Nitric oxide improves high zinc tolerance in maize plants

A short-term experiment was carried out to study the effects of exogenous nitric oxide (NO) on some growth parameters and mineral nutrients of maize grown at high zinc (Zn). Maize seedlings were planted in pots containing perlite and subjected to 0.05 or 0.5 mM Zn in nutrient solution. Nitric oxide (0.1 mM) was sprayed to the leaves of maize seedlings. High Zn reduced total dry matter, chlorophyll (Chl.) content and leaf relative water content (RWC), but increased proline content and membrane permeability. Foliar application of NO significantly increased chlorophyll content, RWC and growth of plants treated with high Zn, and significantly reduced their membrane permeability and proline contents. High Zn resulted in increased leaf and root Zn, but lower concentrations of leaf phosphorus (P), and iron (Fe). Foliar application of NO lowered leaf and root Zn and increased leaf and root nitrogen (N) and leaf Fe in the high Zn plants. These results clearly demonstrated that externally-applied NO induced growth improvement in maize plants was found to be associated with reduced membrane permeability under high zinc. Results can be concluded that NO may be involved in nutritional and physiological changes in plants subjected to high Zn.     

Dynamics of Particulate Organic Matter following biomass addition from fallow-improvement species in southern Mali

Knowledge about the nature and turnover rates of soil organic matter (SOM) is a key to soil fertility maintenance, especially in traditional farming systems. Particulate organic matter (POM), rather than total SOM content, is now considered a better measure of the soil's fertility. Fractionation of SOM, based on particle-size distribution after dispersion, was carried out on soil samples collected from a field experiment at N'Tarla, Mali (12.25° N latitude, 5.42° W longitude, Typic Plinthustalf). Biomass of off-site grown Gliricidia sepium (Jacq.) Walp. (gliricidia), Pterocarpus erinaceus Poir.(pterocarpus), and Stylosanthes hamata (L.) Taub.(stylosanthes) was applied to a maize (Zea mays L.) crop for two consecutive years. A significant decrease was noted in the soil's POM and POM-N contents after harvest of maize in both years as compared with the initial value measured at the beginning of the experiment. Small POM fraction (0.053 to 0.250 mm, POM₅₃) contributed more to total POM than large POM fraction (0.250 to 2.000 mm, POM₂₅₀). The POM N content was better correlated with maize grain yield than POM total weight, and the N content of POM₅₃ was better related to maize grain yield (R² = 0.55) than that of POM₂₅₀ (R² = 0.20). Total SOM was poorly correlated with maize grain yield (R² = 0.14). The results indicate that the quality of the applied biomass is of greater value than its quantity in sustaining maize grain yield, and POM₅₃ might be a better indicator of soil fertility status than POM₂₅₀ and total POM. This revised version was published online in June 2006 with corrections to the Cover Date.     

Lingual arch bar application for treatment of rostral mandibular body fractures in cats

Objective: To describe a lingual arch bar technique for fixation of rostral mandibular body fractures and report outcome in 16 cats. Study Design: Original study. Animals: Cats (n=16) with rostral mandibular body fracture (10 bilateral, 6 unilateral) just caudal to the canine teeth. Methods: Orthodontic wire (Dentaurum^®; 0.9 mm) was used as a lingual arch bar by contouring it to the shape of the lingual side of the alveolar margin, and secured by circum‐mandibular wires passed interproximal to teeth. Stability of fixation, occlusion, tolerance to the lingual arch bar, degree of secondary gingivitis/periodontitis, and ability to eat were evaluated clinically, and fracture union was assessed radiographically. Results: The lingual arch bar was well tolerated. Eleven cats without a feeding tube were able to eat within 24 hours. Time to fracture union and appliance removal ranged from 28 to 64 days (mean, 42.5 days). Malocclusion of the rostral part of the fracture occurred in 5 cats; however only 1 required correction. Conclusions: Intraoral stabilization of rostral mandibular fractures using a lingual arch bar is a simple and effective method for the treatment of rostral mandibular fractures just caudal to the canine teeth.     

Calcium Sulfate Improves Salinity Tolerance in Rootstocks of Plum

ABSTRACT

Three vegetative rootstocks of plum (Prunus domestica), Marianna GF 8-1 (Prunus cerasifera × munsoniana), Myrobolan B (P. Cerasifera) and Pixy (P. Insititia) were grown in pots containing sand and irrigated with complete nutrient solution to investigate the effect of calcium sulfate supplied to the nutrient solution on plants grown under salt stress. Treatments were (1) control (C): nutrient solution alone; (2) S (salinity stress): 40 mM NaCl; (3) S+Ca1: 40 mM NaCl +2.5 mM calcium (Ca) and (4) S+Ca₂: 40 mM NaCl + 5 mM Ca. Calcium was supplied as CaSO₄. The plants grown under 40 mol L^?1 NaCl produced less dry matter and had lower chlorophyll content than those without NaCl. Supplementary CaSO₄ at both 2.5 and 5 mM concentrations ameliorated the negative effects of salinity on plant dry matter and chlorophyll content. Salt treatment impaired membrane permeability by increasing electrolyte leakage. The addition of calcium sulfate partially maintained membrane permeability. Sodium (Na) concentration in plant tissues increased in both leaves and roots of plants under the high NaCl treatment. Pixy had much lower Na. The CaSO₄ treatments lowered significantly the concentrations of Na in both leaves and roots. Pixy was more tolerant to salinity than the other two rootstocks. The accumulation of Na in leaves and roots indicates a possible mechanism whereby Pixy copes with salinity in the rooting medium, and/or may indicate the existence of an inhibition mechanism of Na transport to leaves. Concentrations of Ca and K were lower in the plants grown at high NaCl than in those under the control treatment, and these two element concentrations were increased by calcium sulfate treatments in both leaves and roots, but remained lower than control values in most cases.     

RESPONSES OF SOME ENZYMES AND KEY GROWTH PARAMETERS OF SALT-STRESSED MAIZE PLANTS TO FOLIAR AND SEED APPLICATIONS OF KINETIN AND INDOLE ACETIC ACID

The study examined the effects of kinetin (KIN) and indoleacetic acid (IAA) applied as seed treatment or sprayed on leaves of salinity stressed plants. Five -week old maize (Zea mays L. cv. ‘DK 647 F1’) plants were grown in pots containing peat and perlite in 1:1 (v/v) mixture. Different treatments used were: 1) control (nutrient solution alone), 2) salt stress [100 mM sodium chloride (NaCl)], 3) 100 mM NaCl and 1 mM kinetin (KIN), 4) 100 mM NaCl and 2 mM KIN, 5) 100 mM NaCl and 1 mM indole acetic acid (IAA), 6) 100 mM NaCl and 2 mM IAA, 7) 100 mM NaCl and 25 mg L^?1 KIN and 8) 100 mM NaCl and 25 mg L^?1 IAA. In treatments 7 and 8 application was to the seeds, for treatments 3-6 it was applied to foliage. The seeds were soaked in KIN or IAA solution for 12 h. Salt stress reduced the total dry matter, chlorophyll content, and relative water content (RWC), but increased proline accumulation, activities of superoxide dismutase (SOD; EC 1.15.1.1), peroxidase (POD; EC. 1.11.1.7), catalase (CAT; EC. 1.11.1.6) and polyphenol oxidase (PPO; 1.10.3.1) and electrolyte leakage. Both foliar applications of KIN and IAA treatments overcame to variable extents the adverse effects of NaCl stress on the above mentioned physiological parameters. However, seed treatments with KIN or IAA did not improve salinity tolerance in maize plants. Furthermore, foliar application or seed treatments with KIN and IAA reduced the activities of antioxidant enzymes in the salt stressed-plants. Salt stress lowered some macronutrient concentrations [calcium (Ca) and potassium (K) in leaves and roots, phosphorus (P) in roots] but foliar application of both KIN and IAA increased Ca in both leaves and roots and P in leaves. Foliar application of IAA increased K concentrations in leaves of the salt-stressed plants. Foliar application of KIN and IAA, especially at 2 mM concentration, counteracted some of the adverse effects of NaCl salinity by causing the accumulation of proline and essential inorganic nutrients as well as by maintaining membrane permeability.     

《中国近现代史纲要》中的爱国主义教育

高校《中国近现代史纲要》课教学过程中,应当注重爱国主义教育的科学性、时代感和针对性。运用科学的历史观和方法论分析评价历史问题、历史人物;注意历史与现实的结合,为爱国主义思想和传统注入新鲜的时代内涵;针对学生的思想实际,解答他们所关注的社会热点、疑点问题。这些对于提高教育的说服力、吸引力和实效性有着重要作用。     

Stomach impaction in ostriches (Struthio camelus): blood chemistry,hematology, and treatment

This study involved 14 ostriches of both sexes between 3 and 24 mo of age. Some hematologic and biochemical parameters were studied in animals with stomach impaction. Clinical examination of the birds revealed anorexia, emaciation, decreased defecation, listlessness, separation from the flock, and recumbence. The total number of leukocytes (10.4 x 10(3) mm3), the concentrations of serum glucose (166 mg/dl), and total protein (2.4 g/dl) decreased; serum creatine phosphokinase (1240 U/L) and alkaline phosphatase (598 U/L) increased; whereas no changes were found in the concentrations of calcium, phosphorus, magnesium, zinc, and copper. Medical treatment was initiated in 13 animals; six of them recovered and seven birds died. Necropsy revealed edema, erosions, and hemorrhagic ulcers in the stomach of the dead birds. Foreign bodies such as sand; stone; pieces of wood, glass, and plastic; and metallic objects were encountered in the stomach at the necropsy. In one bird, metallic foreign body was diagnosed and the bird was referred to surgery. Under stress factors, ostriches tend to eat foreign material; therefore, adequate housing, nutrition, and care are crucial in prevention of stomach impaction.     

Freeze Injure and Antioxidant Enzyme Activity of Grapevine (<Emphasis Type="Italic">Vitis Vinifera</Emphasis>) Under Bio-Boron Fertilizer Applications

This study was conducted to determine the effects of plant growth promoting bacteria (PGPR) and boron (Bio-B) on the plant freeze injury, antioxidant enzyme activity and fruit yield of grapevine cultivar. The experimental plot was a completely randomized design with 5 replicates. As a trial model Bio-B and control were used as fertilizer agent. Bio-B fertilizer has been applied in different ways as soil?+?foliar, soil and foliar application methods to grapevine plants. Data through 2 years trials results showed that the use of Bio-B significantly decreased freeze injury and increased antioxidant enzyme activity of grapevine leaf. The highest damage rate at control group occurred with ?20?^°C and 94.89% ratio. In the same temperature degree at grape plant, the damage ratio of the Bio-B application from soil decreased by 21.55%; the application from leaf by 25.53% and with the application from soil?+?leaf by 26.24%. In addition to this, compared with control, in the CAT, POD and SOD enzyme activities increases occurred with the ratios as 28.57%, 22.05% and 39.25%, respectively. Generally, as results of this study under field conditions, Bio-B fertilizer application decreased freeze injure and increased antioxidant enzyme activity of the grapevine plant.