Fenugreek root exudates show species-specific stimulation of Orobanche seed germination

Various Orobanche species are weedy and cause severe reduction in the yields of many important crops. The seeds of these parasitic weeds may remain dormant in the soil for many years until germination is stimulated by the release of a chemical signal from a host plant. In order to determine the effects of fenugreek root exudate on the induction of Orobanche crenata, Orobanche ramosa and Orobanche foetida seed germination, root exudate was collected from hydroponically grown fenugreek seedlings. Fractionation patterns obtained from column and thin layer chromatography of the fenugreek root exudate showed a set of metabolites differing in their polarity with stimulatory activity on Orobanche seed germination. The crude root exudate stimulated both O. ramosa and O. crenata seed germination to the same level caused by the synthetic germination stimulant GR24 at 10 mg L^?1. It also stimulated O. foetida seed germination which did not respond to GR24. Active fractions of root exudate stimulated the germination of Orobanche species differentially.     

黄花刺茄浸提液对番茄种子萌发及幼苗生长的影响

为明确入侵植物黄花刺茄对当地主栽经济作物番茄种子萌发和幼苗生长的影响,本文采用培养皿滤纸法,在智能光照培养箱的变温控制条件下,分别研究了黄花刺茄根、茎、叶浸提液对番茄种子发芽率、发芽指数及幼苗根长和苗高的影响。结果表明:(1)黄花刺茄不同器官的浸提液对番茄种子发芽率、发芽指数、幼苗根长和苗高的影响不同,其茎、叶浸提液的化感作用较为显著(P<0.01)。(2)黄花刺茄同部位浸提液对番茄种子发芽率、发芽指数、幼苗根长和苗高不同指标的影响也不同。根浸提液对种子发芽率、幼苗根长影响不显著(P>0.05),但对种子发芽指数的影响极显著(P<0.01)。茎和叶浸提液各浓度对种子发芽指数的影响比种子发芽率、幼苗根长和苗高的影响显著(P<0.01)。     

转基因玉米种子萌发期抗旱性鉴定

采用聚乙二醇(PEG)高渗溶液,对13个转基因玉米自交系进行了种子萌发期模拟水分胁迫发芽试验,研究了渗透胁迫模拟干旱对抗旱转基因玉米种子萌发状况的影响。结果表明:干旱胁迫对玉米发芽势、发芽率、根数、胚根长、胚芽长、贮藏物质转化率等均有不同程度的影响,不同转基因玉米自交系在抗旱性上存在明显差异。同时,使用隶属函数法对参试转基因玉米自交系的种子萌发抗旱性进行了分析评价,其中SD10为萌发期抗旱性较强的自交系;CBF-3-4、SD13、SD05、CBF-1-4、CBF-6-5、SD-P3、SD-P5为萌发期抗旱性中等的自交系;SD06、CBF-3-1、SD07、SD-P1、SD-P4为萌发期抗旱性较弱的自交系。种子萌发抗旱指数与隶属函数对玉米自交系抗旱性分析结果比较一致。     

7种激素对蒺藜状苜蓿种子发芽的影响

本实验旨在研究蒺藜状苜蓿种子发芽对外源激素的响应。使用6-BA、GA3、ABA、NAA、乙烯利I、AA和IBA共7种激素,每一激素各设0.1、1.0、1.5、2.0、5、10、201、000μmol/L共8种浓度梯度,浸湿滤纸发芽床,置50粒蒺藜状苜蓿种子进行发芽试验,以蒸馏水处理为对照,设3个重复,统计发芽率、发芽势、发芽指数和发芽天数。结果显示:外源激素20μmol/L 6-BA、GA3、乙烯利和5μmol/L IAAI、BA促进蒺藜状苜蓿种子发芽,NAA和ABA抑制蒺藜状苜蓿种子发芽,ABA抑制能力较强。     

Impacts of snow on seed germination are independent of seed traits and plant ecological characteristics in a temperate desert of Central Asia

Seed germination profoundly impacts plant community composition within the plant life cycle. Snow is an important source of water for seed germination in the temperate deserts of Central Asia. Understanding how seed germination responds to variations in snow cover in relation to seed traits and plant ecological characteristics can help predict plant community sustainability and stability in Central Asia under a scenario climate change. This study investigated the seed germination of 35 plant species common to the Gurbantunggut Desert in Central Asia under the three snow treatments: (1) snow addition; (2) ambient snow; and (3) snow removal. Two-way analysis of variance (ANOVA) tests were performed to assess interactions among the impacts of snow treatments, seed traits and plant ecological characteristics on seed germination. Phylogenetic generalized least-squares (PGLS) model was used to test the relationships between seed traits and seed germination. The results demonstrated that snow variations had no significant impacts on seed germination overall. Seed germination under the snow addition treatment was similar with that under the ambient snow treatment, irrespective of seed traits and plant ecological characteristics. Snow removal only had negative impacts on seed germination for certain groups of seed traits and plant ecological characteristics. Seed mass positively affected seed germination, showing a linear increase of arcsin square root-transformed seed germination with log-transformed seed mass. Seed shape also profoundly impacted seed germination, with a higher germination percentage for elongated and flat seeds. Seed germination differed under different plant life forms, with semi-shrub species showing a significantly higher germination percentage. Most importantly, although snow treatments, seed traits and plant ecological characteristics had no interactive effects on seed germination overall, some negative impacts from the snow removal treatment were detected when seeds were categorized on the basis of seed mass and shape. This result suggests that variations of snow cover may change plant community composition in this temperate desert due to their impacts on seed germination.     

黄土丘陵植被恢复过程中土壤种子库萌发数量特征及动态变化

采用野外定点采样与室内土壤种子萌发试验相结合的研究方法,选取黄土丘陵区典型草原带宁夏固原地区不同植被恢复年限(2,5,12,24,35,55,75 a)及当年农地(对照)的8个样地,研究该区土壤种子库萌发数量特征及动态变化.结果表明,8个不同植被恢复年限样地土壤中可萌发的种子的平均数量为3542.5粒/m2,可萌发种子以双子叶植物为主,约占萌发总数的90%.0～5 cm土层可萌发种子数量变化于166.7～9100.0粒/m2;5～10 cm土层变化于133.38～2120.02粒/m2.土壤中可萌发种子数量随着恢复年限的增加表现先增加后下降的趋势.土壤中可萌发的种子数量随时间的变化近似单峰型,双子叶植物峰值主要出现在第4～6周,而单子叶植物萌发高峰在5～6周.表明在环境,气候等条件适宜时,黄土丘陵区典型草原带可萌发的土壤中的种子可形成萌发高峰.     

不同产地扁蓿豆种子萌发期抗旱性综合评价

采用不同渗透势聚乙二醇（PEG6000）溶液模拟干旱胁迫,研究了甘肃景泰、陇西、镇原、永昌、天水、榆中、宁县、夏河、临夏、渭源和内蒙古土默特、陕西陇县12个扁蓿豆（Medicago ruthenica）居群种子萌发期的抗旱性。结果表明,PEG胁迫降低了扁蓿豆种质资源的发芽率、发芽指数、活力指数,抑制了胚芽和胚根的生长。-0．3 MPa的渗透势胁迫可促进陇西扁蓿豆种子的萌发,且在此浓度下其相对发芽指数和相对活力指数均显著高于其他11份材料。在-0．3 MPa PEG胁迫下景泰和土默特扁蓿豆的相对胚根长较高,表现出一定的抗旱性;高渗透势的胁迫严重抑制了扁蓿豆胚芽和胚根的生长。以种子萌发期的相对发芽率、相对发芽指数、相对活力指数、相对胚根长和相对胚芽长等5项为指标,应用隶属函数法对12份扁蓿豆抗旱性进行综合评价,抗旱性强弱依次为：景泰＞陇西＞土默特＞镇原＞永昌＞天水＞榆中＞宁县＞夏河＞临夏＞陕西陇县＞渭源。     

NaCl胁迫对花棒种子萌发的影响

用不同浓度的NaCl溶液对花棒(heydeysarum scoparium)种子进行胁迫萌发实验,观察其发芽率和萌发后种苗的生长情况,并测定萌发吸水率及淀粉酶活性.结果表明:花棒种子萌发对盐胁迫有一定的适应性,当NaCl盐浓度≤0.9%时,种子的发芽率均能达到90%以上;但随着NaCl浓度的增加,种子的萌发吸水受到抑制,淀粉酶活性降低,发芽率、发芽指数和活力指数均呈逐渐下降趋势.当NaCl盐浓度≤0.6%时,种子萌发出的幼苗生长基本不受影响;但当NaCl盐浓度≥1.5%时,胚根伸长基本停止.     

拌种防治玉米二点委夜蛾的药剂筛选及其安全性研究

为了筛选拌种防治二点委夜蛾的有效药剂,并明确其对玉米种子萌发的安全性。本文通过培养皿法和室内盆栽试验比较了9种不同类型杀虫剂拌种对玉米种子萌发的影响以及保苗效果。结果表明,60%溴氰虫酰胺SC和20%氯虫苯甲酰胺SC拌种处理效果较好,保苗效果分别达到90.02%和70.07%,可将死苗率控制在10%以内,被害指数控制在20%以内,且对玉米出苗安全。因此,60%溴氰虫酰胺SC和20%氯虫苯甲酰胺SC可作为拌种防止玉米二点委夜蛾为害的有效药剂。     

褪黑素浸种对大豆种子萌发过程中干旱胁迫的缓解效应

以大豆干旱敏感型品种绥农26为材料,采用室内培养法,研究不同浓度褪黑素(0、100、300、500、800μmol·L^-1)浸种对6%PEG-6000模拟干旱胁迫条件下大豆种子萌发的影响。结果表明:干旱胁迫处理抑制了大豆种子萌发,与对照(蒸馏水处理种子)相比,处理D(6%PEG处理种子)的发芽势、发芽率、根体积和鲜重显著降低,降幅分别为38.14%、23.72%、21.4%、25.6%;根系电导率、MDA和H₂O₂含量大幅上升,增幅分别为51.18%、83.33%和60.60%。而褪黑素浸种处理(100、300、500、800μmol·L^-1)显著缓解了干旱胁迫对种子萌发的抑制,促进了根系生长,其中以根直径和干重提升最为显著,分别增加了16.38%、29.73%、34.97%、31.72%和10.70%、14.28%、10.70%、25.00%;抗氧化酶(SOD、POD、CAT、APX)活性提高,其中处理M500+D(500μmol·L^-1褪黑素+6%PEG)效果最为显著,增幅...     

Ni~(2+)、Cu~(2+)胁迫对柠条种子萌发特征的影响

干旱区矿业废弃地生态修复植物的科学选择是生态治理的前提。文中以干旱区生态恢复的优势植物柠条(Caragana korshinskii Kom)为研究对象,研究了Ni2+、Cu2+在不同浓度条件下对其种子萌发特征的影响,以期为矿业废弃地及重金属污染土壤的生态修复提供科学依据。结果表明:在Ni2+或Cu2+胁迫条件下,柠条种子的发芽率、发芽势、发芽指数及活力指数都有不同的响应特征,低浓度时对种子萌发影响不明显,甚至有促进作用,当Ni2+浓度为20mg/L或Cu2+浓度为50mg/L时柠条种子的萌发较快,发芽率相对较高,且有利于干物质的积累;高浓度时则有较强的抑制作用,其中Ni2+的抑制作用要高于Cu2+;Ni2+和Cu2+对胚根的生长均具有抑制作用并随着浓度的升高而逐渐增强。     

Effects of temperature and light on seed germination of ephemeral plants in the Gurbantunggut Desert,China: implications for vegetation restoration

Seed germination is a key transitional stage in plant life cycle and is strongly regulated by temperature and light. Therefore, research on the effects of temperature and light on seed germination is extremely meaningful for vegetation restoration, especially in desert ecosystems. Seeds of 28 ephemeral plants collected from the Gurbantunggut Desert of China were incubated at different temperatures (5°C/1°C, 15°C/5°C, 20°C/5°C, 25°C/10°C and 30°C/15°C) in 12-h light/12-h darkness or continuous darkness regimes, and the responses of seed germination to temperature and light and the germination speed were studied in 2016. Results showed that seed germination percentage of the 28 ephemeral plants significantly differed to temperature and light. We classified the studied plants as the following groups based on their responses to temperature: 1 low temperature responsed plants, 12 moderate temperature responsed plants, 7 high temperature responsed plants, 4 non-responsed plants and 5 plants of no germination. It should be noted that Corispermum lehmannianum Bunge is sensitive to both moderate and high temperatures. There were 4 groups of plant in response to light, i.e., 7 light responsed plants, 10 dark responsed plants, 6 light non-responsed plants and 5 plants of no germination. Based on seed germination speed of the 28 ephemeral plants, we divided them into 4 patterns of germination, i.e., very rapid, moderately rapid, moderate and slow. Combining variations of temperature, precipitation and sand dune types in the study area, we suggested that very rapid and moderately rapid germinated plants could be used to moving sand dunes in early spring during vegetation restoration, moderate germinated plants could be used to semi-fixed sand dunes in late autumn, and slow germinated plants could be used to sand plain in summer. Thus, seedling establishment and vegetation restoration would be improved by considering seed germination characteristics of these ephemeral plants in the Gurbantunggut Desert, China.     

外源NO对渗透胁迫下黑麦草种子萌发及活性氧代谢的影响

以黑麦草为试材,研究了一氧化氮(NO)供体硝普钠(SNP)对聚乙二醇6000渗透胁迫下种子萌发、幼苗叶片活性氧代谢和渗透溶质积累的影响,探讨外源NO对渗透胁迫下牧草生理响应的调节作用.结果表明:100μmol/L SNP显著提高了渗透胁迫下黑麦草种子的发芽率、发芽指数和活力指数,缓解了植株鲜重和干重的下降幅度,提高了幼苗叶片SOD、POD、APX、质膜H+-ATPase活性及谷胱甘肽、可溶性糖、游离氨基酸、脯氨酸、K+、Na+含量和植株含水量,降低了O2-.产生速率及H2O2、丙二醛和可溶性蛋白含量.表明外源NO能够促进渗透胁迫下黑麦草种子的萌发,对渗透胁迫引起的黑麦草幼苗膜脂过氧化具有缓解作用.     

光对入侵性植物黄顶菊种子萌发及植株生长的影响

入侵性杂草黄顶菊原产南美,2003年在我国河北省衡水湖首次报道。采用室内控制试验,对光与黄顶菊种子发芽及植株生长的关系进行了研究。结果表明：黄顶菊种子属光敏型,种子需要光刺激才能发芽。但其萌发对光强要求不严,1 000 lx光照强度30 ℃培养6、12 h和24 h转入暗培养,5 d后黄顶菊种子发芽率分别为67.0%、88.0%和95.8%。黄顶菊种子出苗与光照关系密切,播种在土壤表面、0.5 cm和1 cm深土层的种子出苗率分别为96.0%、8.0%和0。随光照强度减弱,植株的生物量及繁殖力显著降低。黄顶菊在35%自然光强下生长时其生物量、结实数比自然光强下分别降低55.0%和55.6%。上述结果为预测黄顶菊的适生区域及制订有效的防除策略提供了科学依据。     

Seed production and subsequent seed germination of Senecio vulgaris (groundsel) grown alone or in autumn-sown crops

Senecio vulgaris is a common weed of agriculture in the UK, but is also of food value to invertebrates and birds. Thus, it may be beneficial to retain it within agricultural ecosystems to enhance overall biodiversity. A less intensive approach to weed management requires a sound understanding of weed population dynamics so as to avoid unacceptable population growth. Experiments were carried out in 2003 and 2004 to assess seed production, and subsequent germination, by S. vulgaris growing alone, in winter wheat, or in winter field beans. Plant and seed samples were collected during May and June. There was a strong allometric relationship between capsule number and plant weight, irrespective of the year or the presence of crop competition. Numbers of seeds/capsule varied slightly from 51 to 66 seeds per capsule. Plants growing alone were estimated to produce 8471 to 12 887 seeds per plant, whilst those in wheat only 923 to 2156. Germination tests in Petri dishes in incubators showed that virtually all seeds were viable and germinated under daily alternating light:dark conditions within 10 days. Seeds in continuous dark germinated less readily, reaching only 30% after 21 days. On the basis of this and other published work, it would appear that the retention of S. vulgaris in arable fields will not pose a major threat to the long-term viability of crop production.     

差巴嘎蒿(Artemisia Halodendron)种子萌发对土壤温度、水分和埋深的响应

差巴嘎蒿(Artemisia halodendron)是科尔沁沙地植被的关键种之一,它在沙地植被的恢复演替过程中扮演着重要角色,也被广泛应用于人工固沙活动中。为了了解差巴嘎蒿对风沙环境的适应特点,试验研究了其种子萌发对土壤温度、水分和埋藏深度的响应模式。结果表明:差巴嘎蒿种子在4月和5月的土壤温度条件下萌发良好,总萌发率可达到96%,在7月的土壤温度条件下萌发较差,总萌发率低于50%;若以试验前3天的总萌发率为准,则5月的萌发率远大于其它两个月。在0MPa、-0.1MPa、-0.2MPa、-0.4MPa、-0.8MPa和-1.6MPa水势下,差蒿种子的总萌发率分别为89%、83%、80%、46%、17%和0%。在0.5cm、1.0cm和2.0cm埋深下,最终出苗率分别为90%、32%和9%,当埋深大于4cm后,种子无法出苗。种子萌发对温度、水势和埋深的这种响应模式总体上不利于差巴嘎蒿实生苗在科尔沁沙丘生境中的存活。     

Effects of after-harvest period and environmental factors on seed dormancy of Amaranthus species

The effects of seven constant temperatures (10–40°C at 5°C intervals) and seven after‐harvest periods (30–540 days after harvest) were evaluated on seed germination of nine Amaranthus species (A. albus, A. blitoides, A. cruentus, A. deflexus, A. graecizans, A. hybridus, A. lividus, A. retroflexus and A. viridis). Seeds of A. blitoides and A. viridis were also tested at alternating temperatures of 10/30°C (12/12 h thermoperiod) in continuous darkness and in an alternating 12/12 h dark/light photoperiod. With the exception of A. blitoides and A. viridis, germination increased as temperature increased from 20 to 35°C; the latter representing the optimum temperature (70–100% germination). At 10 and 15°C constant temperatures, no significant seed germination occurred in A. albus, A. deflexus, A. graecizans and A. lividus, while in A. cruentus, A. hybridus and A. retroflexus there was no germination at 10°C, but at 15°C more than 60% germination occurred. Germination was influenced strongly by after‐ripening period in A. cruentus, A. hybridus and A. retroflexus, partially in A. deflexus, and barely in A. graecizans and A. lividus. Seeds of A. blitoides and A. viridis required alternating temperatures and light to achieve high germination percentage (>90%). Primary dormancy in Amaranthus plays a fundamental role in extending germination over a longer period, so that the probability of seedling survival is maximised. The present study adds to the understanding of the environmental control and germination ecology of Amaranthus species and provides data that can contribute to predicting weed emergence dynamics.     

苦豆子种子发芽特性研究

对苦豆子破除种子硬实、提高活力指数的方法及最适发芽的土壤含水量和播深进行了测定与研究,结果表明:苦豆子种子发芽困难的原因是种皮致密,吸胀困难;提高发芽率的措施是砂纸摩擦或65%H2SO4处理20 min;提高种子活力的措施是65% H2SO4处理20 min后,再用0.02%GA3处理;苦豆子种子萌发的适宜土壤含水量为8%～12%,播种的最适深度是0～3 cm.     

三唑酮种子包衣对冬小麦种子萌发和幼芽抗逆因子的影响

为评价三唑酮种子包衣对冬小麦种子萌发的安全性,以苯醚甲环唑为对照药剂,研究了不同包衣剂量三唑酮对周麦22和铭贤169小麦种子发芽及周麦22抗逆相关生化因子的影响。结果表明:周麦22和铭贤169小麦种子发芽指数、种子活力指数和发芽率均与三唑酮包衣剂量呈负相关,且符合指数方程Y=A+B×e(-x/k),但铭贤169种子发芽指数、种子活力指数和发芽率对三唑酮剂量变化更敏感;三唑酮种子包衣能引起小麦幼芽体内赤霉素(gibberellins,GAs)含量降低和脱落酸(abscisic acid,ABA)含量升高,且GAs含量下降程度和ABA水平升高程度均随三唑酮包衣剂量的增加而增加,从理论上解释了三唑酮可对小麦种子萌发产生抑制作用且抑制作用与包衣剂量相关的原因。但通过对幼芽相关抗逆因子的研究表明,三唑酮包衣有利于新长成幼芽中叶绿素含量、根系呼吸速率、可溶性蛋白质含量和α-淀粉酶活性的增加以及细胞膜通透性降低,说明三唑酮包衣在一定程度上有助于新长出幼芽抗逆性的增加。相比之下,苯醚甲环唑对小麦种子萌发的抑制作用比三唑酮小,且更有利于幼芽抗逆性增加。     

Soyasapogenol B and trans-22-dehydrocam- pesterol from common vetch (Vicia sativa L.) root exudates stimulate broomrape seed germination

BACKGROUND: Orobanche and Phelipanche species (the broomrapes) are root parasitic plants, some of which represent serious weed problems causing severe yield losses on important crops. Control strategies have largely focused on agronomic practices, resistant crop varieties and herbicides, albeit with marginal success. An alternative control method is the induction of suicidal seed germination with natural substances isolated from root exudates of host and non‐host plants. RESULTS: Soyasapogenol B [olean‐12‐ene‐3,22,24‐triol(3β,4β,22β)] and trans‐22‐dehydrocampesterol [(ergosta‐5,22‐dien‐3‐ol, (3β,22E,24S)] were isolated from Vicia sativa root exudates. They were identified by comparing their spectroscopic and optical properties with those reported in the literature. Soyasapogenol B was very specific, stimulating the germination of O. minor seeds only, whereas trans‐22‐dehydrocampesterol stimulated P. aegyptiaca, O. crenata, O. foetida and O. minor. CONCLUSION: Soyasapogenol B and trans‐22‐deydrocampesterol were isolated for the first time from Vicia sativa root exudates, and their biological activity as stimulants of Orobanche or Phelipanche sp. seed germination was reported. Copyright © 2011 Society of Chemical Industry