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71.
Purple flowering stalk (Brassica campestris ssp. chinensis var.purpurea Hort.) was generally regarded as a recalcitrant species for microspore culture in Brassica crops. Conditions for reliable induction of microspore embryogenesis were studied in 12 genotypes of purple flowering stalk. A treatment of short heat shock to microspore by incubating at 32 °C for 18 h was suitable for the survival of microspores, sustained cell divisions, and further induced embryogenesis. Subsequently, the reduced concentration of macro salts (1/2 NLN) provided an optimal condition for the development of embryoids. Under the optimized conditions for microspore embryoid development, 10 genotypes responded to microspore culture with the frequencies ranging from 2.7 to 70.5 embryoids per dish. However, regenerated plants were obtained from 9 genotypes, and more than 75% these regenerated plants were double haploid. This report establishes an efficient protocol for microspore culture and offers great potential for DH breeding in purple flowering stalk. 相似文献
72.
Estimation of actual evapotranspiration for a drip-irrigated Merlot vineyard using a three-source model 总被引:3,自引:3,他引:0
A study was performed in order to evaluate the three-source model (Clumped model) for direct estimation of actual evapotranspiration
(ETa) and latent heat flux (LE) over a drip-irrigated Merlot vineyard trained on a vertical shoot positioned system (VSP) under
semi-arid conditions. The vineyard, with an average fractional cover of 30%, is located in the Talca Valley, Region del Maule,
Chile. The performance of the Clumped model was evaluated using an eddy covariance system during the 2006/2007 and 2007/2008
growing seasons. Results indicate that the Clumped model was able to predict ETa with a root mean square error (RMSE), mean bias error (MBE), and model efficiency (EF) of 0.33, −0.15 mm day−1 and 74%, respectively. Also, the Clumped model simulated the daytime variation of LE with a RMSE of 36 W m−2, MBE of −8 W m−2, and EF of 83%. Major disagreement (underestimated values) between observed and estimated values of ETa was found for clear days after rainfall or foggy days, but underestimated values were less than 10% of the data analysis.
The results obtained in this study indicate that the Clumped model could be used to directly estimate vine water requirements
for a drip-irrigated vineyard trained on a VSP. However, application of the Clumped model requires a good characterization
of the drip-irrigated vineyard architecture. 相似文献
73.
74.
我国粮食综合生产能力效率评价及政策建议 总被引:3,自引:0,他引:3
为提高我国粮食综合生产能力、确保国家粮食安全,需要对当前粮食综合生产效率进行评价.通过分析粮食综合生产能力的影响因素,建立评价指标体系,并运用DEA分析方法,对1990-2006年我国粮食综合生产能力进行效率评价.研究结果表明,历年的粮食生产效率普遍较高,平均效率值为0.9985.DEA整体技术有效的年份有13年,而造成部分年份生产无效率的原因在于较低的规模效率.在效率优化的基础上,提出了相关政策建议. 相似文献
75.
Yoshimasa Sugiura Kohji Matsuda Takashi Okamoto Makoto Kakinuma Hideomi Amano 《Fisheries Science》2008,74(1):180-186
To investigate the anti-allergic effects of the brown alga Eisenia arborea. A strain of Brown Norway rats know to strongly respond to immunoglobulin E (IgE) were used as an allergy model animal. The
rats were immunized with ovalbumin by oral administration. The levels of serum IgE and histamine were suppressed in the rats
fed a diet supplemented with dried E. arborea powder. As for the cytokine pattern, the interferon-γ production in the spleens and mesenteric lymph nodes (MLN) was enhanced,
and the interleukin-4 (IL-4) production in the spleens and/or IL-10 production in the spleens and MLN were suppressed. These
results, together with the change in the Th1/Th2 balance, indicate that the rats fed with E. arborea became more anti-allergic, suggesting that E. arborea might possess anti-allergic effects. 相似文献
76.
Muzaffer Mustafa Harlioğlu 《Aquaculture International》2008,16(4):351-360
This review focuses on the present distribution of populations of the crayfish Astacus leptodactylus that are harvested in Turkey. It also examines the history of this harvest and the impact that crayfish plague has had on them. Crayfish plague, caused by the fungus-like organism, Aphanomyces astaci Schikora, 1906, is a severe parasite of freshwater crayfish and has caused a lot of damage to A. leptodactylus populations in Turkey since 1984. Turkey was the largest provider of A. leptodactylus to Western Europe from 1970 (or possibly earlier) until 1986. For example, the peak production was reached in the early 1980s, with over 5,000 tonnes being exported in 1984. On the other hand, as a result of the crayfish plague the harvest of A. leptodactylus was reduced severely in most populations in Turkey after 1985. The harvest was only 320 tonnes in 1991. After the occurrence of crayfish plague in Turkey, in order to increase crayfish production uncontrolled A. leptodactylus stockings have been carried out in many waterbodies throughout Turkey. These introductions have caused an increase in the number of A. leptodactylus populations, but exploitation of A. leptodactylus is still under the pressure of the plague, although there has been a steady increase in crayfish production in recent years. The harvest increased to 2,317 tonnes in 2004. Fortunately, among those populations affected by crayfish plague, large amounts of A. leptodactylus can still be harvested from three lakes, ?znik (Bursa), E?irdir (Isparta) and Çivril (Denizli). Thus, it seems that A. leptodactylus has a degree of resistance to crayfish plague. It is therefore interesting to investigate the resistance of A. leptodactylus caught from these populations to crayfish plague. 相似文献
77.
Youji Wang Menghong Hu Weimin Wang Ling Cao Yi Yang Biping Lü Rongrong Yao 《Aquaculture International》2008,16(6):539-549
The diel feeding rhythm and ontogenesis during early life stage of loach Misgurnus anguillicaudatus were investigated under experimental conditions (light: L 06:00–18:00, D 18:00–06:00 h). Morphological and behavioral developments
of loach from newly hatched to 40 days after hatching were observed. Larvae were able to prey on daphnia 3–4 days after hatching
at 23 ± 0.5°C. As the larvae grew, they showed an increasing feeding capacity and a distinct feeding rhythm. Feeding intensity
and incidence for day-4 larvae were highest at 10:00 and 16:00 h. The highest levels of feeding intensity for day-12 larvae
occurred at 08:00, 12:00, and 18:00 h as did feeding incidence. By day 20, when the larvae metamorphosed, the highest levels
of feeding intensity occurred at 06:00, 18:00, and 24:00 h and were concurrent with the highest feeding incidence. After metamorphosis,
feeding capacity had again increased considerably and, in contrast to the earlier stages before day 20, feeding intensity
for day-30 juveniles peaked at 05:00 and 20:00 h, about 1–2 h after the maximum feeding incidence. The feeding rhythm of loach
juveniles at day 40 was almost the same as the day-30 juveniles. The estimated maximum daily feeding rates were 43.1%, 33.4%,
19.0%, 12.8%, and 5.8% of body weight on days 4, 12, 20, 30, and 40, respectively. Thus, loach was found to have different
feeding rhythms in the pre- and post-metamorphosis stages, with the highest feeding activity in daytime during the larval
planktonic stage before metamorphosis, and intensely nocturnal feeding behavior during the juvenile benthic stage after metamorphosis. 相似文献
78.
79.
文心兰类原球茎的诱导与增殖技术的优化 总被引:2,自引:0,他引:2
以文心兰试管苗叶片为材料,在(25±1)℃,光照强度24~30μmol/m2.s,光照时间10 h/d下研究类原球茎的诱导和增殖技术。结果表明:①蔗糖适于作为类原球茎诱导的碳源,类原球茎诱导率52%,单位叶片类原球茎2.725个;②附加3~5 mg/L的Ad处理有利于类原球茎诱导(诱导率57%,单位叶片类原球茎数量3.725~4个);③6-BA是影响文心兰类原球茎增殖的主导因子,中等浓度的6-BA(3.0 mg/L)有利于类原球茎的增殖,增殖率(15.29)极显著高于其它水平;④培养基1/2MS+6-BA 3.0 mg/L+2,4-D 1.0 mg/L+NAA 0.4 mg/L+蔗糖20 g/L最有利于文心兰类原球茎的增殖,增殖率最高(15.95),极显著高于其它处理组合。 相似文献
80.