采用EF-1α序列及气生菌丝上的孢子形态特征对九州镰孢菌、拟枝孢镰孢菌和厚垣镰孢菌的鉴定

对九州镰孢菌Fusarium kyushuense、厚垣镰孢菌F. chlamydosporum 和拟枝孢镰孢菌F. sporotrichioides在气生菌丝上产生的孢子进行了比较。九州镰孢菌在气生菌丝上产生多隔孢子（即中型分生孢子）;厚垣镰孢菌在气生菌丝上产生的主要是0隔针叶状分生孢子;拟枝孢镰孢菌在气生菌丝上产生两种类型的分生孢子：芜菁形、单胞分生孢子以及椭圆形、0－1隔的分生孢子。多隔的气生孢子（中型分生孢子）在厚垣镰孢菌和拟枝孢镰孢菌这两个种中偶尔可以观察到,但是不应作为对这两个种进行鉴定的主要     

PEG引发紫花苜蓿和沙打旺种子的生理生态效应

牧草种子田间出苗率低是我国草业生产亟待解决的技术问题。采用较高渗透势和短时间的聚乙二醇引发技术(-0 .6MPa,2 4h) ,研究了引发对紫花苜蓿 (Med icago sativa )和沙打旺 (Astragalus adsurgens)不同质量种子萌发的促进作用及其生理生态效应。结果表明引发可显著 (p<0 .0 5)提高种子的早期发芽率和发芽指数 ,缩短达 3 0 %出苗的天数 ,但对最终发芽率无显著影响。引发效果因植物种、种批质量和萌发条件不同而异 ;其中 ,沙打旺大于紫花苜蓿 ,质量中等或中等偏下种批大于质量高或质量低的种批 ,在低温和干旱逆境条件下萌发大于适宜条件萌发。引发种子的丙二醛含量和水浸电导率极显著 (p<0 .0 1)低于对照 ;引发回干 2 4h种子的水浸电导率与引发种子的相当。引发种子在萌发吸水 0～ 3 0 h的吸水量极显著高于对照 ,在 2 4～ 72 h的可溶性糖和脯氨酸含量分别显著和极显著高于对照     

黄土高原区苜蓿与小麦轮作系统根部入侵真菌研究

以甘肃庆阳黄土高原地区草田轮作系统中苜蓿(Medzfago sativn)和小麦(Triticum aestivum)为研究材料,分别于2002年两种作物的拔节期(分枝期)、开花期、成熟期和幼苗期(第3茬分枝期)取样,分离、鉴定了根部入侵真菌,测定了分离所得根部入侵真菌对其寄主作物及另一种轮作作物的致病力。结果表明：在试验区内共分离到27种根部入侵真菌,包括自小麦根系分离到26种,苜蓿侧根分离到23种,其中22种为苜蓿和小麦共同的根部入侵真菌。两种作物根部入侵真菌区系中优势种明显不同,苜蓿根部最主要的5种入侵真菌按分离率的高低依次为尖镰孢(Fusarium oxysporum)17．0％、大孢肉座菌(Selinia sp．)15．4％、茎点霉(Phoma medicaginis)9．5％、腐皮镰孢(Fusarium solani)6．7％及柱孢(Cylindrocarpon destructans)6．6％;而小麦根部5种最主要的入侵真菌按分离率的高低依次为黑团孢(Periconia sp.)15．0％、丝葚霉(Papulaspora sp．)12．1％、多主枝孢(Cladosporium herbarum)5．4％、丝核菌(Rhizoctonia sp．)4．0％及尖镰孢3．9％;总的真菌分离率亦是苜蓿高于小麦。苜蓿与小麦的根段带菌率均有随生长季的延长而增高的特征。在试验条件下,参试的苜蓿、小麦根部入侵真菌对苜蓿和小麦均有一定的致病力,但对苜蓿种子和幼苗的致病力强于对小麦种子和幼苗的致病力。在轮作体系中,小麦田轮作苜蓿应注意防治根部入侵真菌的危害。     

甘蓝型油菜种子发芽率QTL定位及相关生理性状

利用GH06×P174组合衍生的183个重组自交系进行种子发芽率遗传分析及种子发芽期间种子生理性状分析。用复合区间作图法对在室温下保存两年的种子(STY)、保存1年的种子(SOY)与新收获种子(FS)发芽率进行QTL定位。另外对保存两年的种子及新收获的种子萌发期间脂肪酶活性、电导率、还原糖含量、总糖含量及根系活力进行了测定, 并对结果进行分析。结果表明3批种子的发芽率QTL位点各不相同, 保存两年的种子在第9、14、17条连锁群上分别检测到1个位点, 保存1年的种子在第5、9条连锁群上各检测到1个位点, 新收获的种子在第4、18条连锁群上分别测检到1个位点。研究发现, 3批种子的发芽率相关性不显著, 发芽率差异达到极显著水平, 同时保存不同年份种子的发芽率QTL各不相同, 这表明甘蓝型油菜发芽率受很多不同因素所控制。保存两年及新收获种子的发芽率与电导率之间的相关性均达到极显著负相关, 表明可以通过电导率的测定估测发芽率, 电导率的研究对种子发芽率的研究具有重要意义。     

浙江省仓贮稻谷大米真菌区系的研究

在浙江省采集仓贮稻谷及大米样品,共分离到真菌17属48种(不包括酵母菌)。其中:曲霉属(Aspergillus)18种,青霉属(Penicillium)10种,镰孢霉属(Eusarium)4种。研究表明:在浙江省地区之间,贮粮真菌种类无明显差异。稻谷加工成大米后,籽粒表面带菌量及内部带菌率均明显下降,其真菌区系以贮藏真菌为主。稻谷在贮藏前以田间真菌为主。贮藏1—4个月的稻谷因贮藏真菌的种类、数量明显增长,而田间真菌的种类和数量仍保持在较高的水平上,其表面带菌量及谷粒带菌率处于高峰期;贮藏1年以上的稻谷,其主要带菌种类为贮藏真菌,带菌量及带菌率明显下降。早籼谷和晚粳谷在相同贮藏条件下其带菌种类和数量基本一致。     

影响杏黄兜兰种子萌发的因素

通过在不同条件下杏黄兜兰 (Paphiopedilumarmeniacum)种子萌发的观察 ,对影响其萌发的诸因子报道如下 :1)果实的生长期与种子的萌发率有关。实验表明种子采自生长期为 6 0d的果实 ,发芽率为 3 5 % ,采自 12 0d的果实 ,发芽率为 4 0 % ,采自 180d的果实 ,发芽率为 18 3%。 2 )培养基也会影响到种子的萌发 ,种子在 1 5MS内培养 ,萌发率明显高于培养于MS ,RE和改良HyponexNo 1内的种子。 3)培养基 (1 5MS)掺入添加物也会影响到种子的萌发率 ,如掺入 10 %椰子水会促使种子的萌发率达到很高的水平 ,掺入马铃薯泥 (5 0g L)或胰化胨 (2g L) ,种子的萌发率会达到较高的水平 ,而掺入香蕉泥则会对种子的萌发率产生负面影响 ,掺入活性炭 (2g L)会促使种子萌发和幼苗发育。 4 )与固态培养基相比 ,种子在液体悬浮培养基内的萌发速度更快 ,幼苗更为整齐划一。     

湖北省蔬菜根际土壤中的镰孢菌分布特征

为明确湖北省蔬菜产区镰孢菌(Fusarium spp.)的种类及分布特征,本研究从湖北省13个地级市蔬菜产区采集根际土壤样品55份,对土样中的镰孢菌进行分离、纯化和鉴定,获得271株镰孢菌;通过镰孢菌特异性引物扩增、测序等分子生物学技术,鉴定出尖孢镰孢菌(F. oxysporum)118株,占分离菌株43.6%;木贼孢菌(F. equiseti)46株,占17.0%;共享镰孢菌(F.commune)45株,占16.6%;茄病镰孢菌(F. solani)31株,占11.4%;藤仓镰孢菌(F. fujikuroi)11株,占4.1%;镰孢霉菌(F.delphinoides)6株,占2.2%;轮纹镰孢菌(F. concentricum)5株,占1.8%;三线镰孢菌(F. tricinctum)3株,占1.1%;镰孢菌属(Fusarium spp.)6株,占2.2%。通过与致病菌尖孢镰孢菌番茄专化型(F. oxysporum f. sp. lycopersici)菌株进行对峙培养,筛选出拮抗镰孢菌16株,包括尖孢镰孢菌(F. oxysporum)4株,茄病镰孢菌(F. solani)4株,轮纹镰孢菌(F. concentricum)3株,三线镰孢菌(F.tricinctum)3株,木贼孢菌(F. equiseti)和藤仓镰孢菌(F. fujikuroi)各1株。本研究明确了湖北省蔬菜产区的镰孢菌属真菌的种类和多样性特征,为蔬菜镰孢菌病害的防治提供科学依据。     

光照和温度对毛茛铁线莲种子萌发的影响

采集毛茛铁线莲(Clematis ranunculoides)野生植株种子,观察其外观形态,检测种子千粒重,研究光照和温度对种子萌发的影响。通过室内发芽试验,测定不同光照和温度条件下毛茛铁线莲种子发芽率和发芽势。结果表明,毛茛铁线莲种子的千粒重为(1.6624±0.0006)g;种子萌发最适温度为20～25℃,在此温度下,8 d开始萌发,3～4周萌发完全,萌发率达90.33%,温度升高或降低都会导致毛茛铁线莲种子萌发率降低;光照和黑暗对毛茛铁线莲种子萌发无显著影响。     

三江平原地区大豆根腐病病株上镰孢菌的分离鉴定

为了明确引起三江平原地区大豆根腐病的镰孢菌(Fusarium)种类及优势种群,对该地区大豆根腐病样本进行了采集。通过组织分离和形态学鉴定,共鉴定出6种镰孢菌,分别为木贼镰孢(F.equiseti)、尖孢镰孢(F.oxysporum)、芬芳镰孢(F.redolens)、半裸镰孢(F.semitectum)、腐皮镰孢(F.solani)和拟轮枝镰孢(F.verticillioides)。其中尖孢镰孢(F.oxysporum)的分离频率最高,达16.67%。对6种镰孢菌的形态学特征进行了描述。     

盐分和温度对盐节木种子萌发的影响

采用多因素交叉试验设计,探讨了不同盐分类型、盐分浓度以及温度对盐节木(Halocnemum strobilaceum)种子萌发的影响。结果表明:15~25℃范围是盐节木种子萌发的最适温度范围,5~15℃和25~35℃的变温不利于种子萌发;最适温度下,单盐和土盐浓度分别小于0.96%和0.6%(电导率小于9.375dS/m)时可促进种子萌发,当浓度分别高于0.96%和0.6%(电导率大于9.375dS/m)时,单盐处理下的种子萌发率随浓度升高而降低,土盐处理下的种子萌发率随浓度升高表现为先升高后下降,但2种盐处理下的平均种子萌发率差异不显著(P>0.05),非最适温度下,2种盐处理下的平均种子萌发率差异显著(P<0.05)。由此得出:盐分浓度和温度是影响盐节木种子萌发的关键因素,土盐对种子萌发的抑制作用较单盐的小。     

A sensitive and specific PCR-based discrimination of split red vetch and lentil seeds

A PCR-based marker technique was developed to discriminate between morphologically similar split seed of vetch (Vicia sativa) and lentil (Lens culinaris subsp.culinaris). Sequence tagged microsatellite site (STMS) markers were more discriminatory than markers produced from the nontranscribed spacer (NTS) region of the 5S ribosomal RNA gene. A sequence characterized amplified region (SCAR) marker, developed from the 5S rRNA NTS region, was sensitive when resolved on agarose. However, the fluorescent-labeled 5S rRNA SCAR marker was unable to discriminate between vetch and lentil, probably because of the low copy number of the marker, and was not visualized on agarose. An STMS primer-pair (PSMPSAD123), developed from field pea, was able to discriminate split red cotyledon vetch from split red cotyledon lentil because it produced specific markers at 563 bp for lentil and 353 and 474 bp for vetch. The vetch-specific STMS marker was conserved among all species of theVicia genus used in this study and was sensitive enough to discriminate both on agarose gels and on polyacrylamide gel-based fluorescent systems. The fluorescent-tagged STMS analysis revealed peaks for vetch and lentil at the expected sizes in admixtures of milled vetch and lentil seeds, and it was sensitive enough to detect one vetch seed in 1999 lentil seeds. The development of PCR-based tests for detecting the level of vetch seed contamination in lentil export seed may provide a method for quality assurance of export lentil seed.     

Mimicry of lentil and the domestication of common vetch and grass pea

A hypothesis is proposed whereby weedy vetch (Vicia sativa L.) seed moved with seed of the cultivated lentil (Lens culinaris Medikus) as a tolerated weed during the spread of the lentil from the Fertile Crescent in the Near East to its current distribution. As a result, selection occurred in vetch weeds for a reduction in dormancy/hard-seededness, increased competitive ability and biomass, and phenological adaptation to new environments⇆redisposing the weed for domestication. The cropping of common vetch for forage in pure culture followed. Archaeological evidence of admixtures of grass pea (Lathyrus sativus L.) in Neolithic finds of lentil, pea (Pisum sativum L.) and bitter vetch (Vicia ervilia (L.) Wild.) suggests a similar process of selection in grass pea for a weedy habit from which domestication later occurred.     

Seed dispersal in relation to the domestication of Middle East Legumes

Modification of seed dispersal was perhaps one of the most important steps towards domestication of seed crops. Among the legumes of the Middle East, four patterns of such modification can be distinguished in the process of domestication. The initial stage of domestication of lentil, pea and grass pea was apparently due to a single mutation in a major gene that prevented pod dehiscente. In chick pea the domesticated type was formed by accumulation of several mutations in minor genes that reduced the amount of pod dropping and shattering. From a seed dispersal point of view, fenugreek was preadapted to cultivation since the wild species do not shatter their seeds. In the bitter vetch and common vetch partial seed shattering apparently was tolerable and desirable under cultivation since the seed served merely for sowing the next year crop.     

杉木种子涩籽地理流行趋势的研究

本文应用趋势面分析福建省杉木种子涩籽地理流行趋势,建立涩籽地理流行数学模型,阐述其流行规律,绘制山涩籽地理流行图,并将其划分成四个区：1．闽西南杉木涩籽流行递减区;2．闽东南杉木涩籽流行递增区;3．闽北杉木涩籽流行递减区：4,闽中北闽西北杉木涩籽流行渐稳区。同时建议将大型杉木种子园建在建瓯县。     

华中地区藤本种子植物区系的研究

以湖南和湖北两省为代表对华中地区藤本种子植物的区系进行了研究。本区共有藤本种子植物62科175属838种,其中土著种类有60科159属784种。在科、属、种的水平上对藤本种子植物区系特性进行了较深入的统计和分析,并对本区藤本种子植物与邻近地区的关系、本区内的藤本种子植物的地带性分异进行了探讨。统计表明,本区藤本种子植物种数占该区种子植物总种数的11%,且61.7%的种类主要集中在30种以上的大科中;热带分布型明显多于温带分布型;泛热带、热带亚洲、东亚（中国）特有和东亚—北美间断分布科属比较集中,其中许多属为古老成分;本区藤本种子植物特有成分丰富,计有东亚特有科1科、中国特有属6属、中国特有种507种（其中华中地区特有种35种）。通过研究认为：本区藤本种子植物具有种类丰富、分布类型多样、特有成分较多、区系较古老的特点;与本区的全部种子植物区系相比,藤本种子植物区系的热带性更强,具有明显的热带亲缘性,并与喜马拉雅及中国西南有较强的地理渊源。     

冬季作物对稻田土壤微生物量碳、氮和微生物熵的短期影响

研究不同的冬季作物马铃薯、黑麦草、紫云英、油菜在"冬季作物-双季稻"轮作种植制度下短期内对稻田土壤微生物碳、氮和微生物熵的影响,在湖南省土壤肥料研究所的实验网室内设置了小区试验.试验结果表明:几种冬季作物均提高了稻田土壤微生物碳、氮含量,黑麦草明显提高了土壤微生物量碳和微生物熵,紫云英明显提高了土壤微生物量氮.冬季作物对土壤微生物量碳和土壤微生物量氮的季节性影响变化趋势基本一致,紫云英、马铃薯处理的土壤微生物量C、N含量均在水稻生育期间8月中旬达到最大值.     

Burial increases seed longevity of two Artemisia tridentata (Asteraceae) subspecies

? Premise of the study: Seed longevity and persistence in soil seed banks may be especially important for population persistence in ecosystems where opportunities for seedling establishment and disturbance are unpredictable. The fire regime, an important driver of population dynamics in sagebrush steppe ecosystems, has been altered by exotic annual grass invasion. Soil seed banks may play an active role in postfire recovery of the foundation shrub Artemisia tridentata, yet conditions under which seeds persist are largely unknown. ? Methods: We investigated seed longevity of two Artemisia tridentata subspecies in situ by retrieving seed bags that were placed at varying depths over a 2 yr period. We also sampled naturally dispersed seeds in litter and soil immediately after seed dispersal and before flowering in subsequent seasons to estimate seed persistence. ? Key results: After 24 mo, seeds buried at least 3 cm below the soil surface retained 30-40% viability whereas viability of seeds on the surface and under litter declined to 0 and < 11%, respectively. The density of naturally dispersed seeds in the seed bank was highly heterogeneous both spatially and temporally, and attrition varied significantly by region. ? Conclusions: Our study suggests that Artemisia tridentata has the potential to form a short-term soil seed bank that persists longer than has been commonly assumed, and that burial is necessary for seed longevity. Use of seeding techniques that promote burial of some seeds to aid in formation of a soil seed bank may increase restoration potential.     

Functional trade‐offs and the phylogenetic dispersion of seed traits in a biodiversity hotspot of the Mountains of Southwest China

The diversity of traits associated with plant regeneration is often shaped by functional trade‐offs where plants typically do not excel at every function because resources allocated to one function cannot be allocated to another. By analyzing correlations among seed traits, empirical studies have shown that there is a trade‐off between seedling development and the occupation of new habitats, although only a small range of taxa have been tested; whether such trade‐off exists in a biodiverse and complex landscape remains unclear. Here, we amassed seed trait data of 1,119 species from a biodiversity hotspot of the Mountains of Southwest China and analyzed the relationship between seed mass and the number of seeds and between seed mass and time to germination. Our results showed that seed mass was negatively correlated with seed number but positively correlated with time to germination. The same trend was found regardless of variation in life‐form and phylogenetic conservatism. Furthermore, the relation between seed mass and other seed traits was randomly dispersed across the phylogeny at both the order and family levels. Collectively, results suggest that there is a functional trade‐off between seedling development and new habitat occupation for seed plants in this region. Larger seeds tend to produce fewer seedlings but with greater fitness compared to those produced by smaller seeds, whereas smaller seeds tend to have a larger number of seeds that germinate faster compared to large‐seeded species. Apart from genetic constraints, species that produce large seeds will succeed in sites where resource availability is low, whereas species with high colonization ability (those that produce a high number of seeds per fruit) will succeed in new niches. This study provides a mechanistic explanation for the relatively high levels of plant diversity currently found in a heterogeneous region of the Mountains of Southwest China.     

Seed size variation within Zostera marina L. (Zosteraceae)

In 1997 and 1998 seeds were collected from the seagrass, Zostera marina L. (Zosteraceae) from Long Island, New York, USA (var. typica ), Shaw Island, Washington, USA (var. latifolia ) and Izembek Lagoon, Alaska, USA (var. izembekensis ) to determine if seed size varied between the varieties, if seed size varied within the same variety, and if the relationship between seed length and seed weight was linear. Measurements of seed length revealed statistically significant differences in this metric between varieties associated with smaller intertidal plants (var. typica and var. izembekensis ) and larger plants from the subtidal region (var. latifolia ). It was also found that seed length varied within the same variety and verified that the cross-sectional shape of these seeds was primarily elliptical. Using seed cross-sectional area and weight from a randomly selected batch of seeds from the three locations sampled in 1998, a linear model was created to determine seed weight and seeds from var. latifolia were found to be heavier than seeds from var. typica . The potential advantage of heavy seeds for subtidal seeds in search of safe sites is discussed, together with the merit of using the model to calculate the weight of other elliptical seeds within the Zosteraceae and other seagrass families.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 142 , 281–288.