Asymbiotic Germination and Low-temperature in Vitro Conservation of Cymbidium Dayanum

[Objective] The aim of the research was to establish asymbiotic germination and low-temperature in vitro conservation technique system of Cymbidium dayanum by using plant tissue culture technique to realize its rapid propagation and long-term conservation in vitro. [Method] With mature seeds of C. dayanum as explants, different media were selected to establish asymbiotic germination technique system. With protocorms as materials, conservation, resumptive proliferation and plant regeneration conditions were selected to establish low-temperature in vitro conservation technique system preliminarily. [Result] Mature seeds of C. dayanum could germinate after cultured 90 days on MS media as well as ＂Hyponex 1＂ media. The germination rate reached more than 98%. Protocorms inoculated in ＂Hyponex 1＂ media could be conserved continuously at 5 ℃ in dark for more than 18 months and the survival rate could reach 90%. Conserved protocorms could realize resumptive preliferation culture both on 1/2 MS and ＂Hyponex 1＂ media. The seed- ling-strengthening and rooting media were 1/2 MS media. [Conclusion] This research provided practical basis for in vitro conservation and rapid propagation of C. dayanum germplasm resource.

Combining Ability and Genetic Effects of Germination Traits of Brassica napus L.Under Waterlogging Stress Condition

Cross combinations from six rapeseed cultivars and lines were evaluated under waterlogging stress condition in order to understand the genetic mechanism of waterlogging tolerance of Brassica napus L.and provide reasonable improvement programs.There were six germination traits investigated on combining ability and heritability using complete diallel crossing method designed for 30 combinations from those six cultivars and lines.The traits included relative root length,stem length,fresh weight per plant,survival rate,electrical conductivity,and vigor index.After flooding treatment,the six traits of parents and F1 were analyzed.The general combining ability（GCA） and special combining ability（SCA） of germination traits were analyzed using Griffing I method.Among 30 cross combinations,the GCA was significantly different among six waterlogging resistance traits.The SCA of these traits was significantly different except the SCA of electrical conductivity.As a representative trait of waterlogging tolerance in rapeseed,relative vigor index had the highest narrow heritability and relatively low broad heritability.The cultivars Zhongshuang 9 and P79 had higher tolerance potential to waterlogging stress.It can be concluded that combining ability and genetic effects of relative vigor index during germination stage could be used to identify the waterlogging tolerance of rapeseed in breeding program.

Genetic Control of Germination Ability under Cold Stress in Rice

An F9 recombinant inbred lines （RIL） population, derived from a cross between IR28 （Oryza sativa L. spp. indica） and Daguandao （O. sativa L. spp. japonica）, was used to construct a molecular linkage map and to identify germination ability including the traits of imbibition rate, germination rate, germination index, root length, shoot length and seed vigor at 14℃ for 23 d. A composite interval mapping approach was applied to conduct genetic analysis for germination ability. The frequency distributions of the germination ability traits under the cold stress in the RIL population showed continuous segregation, suggesting they were quantitative traits controlled by several genes. A total of seven QTLs were identified on chromosomes 4 6 and 9, including two for imbibition rate （qIR-6, qIR-9）, one for germination rate （qGR-4）, two for germination index （qGI-4-1, qGI-4-2） and two for root length （qRL-4-1, qRL-4-2）. There were no detected QTLs controlling shoot length and seed vigor. The phenotypic variance explained by a single QTL ranged from 9.1% to 37.0%, and two major QTLs, qlR-6 and qGI-4-2, accounted for over 30% of the phenotypic variance. The expressions of QTLs were developmentally regulated and growth stage-specific. Most of the QTLs observed here were located in the regions similar to the QTLs for rice cold tolerance reported previously, indicating that these QTLs were reliable. However, qRL-4-2 is not reported before.

Effect of Low Temperature on Germination Characteristics of Rice Cultivars

The effects of low temperature on germination characteristics of rice seeds were studied,using three rice varieties as materials.The results showed that the germination rate,germination energy,germination index,vigor index,shoot length and root length all reduced with the decrease of temperature.When the treatment temperature was 10 ℃,whether or not cold-resistant varieties,the values of all parameters showed an extremely significant difference from the control's.When the stress temperature was 15 ℃,compared with the normal condition,the parameter values of the non-tolerant variety( Changbai 9) had an extremely significant difference and the germination rate,germination potential,seedling length and root length of two cold-tolerance varieties( Jisheng 202 and Tongjing 9) had little difference from the control.Therefore,the above four indicators at 15 ℃ can be considered as the evaluation indices of cold tolerance at early stage.

Comparative Transcriptome Analysis of Seed Germination of a Cotton Variety with High Tolerance to Low Temperature

Gossypium hirsutum L.is an important cash crop native to the subtropics and is widely cultivated around the world.Low temperature is an important stress that seriously affects seed germination and emergence during planting.In this study,transcriptomic profiles of low-temperature-and normal-temperature-germinated seeds of Xinluzao 25,a variety with low-temperature tolerance and high germination rates,were analyzed and compared.The following results were obtained.(1)A total of 81.06 Gb of clean data were obtained after transcriptome sequencing and assembly,and 76,931 non-redundant Unigene sequences were obtained after data consolidation and concatenation;of these,69,883 Unigene sequences were annotated.In addition,55,463 Unigene transcript sequences(72.2%)were annotated for Gene Ontology(GO)classification,and 26,629 genes were involved in 50 metabolic pathways identified by Kyoto Encyclopedia of Genes and Genomes(KEGG)analysis.(2)Three main pathways related to low-temperature tolerance of seed germination were identified:starch and sucrose metabolism,phenylpropanoid biosynthesis,and cysteine and methionine metabolism.Their main molecular functions involve the regulation of abscisic acid and activities of enzymes such as amylase,peroxidase,and oxidoreductase.During germination at low temperature,more genes were down-regulated than up-regulated genes at the protrusion stage(2 mm),and more genes were up-regulated than down-regulated at the germination stage(30 mm)after protrusion.(3)The enzyme activities at the two stages showed that amylase,peroxidase,catalase,and glutathione reductase had higher activities when the seeds germinated at 15℃.In this study,high expression of amylase,peroxidase,catalase,and glutathione reductase genes may be the main cause of increased tolerance to low temperature.

Modulation of Anti-Oxidation Ability by Proanthocyanidins during Germination of Arabidopsis thaliana Seeds

Proanthocyanidins （PAs） as the end products of flavonoid biosynthetic pathway mainly accumulate in seed coat but their biological function is largely unknown. We studied the anti-oxidation ability in seed coat and germination changes under externally applied oxidative stresses in PAs-deficient mutants of Arabidopsis. Germination of PAs-deficient mutant seeds was faster than that of wild-type under low or no oxidative stress, suggesting a PAs-induced inhibition of germination. When the applied oxidative stress was high, germination of PAs-deficient mutants was lower than that of wild-type, suggesting a loss of PAs-related anti-oxidation ability in the mutants. Using ABA signaling mutants, our studies demonstrated that both ABA signaling pathway and PAs were important for the response to serve oxidative stress during seed germination. However, the discrepancy of the response between abi mutants and PAs mutants to oxidative stress suggests that ABA signaling pathway may not play a major role in PAs＂ action in alleviating oxidative stress. Under low or no oxidative stress, germination was mainly determined by the ABA content in seed and the PAs-deficient mutant seeds germinated faster due to their lower ABA content than wild-type. However, oxidative injury inhibited germination when PAs-deficient seeds germinated under high oxidative stress, Wild-type exhibited higher germination under the high ox- idative stress due to the PAs＇ anti-oxidation ability. Oxidative stress applied externally led to changes in endogenous PAs contents that coincided with the expression changes of PAs biogenesis genes. PAs modulated the activities of some key enzymes that controlled the levels of reactive oxygen species and the anti-oxidation capacity during the seed germination. This work suggests that PAs contribute to the adaptive mechanism that helps germination under environmental stresses by playing dual roles in both germination control and anti-oxidation reaction.

Developmental Competence of Frozen-thawed Germinal Vesical Porcine Oocytes by Vitrification Method following Maturation,Fertilization and Culture In Vitro

The purpose of this study was to evaluate the viability and subsequent developmental ability of porcine germinal vesicle（GV） oocytes vitrified step-wise exposure to cryoprotectants. Oocytes were transferred to a vitrification solution composed of 10% ethylene glycol（EG）,10% dimethyl sulfoxide（DMSO）, 300 g/L-1 Ficoll and 0.5 mol/L-1 sucrose（EDFS40） in a direct manner （non-preequilibrium） or in step-wise manner（ single- and two-step preequilibrium）. After vitrification and storage in liquid nitrogen, the oocytes were thawed,washed and in vitro maturation, fertilization and culture. In the non-preequilibrium group, the rates of post-thawed oocytes surviving, maturing to metaphase-Ⅱ, cleavage rate and blastocysts rate was significantly lower than that of sigle- and two-step preequilubrium groups（P<0.05）. In the single- and two- step groups, the rates of metaphase-Ⅱ stage were 46.8%, 42.7% and 49.7%, respectively, the rates which developed to blastocysts were 10.5%,11.1% and 14.8%, respectivaly. In the non-vitrified control group,the rates of oocytes maturing to metaphase-Ⅱ, developing to blastocysts was significantly higher than that vitrified groups（P<0.05）. The present study shows that the vitrification of porcine GV oocytes by a step-wise method involving two-steps preequilibrium may have advantage in maintaining the viability and subsequent production of blastocysts.

干旱胁迫下冬小麦不同品种萌发特性差异的研究

干旱是影响小麦生产的重要逆境,可以造成萌发成苗质量下降。为了解当前小麦品种在干旱胁迫下的种子萌发特性,采用沙培控水法研究了生产上应用广泛的128个小麦品种的干旱萌发特性;筛选出干旱萌发特性差异显著的6个小麦品种(山农28号(SN28)、长6878(C6878)、烟农19(YN19)、山农23号(SN23)、鑫麦296(XM296)和新麦38(XM38))进行干旱胁迫下种子萌发过程中的生理生化分析。结果表明,根据活力指数的耐旱系数进行聚类分析,将128个小麦品种的干旱萌发特性分为好、较好、中等、较差、差5类。山农28号和长6878等18个干旱萌发特性好的小麦品种种子萌发快,幼苗整齐健壮;新麦38、乐麦185等26个干旱萌发特性差的小麦品种种子萌发慢、萌发时间分散、发芽率低且幼苗整齐度差。进一步对不同干旱萌发特性的小麦品种进行生理生化指标测定表明,干旱萌发特性好的山农28号和长6878干旱萌发前期大分子修复基因TDP1表达水平显著高于对照;干旱萌发前期POD活性也显著高于对照;α-淀粉酶和半胱氨酸蛋白酶活性受干旱影响较小,萌发后期的可溶性蛋白含量显著高于对照。而干旱萌发特性差的鑫麦296和新麦38在干旱胁迫下种胚DNA和蛋白质修复基因表达水平上升相对滞后;在干旱胁迫下的半胱氨酸蛋白酶活性显著降低。上述结果表明,干旱萌发特性好的小麦品种在干旱胁迫下萌发成苗过程中种胚大分子修复能力和种子抗氧化能力强,贮藏物质动员早,最终种子萌发速度快,出苗质量高。

草豆蔻种子的萌发与贮藏特性研究

采用实验室双层纸上发芽法,通过温汤、苏打水和NAA浸种处理草豆蔻种子,并进行干燥和保湿贮藏实验,探究草豆蔻种子的萌发特性和贮藏特性。结果表明,草豆蔻种子不耐高温,30~60℃温汤浸种30 min,草豆蔻种子可以萌发,70℃以上难以发芽;用苏打水浸泡2 h、8 h,NAA_(5)及NAA_(50)浸种比清水处理发芽势高。在干燥和湿沙贮藏条件下种子生活力差异极显著,贮藏条件和贮藏时长的交互作用下,种子生活力差异极显著;草豆蔻种子不做处理常温放置在室内,30~60 d便会失活,但在低温潮湿环境下,种子生活力可以维持5个月以上;最优贮藏方式是保湿保鲜(2~3℃)贮藏,在第5个月使用TTC染色法仍有87%的草豆蔻种胚具有活力。

关键生长期氮磷肥组合对本土老芒麦种子产量及萌发力的影响

为探讨营养生长及生殖生长关键期氮、磷配肥组合对高寒区本土老芒麦种子产量及发芽力的影响,设计Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ组不同的氮磷肥追施组合,在分蘖-拔节期和抽穗-开花期,分别追施Urea(尿素)+Urea=75 kg/hm^(2)+75 kg/hm^(2)、Urea+SSP(过磷酸钙)=75 kg/hm^(2)+150 kg/hm^(2)、SSP+SSP=150 kg/hm^(2)+150 kg/hm^(2)、SSP+Urea=150 kg/hm^(2)+75 kg/hm^(2)和DAP(磷酸二铵)+DAP=150 kg/hm^(2)+150 kg/hm^(2),Ⅵ组为对照,不追肥,研究不同施肥组合对老芒麦种子产量及产量组分、种子发芽力的影响。结果表明,分蘖-拔节期和抽穗-开花期采用DAP+DAP(V组)、SSP+Urea(Ⅳ组)和Urea+SSP(Ⅱ组)施肥组合通过增加穗数/株、分蘖数、生殖枝数、小穗数/穗、种子数/穗和小花数/穗等种子产量因子,在一定程度上提高了老芒麦的潜在种子产量、表现种子产量和实测种子产量,也改善了种子发芽势、发芽指数和活力指数。Ⅴ组、Ⅳ组和Ⅱ组实测种子产量分别较对照增产569.21、420.07和363.05 kg/hm^(2),种子发芽势提高了27.13%、29.78%和27.13%,发芽指数提高了28.26%、19.37%和23.51%,活力指数提高了47.85%、44.19%和49.51%。老芒麦种子产量与穗数/株、生殖枝数、分蘖数、小穗数/穗、小花数/穗和种子数/穗均呈极显著正相关,与穗长和种子千粒重呈显著正相关。综上所述,穗数/株、分蘖数和生殖枝数是影响本土老芒麦种子产量的主要因子,分蘖-拔节期和抽穗-开花期适时追施氮磷二元肥或交互施用氮、磷肥,可显著增加种子产量主要组成因子,提高种子产量,并改善种子萌发力。

地被菊花粉生活力测定及影响因素研究

花粉生活力的高低直接影响地被菊杂交育种效率的高低或成败。快速准确测定不同地被菊品种的花粉生活力,可为正确选择杂交组合和授粉时间等提供参考依据,也是保证杂交育种顺利进行的关键。采用ME3液体培养基为基本培养基,探讨了地被菊花粉离体萌发的培养时间、适宜培养基和影响花粉生活力的主要因素,结果表明:花粉离体培养后90 min,花粉萌发率达到最高值;地被菊花粉萌发的适宜培养基为ME3+蔗糖100 g/L+PEG4000 150g/L或ME3+蔗糖150 g/L+PEG4000 150 g/L,150 g/L的PEG600和250 g/L的PEG4000也对花粉萌发有一定促进作用;温度是影响地被菊花粉萌发的重要因素,其中10,15,20℃是地被菊花粉萌发的适宜温度,高温会抑制花粉萌发;同一天内不同时间段采集的花粉生活力不同,其中13:00采集的花粉生活力最高,11:00-15:00也有较高的生活力。

青藏高原东缘唇形科植物种子大小对萌发的影响研究

以青藏高原东缘地区24种唇形科(Lamiaceae)种子为材料,在室外自然光照条件下进行萌发试验,研究种子大小与萌发特性的关系,为当地的植被保护或恢复对策的制定提供一定的科学依据。结果表明:24种唇形科植物种子的百粒重为0.0061～0.5688 g,跨越2个数量级,平均大小0.1200 g,60%的物种种子百粒重小于0.1200 g,表明在青藏高原东缘唇形科植物种子中小种子占优势。种子大小与萌发率和萌发速率指数呈极显著负相关(P<0.01);种子大小与集中度呈极显著正相关(P<0.001);种子大小与萌发开始时间的相关性不显著。这些结果说明,这24种唇形科植物的大种子物种和小种子物种有2种相反的萌发对策:小种子萌发率高,萌发速率快,萌发历期短,萌发整齐性好;大种子与小种子相反,并共同与其扩散能力构成了一个由小种子物种(拓植能力)到大种子物种(竞争能力)的连续体,从种子萌发对策上解释了大、小种子物种在同一自然群落中如何共存的问题。

柠檬醛致黄曲霉孢子丧失萌发力的机制

通过由倒置显微镜、衍射光栅和线阵光电偶合器件CCD(chargecoupleddevice)等构成的显微多道分光光度系统及由计算机DEPHI编程工具编制的单细胞凝胶电泳SCGE(single cellgelelectro phoresis)图像分析系统 ,摄取荧光显微镜所呈图像 ,再由图像捕捉卡将CCD产生的图像信号送入计算机 ,将柠檬醛对黄曲霉质膜和核DNA损伤的图像进行显示存储和分析处理 ,测定彗星长度、荧光强度、矩类及头尾DNA含量比等彗星参数指标 .结果发现Olive尾矩、尾长、尾分布矩等彗星尾参数指标与柠檬醛致黄曲霉损伤浓度呈正相关性 ,当致损浓度达到 1 5mg L以上时 ,DNA损伤为致死性损伤 ,不能被细胞内修复系统所修复 .揭示柠檬醛通过损伤质膜而进入细胞 ,对DNA产生不可逆损伤 ,使孢子失去萌发力的机制 .实现将DNA损伤的生化定性检测推进到数值化研究范围 ,为柠檬醛的开发应用提供了重要理论依据 .与国内外同类技术相比 ,本检测观察系统还具有高灵敏度、快速、无扰、多光谱显微测定之特点 .

不同干燥方式对发芽糙米品质的影响

以香粳99为原料发芽制得发芽糙米,研究了日光干燥、普通热风干燥、微波干燥和真空冷冻干燥对其主要营养成分、加工性能指标及色泽的影响。结果表明,真空冷冻干燥对发芽糙米品质影响最小,其次是微波干燥和普通热风干燥。

杜鹃红山茶花粉萌发力及贮藏耐性的研究

以2～3年生嫁接的杜鹃红山茶(Camellia azalea)花粉为实验材料,研究了不同培养基、不同培养温度对其萌发的影响,同时探讨了不同贮藏条件和贮藏时间下花粉生活力的差异。结果表明:杜鹃红山茶花粉在不同培养时间下其萌发率呈抛物线型,花粉在15%蔗糖+0.02%硼酸的培养基上萌发率最高,30℃的培养温度比25℃、20℃更适合杜鹃红山茶花粉萌发。-20℃冷冻保存和液氮保存都是适合杜鹃红山茶花粉长期保存的方式。

小麦发芽富硒工艺及其抗氧化活性的研究

采用不同浓度硒溶液处理研究小麦芽对硒的耐受能力、小麦发芽过程中对硒的最佳富集条件和最佳富硒条件下富硒小麦的主要营养成分和其抗氧化活性。结果表明,小麦发芽对硒最大耐受能力为80μg/mL;小麦发芽富硒的最佳发芽条件为:硒溶液浓度40μg/mL,浸泡6h,发芽10h时喷淋硒溶液,发芽温度20℃,发芽时间2d;富硒发芽小麦的硒含量、有机硒和蛋白质含量显著提高,淀粉含量没有受到显著性影响;抗氧化性分析结果表明,硒能够有效地提高小麦的抗氧化能力。

Larrea tridentata的种子萌发特性

经测定,Larreatridentata种子净度为97.4%,去除种皮能促进种子迅速、整齐地发芽。在砂床、纸床、蛭石床3种发芽基质上种子的发芽率无显著差异,但在砂床和蛭石床上的发芽速度比在纸床上快。在恒温(25℃)和变温(20～30℃)两种温度条件下进行发芽比较,结果显示:在恒温25℃时发芽率高,发芽速度快且整齐,可见25℃较适宜L.tridentata种子发芽。种子萌发时大约前9h为吸水期,且前4h吸水速度最快,吸水量是自身质量的1倍左右。

几种药剂对椭圆叶花锚种子发芽力的影响

目的 研究几种药剂对椭圆叶花锚种子的发芽力的影响。方法 用不同浓度的青霉素、KCN、KNO3、PEG-6 0 0 0、IAA、GA3、6 - BA溶液对椭圆叶花锚浸种。结果 青霉素的 5、2 0、4 0 m g/ L,KCN的 5、2 0 mg/ L,5 %的 PEG-6 0 0 0 ,2 0 m g/ L GA3和 6 - BA的 2 5、75 mg/ L可极显著提高椭圆叶花锚种子平均发芽率、平均发芽势 ,其中以 6 - BA以 2 5 m g/ L 处理效果最好 ,可使其种子发芽率、发芽势分别提高 4 6 .0 %、39.6 7% ;IAA溶液和 KNO3对椭圆叶花锚种子的萌发无明显效果 ;而 15 %、2 5 %的 PEG- 6 0 0 0、80 mg/ L IAA、16 0 mg/ L GA3、10 0 mg/ L 6 - BA则明显抑制种子萌发。用 5 mg/ L 青霉素、2 5 mg/ L 6 - BA分别处理椭圆叶花锚种子后进行的室内土壤播种 ,对种子的萌发无明显影响。结论 不同药剂及同一药剂的不同浓度对椭圆叶花锚种子发芽力的影响不同。

几种药剂浸种对瓠瓜种子发芽力影响的研究

本研究以瓠瓜（LasenariasicerariaStandL．var．clavatamakino）种子为试材，研究了乙烯利（100×10－6、150×10－5）、赤霉素（20×10－6、40×10-6）、油菜素内酯（1：4000、1：6000）对瓠瓜种子发芽力的影响，以清水处理为对照。实验结果表明：乙烯利、赤霉素浸种能显著提高瓠瓜种子的发芽率，20×10-6浓度的赤霉素处理能显著提高瓠瓜种子的发芽势。综合本实验结果，20×10－6浓度的赤霉素处理对提高瓠瓜种子发芽率和发芽势效果明显优于其它处理。油菜素内酯对瓠瓜种子发芽力无显著影响。

杉木无性系插穗生根和发芽影响因子的研究

对9个不同试验处理条件下杉木无性系插穗生根和发芽动态变化情况进行研究.结果表明:不同试验处理的杉木插穗生根和发芽情况存在明显差异.在扦插后前5个月内,随时间推移,沙质插床内半木质化或木质化插穗处理的生根与发芽能力呈上升趋势;赤霉素处理插穗的生根能力表现为先上升后下降的规律,至第4个月发芽能力呈下降趋势,且成活率降低;农田土基质中插穗的生根与发芽能力一般.