1-甲基环丙烯对红星苹果常温贮藏期间生理、品质和电子鼻特性的影响

为了探讨1-甲基环丙烯(1-MCP)对红星苹果贮藏品质、生理以及电子鼻特性的影响，以红星苹果为研究对象，测定1-MCP处理后常温贮藏(20±1)℃过程中果实呼吸速率、乙烯释放速率、内在品质及外观色泽和电子鼻响应情况。结果表明：随着贮藏时间延长，红星苹果采后呼吸速率、乙烯释放速率升高，分别于10,15 d达峰值后降低。同时，果实硬度下降、可滴定酸含量降低，SSC先升高后降低；果皮a^*值、b^*值、C^*值和ΔE^*值升高。1-MCP处理抑制红星苹果贮藏期呼吸速率和乙烯释放速率，延缓果实硬度、SSC和TA含量下降，同时抑制果皮a^*值、b^*值、C^*值和ΔE^*值升高。电子鼻检测表明，1-MCP处理明显减少了硫化物和萜烯类化合物(W1W)、氮氧化合物(W5S)、有机硫化物和芳香族化合物(W2W)、甲基类芳香物(W1S)以及醇类和醛酮芳香化合物(W2S)的生成。判别分析(LDA)能区分不同贮藏时期对照和1-MCP果实的电子鼻感应值...     

套袋对鸭梨采后生理及贮藏品质的影响

以鸭梨为试材,研究了田间套袋对常温(25±2)℃下鸭梨果实呼吸速率和乙烯释放速率以及果实低温(0±0.5)℃贮藏品质的影响。结果表明,套袋并未推迟或提前常温下鸭梨果实的呼吸高峰和乙烯释放高峰,但套袋鸭梨的呼吸高峰低于未套袋鸭梨,而乙烯释放高峰无明显差别。采摘时,套袋鸭梨较未套袋鸭梨果实硬度大、可滴定酸含量高,VC含量低;随着贮藏时间的延长,套袋和未套袋鸭梨果实硬度均有所下降,但套袋鸭梨果实硬度下降更为迅速;可溶性固形物含量(SSC)在贮藏过程中整体上升,贮藏后期(210 d)套袋鸭梨果实SSC显著高于未套袋果实(P0.05),而之前两者无显著差异;套袋鸭梨果实TA含量较未套袋鸭梨下降更为迅速;贮藏初期套装鸭梨果实VC含量较低,但在贮藏后期这种差别已不明显;套袋鸭梨果心褐变指数较低,未套袋鸭梨果心总酚含量高且下降更为迅速,其PPO活性显著高于套袋鸭梨(P0.05),相关性分析表明鸭梨果心褐变指数与PPO活性呈极显著正相关(P0.01),说明套袋处理对抑制鸭梨贮藏期间果心褐变具有显著效果。     

柑桔和红桔采后保鲜技术要点

1 成熟标准　　果皮颜色：75％为黄色或红色。可溶性固形物含量（SSC）与酸度（TA）比为6．5或稍高。2 质量标准　　果实颜色深度及均一性、果实大小、形状、硬度等，无腐烂、冻害、冷害、虫害和疤痕，无异味；口味依赖于SSC和TA比。3 贮藏温度　　5～8℃可贮藏2～6周，因品种、成熟度及病害控制等不同适宜温度不同。4 相对湿度　　90％～95％为宜。5 呼吸速率　 计算热能产生时，表1中数值乘以440得Btu／t·天，乘以122得kcal／t·天。6 乙烯产出速率　　20℃情况下，乙烯产出速率小于0．1μL CH／kg·h。7 对外源乙烯的反应　　（1…     

1-MCP结合硅窗MAP对新疆毛杏贮藏品质的影响

本文研究了1μL/L 1-甲基环丙烯(1-MCP)、硅窗自发气调包装(MAP)、1-MCP+MAP协同处理对新疆毛杏低温冷藏期间贮藏品质的影响。结果表明,硅窗MAP包装贮藏9 d后,CO2含量维持在3.14%~3.61%之间,O2含量维持在7.88%~9.00%之间,说明硅窗具有较好的气体通过率;1-MCP和MAP单独处理可以显著抑制新疆毛杏的呼吸速率,降低果实乙烯释放量,延缓果实TA、硬度下降速率,维持果实贮藏期感官品质;1-MCP+MAP处理具有协同作用,可显著延缓果实硬度、TA、VC含量和果实色调角值H的下降速率,感官品质评价最好。1-MCP和MAP处理对新疆毛杏均有明显的保鲜效果,1-MCP+MAP处理保鲜效果优于单独处理。     

采收成熟度对酥梨常温贮藏品质及保鲜效果的影响

研究晋南和晋中地区4个梨园不同采收成熟度酥梨果实的常温(20℃)贮藏品质、采后生理以及保鲜效果,以探讨山西地区不同产地酥梨果实的最佳采收成熟度和适宜采收期。结果表明:随着采收成熟度的增加(即采收期的推迟),酥梨果实可溶性固形物含量(SSC)先升高后降低,硬度下降明显,酸度较低,果皮颜色L*和a*较高,h°较低,种子颜色指数和单果重较高,贮藏期间腐烂率和果心褐变指数较高,而且发生时间较早,果实呼吸强度和乙烯释放高峰提前。硬度、SSC、种子颜色指数及果实发育时间可作为判断酥梨采收成熟度的标准。酥梨适宜采收成熟度为盛花期达150~162 d,硬度5.5~6.0 kg/cm2,种子颜色指数为60~75,建议晋中地区酥梨适宜采收期为9月15—27日,SSC12.5%,晋南地区为9月7—19日,SSC11.5%。     

不同成熟度枸杞采后品质及生理变化研究

研究枸杞采后品质及生理变化规律,为枸杞鲜果贮运提供理论基础。取不同成熟度"宁杞1号"枸杞鲜果(红果、红黄果、黄果)为试材,在常温(25℃)和低温(4℃)恒温冰箱中贮藏,每天测定果实呼吸强度、乙烯释放速率、过氧化物酶(POD)活性、果胶酶活性、可溶性固形物含量(SSC)、可滴定酸(TA)含量、VC含量。结果表明:各成熟度枸杞均无明显呼吸强度和乙烯释放速率高峰,属于非跃变型果实;红果、红黄果枸杞POD活性随时间呈降低-升高-降低的变化趋势,黄果为持续下降,红果枸杞POD活性显著高于另两个成熟度(P0.05);果胶酶活性逐天上升,其中黄果显著低于另两个成熟度(P0.05);SSC呈先增大后逐渐减小的变化趋势,红果在采后第3天达到峰值;TA含量总体为下降趋势且变化幅度不大,黄果显著高于另两个成熟度(P0.05);VC含量逐天下降,红黄果降幅最大,各成熟度差异显著(P0.05)。此外,同常温相比,低温可抑制枸杞呼吸强度、果胶酶活性的上升,减缓TA含量、POD活性的下降和VC含量的损失,故低温对枸杞鲜果保鲜有积极作用。     

1-MCP处理对海棠果常温货架品质和风味的影响

以不同成熟度海棠果为试材,研究1μL/L 1-MCP处理对常温(25~28℃)货架期果实的贮藏品质和生理变化的影响,并利用电子鼻对不同处理货架期间的海棠果风味进行分析。结果表明,与对照组相比,1-MCP处理可较好地减缓两种成熟度海棠果果实失重率、腐烂率的增加和硬度的下降,保持果实可滴定酸和可溶性固形物含量,同时降低呼吸强度和乙烯生成速率,有效地延缓果实衰老,其中低成熟度海棠果更耐贮藏。电子鼻分析显示:低、高成熟度海棠果在常温货架期主成分分析(PCA)累计贡献率分别为98.74%、99.55%。低成熟度海棠果的两种处理在货架期内部分有交叉,高成熟度海棠果的两种处理在货架期内可以完全区分开,表明1-MCP对高成熟度海棠果风味调控更为明显。     

1-MCP处理对库尔勒香梨低温贮藏期间活性氧代谢及品质的影响

以库尔勒香梨为材料,研究1.0μL/L 1-甲基环丙烯(1-MCP)处理对梨果实低温贮藏(-1.5～0℃、RH 90%～95%)期间活性氧代谢及品质的影响。结果表明:在低温贮藏期间,1-MCP处理可以保持梨果实的过氧化氢酶(CAT)、过氧化物酶(POD)、过氧化物歧化酶(SOD)活性,减缓梨果实O2·产生速率、H2O2含量的上升,减少丙二醛(MDA)的积累;1-MCP处理延缓梨果实色度角、硬度的下降,保持果实的可溶性固形物(SSC)含量和VC含量,推迟呼吸速率高峰的出现,抑制果实蜡质含量的上升,有效保持了低温贮藏期间梨果实的品质。     

贮藏温度对早熟甜瓜采后生理及品质变化的影响

本文以早熟甜瓜品种‘早黄蜜’为试验材料,贮藏在不同温度（25℃、20℃、15℃、10℃、5℃）条件下,研究贮藏温度对果实生理及品质的影响。结果表明：低温贮藏明显降低甜瓜果实的呼吸速率、乙烯产生速率,同时推迟呼吸、乙烯高峰出现的时间。低温贮藏显著延缓果实硬度的降低,延长贮藏期。贮藏温度在贮藏期内对果实可溶性固形物含量的影响较小。早熟甜瓜贮藏在5℃条件下,贮藏19天出现冷害症状,不能正常后熟。‘早黄蜜’甜瓜在10℃条件下贮藏既能延缓成熟,又能正常后熟。     

富士苹果在减压贮藏过程中相关品质指标与硬度的相关性分析

研究了富士苹果在减压贮藏过程中环境中的乙烯含量、多聚半乳糖醛酸酶(PG)活性、β-半乳糖苷酶(β-Gal)活性、果胶质含量与果实硬度的相关性。结果表明,苹果在减压贮藏条件下,贮藏环境中的乙烯含量、 PG活性、β-Gal活性值及最高值均较常压条件下的低,随着贮藏时间的延长,环境中的乙烯含量、PG活性、β-Gal活性增大,引起原果胶水解成水溶性果胶,细胞壁松弛,果实硬度下降,整个贮藏期果实硬度下降了21.7%,常压贮藏条件下硬度下降了35.9%。因此,可判断减压贮藏通过抑制PG活性及β-Gal活性,从而延缓了原果胶的水解速度,抑制了软化速率,延长果实的保质期。     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l^?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10^?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Changes in Seed Yield and Quality with Maturity in Onion (Allium cepa L., cv. 'Early Cream Gold')

Development of onion (Allium cepa L., cv. ‘Early Cream Gold’) seed under cool climate conditions in Tasmania, Australia occurred over a longer duration than previously reported, but similar patterns of change in yield components were recorded. In contrast to previous studies, umbel moisture content declined from 85 to 67 % over 57 days while seed moisture content decreased from 85 to 31 %. Seed yield continued to increase over the duration of crop development, with increasing seed weight compensating for seed loss resulting from capsule dehiscence in the later stages of maturation. Germination percentage was high and did not vary significantly from 53 to 77 days after full bloom (DAF), but mean germination time declined and uniformity of germination increased significantly over the same time period. The percentage abnormal seedlings declined with later harvest date, resulting in highest seed quality at 77 DAF. The results of this study suggest that the decision to harvest cool climate onion seed crops before capsule dehiscence will result in a loss of potential seed yield and quality.     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Water Extraction Process of Chinese Herbal Compound Man Gan Ning

[Objectives]To optimize the water extraction process of Chinese Herbal Compound Man Gan Ning and establish a method for its extraction and content determination...     

Present status and future strategy in breeding faba beans (Vicia Faba L.) for resistance to biotic and abiotic stresses

Progress is being made, mainly by ICARDA but also elsewhere, in breeding for resistance to Botrytis, AScochyta, Uromyces, and Orobanche; and some lines have resistance to more than one pathogen. The strategy is to extend multiple resistance but also to seek new and durable forms of resistance. Internationally coordinated programs are needed to maintain the momentum of this work.Tolerance of abiotic stresses leads to types suited to dry or cold environments rather than broad adaptability, but in this cross-pollinated species, the more hybrid vigor expressed by a cultivar, the more it is likely to tolerate various stresses.     

Optimization of Extraction Technology and Determination of Content of Total Phenols of Leaves in Acanthopanax giraldii Harms

[Objectives] To determine the optimum extraction technology for total phenols of leaves in Acanthopanax giraldii Harms.[Methods]The single factor test and ortho...     

Cytoplasmic male sterility,resistance to gall mite and mildew,and season of leafing out in black currants

Summary Cytoplasmic male sterility (cms) is described in the F₁ hybrids Ribes × carrierei (R. glutinosum albidum × R. nigrum) and R. sanguineum × R. nigrum. In backcrosses to R. nigrum, progenies with R. glutinosum cytoplasm were either all male sterile, or segregated for full male fertility (F) and complete (S) and partial (I) male sterility. Ratios of F:I+S suggested that two linked genes controlled cms, F plants being dominant for one (Rf ₁) and recessive for the other (Rf ₂).Segregation for cms in relation to three linded genes, Ce (resistance to the gall mite, Cecidophyopsis ribes), Sph ₃(resistance to American gooseberry mildew, Sphaerotheca mors-uvae) and Lf ₁(one of two dominant additive genes controlling early season leafing out) indicated that Rf ₁and Rf ₂were in this linkage group. The gene order and approximate crossover values appeared to be: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqef0uAJj3BZ9Mz0bYu% H52CGmvzYLMzaerbd9wDYLwzYbItLDharqqr1ngBPrgifHhDYfgasa% acOqpw0xe9v8qqaqFD0xXdHaVhbbf9v8qqaqFr0xc9pk0xbba9q8Wq% Ffea0-yr0RYxir-Jbba9q8aq0-yq-He9q8qqQ8frFve9Fve9Ff0dme% aabaqaciGacaGaamqadaabaeaafaaakeaacaWGdbGaamyzamaamaaa% baGaaiiiaiaacccacaGGWaGaaiOlaiaacgdacaGG0aGaaiiiaiaacc% caaaGaaiiiaiaacccacaGGGaGaamOuaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaaccdacaGGUaGaaiOmaiaacs% dacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaaaacaWGsbGaamOzaSGa% aGOmaOWaaWaaaeaacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccaaaGaamitaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccacaGGGaaaaiaadofacaWGWbGaamiAaSGa% aG4maaaa!6E4D!\[Ce\underline { 0.14 } Rf1\underline { 0.24 } Rf2\underline { } Lf1\underline { } Sph3\]. Crossover values of 0.36 for Ce-Lf ₁, and 0.15 for Lf ₁-Sph ₃were estimated from the relative mean differences in season of leafing out between seedlings dominant and recessive for Ce and Sph ₃.It is suggested that competitive disadvantage of lf ₁-carrying gametes and/or zygotes at low temperatures may be implicated in the almost invariable deficit of plants dominant for the closely linked mildew resistance allele Sph ₃. Poor performance of lf ₁- (and possibly lf ₂-) carrying gametes and young zygotes during periods of low temperature at flowering might also account for the liability of some late season cultivars and selections to premature fruit drop (running off).     

Screening techniques and sources of resistance to parasitic angiosperms

Parasitic angiosperms cause great losses in many important crops under different climatic conditions and soil types. The most widespread and important parasitic angiosperms belong to the genera Orobanche, Striga, and Cuscuta. The most important economical hosts belong to the Poaceae, Asteraceae, Solanaceae, Cucurbitaceae, and Fabaceae. Although some resistant cultivars have been identified in several crops, great gaps exist in our knowledge of the parasites and the genetic basis of the resistance, as well as the availability of in vitro screening techniques. Screening techniques are based on reactions of the host root or foliage. In vitro or greenhouse screening methods based on the reaction of root and/or foliar tissues are usually superior to field screenings and can be used with many species. To utilize them in plant breeding, it is necessary to demonstrate a strong correlation between in vitro and field data. The correlation should be calculated for every environment in which selection is practiced. Using biochemical analysis as a screening technique has had limited success. The reason seems to be the complex host-parasite interactions which lead to germination, rhizotropism, infection, and growth of the parasite. Germination results from chemicals produced by the host. Resistance is only available in a small group of crops. Resistance has been found in cultivated, primitive and wild forms, depending on the specific host-parasite system. An additional problem is the existence of pathotypes in the parasites. Inheritance of host resistance is usually polygenic and its transfer is slow and tedious. Molecular techniques have yet to be used to locate resistance to parasitic angiosperms. While intensifying the search for genes that control resistance to specific parasitic angiosperms, the best strategy to screen for resistance is to improve the already existing in vitro or greenhouse screening techniques.