Effects of carbohydrate source and polyethylene glycol on maturation and germination of somatic embryos in walnut (<Emphasis Type="Italic">Juglans regia</Emphasis> L.)

Low efficiency of somatic embryo maturation, germination, and conversion to plantlets is a major problem in many species including J. regia L. Germination efficiency of somatic embryos is very low in walnut. In this study, effects of two carbohydrate sources, sucrose and maltose (each at 3% and 6%), and two kinds of PEG (4000 and 6000) (each at four levels of 1.5%, 3%, 5% and 7.5%) on maturation and germination of walnut embryos were tested. The number of somatic embryos increased conspicuously on medium containing PEG. Furthermore, higher levels of PEG-4000 (7.5%) could remarkably enhance the morphogenesis of somatic embryos and the number of embryos produced. PEG-4000 stimulated somatic embryo maturation of walnut. This stimulatory effect was dependent on the carbohydrate source used. Sucrose in combination with PEG-4000 produced 50% of cotyledonary and normal somatic embryos. Different concentrations of PEG were effective on the number of embryos with a shoot meristem. PEG-4000 7.5% and sucrose 3.0% produced the highest rate (50.0%) of normal shooting embryos. However, PEG (4000, 6000) and maltose caused an unfavorable effect and increased the frequency of abnormal shaped somatic embryos.     

药隔期低温胁迫对小麦干物质积累、转运和分配及产量的影响

为探明药隔期低温胁迫对小麦产量的影响,以烟农19、新麦26为供试材料,在小麦药隔期进行不同程度(T1:2℃/4h、T2:0℃/4h、T3:-2℃/4h)的低温处理,研究药隔期低温胁迫对小麦干物质积累、转运和分配及产量的影响.结果 表明:药隔期低温胁迫显著降低小麦干物质积累量,不同抗倒春寒性小麦品种间干物质积累量存在差异,抗倒春寒性弱的小麦品种降幅更大.其中烟农19的T1、T2、T3处理分别降低33.4％、46.2％和54.7％,而新麦26则分别降低了50.1％、59.3％和72.4％.不同处理小麦籽粒、穗轴+颖壳、茎鞘+叶的干物质积累量均低于CK,且随着低温胁迫程度的加重呈明显降低趋势.小麦花前干物质的转运量、转运效率以及花前贮藏干物质对籽粒的贡献率均随着低温胁迫程度加重呈降低趋势.同时低温胁迫显著降低小麦籽粒和穗轴+颖壳的干物质分配比例,增加茎鞘+叶的分配比例.T1、T2和T3处理显著降低了小麦的穗粒数和千粒重及籽粒产量,烟农19的T1、T2和T3处理分别减产56.06％、86.36％和98.10％;新麦26的T1、T2和T3处理分别减产96.15％、98.07％和98.46％.药隔期低温胁迫显著降低小麦干物质的积累量、花前干物质的转运量、转运效率以及花前贮藏干物质对籽粒的贡献率和籽粒干物质分配比例,严重减少光合同化物向穗部的转运和分配,影响穗部小花的正常发育,从而导致穗粒数的减少,这是造成小麦减产的主要原因.     

欧洲玉米螟雌蛾鳞片提取液对玉米螟赤眼蜂寄主搜索行为的影响

许多膜翅目寄生蜂在寄主栖息地和寄主定位过程中受化学刺激物的支配(Weseloh,1981;Noldus,1989),在寄主定向和接受行为方面,赤眼蜂利用多种来源于寄主的化学刺激物——利它素(Nordlund等,1976)。寄主鳞片及鳞片正己烷提取物可增强赤眼蜂寄主搜索反应和提高对寄主的寄生率(Lewis等,1972、1985;Shu等,1986;Noldus,1989;王锦举等,1990)。玉米螟赤眼蜂是亚洲玉米螟的优势卵寄生蜂(张荆等,1990),引进到德国后经室内研究表明,其对欧洲玉米螟卵的偏嗜性很强,箱笼及温室条件下对欧洲玉米螟卵     

Growth and Apparent Absorption of Minerals in Broiler Chicks Fed Diets with Low or High Tannin Contents

Sorghum grains with low (0.28 per cent catechin equivalent (%CE) or high (1.36 %CE)) tannin contents were used to study the effect of tannin on growth and on the apparent absorption of Ca, P, Mg, Na, K, Fe and Co by chickens. High-tannin sorghum caused a highly significant (p0.01) reduction in the weight gain and feed intake of broiler chicks compared to low-tannin sorghum and increased the feed conversion ratio (p0.01). The amount of tannin did not affect mortality. The apparent absorption of Ca, P, Mg, Na, K, Fe and Co was reduced (p0.01) by feeding sorghum grains with a high tannin content.     

牛体外受精胚胎衍生干细胞能力影响因素的研究

以牛卵巢卵母细胞体外受精获取囊胚期胚胎，比较体外受精牛胚胎不同获取内细胞团的方法和不同培养液对体外培养胚胎干细胞能力的影响。结果表明，囊胚期胚胎不除去透明带而直接培养产生胚胎干细胞，初次克隆率为55％；胰酶法去透明带分离的内细胞团（ICM）培养产生胚胎干细胞，初次克隆率为90％。免疫外科法去透明带分离的ICM在4种不同的培养液中，初次克隆率分别为16．4％、11．5％、21．8％、18．2％，但是其分离的ICM经传代后形成的衍生细胞不易发生分化，经过4～6代的传代，仍然保持其完整的形态，说明免疫外科法是一种理想的牛ICM分离法，培养液为D20＋LIF（40ng／mL）可用于牛胚胎干细胞培养。     

Viruses of pome fruit trees in Syria

A survey was conducted to evaluate the sanitary status of pome fruit trees in Syria during spring 2003 and 2004 in 6 governorates: Damascus, Al-Qunaitara and Al-Sweida (Southern region), Homs and Hama (Central region) and Latakia (Costal Western region), as the main production areas of pome fruits. Leaf samples from 1077 apples, 54 pears and 14 quince were collected and tested for the presence of Apple chlorotic leaf spot virus (ACLSV), Apple stem grooving virus (ASGV) and Apple mosaic virus (ApMV) in 70 commercial orchards and 3 varietal collections by ELISA. Results showed that the virus infection rates were 34 and 2% in apple and pear, respectively. Quince trees were found to be virus tested free. ACLSV was prevailing on apple with 34%, whereas ASGV and ApMV were found in 2 and 0.2% of tested trees, respectively. Pear trees were infected only with ACLSV (2%). 21 apples and 15 pears representative budwood samples were indexed by grafting on the following indicators: (i) Malus pumila cvs. Virginia Crab and Radiant for apple and (ii) M. pumila cv. V. Crab and Pyrus communis cv. Nouveau Poiteau for pear. The virus infection rates by woody indexing were much higher than ELISA, Apple stem pitting virus (ASPV) and ASGV were found in 86 and 82% of apple tested samples, whereas they were 80 and 60% of pear tested samples, respectively. Additional RT-PCR testing carried out for a limited number of samples confirmed the high incidence of ACLSV ASPV, ASGV and the presence of ApMV. This is the first report on pome fruit viruses in Syria, indicating an unsatisfactory sanitary status of the industry. As a consequence, a certification program is recommended for producing locally healthy propagating material.     

Concentrations of constitutive alk(en)ylresorcinols in peel of commercial mango varieties and resistance to postharvest anthracnose

Mature green mango fruits of commercially important varieties were screened to investigate the levels of constitutive antifungal compounds in peel and to assess anthracnose disease after inoculation with Colletotrichum gloeosporioides. High-pressure liquid chromatography was used to quantify the levels of 5-n-heptadecenylresorcinol and 5-n-pentadecylresorcinol in the peel extracts. The fruit peel of the varieties ‘Kensington Pride’ and ‘Keitt’ were observed to have the highest levels of both 5-n-heptadecenylresorcinol (107.3–123.7 and 49.9–61.4 μg/g FW, respectively) and 5-n-pentadecylresorcinol (6.32–7.99 and 3.30–6.05 μg/g FW, respectively), and the fruits of the two varieties were found to have some resistance to postharvest anthracnose. The varieties ‘Kent’, ‘R2E2’, ‘Nam Doc Mai’, ‘Calypso’ and ‘Honey Gold’ contained much lower concentrations of resorcinols in their peel and three of these varieties were found to be more susceptible to anthracnose. Concentrations of 5-n-heptadecenylresorcinol were significantly lower at the ‘sprung’ and ‘eating ripe’ stages of ripening compared to levels at harvest. Concentrations of 5-n-pentadecylresorcinol did not differ significantly across the three stages of ripening. The levels of these two resorcinols were found to be strongly inter-correlated (P<0.01, r²=0.71), with concentrations of 5-n-heptadecenylresorcinol being an average 18 times higher than those of 5-n-pentadecylresorcinol. At the ‘eating ripe’ stage, significant relationships were observed between the concentrations of each type of alk(en)ylresorcinol and anthracnose lesion areas following postharvest inoculation, P<0.001, r²= 0.69 for 5-n-pentadecylresorcinol, and P<0.001, r²= 0.44 for 5-n-heptadecenylresorcinol.     

Foliar Application of Glycinebetaine and Salicylic Acid Improves Growth,Yield and Water Productivity of Hybrid Sunflower Planted by Different Sowing Methods

Improved planting methods and foliar application of glycinebetaine (GB) and salicylic acid (SA) can improve the water productivity in field crops under limited water supply conditions. A 2‐year field study was conducted to evaluate the possible role of different planting methods and foliar applications of GB and SA in improving the yield, quality and water productivity of hybrid sunflower (Helianthus annuus L.). The crop was planted by flat sowing (75 cm spaced rows) and ridge sowing (75 cm spaced ridges), with GB and SA applied exogenously at 100 and 0.724 mm , respectively, at both budding and flowering stages, while control plots received distilled water. Ridge sowing, rather than flat sowing, improved the biological yield, oil yield, leaf area index (LAI), crop growth rate (CGR), plant height, water‐use efficiency and final achene yield during both the years. Foliar applications of GB and SA at both the stages improved the achene yield, although foliar application of GB at flowering was the most effective. Neither the planting methods nor the foliar application of GB and SA altered the achene oil contents during both the years. Foliar application of GB and SA increased the free proline content of the leaf and GB contents at flowering but reduced the achene protein contents, whereas planting method had no effect on these attributes across the years. Of the foliar applied chemicals, GB was more effective in improving sunflower growth and yield and water productivity than SA. To conclude, ridge sowing coupled with foliar application of GB at flowering stage could be beneficial for achieving maximum yields of hybrid sunflower under relatively water limited conditions in the field.     

Pharmacokinetics and tissue residues of kitasamycin in healthy and diseased broilers

The pharmacokinetics of kitasamycin after intravenous and oral administration in a dose of 300 mg/kg b.wt. was studied in 18 healthy and 18 Salmonella gallinarum naturally infected chickens. The tissue residue of the studied antibiotic was estimated in 36 normal chickens when it was given orally for 7 successive days. Therapeutic level of kitasamycin was achieved after 15 minutes and persisted for 20-22 hours after its oral administration. Higher serum kitasamycin concentrations were recorded in Salmonella gallinarum infected chickens. The elimination half-life of kitasamycin calculated after single intravenous injection was 9.03 hours in diseased chickens corresponding to 3.74 hours in healthy birds. The body clearance was significantly reduced in diseased chickens (23.86 ml/kg/min) when compared to that in normal ones (62.03 ml/kg/min). Kitasamycin treated broilers should not be slaughtered before 3 days from the last dose as it was detected only in bile and caecum at that time but not in edible tissues.