In vitro antioxidant activity of callus culture of carrot （Daucus carom）

Carrot （Daucus carom） is a valuable source of health promoting ingredients such as anthocyanin, carotenes, phenolic compounds etc. These substances are important to man as a source of pharmaceuticals, fragrance, agrochemicals as well as food additives and used for prevention of many chronic diseases. Since these activities may be correlated with the presence of antioxidant compounds, extract of carrot and carrot callus were evaluated for their anthocyanin, flavonoids and total phenolic content as well as total antioxidant activity. Anthocyanin content was measured by spectrophotometric method. Total phenols and flavonoids were analyzed according to the Folin-Ciocalteu method and total antioxidant activity was assessed by ferric reducing/antioxidant power （FRAP） assay. Anthocyanin, flavonoids and total phenolic content were estimated to be 9.36 mg%, 46.96 mg% and 57.01 mg% for callus and 6.82 mg%, 32.96 mg% and 42.69 mg% for carrot, respectively, on fresh weight basis. The total antioxidant activity for the callus and carrot was found to be 51.13 mg, 118.77 mg, 91.08 mg and 140.08 mg equivalent and 79.40 mg, 184.44 mg, 141.43 mg and 217.52 mg equivalent to gallic acid, vitamin C, butylated hydroxyanisole （BHA） and trolox, respectively, when expressed per 100 g on fresh weight basis. The antioxidant activity of fresh carrot was found to be higher compared to its callus.     

Demonstration of secondary infection by Pythium violae in epidemics of carrot cavity spot using root transplantation as a method of soil infestation

Cavity spot of carrot (CCS), one of the most important soilborne diseases of this crop worldwide, is characterized by small sunken elliptical lesions on the taproot caused by a complex of pathogens belonging to the genus Pythium , notably P. violae . In most soilborne diseases the soil is the source of inoculum for primary infections, with diseased plants then providing inoculum for secondary infections (both auto- and alloinfection). Using fragments of CCS lesions to infest soil, it was demonstrated that CCS lesions on carrot residues can cause primary infection of healthy roots. Using a novel soil infestation method, in which an artificially infected carrot root (the donor plant) was placed close to healthy roots (receptor plants) the formation of typical CCS lesions were induced more efficiently than the use of classical soil inoculum and showed that CCS can spread from root to root by alloinfection from transplanted diseased roots. The method also demonstrated the polycyclic nature of a CCS epidemic caused by P. violae in controlled conditions. Secondary infections caused symptoms and reduced root weight as early as two weeks after transplantation of the diseased carrot. This reproducible method may be used for delayed inoculation and for studying the effect of cropping factors and the efficacy of treatments against primary and secondary cavity spot infections.     

丛枝菌根真菌Glomus mosseae单寄主培养体系的建立

 By using transformed Ri T-DNA carrot roots as host, the monoxenic culture of Glomus mosseae was successfully established. Some morphological processes of germination, colonization and spore formation, as well as bi-directional movement of hyphal cytoplasm flow were observed in this system.     

胡萝卜抗HgCl_2变异细胞系的筛选

利用胡萝卜下胚轴愈伤组织 ,以HgCl2 为选择剂 ,通过多步正筛选法 ,获得了抗性变异细胞系 .抗性鉴定结果表明 ,在不同HgCl2 浓度的培养基上 ,抗性系的愈伤组织存活率和鲜质量增殖率均明显高过亲本系 ,抗性系的细胞膜透性也发生了变化 .对抗性系和亲本系愈伤组织进行再分化的结果表明 ,在连续 3～ 4代的分化培养之后 ,愈伤组织都能再生绿苗 .提出了该项研究在预防和治理重金属污染方面的重要意义 .     

AAS法间接测定植物果胶含量的研究

利用果胶在碱性条件下水解成果胶酸,再以ＣａＣｌ２生成果胶酸钙沉淀。利用原子吸收光谱法（ＡＡＳ法）测定果胶酸钙中Ｃａ的含量,乘以换算系数１２．０７２,从间接测定果胶含量,并与经典重量法比较,结果较理想。ＡＡＳ法与重量法测定结果比值为９４．４％～９６．０％,同时因ＡＡＳ法是以Ｃａ的含量换算其果胶含量,大而避免经典重量法因存在少量蛋白质、草酸,而产生的干扰（使结果偏高）,ＡＡＳ法检出限可达μｇ／ｇ级低含     

叶面施硒对不同蔬菜硒富集和产量的影响

以青花菜、胡萝卜和大蒜为试材,叶面喷施不同质量浓度的Na2SeO3,每种蔬菜均设5个Na2SeO3喷施水平,其质量浓度分别为0.1～100 mg/L,0.5～500 mg/L和0.5～1 000 mg/L,蔬菜收获后测定其中全硒、有机硒和无机硒的含量及蔬菜产量。结果表明,叶面施硒可以显著提高各蔬菜中全硒、有机硒和无机硒的含量,有机硒转化率随硒质量浓度的提高而增加;3种蔬菜均喷施质量浓度为100 mg/L Na2SeO3时,以青花菜有机硒富集最高,为对照的135.7倍;除在Na2SeO3质量浓度≤10 mg/L时大蒜产量和Na2SeO3质量浓度为0.1 mg/L时青花菜产量有所增加外,其余Na2SeO3质量浓度均与各蔬菜产量呈负相关。综合分析认为,既有利于有机硒富集又不致产量降低的Na2SeO3叶面喷施浓度以不超过0.5 mg/L为宜。     

Interactions between wild and cultivated carrots (Daucus carota L.) in the Netherlands

Summary An investigation was made into the causes why bolters occur in carrot cultivation. In the first year of cultivation blooming plants are the result of a gene flow from wild to cultivated carrots. Hybridization may occur in areas where cultivated carrots are grown for seed production. Apart from bolters producing inedible roots such hybridization also causes a decline in quality of cultivated carrots in general. Small changes in morphological and phenological characteristics of the wild carrot are due to introgression from the cultivated carrot.     

真空微波和冻干组合降低胡萝卜片的干燥能耗

为减少脱水蔬菜冷冻干燥过程的能耗,以胡萝卜片为试材,采用真空微波和冷冻干燥组合的工艺,即先微波真空后冻干（组合Ⅰ）和先冻干后微波真空干燥（组合Ⅱ）。组合Ⅰ的优化参数为：真空微波阶段微波功率密度1.6w/g,脱去40个百分点的湿基水,冻干阶段升华干燥4 h,解析干燥3 h;组合Ⅱ的优化参数为：冻干阶段升华干燥7 h;真空微波干燥功率密度选1.0w/g以下,采用温度控制模式。所干燥胡萝卜片的β-胡萝卜素保留率和复水率等与纯冻干产品接近,体积保留率比纯冻干稍小,但仍能保持平直的外形;两种组合干燥工艺比纯冻干分别节能47.0%和54.2%,且干燥时间可缩短一半。     

春小麦、胡萝卜复种栽培技术研究

春小麦下茬复种胡萝卜栽培模式可提高单位面积土地利用率,促进农民增产增收。从品种选择、栽培过程、田间管理和收获几方面介绍春小麦、胡萝卜复种栽培技术的操作要点,以期为该栽培模式的大面积推广应用提供技术支持。