孔石莼的同形世代交替

通过实验室培养和显微观察,描述了孔石莼同形世代交替各个阶段的发育情况。雌雄异体的配子体成熟后,放散两鞭毛的配子,雌雄配子接合成合子进而发育成孢子体,孢子体成熟后放散四鞭毛的游孢子,游孢子固着后,可直接发育成配子体。其同形世代交替是单倍体的配子体与二倍体的孢子体相互交替。     

Regeneration, establishment and evaluation of somaclones in Sorghum bicolor (L.) Moench

Novel in vitro techniques have the potential to aid conventional breeding programs. Somaclonal variation is considered to be a useful source of variation and has been demonstrated to be feasible in crop species like wheat, rice and maize. A study was taken up at Tissue Culture Laboratory, University of Agricultural Sciences Dharwad, India, for callus induction, maintenance and regeneration of two well established sorghum varieties, M35-1 and A-1 to study somaclonal variation for both qualitative and quantitative characters. The frequency of callus induction was 90 and 83.3 percent in M35-1 and A-1, respectively, on MS medium with 2 mg l-l of 2,4-D. On higher levels of sucrose (60 gl-l), M35-1 showed good response for both regeneration and rooting, while for variety A-1 BA(0.5 mg l-l) and NAA (0.2 mg l-l) had to be supplemented for satisfactory levels of regeneration (73.3%) and rooting respectively. The regenerated plants (SC₁) were selfed to obtain the seeds for the next generation. In M35-1, variations were observed for chlorophyll, phyllotaxy and midrib structure, while male sterile and branched phenotypes occurred in A-1 families. Combined analysis of variances showed that there was significant difference between and within families for most of the quantitative characters in both cultivars except for the character, fourth leaf breadth in the cultivar A-1. The variation, accompanied by a positive shift from the mean is an indication of the response to selection for any specific character. Occurrence of productive variants among the somaclones of established cultivars like M35-1 and A-1 indicates the possibility of their improvement through somaclonal variation. This revised version was published online in July 2006 with corrections to the Cover Date.     

4种海藻在南美白对虾养殖水体中的生态作用

在实验室条件下,设置南美白对虾单养试验模式及南美白对虾分别与龙须菜、孔石莼、海带、浒苔4种不同海藻混养模式,研究不同海藻对南美白对虾养殖水体中氨态氮(NH_4-N)、亚硝态氮(NO_2-N)、硝态氮(NO_3-N)和磷酸盐(PO_4-P)的清除效果。结果显示,4种海藻对NH4-N、NO_2-N、NO_3-N和PO_4-P的清除率不同,其中,龙须菜组对NH4-N、NO_2-N、NO_3-N、PO_4-P的清除率分别为79.25%、68.00%、65.57%、70.00%,孔石莼组分别为75.47%、60.00%、54.05%、65.00%,海带组分别为71.70%、56.00%、40.54%、57.50%,浒苔组分别为77.36%、76.00%、59.46%、67.50%。各试验组中南美白对虾生长情况均较南美白对虾单养良好,龙须菜组体长、体质量的特定增长率均最高,分别为1.43%、4.24%。可见,4种海藻与南美白对虾混养均可以有效清除南美白对虾养殖水体中的营养盐,南美白对虾与龙须菜混养效果最佳。     

Effect of polysaccharides extracts of algae Ulva rigida on growth,antioxidant, immune response and resistance of shrimp,Litopenaeus vannamei against Photobacterium damselae

This study was carried out to investigate the effect of water‐soluble polysaccharides extract of algae Ulva rigida (WPU) as dietary supplement on growth performance, antioxidant enzyme activity, lysozyme and phenoloxidase activity, and resistance of shrimp (Litopenaeus vannamei) subjected to bacterial infection with Photobacterium damselae. Three replicate groups of shrimp (1.0 g) were fed four diets containing four levels, 0 or control, 0.5, 1 and 1.5 g/kg of WPU for 8 weeks over the growth trial. Thereafter, 30 shrimps from each dietary treatment were infected with bacteria P. damselae to evaluate disease resistance of infected shrimp. The results of this study showed that WPU was effective as a growth promoter for L. vannamei. The best growth rate was observed in shrimp fed 1.5 g/kg of WPU diet. Regarding antioxidant defences, the diets supplemented with three levels of WPU stimulated glutathione peroxidase and catalase activates in experimental shrimps. MDA content of L. vannamei‐fed diet containing WPU 1.5 and WPU 1.0 was lower than WPU 0 and WPU 0. 5 diets. Also, lysozyme and phenoloxidase activities of shrimp receiving WPU at 1.0 and 1.5 level were significantly higher than those fed WPU 0 and WPU 0.5 diets. In addition, using WPU extract in all diets decreased mortality in L. vannamei in a dose‐dependent manner after challenge with P. damselae. These results suggest that incorporation of water‐soluble polysaccharides from green algae U. rigida at 1.5 g/kg doses improves growth and antioxidant activity and enhances the immune responses in shrimp L. vannamei.     

The Turkish Mezzes Formulated with Protein-Rich Green Sea Vegetable (Chlorophyta), Ulva rigida,Cultured in Onshore Tank System

Eating macroalgae (seaweeds) is considered an unusual activity in Turkey, although macroalgae have been known and prized for their nutritional purposes for many years in the Orient. The present study examines the addition of macroalgae to Turkish daily diets. Most Turkish meals begin with mezze, which is literally “a pleasant taste” and is probably derived from the Arabic word mezaq, which means “the taste, the savor of a thing.” The green macroalga Ulva rigida Agardh 1824 (Chlorophyta) was used to develop alternative protein-rich Turkish mezzes, using otherwise traditional recipes.

U. rigida was reared in tanks. The yield of U. rigida in an onshore tank system demonstrated the potential of U. rigida to produce marine biomass. The U. rigidas were used in macroalga-based mezzes. The macroalga substituted grape leaves, spinach, lamb’s lettuce, salicornia, or lettuce and resulted in higher protein content than those vegetables.

The prepared Ulva mezzes were tested in regard to taste, smell, color, texture, and general appearance and scored “pretty good” and “perfect.” The results suggest that Ulva can be produced and utilized for protein rich mezzes in Turkey.     

浒苔与球等鞭金藻相互抑制的实验验证

研究了实验室条件下漂浮绿潮海藻浒苔(Ulva prolifera)与微藻球等鞭金藻(Isochrysis galbana)之间的相互抑制作用,并对作用机制进行了初步探讨。结果表明,在浒苔和球等鞭金藻初接种量分别为1 gFW/L和1×104 cells/mL的共培养系统中,实验初始阶段(前3 d)NO3-、PO43-浓度显著高于浒苔和球等鞭金藻各单培养组,说明共培养系统中浒苔和球等鞭金藻彼此之间产生了显著抑制作用,其中浒苔对球等鞭金藻抑制率为96.62%,球等鞭金藻对浒苔的抑制率为19.67%,从而导致对NO3-、PO43-吸收速率的降低;从第4天到实验结束,共培养体系中NO3-、PO43-浓度逐渐升高,镜检也显示浒苔和球等鞭金藻细胞发生了断裂、肿胀和死亡现象,而单培养组中NO3-、PO43-浓度持续下降,说明共培养系统中由于浒苔和球等鞭金藻的死亡而向培养液中释放了营养盐。本研究表明在营养盐浓度和浒苔生物量相对较低的情况下,浒苔和球等鞭金藻彼此之间存在化感作用。     

烤石莼在几种贮藏条件下的品质变化研究

研究了烤石莼（Ulva pertusa）在几种贮藏条件下的品质变化的特点．从总酸、游离氨基酸、叶绿素等品质指标的变化情况来比较烤石莼几种贮藏条件的优劣．研究结果表明,烤石莼在酶失活后仍然存在明显的品质下降的现象,隔氧、低含水量和低温贮藏是减缓烤石莼贮藏中品质下降速度的重要条件．     

高度支化碳水化合物植物糖原的研究进展

植物糖原是植物su1突变体内存在的一种可溶性的α-D-葡聚糖。由于这些突变体缺乏淀粉脱支酶,导致其在植物胚乳内形成了高度支化的植物糖原纳米颗粒,取代了普通淀粉颗粒的合成。植物糖原是比支链淀粉分支更多、更短,结构更加紧密的球形颗粒。高度支化结构赋予植物糖原相对于淀粉和其他多糖更特殊的性质,可应用于某些独特的领域。通过与支链淀粉对比,对植物糖原的生物合成机理、结构及理化性质等方面的研究进行了全面综述,介绍了植物糖原在应用研究方面的最新进展。     

The relationships between odd‐ and branched‐chain fatty acids to ruminal fermentation parameters and bacterial populations with different dietary ratios of forage and concentrate

The objectives of this study were to investigate the effect of different dietary ratios of forage and concentrate (F:C) on ruminal odd‐ and branched‐chain fatty acids (OBCFAs) contents and to evaluate the relationships between OBCFA and ruminal fermentation parameters as well as bacterial populations tested by real‐time PCR technique. The experimental design was a 3 × 3 Latin square. Three rumen‐fistulated dry Holstein cows were fed three rations with different dietary F:C ratios (F:C; 30:70, 50:50 and 70:30). The rumen samples were collected every two hours (0600, 0800, 1000, 1200, 1400, 1600, 1800, 2000, 2200, 2400, 0200 and 0400 h) over three consecutive days in each sampling period. The results showed that rumen OBCFA profiles are significantly (p < 0.05) affected by the dietary F:C ratios. The concentrations of C11:0, C13:0, iso‐C15:0, iso‐C16:0, iso‐C17:0 and C17:0 were higher in the cows fed dietary F:C ratio of 70:30 than those fed with other two rations. However, the concentrations of anteiso‐C15:0, C15:0 and total OBCFA were on the lowest level in the high forage diet. Correlation and regression analysis showed that ruminal OBCFAs had strong relationships with ruminal fermentation parameters and bacterial populations. In particular, the iso‐fatty acids had potential power to predict butyrate and isoacids metabolized in the rumen, whereas the fatty acids with 17 carbon atoms correlated with ruminal NH₃‐N content. The OBCFA contents have different relationships with fibrolytic and starch bacteria in the rumen. C17:0 and its isomers might be used to predict populations of fibrolytic bacteria.     

孔石莼多糖抗氧化作用的初步研究

研究了孔石莼的多糖提取物对O2^-、OH·的清除作用、抑制脂质过氧化作用、对油脂的抗氧化作用,结果表明,孔石莼多糖提取物对O2^-、OH·具有直接清除作用,对亚油酸脂质过氧化反应有抑制作用,对油脂具有抗氧化作用,并且随着孔石莼多糖浓度的增加,其清除、抑制作用也增强,呈现明显的量效关系。结论：孔石莼多糖有一定的抗氧化活性,其添加浓度与抗氧化活性呈正相关。