The Identification and Exploitation of Resistance in Carrots and Wild Umbelliferae to the Carrot Fly, Psila rosae (F.)

Partial plant resistance to the carrot fly, Psila rosae, has been identified in several Nantes varieties of carrot, Daucus carota, which reduces larval damage to the roots and the number of pupae remaining in the soil after cropping by 50%. The resistance of the Nantes variety 'Sytan' was found to be consistent at 12 sites in 5 European countries over two seasons. The resistance has been shown to be based on antibiosis and correlated with concentrations of chlorogenic acid in the roots. The resistance complements cultural and chemical methods for controlling P. rosae. Thus, in field experiments over two seasons it was shown that carrots could be left in the ground for a longer period providing a greater sowing/harvesting interval with a resistant variety than a susceptible one because of the reduction in damage and the delayed development of insects on the resistant variety. In two seasons at two sites a partially-resistant variety required only one-third of the dose of insecticide to provide a marketable crop compared with a susceptible carrot variety. In a breeding programme involving the variety 'Sytan', male sterile lines, inbreds and selections with improved levels of resistance were developed. Much higher levels of resistance were identified in certain wild Daucus species and 15 years of crossing and selection produced lines with significantly higher levels of resistance than exists in the variety 'Sytan'. A range of resistant carrot material bred at Horticulture Research International has been released to seed companies for use in the production of improved carrot varieties. The partially-resistant variety 'Flyaway' was made available to amateur gardeners in 1993 and to commercial growers in 1995 as a result of this research.     

新型胡萝卜奶片加工工艺研究

对具有营养保健功能的胡萝卜奶片的加工工艺进行初步探讨。结果表明:采用奶粉∶胡萝卜精粉为8∶2、葡萄糖25%、异麦芽低聚糖15%的原料配比,经混合、造粒、干燥、压片等工序制成了一款新型胡萝卜奶片。     

胡萝卜汁与苹果汁复配凝固型酸奶的研制

为得到一种外观诱人、口味独特的具有市场开发价值的营养保健型酸奶,以胡萝卜汁、苹果汁、鲜牛奶为原料,以保加利亚乳杆菌和嗜热链球菌为发酵剂进行乳酸发酵,通过L9(34)正交试验,得出研制凝固型胡萝卜汁、苹果汁复配酸奶的最佳工艺参数:胡萝卜汁、苹果汁、白砂糖、发酵剂的质量分数分别为25%,8%,9%,6%;发酵温度(42±1)℃;发酵时间4 h.     

从长期继代培养的胡萝卜愈伤组织原生质体获得再生小植株

从继代3年以上的胡萝卜(Daucus carota var.sativa Dc.)非胚性愈伤组织酶解分离出大量成活的原生质体,在 DPD、V—KM 和 C81V 培养基中液体浅层培养,获得微愈伤组织后,在固体 N_6和 MS 培养基上分化培养,获得再生小植株。证明长期继代培养的胡萝卜愈伤组织仍具有再生植株的能力。     

西洋参与胡萝卜愈伤组织共培养基质的研究

采用试验优化设计和计算机分析技术,对西洋参(Panax quinquefolium)和胡萝卜(Daucus carota)2种植物愈伤组织共培养的培养基和培养条件进行了研究。结果表明:在培养基MS 2,4-D 1.67 mg/L IAA 0.98 mg/L ZT 0.47 mg/L(蔗糖30 g/L,琼脂8 g/L)上,西洋参和胡萝卜2种愈伤组织生长率分别达到0.271 g/(g.d)和0.137 g/(g.d)。适宜的培养条件为(24±1)℃,光照强度1 700 lx,12 h光暗交替。在此培养基和培养条件下,2种植物愈伤组织可以进行共培养。     

不同干燥方法对胡萝卜复水性及品质的影响

对用热风干燥、微波干燥及热风和微波组合干燥3种干燥方法获得的胡萝卜干制品进行了复水试验,分析了不同干燥方法及不同参数组合对胡萝卜干制品复水性和感官品质的影响。结果表明:利用不同的干燥方法所获得的胡萝卜干制品的复水性能和感官品质有明显差异,降低热风温度、缩短热风干燥时间及减小微波加热功率,均可提高干制品的复水性和质量;热风与微波组合干燥的热风温度、热风干燥后物料的含水率和微波功率分别为65℃、50%和170 W时,干制品具有理想的感官质量和复水性,其复水比为6.02。     

胡萝卜遗传转化体系的建立

以新黑田五寸胡萝卜下胚轴为外植体,研究对胡萝卜抗性植株的影响因素及目的基因的整合情况,建立了较为完善的转化体系。实验结果表明:以胡萝卜下胚轴为材料,用苗龄7d,共培养2d,浸染15min的体系,Kan抗性芽的分化频率可达52%。获得抗性愈伤培养基:B5+0.1mg/L2,4-D+0.2mg/LKT+75mg/LKan+500mg/LCef,抗性芽诱导培养基:B5+100mg/LKan+500mg/LCef;抗性植株生根培养基:B5+0.1mg/LIBA+75mg/LKan+300mg/L:Cef;对转基因植株进行了PCR分子学检测,初步证明外源基因已整合到胡萝卜基因组中。     

Inhibitory effect of chitosan on growth of the fungal phytopathogen,Sclerotinia sclerotiorum,and sclerotinia rot of carrot

The antifungal activity of chitosan on a common fungal phytopathogen, Sclerotinia sclerotiorum, and the control effect on sclerotinia rot of carrot were investigated. Mycelial growth and fungal biomass were strongly inhibited by chitosan. Using propidium iodide stain combined with fluorescent microscopy, the plasma membrane of chitosan-treated S. sclerotiorum mycelia was observed to be markedly damaged. Concomitantly, protein leakage and lipid peroxidation was also found to be significantly higher in chitosan-treated mycelia compared to the control. Chitosan provided an effective control of sclerotinia rot of carrot, with induction of activity of defense-related enzymes including polyphenoloxidase and peroxidase. These data suggest that the effects of chitosan on sclerotinia rot of carrot may be associated with the direct damage to the plasma membrane and lipid peroxidation of S. sclerotiorum, and the elicitation of defense response in carrot.     

胡萝卜肾形肾状线虫病的发生及药剂控制试验

从广东省番禺市胡萝卜根系及根际土分离到１种线虫,经鉴定为肾形肾状线虫,该线虫在胡萝卜的生长期内,以１０￣１１月份虫口密度最大,主要分布于０￣１５ｃｍ土壤层。该线虫危害胡萝卜,是国内胡萝卜上的１种新病害。药剂试验表明供试的几种杀线剂均对肾形肾状线虫有较好的控制作用,其中益舒宝复方Ｂ和Ｅ是值得生产上推广应用的杀线剂。     

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.