Effects of light and temperature on seed germination of Poa pratensis from high latitudes

One‐to‐three‐year‐old seed of Poa pratensis "Lavang”;, “Leikra”; and “Ryss”; was germinated under various temperature and light regimes on a thermogradient plate and on paper or in soil in phytotron compartments. While the optimal constant temperature for germination of Lavang and Leikra in 12 h light/12 h dark cycles was around 16°C, Ryss germinated nearly 100% over the 10–28°C temperature range. Compared with constant temperatures, daily fluctuations, even at the small amplitude 18/15°C, stimulated germination of Lavang and Leikra. Dark germination was inferior to germination in light/ dark cycles at constant temperatures of 15°C and higher, but light showed no advantage at alternating temperature. Continuous light inhibited germination regardless of light source (fluorescent, incandescent or natural). The stimulating effect of daily light/dark cycles increased, but the inhibiting effect of continuous light decreased with increasing seed age. It is concluded that seed of Poa pratensis ought to be covered by a 0.5–1.0 cm soil layer when sown in a northern environment involving continuous light and low soil temperatures.     

草地早熟禾原生质体培养与融合

以草地早熟禾品种RugbyⅡ成熟种子诱导的松软胚性愈伤组织为材料,以酶解法分离出原生质体,进行了原生质体培养;利用PEG融合法对MidnightⅡ和Nuglade的原生质体进行了融合,获得了体细胞杂种愈伤组织。研究了不同酶液组成、酶解时间、愈伤组织继代时间和渗透压对草地早熟禾原生质体游离及生长的影响;预处理对亲本原生质体活力的影响和适宜的融合条件。结果表明:采用继代培养8～10d的胚性愈伤组织,在1.0%纤维素酶+1.0%离析酶+0.5%果胶酶+0.3%崩溃酶条件下,酶解14～17h可得到产量和活力较高的原生质体;原生质体在KM8P培养基中培养3d后出现第1次细胞分裂,2～3周后形成小细胞团,此时添换低渗培养基2～3次,有利于小细胞团持续分裂并形成愈伤组织;试验获得了草地早熟禾品种RugbyⅡ原生质体来源的愈伤组织;5mmol/ml碘乙酰胺处理Nuglade原生质体10min及40μg/ml罗丹明处理MidnightⅡ原生质体5min,能有效地使Nuglade和MidnightⅡ原生质体失活;两品种融合PEG(6000)适宜浓度35%,融合率为9.8%。     

旅游景观园林早熟禾合理施肥试验研究

大庆市草坪建植4年后会出现明显的退化现象,土壤施肥可以改善早熟禾营养状况,有效延缓草坪退化进程。试验采取测土配方施肥的方法研究早熟禾生长变化规律,结果表明:试验末期施肥处理的有机质降低量少于对照,氮磷钾含量高于对照,pH值略低于对照;氮磷配合处理的分蘖密度7～10月显著高于其他处理;50%饼肥处理的叶片宽度最大,6～7月氮肥处理次之,8～10月氮磷处理次之;氮磷肥处理的叶绿素含量最高,对促进叶绿素含量增加效果最佳;氮磷配合处理生长季节内草坪盖度最高,极显著高于对照,50%饼肥氮处理次之;氮磷配合处理可以显著促进早熟禾生长,50%饼肥处理次之。分析认为,氮磷配合处理对促进早熟禾生长效果最佳,100%饼肥处理最差,发酵饼肥施用比例不宜超过50%。     

外源NO对镉胁迫下草地早熟禾种子萌发及幼苗生理特性的影响

为探究可缓解草地早熟禾镉胁迫的最适有效硝普钠(SNP)浓度,以草地早熟禾品种蓝月为试验材料,SNP为NO供体材料,研究不同浓度NO对镉胁迫下草地早熟禾叶片生理特性的影响。结果表明,镉离子浓度为200μmol·L^-1时草地早熟禾的生长受到严重抑制,施加SNP(<100μmol·L^-1)能够促进草地早熟禾种子发芽,增加草地早熟禾幼苗叶绿素含量,提高叶片干物质量、相对含水量,以及叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)活性,而其游离脯氨酸(Pro)和丙二醛(MDA)含量均有所降低。表明低浓度NO(<100μmol·L^-1)可有效缓解草地早熟禾镉胁迫,高浓度SNP(>100μmol·L^-1)则表现出抑制作用。本研究结果为草地早熟禾修复镉污染土壤提供了理论依据。     

填埋场陈垃圾对黑麦草种子发芽的影响

非正规垃圾填埋场的治理和陈垃圾的资源化利用是环保领域一项重要而迫切的任务。选择黑麦草作为试验对象,采用种子发芽的陆生生态毒理方法,研究陈垃圾对植物发芽的影响,以期为陈垃圾利用和非正规垃圾填埋场治理提供一种新的思路。培养基质中陈垃圾的比例分别为20%、80%和100%,使用蒸馏水和土壤作为对照。试验结果表明：陈垃圾的使用能够显著提高黑麦草种子的发芽势和发芽率,但黑麦草种子的发芽势和发芽率随着陈垃圾用量的增加呈现先增大后减小的特征,陈垃圾在培养基质中的最佳比例为80%,与空白和使用土壤作为培养基质相比,发芽率分别提高了34.3%和20.9%,发芽势分别提高了52.0%和24.0%。培养基质中添加陈垃圾有利于黑麦草种子根、芽的发育和生长,在培养基质中陈垃圾的比例为80%的条件下,黑麦草种子的根长、芽长和芽的鲜质量分别比使用土壤时增加了50.0%、46.9%和74.0%。因此,将稳定后的陈垃圾用于草坪种植是可行的,这为陈垃圾的资源化利用提供了一条新的途径。     

Seed Mass,Shape and Dormancy in Arid Temperate Degraded Grassland in Northeastern Inner Mongolia,China

Extensive studies have been conducted on the relationship between seed mass, shape and persistence in soil. However, the relationship between seed mass, shape and dormancy remains unclear. Therefore, in the present study, we investigated the possible relationship of seed mass and shape with dormancy in 124 plant species from different families, differing in their growth forms, in an arid temperate degraded grassland in northeastern Inner Mongolia, China. One‐tailed t‐test was applied to assess the differences in seed mass and shape between dormant and non‐dormant species. Phylogenetically independent contrasts were used to determine whether divergence within individual clades between dormant and non‐dormant seeds was associated with seed mass or seed shape. Our results indicate that the dormant seeds were heavier than 1 mg. Species with dormant seeds had significantly larger seed mass than those with non‐dormant seeds (one‐tailed t‐test = −3·56, p = 0·0005), but there was no significant difference in seed shape between them (one‐tailed t‐test = 0·86, p = 0·195). Furthermore, the relationship between seed mass, shape and dormancy was observed to be linked to phylogeny. Copyright © 2016 John Wiley & Sons, Ltd.     

镉对龙葵种子萌发及子叶抗氧化酶活性的影响

龙葵（Solanum nigrumL.）是Cd超累积植物,可用于植物冶金和Cd污染土壤的植物修复。超累积植物的生理基础研究有助于提高其对Cd的富集效率。龙葵种子在含有不同浓度CdCl（20、30、50、100、150、200μmol·L-1和300μmol·L-1）的琼脂培养基上萌发7d。结果表明,龙葵在200μmol·L-1和300μmol·L-1Cd时发芽率显著降低,而低浓度Cd（30～150μmol·L-1）胁迫下无显著差异;在Cd≥30μmol·L-1时,活力指数、发芽势均显著降低,幼苗的生长受到显著抑制。幼苗生长分析表明：在30～150μmol·L-1Cd处理下根长下降约17%～35%,显著低于200～300μmol·L-1Cd处理（下降79%～90%）;株高随Cd浓度的升高逐渐下降。子叶抗氧化酶活性分析表明：100～150μmol·L-1Cd胁迫下,CAT和APX活性显著上升;在Cd胁迫下,SOD活性降低但维持在较高的活性水平。表明龙葵幼苗能忍耐小于150μmol·L-1Cd,抗氧化酶活性在抵抗Cd毒害方面发挥重要作用。     

Characterization of a USDA Kentucky Bluegrass (Poa pratensis L.) Core Collection for Reproductive Mode and DNA Content by Flow Cytometry

Kentucky bluegrass (Poa pratensis L.) is an important turf and forage grass species with a facultative apomictic breeding behavior. In this study, mature seed and leaf tissue from 38 accessions of a USDA core collection of Kentucky bluegrass were analyzed with flow cytometry to characterize the reproductive mode and DNA content for each accession. Major reproductive pathways for each accession were determined based upon the presence and the position of the peaks observed and the known methods of reproduction for Kentucky bluegrass. While the majority of the accessions exhibited facultative apomictic reproductive behavior with a combination of reduced, zygotic and unreduced, parthenogenic embryo production, obligate sexual or obligate apomictic accessions were also found to be present in this core collection. In addition, reduced, parthenogenic and unreduced zygotic embryos were also detected in several accessions. Flow cytometric analysis of somatic tissue revealed a large range of DNA variation within this core collection. We also examined the sensitivity of flow cytometry in analyzing bulked samples containing a large number of plants with varied DNA content and determined that flow cytometry can effectively detect a plant having a different DNA content within a 15-plant bulk sample. Overall the combination of mature seed and somatic tissue analysis generated important information for the Kentucky bluegrass core collection and can be an effective and affordable tool to characterize even greater numbers of Kentucky bluegrass accessions.     

银杏叶渣制肥对小白菜种子萌发及幼苗生长的影响

为了提高银杏叶的附加值,减少环境污染,本研究以腐殖酸含量为评价指标,采用正交试验优化EM菌种发酵银杏叶渣制备生物有机肥的工艺参数,并测定有机肥中的相关成分,同时验证银杏叶渣有机肥的肥效.结果表明,有机肥最适固态发酵工艺为:发酵时间6 d、液料比去离子水添加比例为71.43％、银杏叶渣添加比例为26.95％、葡萄糖添加比...     

Seed Yield of meadow fescue (Festuca pratensis Huds.) in Norway and Denmark: The effects of locations,cultivars and autumn management

In order to determine genetic differences in seed yield potential, the optimal locations for seed production and optimal management after the first seed harvest, experiments with different timing of cutting and nitrogen application in autumn were conducted in three Scandinavian cultivars of meadow fescue (Saiten—origin 67° N, Fure—origin 61° N, and Senu Pajbjerg—origin 56° N) at the Norwegian locations Kvithamar (63.3° N), Staur (60.5° N), Landvik (58.2° N) and the Danish location Roskilde (55.4° N). The relative seed yields of ‘Saiten’, ‘Fure’ and ‘Senu Pajbjerg’ were 100, 171 and 175 on average for the first ley year, 100, 126 and 141 on average for the second ley year and 100, 115 and 116 on average for third ley year, respectively. A higher seed yield potential of the predominant Danish cultivar probably explains the commonly reported difference in seed yield between Norway and Denmark. Within Norway, seed yields normally decreased from south to north, with the lowest seed yields produced at Kvithamar and the highest at Staur or Landvik. At the coastal locations Kvithamar and, in particular, Landvik, cutting immediately after seed harvest (stubble removal) was necessary in order to maximize seed yields of ‘Fure’ and ‘Saiten’. Cutting at the end of the growing season (10 October) reduced the winter survival and seed yield of ‘Fure’ and ‘Saiten’ at these locations but was favourable at the inland location Staur, which had more stable snow cover. ‘Senu Pajbjerg’ was especially vulnerable to winter damage and did not benefit from cutting of stubble or regrowth at any location. Compared with inputs later in autumn, nitrogen application immediately after seed harvest increased both DM production in autumn and the next year's seed yield at all Norwegian locations.     

Autotoxicity of Phthalate Esters in Tobacco Root Exudates:Effects on Seed Germination and Seedling Growth

Autotoxicity is one of the major factors that impede continuous cropping. It is defined as the toxic influence of chemicals released from one plant species on the germination and growth of individuals of the same species. Here, in order to exam the autotoxicity of tobacco root exudates, root exudates were collected from tobacco plants grown both in cultural solution and on natural soil. Using ultraperformance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry, main autotoxic chemical substances in the root exudates were identified. The autotoxic effects of suspected autotoxins on seed germination (including germination rate, germination potential, germination index, and vigor index) and seedling growth were analyzed. Dibutyl phthalate (or diisobutyl phthalate), dioctyl phthalate, and diisooctyl phthalate were identified in tobacco root exudates. It was observed that high concentrations (greater than 0.5 mmol L^-1) of each identified phthalate ester caused significant (P < 0.05) inhibition of tobacco seed germination and seedling growth. It can be concluded that phthalate esters such as dibutyl phthalate, diisobutyl phthalate, and diisooctyl phthalate in tobacco root exudates may play an important role in tobacco autotoxicity.     

Seed Treatment to Overcome Salt and Drought Stresses During Germination in Safflower (Carthamus tinctorius L.)

Although safflower is drought and salt tolerant, it is susceptible to drought and salinity at the germination and seedling stages. Priming techniques have been used to overcome salinity and drought tolerance at germination stage. Osmopriming potassium nitrate (KNO₃) and hydropriming were used to determine drought [by polyethylene glycol (PEG)-6000 at water potentials of 0, ?0.3 and ?0.6 MPa] and salt electrical conductivity (EC) (values of the sodium chloride (NaCl) solutions were 0, 6 and 12 ds.m^?1) tolerance of primed seeds of safflower. Germination index, shoot/root ration, germination uniformity, days to 50% germination (D50) and abnormal germination percentage were measured. Treatment 0f seeds with hydropriming increased germination index, shoot/root ration and germination uniformity, while decrease days to 50% germination under salt and water stress. Seed treated with KNO₃ reduced abnormal germination percentage in salt stress. KNO₃ improved germination uniformity and germination index of the low water potentials. As salinity increased, germination index and shoot/root ration were decreased, while germination uniformity, days to 50% germination and abnormal germination percentage were increased. Hydropriming enhanced germination under both salt and drought stresses and non-stress conditions. Therefore, hydropriming could be used to improved seed performance of safflower under saline and drought stress. This treatment dose not needs expensive chemicals or sophisticated equipment.     

内蒙古自治区柠条种子害虫为害情况及其对柠条种子质量的影响

2003年对内蒙古自治区各柠条产区种子害虫为害情况的系统调查研究结果表明,柠条种子害虫在内蒙古自治区从东到西各调查样地普遍发生,均为柠条种子小蜂(Bruchophagus neocaraganaeLiao)、柠条豆象(Kytorhi-nus immixtusMotschulsky)、豆荚螟(Etiella zinckenellaTreitschke)3种害虫混合为害,所调查地区各样地为害程度均在 以上,平均种子虫害率为26.53%,虫株率达100%;进行了虫害对种子质量的影响评价试验,结果表明,平均每千粒种子因虫害损失掉的重量是3.12 g,种子发芽率平均降低了9.51%。     

Effect of halotolerant endophytic bacteria isolated from Salicornia europaea L. on the growth of fodder beet (Beta vulgaris L.) under salt stress

The aim of this study was to determine the influence of selected halotolerant endophytic bacteria isolated from the roots of Salicornia europaea on the growth parameters of Beta vulgaris under different concentrations of salinity. Two endophytic strains were selected as inocula for the pot experiment: Pseudomonas sp. ISE-12 (B1) and Xanthomonadales sp. CSE-34 (B2). Surface-sterilised seeds were incubated in the bacterial inoculation suspensions before sowing and cultivated in a sterile mixture of sand and vermiculite (1:1). Six salinity treatments were taken into account: 0, 50, 100, 150, 200 and 300 mM NaCl. Inoculation of seeds with B1 and B2 positively affected germination percentage and germination index and shortened mean germination time, which led to a quickening of the growth stages of seedlings. After 42 days inoculated plants had, in general, a greater root length, higher dry biomass, lower tissue water content and lower specific leaf area compared with the control. While the positive effect of B2 bacteria was visible only at low salinity, strain B1 stimulated plant growth at higher salinities (200 and 300 mM NaCl). We suggest that the superior growth promotion observed for B1 may be related to the higher metabolic activity of these bacteria.     

Temperature requirements for seed germination in species of the genus Allium L.

For taxonomic purposes and because many wild relatives of Allium crops are endangered in their native habitat (Sancir et al., 1989), a collection of Allium species was built up in the IPK at Gatersleben. At present it consists of more than 3000 accessions representing about 330 species. In this context it was necessary to study the seed germination behaviour and dormancy of certain wild Allium species. Therefore, seeds of 91 wild and three cultivated Allium species were tested at germination temperatures of 5°, 11°, 16° and 26°C. The purpose of this study was to develop routine germination tests for the genebank work with wild alliums.     

Inheritance of Seed Shattering in Lolium temulentum and L. persicum Hybrids

Lolium temulentum and L. persicum are non-crop species found in wheat and barley fields. L. temulentum has non-shattering seeds like the associated grain crops, whereas L. persicum seeds shatter after maturity. We analyzed the inheritance mode of shattering tendency by comparing the F₂ of L. temulentum and L. persicum hybrids. The selfed progeny of L. temulentum and L. persicum exhibited typical non-shattering (1.6% shattering) and shattering phenotypes (70.8%), respectively. F₁ hybrids of L. temulentum×L. persicum and its reciprocals were of the shattering phenotype (71.4% and 63.8%, respectively), indicating that shattering is dominant to non-shattering. When the phenotype ratio was assumed to be 15 shattering: 1 non-shattering, the χ² value for F₂ segregation was not significant at the 5% level, and the reciprocal effect was not detected. This indicates that the non-shattering tendency is controlled by two recessive genes. The two-gene inheritance model of shattering tendency suggests that harvest is the selector for seed shattering in cultivated fields, thus the alternative tendency for non-shattering seeds of L. temulentum or shattering of L. persicum would be better adapted to cultivated fields.     

季节性放牧和全年放牧对亚高山草地生态系统中土壤动物和微生物的影响

Grazing and over-grazing may drive changes in the diversity and functioning of below-ground meadow ecosystems.A field soil survey was conducted to compare microbial biomass carbon (Cmin) and soil fauna communities in the two main grassland management systems in subalpine regions of Yunnan Province,China:perennial grazing currently practiced due to increasing herd sizes and traditional seasonal grazing.A three-year exclosure experiment was then conducted to further compare the effects of different grazing practices,including treatments of no mowing,perennial grazing (NM + G),mowing followed by seasonal grazing (M + G),mowing and no grazing (M + NG),and no mowing or grazing (NM + NG).The comparative survey result revealed that Cmin and total density of soil fauna were significantly lower at a perennially grazed site than at a seasonally grazed site.The experiment results showed that in comparison to non-grazing treatments (M + NG and NM + NG),grazing (NM + G and M + G) reduced total fauna density (by 150 individuals m-2) and the number of taxonomic groups present (by 0.32 taxa m-2).Mowing decreased Cmin (by 0.31 mg g-1).Furthermore,the NM + G treatment (perennial grazing) had the lowest density of Collembola (16.24 individuals m-2),one of the two most common taxonomic groups,although other taxonomic groups responded differently to the treatments.Treatment effects on soil fauna were consistent with those on above-ground grasses,in which C:N ratios were greatly reduced by grazing,with this effect being the greatest for the NM + G treatment.In contrast,different grazing treatments had little effect on C:N ratio of soil.Furthermore,the traditional grazing method (mowing followed by seasonal grazing) may have less severe effects on some taxonomic groups than perennial grazing.Therefore,an appropriate management should aim to protect soil fauna and microbes in this area from over-grazing and against further degradation.     

黑麦草对土壤中Pb的富积作用及耐受性研究

通过土培实验研究了在单一因素影响下,不同浓度的Pb对黑麦草种子萌发及幼苗生长的影响,同时测定了其抗性生理指标的改变以及地上部分和根系对Pb的富集作用.实验结果表明,低浓度的Pb(＜500 mg/kg)单一污染时,对黑麦草种子萌发及幼苗生长有促进作用.高浓度时有显著的抑制作用.且随着浓度的升高(500～2 000 mg/kg),抑制作用和毒害作用都加强,各项指标均出现显著降低.同时,随Pb浓度增加,丙二醛(MDA)和可溶性糖含量显著增加,呈极显著正相关.叶片光合色素含量先增后减,呈负相关.黑麦草对Pb有一定的富集能力,当Pb浓度为500 mg/kg时,地上部分相对累计量达到最大.     

厌氧发酵固体剩余物建植高羊茅草皮的生态特征

为了考察沼渣在草皮无土栽培中的适宜性,该文通过大田试验,设计单因素区组试验,以沼渣为原料复合有机基质培植高羊茅草皮,研究了沼渣体积分数改变对复合有机基质理化特性、高羊茅幼苗生长以及高羊茅草皮成坪性状的影响,结果表明：1）T60基质（沼渣体积分数为60%）中全氮、全磷、全钾、速效氮、速效磷、速效钾、有机质含量最高,大于其他3种基质;随着沼渣体积分数提高,复合基质的pH值显著降低,干、湿容重显著降低,入渗率和总孔隙度显著增高,保水性增大;2）复合有机基质对高羊茅幼苗生长有明显促进作用,单位面积幼苗株数、幼苗株高、幼苗叶宽、草皮盖度、颜色等级、均一性和根层厚度均显著高于对照基质,从高羊茅幼苗生长来看,以60%和90%沼渣组成的复合有机基质适于建植高羊茅草皮;3）60%沼渣复合基质下,高羊茅草皮的总生物量、地上以及地下生物量显著大于其他基质,其草皮根冠比明显小于其他基质,该基质显著改变了高羊茅草皮的地上和地下生物量分配格局,促进生物量向地上部分转移,利于草皮生长,因此,该复合有机基质为高羊茅最佳建植基质。