白萝卜振动远红外干燥工艺参数优化

为解决白萝卜干燥加工中存在营养成分损失大、设备能耗大和干制品品质差等问题,利用自行设计的往复振动式远红外干燥机,采用单因素和二次通用旋转组合的试验设计方法,探讨振动频率、加热温度、物料厚度对白萝卜脱水速率、复水率、VC含量和单位能耗的影响及因子间交互作用对指标的影响,建立了各指标与试验因素间的回归模型。采用加权综合评分法和线性功效系数法,将多目标综合优化,确定了干燥工艺的最优参数,即干燥温度68℃,振动频率0.7 Hz,物料厚度7 mm。该工艺条件下白萝卜脱水速率为63.26%/h,复水比为3.94,VC含量为1.98 mg/g,单位能耗为6.55 k J/kg。对在此工艺条件下干燥的白萝卜干制品进行环境扫描电镜(ESEM)分析,结果显示,细胞组织保存比较完整,能够较真实地反映样品的组织结构原貌。优化的工艺条件可有效提高干燥效率,同时降低白萝卜干制品中营养成分的损失,为白萝卜干振动远红外干燥技术在实际生产中的应用提供参考。     

Biofumigant Biomass,Nutrient Content,and Glucosinolate Response to Phosphorus

Information on biofumigant-green manure vegetative biomass, nutrient, and glucosinolate content sensitivity to phosphorus (P) is lacking for species used in potato and sugarbeet production. Therefore, available P effects on field-grown condiment yellow mustard (Sinapis alba, cv. IdaGold) and oilseed radish (Raphanus sativa, cv. Colonel) were evaluated (2001–03). Low soil P was generally more limiting to radish foliage P concentrations or uptake than to the mustard, suggesting inherent differences in their ability to access and accumulate P. While radish P and S concentrations increased with higher P, concentrations in mustard were either unaffected or reduced. Foliage P concentrations were more closely related to biomass of radish (r² = 0.46) than mustard (r² = 0.11). Mustard exceeded radish in biomass and S accumulation. Phosphorus effects on glucosinolates producing ionic or isothiocyanates were relatively insignificant. These biofumigants differ appreciably in their ability to access and accumulate P, but P effects on nutrient content or glucosinolates were minor.     

不同播期对萝卜杂交种种子质量和产量的影响

为了在云南开发萝卜杂交种子生产基地,以雄不育系和自交不亲和系为萝卜亲本的试材,进行不同播期的生产试验,研究萝卜各处理间的生长期、种子产量和质量等方面的差异。结果表明：播期与生长量呈正比,不同播期对开花期没有明显的影响,但对萝卜种子的产量和质量有显著影响,10月15日播种生产出的萝卜种子的产量和质量最好。     

共消化污泥施用对贫瘠土壤性质和蔬菜品质的影响

将市政污泥、餐厨垃圾和果蔬垃圾的共消化污泥进行农业利用,通过分析土壤和蔬菜中营养元素和重金属含量,研究共消化污泥对土壤营养元素变化、蔬菜养分吸收、土壤重金属累积、蔬菜重金属积累的影响。结果表明,共消化污泥施用显著提高了土壤有机质、总氮、总磷含量,且提高幅度与共消化污泥的施用量呈线性关系,同时促进了蔬菜对氮、磷的吸收和利用,但土壤总钾含量和蔬菜对钾的吸收受共消化污泥施用影响较小。共消化污泥施用后,土壤中Zn、Cu和Cd含量增加,尤其是Cd含量增加较明显,并且在蔬菜中累积,但土壤重金属含量均低于土壤环境质量标准二级标准规定的限值,蔬菜可食部分中Cu、Zn、Cr和Cd含量均低于食品中污染物限量规定的限值。因此,在共消化污泥农业利用过程中,仍需重点关注重金属含量的变化和累积。     

Are road verges corridors for weed invasion? Insights from the fine‐scale spatial genetic structure of Raphanus raphanistrum

Raphanus raphanistrum (Brassicaceae) is considered amongst the world's worst agricultural weeds. We address critical issues in its management by studying the pathway of colonisation at local scales. For this, we assessed the small‐scale spatial genetic structure of 231 samples collected from three different sites across the Cape Floristic Region, South Africa, using 11 nuclear microsatellite markers. Although natural pollen and seed dispersal were expected to be restricted, we found no significant relationship between genetic and geographical distance within sites. Instead, our results suggest that R. raphanistrum had colonised new habitats via jump dispersal, rather than through natural diffusive dispersal at local scales. We did not find evidence for road verges as dispersal corridors, as evidenced by a lack of isolation‐by‐distance at local scales. Instead, the absence of spatial genetic structure suggests that R. raphanistrum had rapidly spread throughout its current range, possibly facilitated by human‐mediated actions. Management plans addressing containment or suppression of the weedy species R. raphanistrum (and possibly other weedy species) should take the high degree of connectivity between distant geographical localities into account.     

The present status of biological control of Xanthium (Compositae)

Abstract

The economic threshold level of the mustard aphid, Lipaphis erysimi (Kaltenbach) was determined on the radish seed crop, var Punjab Sufed. Spraying oxydemeton methyl at 300 g a.i./ ha, was monitored at arbitrary set aphid levels from 25 to 150 aphids/plant. The maximum cost benefit ratio (1: 13.1) was achieved at an aphid level of 50 per plant, requiring three sprays. Spraying in the middle of February was the most crucial, as delay of 7 days from this stage resulted in significant decreases in yield in the fixed spray schedule and at the 75‐aphid level.     

萝卜收获机振动松土铲参数的优化

为了确定萝卜收获机振动松土铲的关键参数,利用偏心连杆式振动装置进行松土试验,以机器行走速度、松土铲激振频率和振幅、铲入土角、铲刃倾角作为试验影响因素,土壤孔隙度为响应指标,并采用二次正交旋转回归试验设计,建立了响应指标与各影响因素之间回归数学模型。通过Design-Expert 6.0软件对试验参数进行优化,确定机器行走速度0.64?m/s、激振器频率2?Hz、振幅14.38?mm、铲入土角25.72°、铲刃倾角39.68°为最优参数组合,此时土壤孔隙度为50%～60%,该研究为研究和设计萝卜收获机提供依据。     

同工酶酶谱鉴定萝卜品种的初步研究

采用聚丙烯酰胺凝胶电泳对４个萝卜品种的酯酶（ＥＳＴ）、酸性磷酸酯酶（ＡＣＰ）同工酶进行了初步研究。结果表明：ＥＳＴ谱带只能区分开所的３个品种,ＡＣＰ谱带能将所研究的４个品种区分开。     

从萝卜下胚轴再生完整植株

以萝卜无菌幼苗下胚轴为外植体,研究了不同基因型萝卜品种,不同浓度的NAA、BA、蔗糖、AgNO3对植株再生的影响。基本培养基(BM)为MS无机盐 Gly2mgL 肌醇2mgL 烟酸05mgL VB101mgL 琼脂68gL。试验证明萝卜离体再生主要受基因型和BA、NAA浓度影响。从自交系小红头下胚轴愈伤组织产生的绿色子叶状团块在提高BA、NAA浓度的培养基中大量增殖;降低激素浓度,尤其是BA浓度后,这些子叶状簇生团块发育成大量无根苗,叶片正常。无根苗在添加不同种类的生长素的培养基中生根,并成功地移植入田间。本实验也对AgNO3的作用进行了研究和讨论。     

大量元素水溶肥对萝卜的应用效果

为了解大量元素水溶性肥的田间应用效果和经济效益,以萝卜为试验材料,进行了相关肥效试验。结果表明:大量元素水溶性肥对萝卜的栽培表现较施用尿素好,二者产投比分别为8.96:1和1.96:1,叶面喷施大量元素水溶性肥的经济效益显著,可在萝卜上推广使用。