掌叶覆盆子种子繁殖力关键影响因素分析

掌叶覆盆子野外种群的更新由根蘖繁殖完成,实生苗罕见,种子繁殖力低。本研究从掌叶覆盆子种子的结实特性、采种期、储藏时间、母树来源、激素含量变化与种子萌发等方面对其种子繁殖力影响因素进行了全面的分析。结果表明:掌叶覆盆子种子数量充足,群体内结实特性保持着一致性;当年熟果种子活力达到75.33%,储藏时间超过1年种子活力迅速下降且发芽率为0;不同母树来源种子发芽率无差异;青果、黄绿果时期种子活力和发芽率都较低,熟果和过熟果实种子活力达最高值且基本一致,但熟果GA 3/ABA比值最大,发芽率最高;不管是否添加外源激素,随着果实过熟程度加深,种子发芽率迅速下降,种子休眠程度也随之加深;酸蚀和激素可有效破除休眠,提高发芽率。采种时间、储藏时间、酸蚀和赤霉素催芽等是影响掌叶覆盆子繁殖力的关键因素。     

增产灵对萌发小麦种子的生理生化效应

用不同浓度的PIPA处理予浸泡的小麦种子,对小麦萌发种子细胞内代谢有明显的影响。低剂量(40-80ppm)的PIPA能提高幼苗淀粉酶、过氧化物酶、过氧化氢酶活性,增加叶绿素和核酸含量,从而促进种子萌发和幼苗的生长,而高浓度(120-160ppm以上)表现出上述各项生理指标呈明显的下降趋势。实验表明,一定浓度PIPA能提高酶活性,增加叶绿素和核酸含量,促进幼苗生长良好,为后期的生长发育打下良好的基础。     

不同贮藏年限敖汉苜蓿种子活力及生理特性的研究

种子在贮藏过程中随着贮藏时间的延长出现老化现象,使种子活力下降、生理特性发生变化,从而降低种用价值.为探讨不同贮藏年限紫花苜蓿种子的活力变化,选择室温贮藏0～3年的敖汉苜蓿种子,比较分析种子劣变规律及生理特性的差异.结果表明:收获当年的敖汉苜蓿种子具有较高的硬实率,其抗逆性强,SOD、POD、CAT、MDA和脯氨酸含量最高,而发芽势和可溶性蛋白含量最低.贮藏起初2年,种子硬实率、不正常种苗数、死种子数、SOD、POD、CAT、MDA和脯氨酸含量降低,发芽率、发芽势和可溶性蛋白含量增加.随着贮藏时间的延长,种子可溶性蛋白含量降低,SOD、POD、CAT、脯氨酸和MDA积累量增加,种子质量下降,不正常种苗数和死种子数增多,种子活力下降.综合试验结果,贮藏2年有利于打破种子休眠,其种子质量最佳,种子发芽能力最强,但是种子抗逆性不高;贮藏1年存在轻度休眠,应进行打破硬实处理;贮藏3年的种子活力下降,其种用价值降低,不利于在人工草地建植中使用,生产中应贮藏2年后再播种效果较好.研究结果能较好地说明苜蓿种子在贮藏期间的活力变化,为我国人工草地建设中合理使用苜蓿种子提供理论依据.     

大葱种子人工老化与膜脂过氧化的研究

大葱种子经过人工老化处理后,其发芽率、发芽指数、活力指数下降,活力指数较发芽率和发芽指数下降明显,种子老化6天后活力指数比对照下降70％。脱氢酶、SOD、POD活性和GSH含量也呈下降趋势,而浸出液可溶性糖、MDA、自由基、H2O2的含量增加,GSH、H2O2、自由基、可溶性糖含量与种子活力显著相关,并且较其他指标变化更为显著。说明大葱种子人工老化过程中膜脂过氧化加剧,膜结构和功能遭到破坏。因此,大葱种子人工老化与膜脂过氧化直接相关。     

不同含水量对大葱种子活力的影响

本试验通过人工老化的方法,研究不同含水量对大葱种子活力的影响.结果表明:将种子含水量由8.4%降至5.5%～2.5%,不影响大葱种子活力,其发芽率、发芽指数、活力指数、脱氢酶、电导率、可溶性糖含量和MDA含量无显著变化;当含水量低于2.0%时,种子活力显著下降.经人工老化处理后,含水量在5.5%～2.5%的种子,其活力保持较高水平,且显著提高种子抗老化的能力.     

非破坏性方法测定小麦种子活力研究

低温10℃贮存6个月后，重复吸水－回干处理有提高小麦种子活力的作用，但高温35℃贮存6个月后，除1次浸泡2h或4h的处理处，其他处理随浸泡时间的延长和浸泡次数的增加种子活力明显下降。两种温度贮藏后，整粒种子的过氧化物酶和酯酶同工酶谱带变化处理与对照间无明显差异，电导率，可溶糖糖，氨基酸和紫外光密度4项种子渗漏物测定指标中，可溶性糖含量与种子活力密切相关。最终筛选出一个非破坏小麦种子活力的监测方法，即：小麦种子浸光2h或4h后，种子在室温下经适当干燥至原含水量后可继续保存，浸泡液被用于测定可溶性糖含量。     

超低水分贮藏对几种高油分种子生理特性的影响

试验对超低水分贮藏的四种高油分种子生理特性变化进行了研究。结果表明,油菜、萝卜种子活力与浸泡液电导率呈负相关,而不同活力的芝麻种子浸泡液电导率间无显著差异。经50℃老化贮藏14天后,超低水分的油菜、萝卜种子能保持较高的脱氢酶活性(油菜种子水分:0.7%～3.3%,萝卜种子水分:0.9%～3.2%)和过氧化物酶活性(油菜种子水分:0.7%～2.8%.萝卜种子水分:0.9%～3.2%)。高温贮藏后,水分为1.2%～3.0%的油菜种子活力较强,具较高的超氧物歧化酶活性。油菜、萝卜、种子内源激素脱落酸(ABA)的含量随种子活力下降而显著上升,水分为5.1%(低活力)的油菜种子ABA含量是水分为1.2%(高活力)种子的3.7倍,萝卜种子胚中轴(胚本部)中ABA含量大大高于子叶中的含量,前者是后者的3～6倍。     

超干贮藏对棉花种子活力及生理特性的影响

用氧化钙超干燥使棉花(中棉所12)种子含水量降至2.8%。超干贮藏后,由于硬实率明显提高,直接发芽测定结果表明,超干种子的发芽力、活力低于常规贮藏种子;而破除种皮限制后,超干种子发芽力、活力高于常规贮藏种子。对生理指标的测定表明,超干种子的ABA含量明显低于常规贮藏种子,而脱氢酶、POD、SOD活性和GA1/3含量均高于常规贮藏种子。说明超干贮藏有利于棉花种子活力的长期保持,但发芽前需要破除种皮。缓湿处理可使棉花超干种子的发芽力、活力显著提高,相对电导率和ABA含量明显降低,对GA1/3和iPAs含量亦有明显的提高作用,而对脱氢酶、POD、SOD活性无明显影响。     

水杨酸和脱落酸对低温下寒地冬小麦种子萌发的影响

用不同浓度的水杨酸(SA)和脱落酸(ABA)单独及组合处理对寒地冬小麦种子进行浸种,在低温(4℃)下测定种子的发芽率、发芽势和发芽指数等萌发指标,种子芽长和根长,芽和根鲜重及干重以及丙二醛含量等生理指标,研究SA和ABA对低温胁迫下冬小麦种子萌发的影响.结果表明:低温胁迫下,一定浓度的SA和ABA浸种处理冬小麦的种子,可显著促进种子的萌发,并且,SA的抗寒效果比ABA更明显,二者配比组合(10-4 mol/L SA和10-5 mol/L ABA)具有最显著的缓解低温的效果.     

不同脱绒方式对棉花种子活力及萌发期生理特性的影响

以带绒棉花种子为对照,研究了不同脱绒方式对棉花种子活力及萌发期生理特性的影响。结果表明：棉花种子脱绒后,种子吸水速率、种子相对电导率、棉花种子萌发期相对电导率及丙二醛含量显著增加;发芽率、棉芽中可溶性蛋白质与可溶性糖含量明显降低;脱绒处理对棉花种子造成了不同程度的损伤,使其抗低温能力显著降低;相对于硫酸脱绒处理,机械脱绒对保护棉花种子活力及抗低温能力效果较好。     

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.     

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.     

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.     

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...     

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.