The role of Chinese cabbage as a trap crop for flea beetles (Coleoptera: Chrysomelidae) in production of white cabbage

During the years 2002 and 2003, preference of flea beetles, Phyllotreta spp., to white and Chinese cabbage, grown in monoculture and in mixed crop, was tested. The aim of the research was to determine if Chinese cabbage is an appropriate trap crop for this pest in the production of white cabbage, an important vegetable in Europe and in North America. The number of beetles on Chinese cabbage in monoculture and in mixed crop did not differ significantly. In both treatments the number of adults of flea beetles on Chinese cabbage and the percentage of damaged leaf area they caused, were significantly higher than that on white cabbage. Statistically significant and positive correlation was established between leaf damage and number of flea beetles. It was stronger in 2003, which was less favorable for the crop with regards to the weather conditions (drought and high air temperatures). No significant differences were found in the number of adults and in most evaluations also in the damage assessments on white cabbage when grown in monoculture and in mixed culture. Therefore, we concluded that Chinese cabbage grown in mixed crop with white cabbage is not a suitable control measure for reducing the damage caused by flea beetles.     

白菜与甜菜间作的生长与资源利用效果

通过设置不同的白菜与甜菜间作密度,监测了复合群体的叶面积指数、漏光率以及各作物产量,研究复合群体的生长动态,光资源分布以及产量产值效应。结果表明:在间作群体中,白菜依其速生优势而表现偏利效应,间作甜菜前期受白菜遮蔽胁迫,其生育期叶面积指数始终低于单作;白菜收获后甜菜通过叶层自动空间散布提高光能截获率,促进了后期光合补偿性生产;白菜2行∶甜菜1行间作(BT1)处理,白菜的实际产量比"预期"产量极显著增高26.7个百分点,甜菜比"预期"产量增高34.0个百分点;白菜2行∶甜菜2行间作(BT2)处理,白菜、甜菜的实际产量比"预期"产量分别极显著增高59.3、53.0个百分点;BT1、BT2间作群体较白菜单作经济效益分别提高10.2、23.7个百分点,较甜菜单作经济效益分别提高91.5、115.1个百分点。分析表明,间作种植显著提高了地气资源的利用效率,BT1间作LER为1.29;BT2间作LER高达1.56。     

不同复合肥处理在小白菜生长条件下的淋失研究

应用完全随机设计,通过土柱培养试验与盆栽培养试验相结合,研究海德鲁15-15-15、撒可富15-15-15、云河15-15-15这3种复合肥在不同栽培条件下的养分淋溶损失及其对小白菜产量的影响。结果表明:无作物栽培条件下,海德鲁复合肥的磷、钾养分淋溶损失较大;有作物栽培条件下,云河复合肥的氮、钾养分淋溶损失量大;海德鲁复合肥、撒可富复合肥适合在小白菜生产上施用。     

Effects of field and landscape variables on crop colonization and biological control of the cabbage root fly Delia radicum

Agriculture intensification has deeply modified agroecosystems from field to landscape scales. To achieve successful pest control using natural enemies, understanding species interactions over all scales remains a challenge. Using the cabbage root fly as a model, we studied whether field and landscape characteristics influenced colonization and infestation of broccoli fields by the pest and its control by natural enemies. We also determined whether species of different trophic level or host specialization would respond to environmental characteristics at the same spatial extent. During a multiple-species and multiple-spatial extent study in northwestern France, we recorded pest colonization and infestation in 68 fields, collected associated natural enemies and assessed crop damages. In each field, we considered management practices and characterized the surrounding landscape in 50–500 m-wide buffers. Our main findings are that Delia radicum and its main natural enemies respond to both field and landscape characteristics. Semi-natural areas supported both crop colonization by pests and natural enemy action. The pest and its enemies differed in their responses to field or landscape variables. Landscape elements such as field banks favored the movement of the pest while impeding the movement of some natural enemies. Pest pressure did not increase with the neighboring density of Brassica crops. The presence of natural enemies did not reduce crop damage but reduced pest emerging rates. Finally, specialist parasitoids responded to the landscape at larger spatial extents than generalists. These results outline the complexity of improving pest control through landscape management.     

不同作物根系分泌物对莴苣化感作用的研究

通过组织培养的方式,研究了不同作物根系分泌物对莴苣的化感作用。结果表明：不同作物根系分泌的化感物质均能明显抑制莴苣幼苗的生长,其根系生长也明显受到抑制。通过隶属函数值可得出,不同作物对莴苣化感作用的大小顺序为黄瓜〉西瓜〉辣椒〉番茄〉白菜。     

Identification and distribution of S haplotypes in Brassica vegetables from China

The amplification efficiency and identification diversity with gene-specific primers derived from S locus glycoprotein gene (SLG) and S locus receptor kinase gene (SRK) were compared, and the geographical distribution for S haplotypes was investigated by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) in 72 genotypes of 5 Brassica vegetables from China. The amplification efficiency and identification diversity with class I SRK primers were generally higher than that with class I SLG in most crops tested. Class I alleles were found in total 66 genotypes and they were classified into 16, 10, 7 and 10 groups for Chinese cabbage, purple flowering stalk, cauliflower and cabbage respectively. The number of amplification accessions and identification diversity using the primers of class II SLG and SRK were quite similar. Class II alleles were detected in 55 genotypes and further grouped into one type in mustard and three in other crops. The nucleotide sequences showed high similarity between identical S haplotypes determined by reciprocal pollination and PCR-RFLP tests. It demonstrated that the PCR-RFLP analysis was feasible for identification of S alleles, and SRK should be considered as a better marker for the identification of S haplotypes than SLG. The types of S haplotypes are highly diverse in Brassica vegetables from China. Nevertheless, they were geographically limited in some Brassica vegetables, so the exchange of germplasm resources should be enhanced for breeding.     

土壤调理剂与酵素施用对土壤理化性质及甘蓝产量的影响

以春甘蓝主栽品种"中甘56"为试材,研究土壤调理剂和酵素对土壤理化性质及甘蓝产量的影响。结果表明:施用土壤调理剂和酵素可促进甘蓝生长,缩短品种生育期,使其提早成熟,并显著提高净菜产量。与栽培前土壤相比,所有处理土壤速效磷含量均大幅度下降;与对照相比,施用土壤调理剂的土壤有机质含量显著下降。栽培后茬作物时,要增施有机肥和磷肥。综合分析,土壤调理剂与酵素可进行大面积的推广应用。     

桔红心大白菜及其近等基因系生长发育过程中胡萝卜素含量变化规律初探

以桔红心大白菜及其白心大白菜近等基因系、1组近等基因系和桔红心自交系杂交的杂种一代4份材料为试材,采用HPLC法测定不同生育期及其内外叶的胡萝卜素含量。结果表明:具有红色基因r的材料,苗期胡萝卜素含量高于其它生育期,在莲座期和结球期胡萝卜素含量均为外叶高于内叶;具有Rr的材料,表现型虽为白心,但胡萝卜素含量明显高于白心纯合体的材料。     

2种钙肥对菜心生长及品质的影响

采用73.0 mg/L的果蔬钙肥及1.25 g/L、2.5 g/L和3.75 g/L 3种浓度的氯化钙溶液对菜心进行叶面喷施,研究不同钙肥处理对菜心生长及品质的影响。试验结果表明,不同的钙肥处理均可促进菜心的生长发育,提高叶绿素含量、增加菜心的产量、改善菜心品质,但存在差异,73.0 mg/L的果蔬钙肥处理效果最好,低浓度氯化钙处理对菜心产量和品质影响很小,中浓度氯化钙处理影响比较大,高浓度氯化钙处理比中浓度处理效果差。在不同的生长发育期,作用效应有所不同,在菜心生长的初期各钙肥处理影响不大,生长中后期影响比较大。     

我国设施园艺作物生长模型研究进展

作物生长模型是温室生产智能化操作与管理软件的核心部分,对温室设施中作物生长环境参数的调控和发挥设施农业优质高效的生产功能具有重要作用.对目前国内设施园艺作物生长模型和专家系统的研究现状、生产应用进行了综述,认为近年来国内在温室栽培的黄瓜、番茄、甜瓜等作物的生长模型和应用上建立了一系列综合、完整的体系,在建模技术及算法上均有创新.但在模型的适应性、准确性、可靠性等方面还比较薄弱,有待进一步加强,从而促进我国设施园艺作物生长模型的进一步研究和提高实用化程度.     

麦后栽培二茬大白菜效应分析

对麦后栽培二茬大白菜的模式进行产量、经济效益及互作效应的研究。结果表明:该模式比单栽白菜模式土地利用率提高10%;采用垄作栽培的大白菜平均产量要比平作高16.13%;大白菜病情指数明显低于平作栽培;小麦平均生育期垄作比平作提前2～3d;垄作栽培蓄水保墒作用明显。     

Regulated deficit irrigation in green bean and watermelon greenhouse crops

Mediterranean greenhouse growers of watermelon and green bean crops tend to reduce slightly the soil water availability during the flowering phase to enhance the fruit number and yield, but without measuring the soil or the plant water status. This deficit irrigation strategy (RDI) was studied on two representative growth cycles of green bean and one of watermelon. In each case, a well-watered crop acted as control.In the three well-watered vegetable crops, soil water matric potential (SMP) values were between −20 and −30 kPa throughout most of the respective growth cycles. These values avoid water deficits in Mediterranean greenhouse vegetable crops. The watermelon under RDI presented similar SMP to the well-watered crop, except during the flowering period when it reached values of −50 to −60 kPa, which are similar to, or slightly lower than, those recommended to prevent water deficits for cucurbitaceae crops. The autumn–winter and spring cycles of green bean under RDI presented progressively lower SMP values from the vegetative phase to the first fruit setting than the well-watered crops, reaching minimum SMP values of around −55 kPa for the autumn–winter cycle and of −75 kPa for the spring one. These minimum SMP values are similar for the autumn–winter cycle and lower for the spring cycle than those recommended to avoid water deficits in green bean crops grown in medium-fine textured soils. Overall, mild water deficits during flowering of watermelon and green bean crops grown in Mediterranean greenhouses did not improve the final fruit number or yield. In the two spring cycles (watermelon and green bean) the RDI strategy reduced the aboveground biomass and yield, whereas in the autumn–winter green bean cycle the RDI strategy reduced the vegetative biomass but did not affect yield. SMP threshold values can, however, be used by growers as a tool for controlling the equilibrium between the vegetative and reproductive growth of greenhouse soil-grown crops.     

Some Experiments to Investigate the Control of Apple Sawfly,Hoplocampa Testudinea (Klug), by Concentrate Sprays

Eight-year-old trees of Laxton’s Superb apple on M.II rootstock growing on loamy fine sand of low moisture retention were used to study growth and crop responses to different soil moisture conditions from 1953 to i960 inclusive. Water was applied when soil moisture tensiometers set at 1 ft. depth indicated tensions of : A, 10 cm. Hg ; B, 20 cm. Hg ; C, 50 cm. Hg. Treatment D was unwatered.

Water was applied to an area 12 ft. in diameter around each tree, which was about one-third of the ground area available to each tree. The average amount of water required by each treatment during a season was equivalent to : A, 4-1 ; B, 3-5 ; C, 2-1 inches over its whole area.

Comparison of soil moisture deficits in the unwatered plots in the very dry season of 1959 with amounts of water applied to the other trees suggested that the rate of water loss throughout the experiment was not seriously affected by the treatments applied.

The water treatments stimulated trunk and shoot growth ; growth differences between differently treated trees could be adequately explained in terms of soil moisture tension and root-occupied soil volume. Evidence was found of serious leaching under the wettest treatment, and this may have caused a lower growth and crop response to treatment A than to B in the later years of the trial.

Crop increases were directly related to growth increases. Despite the marked effects of water treatments on shoot numbers and on crop increase the growth and crop relationship was virtually unchanged.

Treatments A, B and C increased total crops by 40%, 46% and 25% respectively, and marketable crops by 44%, 55% and 42% respectively. There was no marked effect of treatment on fruit size, though the increased proportion of fruit of a commercial size from the watered trees was of importance. Treatment B provided the largest total and marketable crops, but treatment C provided the greatest increase in marketable crop for each inch of water applied.     

Antioxidant potency of white (Brassica oleracea L. var. capitata) and Chinese (Brassica rapa L. var. pekinensis (Lour.)) cabbage: The influence of development stage,cultivar choice and seed selection

The accumulation of total phenols (TP, Folin-Ciocalteu method) and total flavonoids (TF, colorimetric assay with AlCl₃) and the evolution of antioxidant capacity (FRAP assay, DPPH and ABTS radical scavenging assays) have been monitored in juices of Croatian white cabbage (Brassica oleracea var. capitata) cultivars Vara?dinski and Ogulinski, as well as Chinese cabbage (Brassica rapa var. pekinensis), at various developmental stages. Measurements were performed every four weeks, starting from planting to full maturity, throughout the course of eight months. In the first 8–12 weeks, the TP and TF contents as well as antioxidant capacity increased significantly in all analyzed juice samples and in most even doubled. This rapid increase was followed by a gradual decrease in values derived from all assays, over the course of 12–30 weeks, to the final values which were in all cases lower than the values measured at week 4. The results also point to significant variability in TP and TF contents and antioxidant capacity at the fully mature stage between white and Chinese cabbage juices and between juices extracted from cultivars Ogulinski and Vara?dinski.     

无花果不同器官浸提液对几种蔬菜和豆类种子发芽和生长的影响

通过浸种发芽率测定和生长量比较，研究了无花果对几种蔬菜和豆科作物的他感效应。结果表明，无花果不同器官浸提液浸种处理对供试的几种蔬菜和豆科作物的种子发芽和生长均有程度不同的抑制作用；主要表现为叶浸提液浸种、高浓度浸提液浸种的抑制作用大；对西瓜、杨花萝卜、赤豆和绿豆的抑制作用较大。此外，加时浸提、加热浸提和乙醇浸提均能增强浸提液对小白菜种子发芽的抑制作用。     

NaCl胁迫对不同生育时期大白菜生长及生理的影响

研究了NaCl胁迫对不同生育时期大白菜的影响。研究结果表明,大白菜种子期和幼苗期对NaCl胁迫的反应较为敏感,100 mmol/L的NaCl胁迫对大白菜种子发芽势、发芽率无显著影响,显著降低大白菜种子的发芽指数,对幼苗期大白菜地上部鲜干质量无显著影响,但显著降低根鲜干质量;150 mmol/L NaCl胁迫下大白菜幼苗根系活力显著下降,丙二醛含量显著升高;成株期大白菜对浓度150 mmol/L以下的NaCl胁迫反应不敏感。     

基于SPAD值的大白菜氮素营养诊断和推荐施肥模型研究

以大白菜卵圆型品种"锦抗1号"和直筒型品种"乡情80"为试材,在6个氮肥水平下,研究了叶片SPAD值与氮素营养诊断指标、施氮量的关系以及施氮量对产量的影响。结果表明:在大白菜莲座期和结球期,2个品种的叶片SPAD值与氮素营养诊断指标及施氮量有很好的相关性;2个生育期"锦抗1号"的临界SPAD值分别为40.45、42.45,"乡情80"的临界SPAD值分别为38.57、40.36;建立了基于叶片SPAD值的大白菜氮肥推荐施肥模型。综上所述,大白菜叶片SPAD值可以作为氮素营养诊断指标,并能推荐氮肥的施用。     

根癌农杆菌介导的白菜类作物转化体系研究进展

白菜类作物是我国乃至世界性的大众蔬菜,利用农杆菌介导技术将目的基因转入蔬菜中,从而选育具有特殊性状的新品种。文章综述了根癌农杆菌介导的白菜类作物高频再生转化体系构建的影响因素,简要介绍了转化植株的分子检测及遗传行为,在此基础上分析了目前遗传转化技术在白菜类作物改良上存在的问题及广阔的应用前景。     

枸杞园间作绿肥作物栽培技术研究

分别以毛苕子和箭筈豌豆2种绿肥作物的播量和绿肥专用肥用量为因素,通过采用L8(27)正交实验方案设8个处理进行绿肥与枸杞间作的可行性研究。结果表明:除不同绿肥作物种类在株高上具有明显差异外,同一绿肥作物及其不同播量、以及施用绿肥专用肥与否对绿肥作物鲜草产量、株高、根瘤菌生长情况等指标均无显著性影响。建议生产上根据具体情况选择其中之一进行栽培;播量以箭筈豌豆8 kg/667m2、毛苕子5 kg/667 m2为宜;栽培中无需施用专用肥。