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A critical account on the inception of Striga seed germination 总被引：2，自引：0，他引：2
The seeds of the parasitic weed Striga germinate in response to stimulants exuded by the roots of host plants and some nonhost plants. Literature data are summarized that support the view that strigolactones induce germination of parasitic weed seeds via a receptor-mediated mechanism. The suggestion by Lynn et al. that the strigol D-ring is solely responsible for germinating Striga seeds via a redox reaction was based on hypothesized structural similarities between the natural compound dihydrosorgoleone (SXSg) and the strigol D-ring. Experiments have shown that the mechanistic connection between SXSg and the strigol D-ring is not valid, and therefore the proposed redox mechanism for the induction of Striga seed germination by strigolactones does not hold. 相似文献
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Wigchert SC Kuiper E Boelhouwer GJ Nefkens GH Verkleij JA Zwanenburg B 《Journal of agricultural and food chemistry》1999,47(4):1705-1710
Striga and Orobanche seeds germinate in response to a host-derived germination stimulant. Dose-response curves of the synthetic strigolactone analogues GR 24 and Nijmegen 1 were determined, and their activities were compared to that of the naturally occurring stimulant sorgolactone. Typical sigmoidal curves were obtained. ED(50) values for GR 24 were in the order of 10(-)(9)-10(-)(8) mol/L; for Nijmegen 1 these values were 3 orders of magnitude higher. Both synthetic stimulants are appreciably active at low concentrations and merit investigation as agents for the suicidal germination approach (i.e., treatment of the soil with stimulant in the absence of a host). 相似文献
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Soil salt and NaCl have different effects on seed germination of the halophyte Suaeda salsa
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下载免费PDF全文 Ruiru Gao Xiaoya Wei Zhan He Ruihua Zhao Kai Wang Xuejun Yang Jeffrey L. Walck 《植物养料与土壤学杂志》2018,181(4):488-497
Seed germination is a key life‐history stage of halophytes. Most studies on seed germination of halophytes have focused on the effects of a single salt, while little information is available on the effects of mixed salt in the natural habitat. Due to the contribution of multiple ions in saline soil, we hypothesized that the effect of mixed salt on seed germination will differ from that of a single salt and the mechanism of how germination is affected will differ as well. The effects of mixed salt and NaCl on germination, water imbibition, and ionic concentrations of seeds of Suaeda salsa (L.) Pall. were compared at various salinity levels. Germination percentage (GP) and rate (GR) decreased with increasing salinity level, regardless of salt type. There was no difference in GP or GR between mixed salt and NaCl when the salinity level was below 20 dS m?1. Above 20 dS m?1, GP and GR in NaCl were lower than those in mixed salt. At the same salinity level, Na+ concentration in seeds was higher in NaCl than that in mixed salt, but the reverse was true for Ca2+ and Mg2+ concentrations. Imbibition rate for seeds in NaCl was lower than that in mixed salt at the same salinity level. Addition of Ca2+ and Mg2+ alleviated the inhibition of NaCl on seed germination. In conclusion, our results suggest that the effects of soil salts and NaCl on seed germination are different, and using NaCl instead of soil salt might not be realistic to show the effect of saline stress on seed germination of halophytes in the natural habitat. 相似文献
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试验研究了从山豆根(Menispermum dauricum DC.)组培根中提取、分离独脚金属杂草[Striga hermonthica(Del)Benth]发芽刺激物质,其提纯、分离过程是首先将发芽剌激物质吸附在XAD-4树脂表面后采用甲醇脱洗,通过乙酸乙脂:水分配提取,活性物质在Sephadex LH20开口型人工填充柱上进行柱层析,活性组分合并后进一步采用商业提供的C18 Sep-Pak(10g)柱进行柱层析,之后采用分取和分析高效液相色谱提纯、分离,每一步提纯过程中均采用Striga种子发芽实验鉴定活性物质的存在。高效液相色谱分析表明有3种活性物质,其中主要活性物质与Strigol有十分相似的色谱特性,最后经质谱鉴定为Strigol或Strigol类似物质,并首次报道Strigol是植物的代谢产物。 相似文献
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Ueno K Nomura S Muranaka S Mizutani M Takikawa H Sugimoto Y 《Journal of agricultural and food chemistry》2011,59(19):10485-10490
Striga gesnerioides is a root parasitic weed of economic significance to cowpea (Vigna unguiculata) crops in Western Africa. Seeds of the parasite germinate in response to cowpea root exudates. Germination stimulants for the seeds were isolated from the hydroponic culture filtrate of cowpea, and their structures were unambiguously determined as (-)-(3aR,4R,8bR,2'R)-ent-2'-epi-orobanchol and (+)-(3aR,4R,8bR,2'R)-ent-2'-epi-orobanchyl acetate, on the basis of mass, CD, and (1)H NMR spectra; optical rotatory power; and chromatographic behavior on HPLC. The alcohol was first isolated and identified from the cowpea root exudates, and the acetate may be the same compound that had been previously isolated from the exudates and designated as alectrol. Identity of the stimulants produced by cowpea to those produced by red clover (Trifolium pratense) was confirmed. 相似文献
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小芸木种子生理特性及萌发影响因素的初步研究 总被引：6，自引：1，他引：6
对分布于滇南热带雨林的小芸木种子的萌发生理进行初步研究 ,结果表明 :小芸木种子是一种顽拗性种子 ,含水量为 4 8%～ 50 %的种子在 2 0、 2 5和 30℃发芽率达 90 %以上 ;含水量在 4 5%以下时 ,发芽率在 63%以下 ;种子含水量降低至 2 5.78% ,胚含水量降至 1 3.4 4%时 ,均完全失去发芽力。种子有休眠特性 ,轻度脱水、流水冲洗可以打破休眠。种子在 2 0、2 5、30℃恒温条件下 ,发芽率较高且较快 ,而在 1 2、4 0℃和室温 (白天 2 4～ 35℃ ,夜间 1 6～ 2 4℃ )时发芽率低且较慢。随着含水量的降低 ,种子萌发时对温度和光照的敏感性升高 ,低温对种子萌发的抑制作用加强 ;用 0 .0 1 %的高锰酸钾溶液处理含水量为 4 5.0 4 %的种子 ,在 2 0、 2 5、 30℃种子萌发率可提高 1 5%～ 60 % 相似文献
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为研究筛选可提高或促进黔南扁穗雀麦(Bromus carticus cv.Qiannan)种子萌发、幼根发生的溶磷菌,探索供试培养基对溶磷菌的生长及黔南扁穗雀麦种子萌发的影响,开展了溶磷菌Br24在以LB和PDA培养基为基质的不同剂量处理下对黔南扁穗雀麦种子发芽影响的培养试验。结果表明,改良LB培养基是溶磷菌生长较好的基质;经PDA培养液处理的扁穗雀麦种子,出苗速度和出苗整齐度较好;以LB和PDA作为培养基质,活化48 h的Br24菌液浸种6 min或分别接种菌液量不超过2 mL与1 mL,扁穗雀麦种子发芽率最好。菌株Br24可作为溶磷接种剂,具有一定生产和推广应用价值。 相似文献
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四倍体西瓜作为三倍体无籽西瓜的母本,其性状对三倍体西瓜组合选配起着重要作用,其中四倍体西瓜种子性状对三倍体西瓜品种的种子发芽率、成苗率、采种量起关键作用。为研究四倍体西瓜种子的性状变异,以41组秋水仙素诱导的T6同源四倍体西瓜为试验材料,以其诱导前的同源二倍体为对照,比较加倍后四倍体西瓜种子发芽率、单瓜种子数、百粒重和形态结构变异。结果表明,秋水仙素诱导加倍后,四倍体种子发芽率、单瓜种子数均低于其同源二倍体,但种子长度、宽度、厚度、喙宽、种皮厚度和百粒重均大于其二倍体。四倍体西瓜的单瓜种子数与其二倍体西瓜的种子数极显著相关,二倍体和四倍体西瓜的百粒重与其本身的长度和宽度极显著相关,四倍体西瓜种子种皮厚度与多个性状都显著相关,但四倍体种子的发芽率除与其种子的喙宽显著相关外,与其他性状都无显著相关性。本研究通过比较人工诱导的同源四倍体与其原始二倍体西瓜种子的差异,为诱导四倍体的选择及多倍体西瓜育种提供了一定的理论依据。 相似文献
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为探讨FeSO4引发提高秦艽种子萌发抗性的生理机制,同时设置水引发处理,以未作任何处理的种子为对照(CK),研究了0.6%FeSO4引发处理24 h对种子膜透性、储藏性物质、能量、激素及抗性相关酶等方面的影响。结果表明:FeSO4引发降低了种子膜透性,提高种子活力,在吸水12 h和24 h时,电导率分别较CK降低了6.61%和11.67%;调动了种子内部储藏物质的代谢,蔗糖含量减少9.57%,可溶性蛋白增加49.63%,饱和脂肪酸中的豆蔻酸和木焦油酸甲酯含量分别增加4.93%和9.03%,不饱和脂肪酸中的山嵛酸、油酸、亚油酸和亚麻酸分别减少6.73%、8.18%、8.40%和6.70%;改变了种子激素平衡,其中脱落酸的含量下降64.78%,赤霉素含量增加近22倍;加速了种子能量代谢, ATP含量增加2.16倍,细胞色素C氧化酶活性增加67.91%。此外,FeSO4引发使线粒体非酶促系统中谷胱甘肽含量和抗坏血酸的含量分别增加74.08%和10.89%,使细胞内酶促系统超氧化物歧化酶、过氧化氢酶和抗坏血酸过氧化物酶活性分别增加285%、179%以及19.6%。因此,FeSO4引发对种子萌发是一个综合过程,一方面可促进种子物质代谢和提高能荷水平,一方面可改善种子内部生理状态和提高胁迫响应能力,从而提高种子活力,促进种子快速和整齐萌发。 相似文献
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为了获得花梨木快速繁殖无菌苗,本试验以花梨木种子为材料研究不同植物生长调节剂对种子萌发、愈伤组织形成、腋芽萌发和生根的影响。结果表明：培养基MS＋0.5 mg/LGA3最适合种子萌发;3.0 mg/L的BA与0.5mg/L的IAA的培养基为最佳生根培养基。 相似文献
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Aria Dolatabadian Mozafar Sharifi 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(5):456-464
Abstract The effects of pretreatment with salicylic acid on wheat seed germination (Triticum aestivum L. cv. Roshan), lipid peroxidation, and superoxide dismutase, catalase, polyphenol oxidase, and peroxidase activity were studied under conditions of salt stress. Seeds treated with different concentrations of salicylic acid were used for measuring germination traits. Salt stress was induced by sodium chloride solution. Seeds were soaked in salicylic acid solution for 24 h, dried with sterile paper, transferred to sterile Petri dishes, and treated with 10 ml NaCl solution at different concentrations. After 1 week, the number of germinated seeds, root length, seedling length, and dry weight were recorded. Antioxidant enzyme activity and lipid peroxidation were also assayed. Salinity decreased seed germination. Thus, a high concentration of NaCl (200 mM) decreased germination by 17.6% compared with control treatment. Salicylic acid significantly increased germination in stressed and control seeds. Salicylic acid increased the level of cell division of seedlings and roots, which increased plant growth. Salt stress significantly increased the activity of the antioxidative enzymes catalase, superoxide dismutase, peroxidase, and polyphenol oxidase in wheat seedlings, and salicylic acid reduced the activity of antioxidant enzymes as stress signal molecules. Our results indicated that scavenging of reactive oxygen species was effective, especially by salicylic acid, and that membrane damage was limited. The aim of the present work was to study the character of changes in enzymatic systems induced by NaCl and salicylic acid in wheat seedlings under conditions of salt stress. In brief, salicylic acid treatment reduced the damaging action of salinity on embryo growth and accelerated a restoration of growth processes; thereupon it may be effective for the improvement of seed germination in arid and semi-arid regions. 相似文献
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~(60)Coγ辐射对毛竹种子活力及早期幼苗生长的影响 总被引：9，自引：0，他引：9
以毛竹(Phyllostachys edulis)干种子为材料,采用室内发芽实验、电导率测定和TTC活力测定以及早期幼苗生长分级等4种方法研究了60Coγ射线对种子活力及早期幼苗生长的诱导效应。结果表明:当辐照剂量低于100Gy时,辐照能加快种子萌发进程,提高发芽率;而当剂量超过100Gy,则对毛竹种胚组织造成损伤,抑制细胞生长和分裂,不同程度地延迟了毛竹种子发芽过程,降低了种子活力,造成早期苗高和根生长受到明显抑制,抑制作用随辐照剂量的增大而增强。毛竹种子发生诱变效应的最佳辐照剂量范围为100~175Gy。24h电导率与发芽率、发芽指数、活力指数、苗高和根生长等活力指标间存在极显著线性关系,是快速检验毛竹种子活力的重要指标。24h电导率和苗高又可作为检查辐射后毛竹种子活力变化和发生诱导效应的有效指标。 相似文献
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以1Gy/min的剂量率,用不同剂量（0~800Gy）的60Co γ射线辐照续随子干种子,对M1种子萌发情况及苗期性状进行调查。分析结果显示,在供试剂量范围内,辐照对续随子发芽率无明显影响,对发芽势、发芽指数、活力指数及幼苗生长量有显著或极显著的抑制效应;且抑制效应随剂量的增加和幼苗的生长而增大。在以上数据分析的基础上,以活力指数下降一半时的脊梁VID50及幼苗半致癌剂量GR50为标准,通过回归分析初步预测,供试续随子适宜辐照诱变剂量约为400~600Gy. 相似文献
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Zinc‐biofortified seeds improved seedling growth under zinc deficiency and drought stress in durum wheat
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下载免费PDF全文 High zinc (Zn) concentration of seeds has beneficial effects both on seed vigor and human nutrition. This study investigated the effect of Zn biofortification on growth of young durum wheat (Triticum durum cv. Yelken) seedlings under varied Zn and water supply. The seeds differing in Zn concentrations were obtained by spraying ZnSO4 to durum wheat plants at different rates under field conditions. Three groups of seeds were obtained with the following Zn concentrations: 9, 20, and 50 mg Zn kg?1. The seeds differing in Zn were tested for germination rate, seedling height, shoot dry matter production, and shoot Zn concentration under limited and well irrigated conditions in a Zn‐deficient soil with and without Zn application. In an additional experiment carried out in solution culture, root and shoot growth and superoxide dismutase activity (SOD) of seedlings were studied under low and adequate Zn supply. Low seed Zn concentration resulted in significant decreases in seedling height both in Zn‐deficient and sufficient soil, but more clearly under water‐limited soil condition. Decrease in seed germination due to low seed Zn was also more evident under limited water supply. Increasing seed Zn concentration significantly restored impairments in seedling development. Drought‐induced decrease in seedling growth at a given seed Zn concentration was much higher when soil was Zn‐deficient. Increasing seed Zn concentration also significantly improved SOD activity in seedlings grown under low Zn supply, but not under adequate Zn supply. The results suggest that using Zn‐biofortified seeds assures better seed vigor and seedling growth, particularly when Zn and water are limited in the growth medium. The role of a higher antioxidative potential (i.e., higher SOD activity) is discussed as a possible major factor in better germination and development of seedlings resulting from Zn‐biofortified seeds. 相似文献
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Takahiro Ogura Michio Sunairi Mutsuyasu Nakajima 《Soil Science and Plant Nutrition》2013,59(1):217-227
The effects of 2-methylisoborneol (MIB) and geosmin, the main sources of soil odor produced by microorganisms, on plant seed germination were examined for 15 kinds of Brassicaceae seeds including radish (Raphanus sativus var. radicula). Authentic MIB or geosmin was used at the concentration of 100 mg L-1 in the assay, the effects were quantitatively indexed based on four parameters of cumulative seed germination: the final germination percentage, germination onset, weighted mean rate, germination index. MIB and geosmin inhibited germination of all kinds of seeds tested for these parameters. Radish variety “Comet” was the most affected of all of the tested plant seeds. The estimated 50% inhibitory concentration values on germination of “Comet” were 70.5 and 7.5 mg L-1 for MIB and geosmin, respectively. We also conducted the primary characterization of the inhibition by MIB and geosmin on “Comet” seeds. Our findings were as follows: (1) onset of seed imbibition was not affected; (2) germination of seeds pre-imbibed in the control solution until approx. 2 h before germination onset was inhibited by subsequent MIB or geosmin treatment; (3) growth of seedlings was not significantly affected; (4) the germination was restored by stratification, gibberellin A3 treatment, or seed coat removal; and (5) light irradiation affected the degree of inhibition. These results suggest that inhibition by MIB and geosmin is restricted to the germination process, at least in the early stage of growth, that they act as growth -regulating substances. 相似文献
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种衣剂对低温处理下棉花胚根及幼苗外部形态和超微结构的影响 总被引：2，自引：0，他引：2
以棉种‘新陆中54号’为材料,用3种种衣剂(棉1、棉2、棉3)包衣棉种后播种于塑料营养盒内,25℃恒温培养,分别在第4天(棉种长出胚根)和第7天(棉株幼苗)均进行5、10、15、20℃共4个低温处理,与各低温下未包衣种子(对照,CK)进行比较,低温处理24h后,观察各处理棉花胚根、幼苗外部形态和超微结构的变化,以期通过模拟新疆早春"倒春寒"发生特点,考察种衣剂对提高棉花耐寒性的功效。结果表明:20℃下种衣剂处理与CK无差异,种子萌发正常,发芽率在92.24%~95.51%,3种种衣剂包衣处理胚根生长量为3.66~3.81cm,幼苗叶色浓绿,茎杆直立,胚根细胞中线粒体结构完整,叶肉细胞中线粒体、叶绿体结构规则;15℃低温下种衣剂处理棉种发芽率较CK提高4.45~6.98个百分点,胚根生长速度下降,但包衣处理生长量较CK提高25.27%~36.05%,幼苗叶色浓绿,棉苗直立,胚根细胞中线粒体内脊清晰,叶肉细胞中叶绿体、线粒体结构清晰,细胞器结构和数量明显优于CK;10℃低温下棉种发芽受到抑制,但包衣处理较CK发芽率提高0.73~4.25个百分点,19.15%~42.55%的幼苗叶片下垂萎蔫,保持正常温度后种衣剂处理棉苗很快恢复到正常形态,胚根细胞中线粒体、内质网数目多于CK,叶肉细胞中叶绿体轮廓清晰,内含物较少;5℃低温下各处理棉种发芽率均低于50.00%,CK幼苗叶色脱水失绿,萎蔫下垂,萎蔫率达74.47%,叶绿体膨胀成圆球形、轮廓模糊,包衣处理幼苗萎蔫率在60.42%~67.45%,叶肉细胞中叶绿体结构完整,呈椭球型,线粒体结构较规则、内含物浑浊。研究表明种衣剂能促进低温处理下种子萌发、提高发芽率和胚根生长速度、保护棉苗外部形态和细胞超微结构稳定,维持正常生长,增强幼苗抵御低温的危害能力。 相似文献
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极低频高压脉冲电场提高陈年棉种活力的参数优化 总被引：1，自引：1，他引：0
为研究极低频脉冲电场对陈年棉种活力的影响,该文利用高压脉冲电源和弧形电极-平板组成的电场系统在极间距离为50 mm条件下,以16 k V、10 Hz为中心点,利用Design-expert软件设计正交试验,高压脉冲电场处理棉种时间为40 s。并利用响应面分析法,对发芽势、发芽率、发芽指数、活力指数等4个指标进行参数优化,得出最优处理电压为16.25 k V,最优频率为10.90 Hz。在此基础上,对优化条件进行了试验验证。结果表明:陈年棉种在脉冲电压16.25 k V、脉冲频率10.90 Hz处理条件下,与对照相比,发芽势提高了44.2%,发芽率提高了56.8%,发芽指数提高了64.3%,活力指数提高了81.8%,各指标都达到极显著差异(P0.01)。陈年棉种的电场生物学效应对电场电压和频率都具有选择性,在电压为16.25 k V、频率为10.90 Hz的脉冲电场作用下,陈年棉种的电场生物学效应最明显,研究结果为后续作物种子高压电场处理的参数优化提供参考。 相似文献