红心萝卜力学特性试验研究

利用万能试验机对红心萝卜试样进行压缩、剪切及拉伸试验,研究了加载速度、位置对红心萝卜的弹性模量及抗压强度的影响,探索了红心萝卜力学结构,得到了红心萝卜皮的弹性模量和最大抗压强度,确定了红心萝卜的剪切特性。试验表明:加速度对弹性模量及最大抗压强度的影响显著,随着加载速度的增大,红心萝卜的弹性模量逐渐增加,而最大抗压强度先增大、后减小;当加载速度为10mm/mim时,抗压强度最大,红心萝卜头部弹性模量及最大抗压强度最大,中部次之,尾部最小;红心萝卜纵向试样的弹性模量及最大抗压强度大于横向试样的数值,红心萝卜芯部弹性模量及最大抗压强度大于萝卜外部试样的数值,红心萝卜皮的弹性模量及最大抗压强度比萝卜内部的小;红心萝卜的平均剪切强度为0.058MPa,剪切力峰值与试样的横截面积呈线性相关。     

基于动网格的白萝卜热风干燥热质传递研究

针对果蔬干燥过程模拟时未能考虑收缩对几何模型及热质传递的影响而导致求解精度较差的问题,采用动网格技术优化果蔬热风干燥过程中热质传递的数学模型。选择结构均匀、干燥过程收缩率较明显的白萝卜作为代表性物料,试验结果表明：样品长度对收缩特性具有显著影响,当样品长径比为10时,干燥收缩的各向同性率最优,此时Hatamipour模型是最适合描述白萝卜热风干燥收缩规律的模型。基于动网格技术将收缩方程与热质传递方程耦合后探究白萝卜热风干燥的热质传递规律,结果表明：考虑收缩后由于迁移路径变短,物料内部水分脱除速率加快且表层水分梯度降低;与未考虑收缩情况相比,干燥前中期水分蒸发量较大而后期含水率较小,使得物料温度先迅速升高至30℃后缓慢提升至60℃的平衡温度,该趋势更接近试验值;考虑收缩方程后,物料内、外部含水率和温度模拟结果的偏差分别从17%~8%、12~2℃降低至14%~3%、3~2℃。结果表明：基于动网格的数值模拟具有更高的计算精度,为分析热风干燥过程中的热质传递规律提供了可靠的模型。     

春瓠子-夏大白菜秧-秋黄瓜-冬萝卜高效栽培模式

从2008年开始武汉市蔬菜技术服务总站在武汉市东西湖区成功示范了保护地春瓠子-夏大白菜秧-秋黄瓜-冬萝卜高效栽培模式.从周年茬口安排、品种选择及用种量、整地施肥、播种育苗、定植密度、田间管理、病虫害防治、及时采收等方面对该模式进行了较为全面深入系统的实践和探索.     

萝卜采后生理与保鲜技术研究进展

萝卜在贮藏过程中,常会出现生根发芽、水分散失、糠心、腐烂等现象,从而对萝卜的食用和加工产生严重的不良影响.因此,研究萝卜贮藏中的生理变化与保鲜技术对萝卜产业发展具有重要意义.本文针对萝卜采后保鲜过程中所面临的问题,对萝卜采后生理与保鲜技术研究的最新进展进行了综述,并提出萝卜采后研究发展方向.     

益微制剂在三种蔬菜上的应用效果试验

采用益微制剂分别在白菜、小萝卜和番茄三种蔬菜作物上进行处理,观测其对三种作物的植株长势、品质和重量的影响。结果表明:使用益微制剂后白菜、小萝卜和番茄的植株生长势、品质和产量明显比未喷洒的要好。从而得出,益微制剂提高了蔬菜的产量和品质。     

Clubroot resistance introgression in interspecific hybrids between Raphanus sativus and Brassica napus

Clubroot is a prevailing soil-borne disease affecting rapeseed production worldwide.However,few clubroot resistant rapeseed accessions were available for breeding.Identification and introgression of new clubroot resistant genes from closely related species by distant hybridization is an effective strategy.In the present study,9 radish(Raphanus sativus L.,2n=18,RR)lines resistant to Plasmodiophora brassicae pathotype 4 were used as donors to transfer clubroot resistance into a susceptible rapeseed(Brassica napus L.,2n=38,AACC)line by distant hybridization combined with embryo rescue.Nine intergeneric crosses were made but only 1(411×93039)produced F1 plants both from embryo rescue and natural seed-setting.Authenticity of triploid F1 hybrids(2n=28,ACR)were verified by flower color,cytological observation and molecular marker analysis,and 2 genuine F1 hybrids were identified.After chromosome doubling,these synthetic allohexaploid plants(2n=56,AACCRR)became partially fertile(pollen viability rate=35%)and were backcrossed with rapeseed parent to generate a BC1 population(2n=47,AACCR).Totally 178 BC1 plants were obtained,of which the majority(96.1%)were resistant to clubroot.These backcrossing progenies could be used for the breeding of new rapeseed varieties resistant to clubroot.     

NaCl处理对萝卜芽苗菜生长和异硫氰酸盐含量的影响

通过不同浓度NaCl (0.00、0.25、0.50、0.75、1.00、2.00、3.00、4.00、5.00和10.00 mg/mL)处理,探讨盐胁迫对萝卜种子萌发、芽苗菜生长及其异硫氰酸盐含量的影响。结果表明,当NaCl浓度小于0.50 mg/mL时,萝卜种子可正常发芽;超过0.50 mg/mL,种子发芽则受到严重抑制。不同浓度NaCl处理对萝卜芽苗菜生长影响明显,下胚轴长度、根长和鲜重3个指标均表现为先升高后降低的趋势。当浓度为0.50 mg/mL时,下胚轴长度达到最大,而根长和鲜重在浓度为3.00 mg/mL时达到最大。随着NaCl浓度升高,萝卜芽苗菜中总异硫氰酸盐含量呈先升后降趋势,其含量在浓度0.25 mg/mL时达到最高,比对照增加了6.89%。综上,利用0.25 mg/mL NaCl处理萝卜种子效果最佳,既可促进萝卜芽苗菜生长,提高异硫氰酸盐含量,又不影响种子活力。     

海藻提取物缓解高温对樱桃萝卜胁迫效应的研究

选取樱桃萝卜(Raphanus sativus L.var.radculus pers)为研究对象,在盆栽试验条件下以清水处理为对照(CK),并以浓度为66.7 mg·L^-1的芸苔素内酯为阳性对照(BHG),通过添加不同浓度(100.0、200.0 mg·L^-1)的海藻提取物处理(SWE-1、SWE-2),探究了在高温胁迫(30℃)条件下海藻提取物对樱桃萝卜产量、果实品质、内源激素水平以及抗氧化酶系统的影响。结果表明,SWE-1、SWE-2均可有效缓解高温对樱桃萝卜生长造成的胁迫效应,以SWE-2处理效果最好。与CK处理相比,SWE-2处理的果实鲜重显著提高180.0%,可溶性蛋白含量显著提高35.2%;其叶片的SPAD值显著提高16.8%,硝酸还原酶活性显著提高57.7%,生长素含量显著提高145.4%,而脱落酸含量显著下降42.0%,丙二醛含量显著下降59.2%,谷胱甘肽还原酶活性提升15.7%,抗坏血酸过氧化物酶活性显著上升9.4%。与BHG处理相比,SWE-2处理的果实鲜重显著提高43.5%;可溶性蛋白含量显著提高49.6%,维生素C...     

Organic fertilizers derived from plant materials Part II: Turnover in field trials

Our aim was to investigate two different organic fertilizers derived from plant materials (OFDP) with respect to their nitrogen (N) and carbon (C) turnover in field trials planted with small radish (Raphanus sativus L. var. sativus) and white cabbage (Brassica oleracea L. convar. capitata var. alba) or fallow. The two fertilizers investigated were coarse seed meal of yellow lupin (Lupinus luteus L.) and coarse meal of castor cake (Ricinus communis L.). Under cool spring conditions, the soil turnover of yellow lupin–seed meal was slightly enhanced compared to castor‐cake meal. During the vegetation period of the vegetables, N added with both fertilizers was metabolized more or less completely by soil microorganisms. Due to similar efficiencies of the fertilizers tested, no significant difference could be found in the N uptake of plants. From this point of view, yellow lupin–seed meal, which can be produced by farmers themselves, has the potential to replace the widely used castor‐cake meal. Considerable amounts of N may remain in the field after fertilization with OFDPs either as mineral N or as easily mineralizable organic N. This N should be utilized immediately by a succeeding crop to avoid leaching losses.