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Weed infestation is among the main biotic factors affecting growth and yield of various crops. This issue is more drastic for cereal crops like wheat which is the staple food crop of over 2.5 billion population of the world. One the control strategies is to investigate the distribution pattern of weeds under field conditions. In this regard, a survey study was conducted to investigate the distribution pattern of weed species in wheat crop during 2016-18 in district Khanewal, Punjab Pakistan. Thirty-six weed species distributed among fifteen different families were collected from the study area. Family Poaceae was the predominant with 10 species, while family Asteraceae was the second most dominant family with four weed species. Cynodon dactylon (L.) Pers. was the most frequently found specie with frequency value of 79.1% while Paspalum distichum had the highest importance value index (6.96) among the weeds of the study area. Based on these findings, it is recommended to create awareness among the farmers about the identified weeds so that weed infestation could be controlled with the recommended practices. [ABSTRACT FROM AUTHOR]

The present paper provides informations about the presence and chorology of Paspalum distichum L. plant species in Oltenia. Nationally is known only from Danube Delta (Letea forest and Rusca channel), where has a very good development and from Caraş-Severin (at the mouth of Nera river into the Danube, place where it forms a small delta). The identification of this taxa presence along the Danube, in other place except those mentioned in the specialty literature make us to believe that in the future this species area will expand on the Romanian Danube bank from the entrance to the mouth into the Black Sea. [ABSTRACT FROM AUTHOR]

Copyright of Southwest China Journal of Agricultural Sciences is the property of Editorial Department of Southwest China Journal of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Western North American Naturalist is the property of Monte L. Bean Life Science Museum and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In late-successional steady state ecosystems, plants and microbes compete for nutrients and nutrient retention efficiency is expected to decline when inputs exceed biotic demand. In carbon (C)-poor environments typical of early primary succession, nitrogen (N) uptake by C-limited microbes may be limited by inputs of detritus and exudates derived from contemporaneous plant production. If plants are N-limited in these environments, then this differential limitation may lead to positive relationships between N inputs and N retention efficiency. Further, the mechanisms of N removal may vary as a function of inputs if plant-derived C promotes denitrification. These hypotheses were tested using field surveys and greenhouse microcosms simulating the colonization of desert stream channel sediments by herbaceous vegetation. In field surveys of wetland (ciénega) and gravelbed habitat, plant biomass was positively correlated with nitrate (NO) concentration. Manipulation of NO in flow-through microcosms produced positive relationships among NO supply, plant production, and tissue N content, and a negative relationship with root:shoot ratio. These results are consistent with N limitation of herbaceous vegetation in Sycamore Creek and suggest that N availability may influence transitions between and resilience of wetland and gravelbed stable states in desert streams. Increased biomass in high N treatments resulted in elevated rates of denitrification and shifts from co-limitation by C and NO to limitation by NO alone. Overall NO retention efficiency and the relative importance of denitrification increased with increasing N inputs. Thus the coupling of plant growth and microbial processes in low C environments alters the relationship between N inputs and exports due to increased N removal under high input regimes that exceed assimilative demand. [ABSTRACT FROM AUTHOR]

Dominance of invasive species is often assumed to be due to a superior ability to acquire resources. However, dominance in plant communities can arise through multiple interacting mechanisms, including disturbance. Inter-specific competition can be strongly affected by abiotic conditions, which can determine the outcome of competitive interactions. We evaluated competition and disturbance as mechanisms governing dominance of Phyla canescens (hereafter lippia), an invasive perennial forb from South America, in Paspalum distichum (perennial grass, hereafter water couch) meadows in floodplain wetlands of eastern Australia. Water couch meadows (in the study area) are listed under the Ramsar Convention due to their significance as habitat for migratory waterbirds. In the field, we monitored patterns of vegetation boundaries between the two species in response to flooding. Under controlled glasshouse conditions, we explored competitive interactions between the native water couch and lippia subject to different soil moisture/inundation regimes. We did this using a pairwise factorial glasshouse experiment that manipulated neighbor density (9 treatments) and soil moisture/inundation (4 treatments). In the field trial, inundation increased the cover of water couch. Under more controlled conditions, the invader had a competitive effect on the native species only under dry soil conditions, and was strongly inhibited by inundation. This suggests that dry conditions favor the growth of the invader and wetter (more historical) conditions favor the native grass. In this system, invader dominance is governed by altered disturbance regimes which give the invader a competitive advantage over the native species. [ABSTRACT FROM AUTHOR]

This study assessed the heavy metal (Cr, Mn, Ni, Cu, Zn, and Pb) uptake and its effect on biochemical parameters in Paspalum distichum, a wetland plant. Sludge collected from Bhalswa waste dump, New Delhi, was used as heavy metal source and dosed in different proportions viz. 20%, 40%, 60%, and 80% to the garden soil. The plants accumulated metals mostly in belowground organs. The metal accumulation followed the order: Cr>Mn>Cu>Zn>Ni>Pb. The range of heavy metal concentration in tissue of belowground organs after 180 days of growth was 1,778.65–4,288.01 ppm Cr, 828.11–1,360 ppm Mn, 236.52–330.07 ppm Ni, 155.79–282.35 ppm Cu, 27.05–91.16 ppm Zn, and 27.09–50.87 ppm Pb. The biochemical parameters viz. chlorophyll and protein contents and peroxidase (POD) activity exhibited no considerable adverse effect indicating the plants’ tolerance towards heavy metals. The high POD activity and synthesis of new protein bands at high sludge-dosed plants were also in support of this fact. [ABSTRACT FROM AUTHOR]

The article explores the node and joint failure inducted in glued-laminated bamboo beams. It reveals that the failure is originated at the outermost lamination on the tension side of the beams filled in bending. It explains that the failure in both unjointed and jointed laminations filled in tension is examined, because the outermost laminations at the tension side of the beam are submitted to a consistent force. It says that the failure of unjointed laminations for Phyllostachys pubescens is always originated at a joint to prevent the redistribution of stresses. It concludes that the failure in beams can be originated because of the scholastic behavior of the force of nodes and joint.

Little information exists about the establishment of native longleaf pine flatwoods species for use in restoration efforts and as buffers around natural areas in the southeastern United States. Composition of groundcover in these systems is dominated by perennial graminoid species. Vegetation in current buffers is generally non-native turfgrass that can escape into natural areas, often reducing establishment and survival of native species. Where management objectives involve actively restoring native groundcover or reducing the probability of invasion by these non-native turfgrasses, identification of native species and restoration methods is needed. We investigated seed germination and establishment of four species native to longleaf pine flatwoods in central Florida and one species native to the adjacent wetland communities. Paspalum setaceum, Panicum anceps, Eustachys petraea, and Eragrostis refracta were directly seeded, and P. distichum was planted as sprigs into three former P. notatum pastures. Irrigation, fertilization, weed control, and mowing treatments were assessed in terms of cover development of the sown species. Paspalum distichum developed the highest percent cover—over 80% in wet areas after 1 year. Mowing had mixed impacts depending on the species, and fertilization never significantly increased cover. Directly seeded species developed sparse cover (0–40%), probably as a result of drought conditions. However, E. petraea and E. refracta appeared more promising for use on rights-of-way when using high sowing rates. A second experiment conducted on a roadside included these two species and sprigged P. distichum. Both E. petraea and P. distichum developed more than 45% cover on the roadside. Establishment of these natives from seed or sprigs was significantly enhanced when site preparation effectively reduced the seedbank of other species present in the soil. [ABSTRACT FROM AUTHOR]

As part of the Water Reforms process, environmental flow rules have been progressively implemented in New South Wales rivers. The Integrated Monitoring of Environmental Flows (IMEF) is a major project established to better understand how rivers and associated wetlands respond to environmental water allocations. The results presented here represent the vegetation data collected for the testing of the hypothesis that "protecting or restoring a portion of freshes and high flows and otherwise maintaining natural flow variability will replenish anabranches and riverine wetlands, restoring their biodiversity". The study site is the Ramsar listed Gwydir Wetlands, located on the Gingham and Gwydir (Big Leather) Watercourses in the Lower Gwydir Valley, 100 km west of Moree. The expansion of irrigated agriculture in the lower Gwydir valley has severely altered flow regimes in the wetlands. The spread of the weed Phyla canescens (Lippia) is of major concern to landholders in the Gwydir Wetlands. Results indicate that Paspalum distichum (Water couch) and Eleocharis plana (Ribbed spike-rush) can maintain dominance over Phyla canescens if flooding occurs on a semi-regular basis. Conversely, Eichhornia crassipes (Water hyacinth) is a rampant noxious weed of open water in the Gwydir Wetlands, and has quickly spread in areas that are inundated for long periods. Management of this weed requires periodic drying of the wetlands to cause desiccation and death of the plants. The flooding requirement of individual species and plant associations in the Gwydir Wetlands are currently not fully understood. By providing better information on the consequence of different flows, the IMEF project will help to develop better management strategies to shift the dominance from introduced species such as P. canescens and E. crassipes to more desirable native plant species. [ABSTRACT FROM AUTHOR]

Discusses a study which reexamined the underlying hypothesis that there is a tendency for introduced plant species to be taller in their introduced ranges than in their native ranges. Use of knotgrass and black mustard; Methods; Effects of origin and location on plant size in Europe versus California and Europe versus the Carolinas as detected by mixed linear models.

Copyright of Weed Research is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Weed Research is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Weed Research is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Weed Research is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

After the removal of domestic cattle and water buffalo in 1982, the monsoonal wetlands of the Keoladeo National Park, India were rapidly overgrown by the grass Paspalum distichum L. We studied the decomposition of above-ground litter of Paspalum distichum and that of ten submersed, floating-leaved, free-floating and emergent species, including the dominants in these wetlands prior to 1982. The only species that had decomposition rates as low as those of Paspalum were the emergents, Pseudoraphis spinescens (R. Br.) Vickery and Typha angustata Bory & Chaub, which had very restricted distributions both before and after 1982. All the previous dominants had much higher decomposition rates. The turnover time for Paspalum litter was estimated to be greater than one year, while litter of the previous dominants all had turnover times of less than one year. Thus, a permanent litter layer could develop in these wetlands that had not been present previously. [ABSTRACT FROM AUTHOR]

The article provides information on the collection of the plant Fimbristylis perpusilla found in Trigg County, Kentucky. Report from the U.S. Department of Agriculture showed that the plant is threatened or endangered. Species associated with the plant include Cyperus odoratus, Eragrostis hypnoides and Paspalum distichum. It cites the possibility that the plant is dispersed through propagule transport by migratory waterfowl or shore birds.