小麦种子在不同贮存条件下保存10年后生活力的差异

冬小麦农大139含水量为6.7%和11.8%。分别密封保存于室温和0～5℃冰箱。10年后,测定其发芽势,发芽率等指标,结果表明:①在室温条件下,含水量为11.8%的种子全部死亡,含水量为6.7%的种子有近50%的发芽率同保存前种子发芽率相比明显下降。②在0～5℃冰箱保存的种子,两种含水量均达到80%左右的发芽率,同保存前相比没有明显差别。统计分析表明,贮存温度及贮存温度和种子含水量的互作对贮存种子活力的影响达到极显著水平。     

莴苣种子于50℃恒温贮藏最佳含水量研究

莴苣种子在50℃下恒温贮藏,不同含水量的种子老化速度差异很大,高水分种子迅速死亡,贮藏第28天,含水量＞6.7%的种子已死亡,而含水量＜6.7%的种子发芽率在90%以上.随着贮藏时间的延长,种子发芽率、活力下降明显,种子贮藏至第392天时,含水量＞4.1%的种子全部死亡,而含水量为1.6%～4.1%的种子其发芽率≥68%.发芽指数和活力指数的下降要快于发芽率.50℃恒温贮藏392d,含水量为2.0%～3.0%的种子活力下降最慢,含水量2.0%～3.0%是莴苣种子50℃恒温贮藏的最佳含水量.     

不同含水量的紫云英种子库存20年后活力研究

为了探讨种子长期贮藏的最适含水量,较为全面评价种子长期保存后的活力,将紫云英种子(初始含水量为9.63%)于35℃下加温干燥,使种子含水量分别降至8.36%、7.74%、6.92%、6.47%和5.97%后经密封包装藏于-1℃种质库条件下进行长期保存,20年后取出测定它们的种子萌发能力、田间生长能力、电导率等.结果表明:经20年保存后,含水量为8.36%、7.74%、6.92%和6.47%的种子发芽率与贮藏前相比差异极显著,发芽率下降明显不适宜长期保存,含水量5.97%的种子发芽率与贮藏前相比差异不明显,活力最高,适合低温长期保存.此研究为绿肥种质资源长期安全保存积累了科学的数据,对指导种质保存具有重要的现实意义.     

在不同贮藏条件下保存15年后深水稻种子活力的研究

在鉴定种子贮藏效果时,如果只用种子发芽率,不能全面反映种子内在的活力。为了探讨贮藏温度和种子含水量对贮藏效果的影响,较为全面评价种子长期保存后的活力。本试验研究了深水稻(Deep water rice)种子从11.3％的含水量干燥至6.5％后经密封包装藏于-1℃温度、(40士5)％相对湿度的种质库和室温两种条件下进行长期保存,15年后取出测定它们的种子萌发能力、田间生长能力、电导率等。结果表明:经15年保存后,在室温条件下含水量11.3％的种子全部丧失了发芽力,含水量6.5％的种子的发芽率下降至贮藏前的53.0％;而在-1℃种质库条件下含水量11.3％的种子发芽率与贮藏前相比差异极显著,发芽率有下降的趋势,即不适宜长期保存,含水量6.5％的种子发芽率与贮藏前相比差异不明显,活力最高,适合低温长期保存。此研究为种质资源长期安全保存积累了科学的数据,对指导种质保存具有重要的现实意义。     

多年超干贮存对大葱种子生理生化特性的影响

大葱种子的贮存效应随着贮存温度和种子含水量的不同而变化。超干含水量的大葱种子(MC2 8% )在 2 0℃温度下密封贮存 11年后 ,种子发芽率和苗长没有明显降低 ,脱氢酶活性、SOD活性及细胞膜完整性均得到较好的维持。 2 8%和 5 3%的大葱种子在 0℃温度下密封贮存 13年后 ,也具有一定的种子发芽率和苗长 ,而 7 4 %和 2 6 %的大葱种子活力全部丧失。这意味着利用超干技术保存大葱种质是可行的     

25种野生花卉种子超低温保存研究

试验研究了中国华北地区14科的25种野生花卉种子的超低温保存技术程序.结果表明:在采后自然含水量下,(1.00%～11.76%),除了祁州漏芦种子进入液氮后炸裂外,其它24种花卉种子经液氮保存后都具有一定的发芽率.液氮保存前后种子发芽率变化不同,可分为3类.12种花卉种子发芽率高于液氮保存前,提高1.3%～34.6%不等,其中牛扁提高最为明显.狭苞橐吾、紫苞风毛菊种子液氮保存前后发芽率无显著差异;大花剪秋萝等10种花卉,液氮保存后种子发芽率降低2.7%～62.6%不等,降低最多的是蓝刺头,种子发芽率为10.7%,是保存前62.6%.液氮保存后化冻方法研究表明,不同花卉采用不同方法,金莲花等11种花卉种子采用18℃自来水冲洗化冻6～7 min,种子发芽率较高;草本威灵仙等8种种子在40℃温水浴化冻6～7 min下,种子萌发率较高;返顾马先蒿等在20℃室温化冻30 min的条件下种子发芽率较高.不同化冻方式对超低温保存后种子发芽率有明显的影响.在可以超低温保存的24种花卉中,72%的种类表现为快速化冻方式优于慢速化冻,其中32%的野生花卉温水浴化冻效果较好.40%的种类自来水冲洗化冻后发芽率较高.     

小麦、玉米种子超低温(-196℃)保存7年后的种子活力

小麦品种“他诺瑞”“京中15号”,玉米品种“华农2号”的种子分别具有3种含水量,其幅度在16.4～15.3%,11.9～10.5%和5.7～5.2%。于1980年11月22日存入液氮(-196℃)中保存。对照种子密封保存于室温。1988年2月25日从液氮中取出,在冰箱中存放4天,再作发芽率、发芽势、根长、芽长、酶活性等测定及根尖染色体观察等,部分“他诺瑞”种子于1988年3月3日播种于网室,以便观察液氮长期保存后种子在田间的生长状况,农艺特征是否产生变异。试验结果证明:①具有3种含水量的小麦和玉米种子经液氮保存7年后其萌发率和萌发势同保存前相比没有明显差别,而含水量为16.4～15.3%,保存在室温的对照小麦和玉米种子全部死亡。经液氮保存后的种子其过氧化物酶活性明显高于室温保存的对照种子。③播种子网室的“他诺瑞”种子出苗后早期生长缓慢,大约40天以后恢复正常,其苗长、叶数、抽穗期、株高、穗长、单株穗数等农艺性状同对照没有明显差别。③观察液氮保存后的“他诺瑞”和“华农2号”种子根尖细胞没有发现染色体不正常行为,面对照种子不正常染色体频率最高达11.7%。观察小麦“京中15号”根尖细胞有丝分裂后期1223个分裂相中只有8个细胞染色体产生不正常现象,其频率为0.65%,而室温保存的对照种子染色体不正常频率高达18.2%。     

几种作物种子"双15"处理后低温贮藏生活力跟踪研究

利用IBPGR的"双15"(温度15℃、相对温度15%)干燥葙,将水稻、花生、小麦、兰豆、绿豆等种子进行"双15"干燥处理,分别在-1℃和-10℃两个低温干燥库贮藏149个月后检测,水稻含水量均比干燥前降低38.2%,发芽率保持在84%～96%,年降速率0.247%;未经"双15"处理进入同样低温干燥库贮藏的稻种最高年降速率3.05%;兰豆、小麦、绿豆种子在-1℃和-10℃两个低温干燥库贮藏含水量分别比干燥前降低44.67%、44.0%,发芽率为74%～93%,年降速率0.467%;花生种子在-1℃和-10℃两个低温干燥库贮藏含水量分别比干燥前降低41.5%、44.6%,发芽率为73%～92%,年降速率0.133%.作物种子含水量、发芽率的年降速率不同,豆类较大,水稻次之,花生较小,其下降值介于0.242%～0.54%和0.133%～0.467%之间.作物种子贮藏年限与发芽率呈极显著相关.表明作物种子资源用"双15"干燥处理后再低温贮藏可行.     

包衣种子寿命的影响

奇珍76甜豌豆包衣种子密封低温贮藏1年后，含水量低于12．0％的种子，仍保持较强生活力；含水量高于12．0％的种子，发芽率下降显著；隔年备种贮藏的适宜含水量为12．0％以下。     

在不同贮存条件保存10年后小麦种子的活力

为了长期保存植物遗传资源,许多国家都修建了干燥低温种质库保存种子。国际植物遗传资源委员会推荐正常型种子 (Orthodox Seed) 长期保存温度-18℃,种子含水量5—7％[陶嘉龄等,1986]。但是如何将种子干燥至适合的含水量,干燥方法极为重要。在鉴定种子贮存效果时,如果只用发芽率,不能全面反应种子内在的活力。为了探讨贮存温度和种子含水量对贮存效果的影响,较为全面评价种子长期保存后的活力。本试验研究了小麦种子在不同贮存条件下长期保存后的萌发能力,田间生长能力,种子过氧化物酶同工酶及活性、根尖染色体行为等的差异。     

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.