Allelopathic effects of Eucalyptus camaldulensis Dehnh. were confirmed in Petri dish and pot experiments in our previous studies. However, the degree to which such effects under controlled experiments exist in more complex ecological settings remains to be tested. Thus, the present study was carried out by incorporating different proportions of ground litter of E. camaldulensis in soil. The growth of three agricultural crops: falen (Vigna unguiculata (L.) Walp.), chickpea (Cicer arietinum L.), and arhor (Cajanus cajan (L.) Millsp.), and two tree species, kala koroi (Albizia procera (Roxb.) Benth.) and ipil ipil (Leucaena leucocephala (Lam.) de Wit) were tested. There were inhibitory effects of leaf litter on germination, shoot and root growth, leaf number, and collar diameter as well as a reduction of nodulation by legume crops (25–80% reduction). The extent of the effects was dependent on the proportion of leaf litter, the species and the type of traits. In contrast to shoot growth, the effect on root growth was more severe. No effect on germination was found with the agriculture crops while the two tree species showed reduced germination. The effect was greater in the presence of higher proportions of leaf litter mixed in soil while in some cases lower proportions stimulated growth. Not all species were suppressed; A. procera, C. cajan, V. unguiculata showed compatible growth while C. arietinum and L. leucocephala were found incompatible. This study provides evidence that E. camaldulensis has allelopathic potential under field conditions and a careful selection of associated crops in agroforestry systems is highly recommended. 相似文献
Resistance of Eucalyptus globulus juvenile foliage to Teratosphaeria leaf disease (TLD) damage has been shown to be under genetic control. Constitutive traits of juvenile leaves such as stomatal density (counted with wax on and with wax removed), total phenolics, total leaf wax, leaf mass per area (LMA) and leaf anatomical features were assessed to determine differences between pairs of resistant and susceptible families. Anatomic features assessed included cuticle, epidermis, palisade spongy mesophyll and total leaf thickness, as well as palisade cell size, shape and intercellular airspace. One interprovenance, one intraprovenance and two within‐family contrasts were used to compare resistant and susceptible pairs of families of Australian origin. The more resistant families had a significantly higher LMA and smaller percentage airspace compared with susceptible families. It is argued that one of the mechanisms by which E. globulus resists TLD involves the closely packed palisade mesophyll cells that increases LMA and reduces airspace, thereby restricting pathogen spread once infection has occurred. 相似文献
A total of 120-day-old broilers were divided into four groups. In group-A, broilers were left without supplementation of minerals and vitamins (control), while the broilers in groups B, C and D were given mineral and vitamin supplementation 1-6, 1-4 and 5-6 weeks, respectively. The results showed that the feed consumption of broilers in groups A, B, C and D was 4 234.61, 4 028.38, 4 169.32 and 4 181.87 g ? b-1; water intake was 9 668.88, 9 295.55, 9 882.11 and 9 402.86 L ? b-1; live body weight was 2 068.90, 2 360.90, 2 255.30 and 2 157.40 g ? b-1, respectively. The feed conversion ratio of broilers in groups A, B, C, D was 2.05, 1.71, 1.85 and 1.94 g ? b-1, carcass weight (wt) was 1 550, 1 656, 1 552 and 1 528.8 g ? b-1, and average dressing percentage was 61.24, 63.02, 62.60 and 60.51 respectively. Weight of heart in groups A, B, C and D was 15.13, 13.16, 11.72 and 11.50 g ? b-1, weight of gizzard was 32.98, 37.48, 37.62 and 33.35 g ? b-1, weight of liver was 51.94, 48.70, 51.94 and 48.70 g ? b-1and spleen weight was 3.48, 3.28, 3.06 and 2.82 g ? b-1, respectively. Average mortality of broilers in groups A, B, C and D was 6, 2, 4 and 5 resulting 20.00%, 8.00%, 13.00% and 16.00% mortality rate, respectively. The haemoglobin level in blood of broilers in groups A, B, C and D was 9.20, 12.23, 10.87 and 7.60 g ? dL-1, white blood cell level 77.47, 89.83, 81.63 and 78.13 (×106μL); red blood cell level 1.85, 2.58, 2.45 and 1.40 (×106μL), respectively. It was concluded that broilers given mineral and vitamin supplementation (Aquavit Electrolyte) for 6 weeks were proven to be most effective regime to result the lowest feed intake, the highest live body weight, better feed conversion ratio, higher carcass weight, better dressing percentage, higher net profit, relatively improved haemoglobin level in blood, increased counts of red blood cells and white blood cells. In all the above parameters, the broilers received mineral and vitamin supplementation for the first 4 weeks and the last 2 weeks showed relatively inferior performance, it is suggested that mineral and vitamin supplementation through water for partial period was not much effective in broiler productivity. Broilers may be supplemented with commercially available minerals and vitamins in drinking water over full rearing period, for achieving higher live body weight and efficient feed conversion ratio. 相似文献
A two-year field experiment was conducted to elucidate the residual and cumulative boron (B) requirements for cotton and wheat crops. For the first time, cotton was sown in randomized complete blocks those received 0.0, 1.0, 1.5, 2.0, 2.5 and 3.0 kg B ha?1 as borax (Na2B4O7.10H20). Later, each plot was divided into two subplots for successive wheat and cotton crops and half of the pots received B at similar rates. Our results revealed that direct application of B at the rate of 2 and 2.5 kg ha?1 produced optimum cotton yield during 2005. The same rates of B were consistent in residual plots but not in cumulative plots for both of the crops in successive years. It was thus concluded that soil applied B at the rate of 2.0 and 2.5 kg ha?1 had significant residual effects on cotton and wheat yields. 相似文献
Biological nitrogen fixation has positive effects in the enhancement of soil nutrition and plants growth, especially under difficult conditions. The study assesses the effect of drought (40% field capacity) on growth, physiological and biochemical parameters of six symbioses involving two Moroccan alfalfa populations Adis-Tata (Ad) and Riche (Rc) and Moapa (Mo) variety and ArfRh2 (Rh2) and AufRh8 (Rh8) rhizobia isolated from Arfoud and Aufous, respectively. Results showed that drought decreased plants growth and nodulation. Physiologically, as response to stress, the nodules membrane stability was negatively affected. Biochemically, activities of peroxidase (POX), catalase (CAT), superoxide dismutase (SOD) and acid phosphatase (APase) increased in leaves and nodules. Ad-Rh2, Rc-Rh2 and Ad-Rh8 have been qualified as more drought tolerant. They showed high antioxidant activities and as consequence less membrane damages especially in their nodules. The increase in nodules health and antioxidant defense could results in the enhancement of plant drought tolerance under stress. 相似文献
Crop wild relatives (CWR) are wild species that are more or less genetically related to crops that can be used to introgress useful genes for improvement of productivity, resistance to biotic and abiotic stresses and quality of cultivated crops. They are important in crop improvement to achieve food security for an increasing population and to overcome the challenges caused by climate change and the new virulence of major diseases and pests. These genetic resources are increasingly threatened in their natural habitats through over-exploitation and land reclamation and degradation. Therefore, their efficient and effective conservation would be taxonomically and genetically valuable and will contribute to maintaining and promoting the sustainability of crop diversity, facilitating agricultural production and supporting the increasing demand for food, feed and natural resources. A checklist of 5780 Crop Wild Relatives (CWR) taxa from North Africa was obtained using the CWR Catalogue for Europe and the Mediterranean (PGR Forum). Of which consists 76% of the flora of North Africa. The checklist contains 5588 (~97%) native taxa and 192 introduced. Families with higher taxa richness are Fabaceae, Asteraceae, and Poaceae. These three families constitute more than 33% of the total taxa included in the checklist. About 9% (502) CWR taxa identified as a priority for conservation in North Africa using four criteria, the economic value of the crop, the relatedness degree of wild relatives to their crop, threat status using IUCN red list assessment, and finally the centre of origin and/or diversity of the crop. Of these, 112 taxa were assigned high, 268 medium and 122 low priorities for effective conservation. Those assessed as threatened using IUCN Red list and national assessment represent approximately 2% (119 taxa) of the CWR in the region. However, 21 taxa are assessed as critically endangered (CR), 53 as endangered (EN), and 45 as vulnerable (VU). Wild relatives of some globally important crops are present, with those related to wheat (Triticum aestivum L. and T. durum L.) and barley (Hordeum vulgare L.) among the highest priority crops for the North Africa region. Amongst CWR assessed as threatened, only 8 (6.7%) CWR are related to food crops, Avena agadiriana B.R. Baum. et G. Fedak (VU), A. atlantica B.R. Baum et G. Fedak (VU), A. murphyi Ladiz. (EN), Beta macrocarpa Guss. (EN), Olea europaea subsp. maroccana Guss. (VU), Rorippa hayanica Maire (VU) and Aegilops bicornis (Forssk.) Jaub. et Spach (VU). The wild relative of Safflower Carthamus glaucus M. Bieb is restricted to Egypt and Libya and assessed as rare in Egypt. The information available about the conservation and threat status of CWR in North Africa still lags behind, and more investigations are required. 相似文献
Adsorption is acknowledged as effective for the removal of pollutants from drinking water and wastewater. Biochar, as a widely available material, holds promises for pollutant adsorption. So far, biochar has been found to be effective for multiple purposes, including carbon sequestration, nutrient storage, and water-holding capacity. However, its limited porosity restricts its use in water treatment. Activation of biochars, when performed at a high temperature (i.e., 900 °C) and in the presence of certain chemicals (H3PO4, KOH) and/or gases (CO2, steam), improves the development of porosity through the selective gasification of carbon atoms. Physicochemical activation process is appropriate for the production of highly porous materials. As well, the morphological and chemical structure of feedstock together with pyro-gasification operating conditions for the biochar production can greatly impact the porosity of the final materials. The effectiveness of activated biochar as adsorbent depends on porosity and on some functional groups connected to its structure, both of these are developed during activation. This study provides a comprehensive synthesis of the effect of several activated biochars when applied to the treatment of organic and inorganic contaminants in water. Results show that high aromaticity and porosity are essential for the sorption of organic contaminants, while the presence of oxygen-containing functional groups and optimum pH are crucial for the sorption of inorganic contaminants, especially metals. Finally, although activated biochar is a promising option for the treatment of contaminants in water, further research is required to evaluate its performance with real effluents containing contaminants of emerging concern.
To study the effect of heterothermia on anaesthetic drug requirements in semi-free ranging Arabian oryx and to assess the temperature quotient (Q10) of oxygen consumption.
Study design
Prospective observational study and controlled metabolic experiment.
Animals
Sixty-eight anaesthetic events in 59 Arabian oryx from Mahazat As-Sayd protected area, Saudi Arabia
Methods
Anaesthesia was induced by remote injection of 25 mg ketamine, 10 mg midazolam and 0.5 mg medetomidine with a variable amount of etorphine based on a target dosage of 20 μg kg–1 and subjective assessment of body mass. Animals not recumbent within 15 minutes or insufficiently anaesthetized were physically restrained and administered supplementary etorphine intravenously depending on the anaesthetic depth. Body temperature (Tb) was measured rectally immediately upon handling of each animal. From six anaesthetized oryx, expiratory gasses for oxygen analysis and metabolic rate calculation were collected at two Tbs; before and after submersion in ice water for approximately 30 minutes.
Results
Forty-two animals (62%) became recumbent with the initial dose, with a mean induction time (± standard deviation) of 9 ± 2 minutes. The remaining animals could be handled but needed 0.3 ± 0.1 mg etorphine intravenously to reach the desired level of anaesthesia. There was a significant positive correlation between Tb and effective etorphine dosage (R2 = 0.48, p < 0.0001). Average Tb of the six animals in which metabolic rate was measured decreased from 40.0 ± 0.5°C immediately after induction to 35.5 ± 0.5°C after cooling. This reduction was associated with a reduction in oxygen uptake from 3.11 ± 0.33 to 2.22 ± 0.29 mL O2 minute–1 kg–1, reflected in Q10 of 2.17 ± 0.14.
Conclusions and clinical relevance
Tb significantly affects anaesthetic requirements in Arabian oryx and should be considered when selecting dosages for anaesthetic induction for species showing diurnal heterothermy. 相似文献
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