Minimally Invasive Surgery Techniques in Exotic Animals

The term minimally invasive surgery refers to procedures performed using endoscopic guidance to enter a part of the body (e.g., laparoscopy, thoracoscopy, arthroscopy, rhinoscopy, gastroscopy). Endoscope-assisted procedures generally use a rigid endoscope to improve visualization and/or access or permit completion of the procedure extracorporeally to access internal body structures through small openings compared with traditional “open” incision techniques. Endoscope-assisted procedures currently performed in exotics include, but are not limited to, exploratory laparoscopy/coelioscopy/thoracoscopy, procurement of thoracic and abdominal organ biopsies, intestinal foreign body removal, cystotomy, and reproductive sterilization.     

Pollination of the invasive exotic shrub Lupinus arboreus (Fabaceae) by introduced bees in Tasmania

Exotic plant invasions threaten ecological communities world-wide. Some species are limited by a lack of suitable pollinators, but the introduction of exotic pollinators can facilitate rapid spread. In Tasmania, where many non-native plants are naturalised, exotic honeybees (Apis mellifera) and bumblebees (Bombus terrestris) have become established. We determined how these species affect the pollination of Lupinus arboreus, an invasive, nitrogen-fixing shrub, which is rarely visited by native pollinators. The proportion of flowers setting seed and the number of ovules fertilised per flower were positively related to the visitation rates of both exotic bee species. There was no effect of bee visitation rates on the proportion of seeds aborted prior to maturity, possibly due to post-fertilisation environmental constraints. We conclude that the spread of B. terrestris may not alter the fecundity of L. arboreus because of the pollination service provided by A. mellifera, and discuss potential interactions between these two bee species.     

Manipulation of Pinus elliottii Seedling Growth through Regulation of Mineral Nutrient Supply

An N-P-K fertilizer trial with Pinus elliottii was analysed to provide regression equations of height and dry mass on soil nutrient levels. Response surfaces and isoquants were plotted. The technique is used to demonstrate the derivation of fertilizer recommendations for the raising of seedlings to predetermined standards.     

Differences in ecological and allelopathic traits among Alternanthera philoxeroides populations

Based on a field investigation and laboratory trials, this study compared the invasive ecology of aquatic and terrestrial alligator weed (Alternanthera philoxeroides G.) ecotypes. The aquatic ecotype showed a stronger eco‐adaptation than the terrestrial ecotype. Alligator weed performed well in wetland and riparian habitats, where it was so competitive that only one‐to‐three other plant types grew successfully in its company. In contrast, it exhibited poor growth in upland fields and parks, where the terrestrial ecotype was dominated by 6–11 other alien plant species. The aquatic ecotype exhibited significantly greater growth inhibition of Microcystis aeruginosa. The ecotypes differed in their pattern of allelopathic inhibition of water blooms. The allelopathic effect of the aquatic ecotype persisted for a period exceeding 20 days, whereas the terrestrial ecotype's allelopathic effect subsided in <5 days. The aquatic ecotype had higher levels of antioxidant compounds, including soluble protein and flavones, and the activity of protective enzymes was also higher, which included superoxidase dismutase, peroxidase and catalase. Alligator weed's unique characteristics derive mainly from its strong allelopathic potential and tolerance of eutrophication in aquatic habitats.     

Downstream drift of round goby (Neogobius melanostomus) and tubenose goby (Proterorhinus semilunaris) in their non‐native area

Several Ponto‐Caspian gobiid species have recently expanded their ranges in Europe and North America. This is the first study to demonstrate passive downstream dispersal (drift) of the round goby (Neogobius melanostomus) and tubenose goby (Proterorhinus semilunaris) in newly colonised areas (River Dyje, Danube basin), a factor that could play an important role in their dispersal. Drift duration (i.e. number of dates on which the species was caught) in round goby was longer than that of both native species and tubenose goby, providing a possible advantage. Size of drifting fish was restricted to a narrow range of 6–8 mm and 5–8 mm for round and tubenose goby, respectively. Drift in both species occurred almost completely during hours of darkness (<1 lux) and fish size did not vary throughout the night. In both species, drift density increased significantly during the first hour after dusk. Round goby density gradually decreased up to dawn, while tubenose goby density varied throughout the night with no clear pattern. Drift of early life stages appears to be an important phenomenon that has not received adequate attention in studies of round and tubenose goby ecology and dispersal.     

Soil and weed management for enhancing arbuscular mycorrhiza colonization of wheat

Tillage and weed control are critical components of cropping systems that need to be combined such that crops benefit from reduced competition. However, weeds may also contribute to the biological diversity within the agro‐environment. This greenhouse study investigated whether common weeds of arable cropping systems were suitable host plants for arbuscular mycorrhizal fungi (AMF), allowing the development of extraradical mycelium (ERM) that can contribute to the early colonization of a following wheat crop, especially in the absence of soil disturbance. Weeds were allowed to grow for up to 2 months before being controlled by soil disturbance or herbicide application (glyphosate or paraquat). Pregerminated wheat seeds were then planted. Chemical control of the weeds prior to sowing enhanced the early arbuscular mycorrhiza (AM) colonization rate of wheat roots, whereas mechanical disturbance was less acceptable as a method of weed control for rapid AM colonization. The type of herbicide (contact or systemic) had no impact on colonization of the wheat crop. Enhanced AM colonization promoted early P acquisition and growth of the crop. Appropriate management of weeds emerging between two consecutive cropping seasons coupled with no‐till soil management could ensure a quick and efficient AM colonization of the following wheat plants.     

Weed Allelopathy,Its Ecological Impacts and Future Prospects

Summary

The importance, characteristics, positive and negative impacts, and future role of weeds as an integral part of the natural and agroecosystems are evaluated and discussed. Interference between plants in nature and the importance of differentiating between competition and allelopathy are interpreted. Allelopathy as one component of weed/crop interference, allelochemicals from weed species and their possible mechanism of action are listed and discussed. Weed species with inhibitory action against cultivated crops, other weed species, and plant pathogens, as well as self-inhibitory (autopathic) species are reviewed. Stimulatory or inhibitory allelopathic effects of different crop plants, trapping and catching species, and the potential of allelopathic weeds in inhibiting or stimulating certain parasitic weed species are discussed and evaluated. Allelopathy as a mechanism and future strategy for agricultural pest control and farm management and the potential use and development of some allelochemicals as natural pesticides or plant growth regulators are also considered and discussed.     

浅议保护性耕作技术推广过程中存在的问题及解决途径

土地采用保护性耕作方法,可有效的防止水土流失,增加土壤蓄水能力,提高雨水利用率,培肥地利,增加土壤有机质,减少耕作次数,降低生产成本,各种农作物增产明显。     

半干旱区农田杂草的生活史对策研究

2008-2009年通过利用当地常见的10种杂草种植于不同处理的农田,研究半干早区农田杂草群落结构以及10种杂草群落组分种对环境因子的响应,结果表明,1)同一物种在不同的气候环境下,可以表现出不同的生活史策略.蝇虫实、田旋花和金荞麦2008年生活史策略分别具有竟争型(C)对策属性、胁迫忍耐型(S)对策属性和中间型(C-...