钙处理对枇杷果实采后生理特性的研究

适当的钙处理可明显减缓枇杷果实的采后生理活力。试验结果表明：氯化钙喷施枇杷,果实Ca2+含量提高,呼吸高峰推迟出现,峰值降低;细胞膜透性、丙二醛（MDA）含量呈上升趋势,随钙浓度提高幅度下降且比对照低;钙调蛋白含量先上升后下降,峰值随钙浓度增大而上升,对照一直呈下降趋势;过氧化物歧化酶（SOD）、过氧化氢酶（CAT）活性随贮藏时间延长逐渐上升后下降,钙浓度愈高幅度愈小;过氧化物酶（POD）、苯丙氨酸解氨酶（PAL）等酶活性均呈上升趋势, PAL活性随钙浓度上升,效果愈明显,POD活性随着钙浓度上升,幅度变小,且均低于对照;同时发现钙浓度过高,果实出现轻微生理病害。说明用1.5%氯化钙对叶、果同时喷施能有效地减缓枇杷果实采后生理活动,又不至于发生生理病害。     

壳寡糖处理对冷藏期间大五星枇杷贮藏品质的影响

以大五星枇杷为试材,研究不同浓度(0.5%、1.5%、3.0%)壳寡糖浸泡处理对枇杷失重率、褐变指数和腐烂指数的影响,筛选出适宜的壳寡糖浓度,并研究了0.5%壳寡糖溶液浸泡处理对枇杷贮藏品质的影响。结果表明,采用0.5%壳寡糖溶液浸泡枇杷果实3 min,可有效抑制枇杷果实失水和褐变,显著降低枇杷果实的腐烂指数,保持较高的可溶性固形物(TSS)、还原型抗坏血酸(As A)及还原糖含量,总酚和类黄酮含量于贮藏前期急剧下降,同时多酚氧化酶(PPO)活性受到一定抑制,使得0.5%壳寡糖处理的枇杷果实较对照褐变程度下降,保持较高的好果率,说明0.5%壳寡糖处理在延缓枇杷果实成熟衰老及提高其抗病性上具有一定作用,可提高冷藏枇杷的贮藏品质及抑制PPO活性。     

枇杷臭氧保鲜技术研究

通过分析枇杷特性、采后生理状况,结合臭氧保鲜特点,对枇杷进行臭氧保鲜技术试验.试验结果表明,枇杷果实用0.4 mg/L臭氧水处理结合4℃低温贮藏,可显著地抑制果实失水,延缓果实可溶性固形物、可滴定酸和VC含量的下降,保持果实新鲜外观与品质,果实贮藏期可达20天以上.     

不同厚度聚乙烯薄膜包装对枇杷贮藏品质的影响

对采后枇杷果实用0.01、0.03 mm厚的聚乙烯薄膜袋包装,以无薄膜散装作为对照,在室温(25±1)℃条件下贮藏,研究不同厚度的聚乙烯薄膜包装对枇杷鲜果的保鲜效果及生理指标变化的影响。结果表明:聚乙烯薄膜包装处理可显著抑制果实失重率的上升,延缓果实可溶性固形物、可滴定酸及VC含量的下降,保持采后枇杷果实的新鲜外观和品质,其中以0.03 mm厚度的聚乙烯薄膜包装处理效果为佳。     

不同处理方法对枇杷贮藏品质的影响

以许昌地区广泛栽培的普通枇杷为试材,研究不同浓度(1.0%、1.5%、2.0%)壳聚糖涂膜处理、热激处理(45℃热水浸泡5 min、50℃热水浸泡2 min)、10%女贞子浸提液处理和0.5%虫蜡涂膜处理对枇杷果实贮藏品质的影响。结果表明,2.0%壳聚糖和0.5%虫蜡涂膜处理可有效抑制采后普通枇杷果实的失重和腐烂,延缓可溶性固形物含量的下降,激发过氧化物酶活性的上升,抑制纤维素酶活性,延缓果实软化进程,具有较好的保鲜效果。     

乔纳金苹果的应力松弛和蠕变特性与其品质相关性分析

为了简化苹果果实品质无损检测技术,探索苹果果肉力学特性与其品质的相关性,本文采用物性分析仪对乔纳金苹果货架期果肉进行蠕变和应力松弛试验,并对化学成分含量进行测定。结果表明:蠕变参数E_1、E_2、η_1、η_2与松弛参数E_1′、E_e、η等在货架期大体呈下降趋势;质构参数(TPA)果肉硬度、内聚性、弹性、咀嚼性等均与蠕变参数初始弹性系数E_1、延迟弹性系数E_2、黏性系数η_1和松弛参数平衡弹性模量E_e、松弛时间T_s、黏滞系数η之间呈显著正相关;可溶性固形物、原果胶分别与蠕变参数初始弹性系数E1、延迟弹性系数E_2、黏性系数η_1和松弛参数平衡弹性模量E_e、零时弹性模量E_0和黏滞系数η之间呈显著正相关;并通过逐步回归分析法构建一元线性回归模型。相关性和主成分分析表明,乔纳金苹果内在品质(可溶性固形物、原果胶)与蠕变、应力松弛黏弹性参数呈显著正相关,苹果果肉质地都具有黏弹性,兼具有黏性和弹性,且贡献率均等。     

枇杷幼果雨雪冻害的理化响应

为了探究-3℃~0℃区间枇杷幼果受冻原因,雨雪天气后采集套袋处理或树冠是否覆膜保护的未受冻和受冻果实,检查其受冻情况和检测其游离脯氨酸等理化指标。结果表明:树冠覆膜保护的果实未受冻,树冠未覆膜的果实、经过雨雪淋洗后受冻;果实套袋处理,悬空于袋内的果实未受冻、与袋子贴近的果实受到冻害;受冻果实的游离脯氨酸含量显著高于未受冻果实;套袋受冻果实的丙二醛含量显著高于未受冻果实,而覆膜和未覆膜果实的丙二醛含量无显著差异;SOD、POD、PPO的活性在未覆膜果实和覆膜果实之间差异显著,未覆膜果实中三者的活性较高,然而这3种酶的活性在套袋果中活性较低,套袋受冻果实和未受冻果实之间无显著差异。本研究表明,不同形态(气液固)的低温传导介质,是导致枇杷幼果在-3℃~0℃区间是否受冻的主要原因,液固态低温传导介质才会导致枇杷幼果受冻,游离脯氨酸含量或许是鉴别枇杷果实是否受冻的关键理化指标。     

枇杷采后酚类物质代谢与果肉木质化的关系

以4℃条件下冷藏的“解放钟”枇杷（Eriobotrya japonica Lindl．cv．Jiefangzhong）果实为试材．对冷藏枇杷果实的果肉硬度、木质素、总酚和各酚类物质含量以及二种相关酶（PAL和PPO）活性进行研究。结果表明：枇杷果实在4℃条件下贮藏期间果肉硬度变化呈上升趋势,与木质素含量变化显著正相关。相关系数为0．9;而总酚及酚类物质则均呈下降趋势,与木质素含量变化趋势相反;PAL和PPO的活性分别在冷藏期间前14d和28d较快上升并保持在较高的水平上,说明PAL和PPO活性与果肉木质化相关。     

不同果间距留果对‘翠冠’、‘丰水’梨产量和果实品质的影响

为研究不同果间距留果对‘翠冠’和‘丰水’梨产量与果实品质的问题,本试验以‘翠冠’和‘丰水’梨为试材,采用果间距法留果,研究了不同果间距留果对产量和果实品质的影响。结果显示：‘翠冠’和‘丰水’2个品种的单果重量、可溶性固形物、可溶性总糖含量均随果间距的增加呈升高趋势;而单株产量、石细胞含量却随着果间距的增大呈降低趋势;但不同果间距留果对果形指数、果心比例、果实硬度影响不大;可滴定酸与维生素C含量均随果间距的增加呈先升高后下降趋势,都是在果间距25 cm处理时达到最大。研究表明,‘翠冠’和‘丰水’在疏果时将果间距控制在25 cm时产量和品质最佳。     

‘灵武长枣’果实裂果特性初步研究

通过对‘灵武长枣’果实裂果特性的研究,以期为‘灵武长枣’生产实践提供理论依据。采集大田10年生‘灵武长枣’果实,在室内采用果实浸泡法,测定不同着色程度和大小果实的吸水量、吸水率、裂果率、裂果指数等,研究‘灵武长枣’果实裂果特征。结果表明,随着浸水时间的延长,‘灵武长枣’果实的吸水量、吸水率呈下降趋势,而裂果率和裂果指数呈上升趋势。‘灵武长枣’全红果总吸水量比75%着色果的多、果实裂果率大,裂果指数是75%着色果的1.49倍,裂果严重。4种果实大小等级‘灵武长枣’果实的总吸水量顺序为:一等果二等果三等果四等果;三、四等果的裂果率大于一、二等果,而一等果的裂果指数最大(0.664)。果实裂果发生与其水分吸收密切相关,果实吸水的关键时期在前24 h。全红果与果个大的果实吸水量大、裂果程度严重。     

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.