condalia warnockii var. kearneyana), amaranth (Cf. Amaranthus hypochondriacus), tobacco (Nicotiana rustica), and a member of the potato family (Solanaceae). At least five more formed part of a cool season crop complex locally cultivated or encouraged by the Hohokam: Chenopodium, tansy mustard (Descurainia), milkvetch (Astragalus), and maygrass (Phalaris). In the Queen Creek area pollen and macrofloral evidence suggests the natural desert vegetation was manipulated by fire to yield harvests favorable to human existence.

Treatment for tansy mustard poisoning

Treatment for tansy mustard poisoning

Germination Characteristics of Three Species ofCruciferae

Germination of tumble mustard (Sisymbrium altissimumL.), tansy mustard (Descurainia pinnata(Walt.) Britton), and yellowflower pepperweed (Lepidium perfoliatumL.) is partially dependent on total degree hours of incubation (temperature above 0 C times the duration of incubation). This relation was similar under constant or alternating temperatures. Alternating temperature regimes with −20 C inhibited germination, and greatly depressed subsequent germination at optimum temperatures. Tansy mustard and yellowflower pepperweed have temperature-dependent after-ripening requirements. Germination of all three species responded similarly to osmotic stress. The relation between tumble mustard germination under osmotic or soil moisture stress is dependent on the texture of the soil substrate. A mucilaginous coating greatly aids the germination of yellowflower pepperweed seeds on the surface of media under low (0.05 to 0.2 bars) moisture tension. Germination of seeds of the three species recovered in soil samples from the field is radically different from that of freshly harvested material. The seeds acquire a dormancy which is broken irregularly under ideal conditions for germination.

Effect of Tansy Mustard (Descurainia intermedia) on Moisture Storage during Fallow

C INCE the work of Cox and Cates (2) in 1912, it had been shown 3 repeatedly that weeds growing in competition with crops decrease yields. These results lead to the general assumption that weeds are detrimental anytime, including a fallow period for moisture conservation. In fact many farmers in the Great Plains area still plow during the winter or when there are no weeds to promote a dust for moisture conservation even though this practice has been shown to be of little value (6, 7). Recent research has shown that where runoff is prevented and weed control is adequate during the fallow period, type of tillage or amount of mulch does not greatly affect moisture storage in the Southern Great Plains (8). Finnell (5) stated that on the heavy soils of the Southern Great Plains 65.8 percent of the rainfall was evaporated, 13.5 percent was runoff, 2.7 percent was lost in tillage operations and 18.0 percent was stored in the soil.