Target-site Mechanisms Involved in Annual Bluegrass(Poa annua L.) Tolerance to Fenoxaprop-P-ethyl

Annual bluegrass （Poa annua L.） was found to be tolerant to fenoxaprop- P-ethyl as well as quizalofop-P-ethyl, haloxyfop-R-methyl, clodinafop-propargyl, fluaz- ifop-P-butyl, cyhalofop-butyl, sethoxydim and tralkoxydim, whereas it was sensitive to clethodim and tepraloxydim. The acetyI-CoA carboxylase （ACCase） IC50 values of five P. annua biotypes were 10.46 to 11.98-fold higher than the susceptible Japanese foxtail （Alopecurus japonicus Steud.）. The presence of the polymorphic lie and Leu at 1 781, which the presence of Leu at 1 781 had been reported to be in- volved in the resistance of grass weeds to ACCase inhibitors, was subsequently i- dentified in the ACCase of P. annua. Furthermore, the expression level of gene that encoding P. annua ACCase was found to be approximately 4.67 to 7.37-fold higher than A. japonicus, possibly explaining the P. annua target site tolerance to fenoxaprop-P-ethyl.

Effects of traffic pollution on the genetic structure of Poa annua L.populations

The genetic composition of Poa annua L. populations with a series of traffic pollution was studied by starch electrophoresis. Five enzyme systems were stained. The results showed that: (1) Traffic pollution can dramatically change genotypic frequencies at some loci of P. annua populations. Significant deviations from Hardy Weinberg equilibrium were observed on loci Fe 1 and Me due to the excess of heterozygotes in some populations. (2) The effective number of alleles per locus and the observed and expected heterozygosity were higher in the pollution series than in the clear control site(Botanic Park population), but the increase was not related with the pollution extent. (3) Most genetic variation was found within populations, and only 6 21% was among populations of the polluted series. Slightly higher differentiation( F ST =7 98%) was observed when the control population was included. (4) The calculated gene flow(Nm) is 2 8841 per generation. The mean of genetic identity is 0 9864 and the genetic distance average to 0 0138

No difference in activity of Sod-1 genotypes of Poa annua to short-term treatment of ambient gaseous organic pollution

Our previous studies indicated that genotypes at locus Sod-1 of Poa annua changed clinally along a gradient of gaseous organic pollution. In the present study, we aimed to know whether there were differential responses of activities of different superoxide dismutase （SOD） genotypes to short-term treatment of ambient gaseous organic pollution. Significant bias from Hardy-Weinberg equibrium was observed on locus Sod-1, and no genotype Sod- l-BB was found. Significantly increased activities were observed in most treatments for genotype Sod-1-AA and in one treatment for genotype Sod-1-AB. However, no significant difference in SOD activities was found between the two genotypes. It was interpreted that fitness difference between the two genotypes was small and treatment duration was too short or extent of ambient organic pollution was too low to lead to differential responses. Other environmental factor effects on activities of superoxide dismutases can also explain the results.

Effects of Different Herbicides on the Control of Malachium aquaticum L. and Poa annua L.

In this experiment,the effects of 13 kinds of herbicides( or mixtures) on the control of two kinds of weeds were studied by pot cultivation with the broadleaf weed Malachium aquaticum L. and Gramineae weed Poa annua L. as the materials. The results showed that the herbicide MCPA-Na had the best and fastest control effect on M. aquaticum L.,and all the M. aquaticum L. died 7 d after treatment;it was followed by the other four herbicides including MCPA-Na + clethodim,MCPA-Na + quizalofop-p-ethyl,bentazon and nicosulfuron·atrazine,and all the M. aquaticum L. died 14 d after treatment. Atrazine was the best herbicide to control Gramineae weeds,followed by nicosulfuron·atrazine,and mesotrione·nicosulfuron·atrazine. The study on the application of field herbicide found that four herbicides including atrazine,mesotrione·nicosulfuron·atrazine,nicosulfuron·atrazine and bentazon had better control effect on weeds. The best herbicide for flax field was MCPA-Na + clethodim,followed by MCPA-Na and MCPA-Na + quizalofop-p-ethyl. The optimized herbicides and combinations had no harmful effects on the growth of corn and flax.

Defoliation affects the root competitive balance for N between Poa annua plants grown in a split‐root box

Background:Plants compete aboveground for light and belowground for patchily distributed nutrients.Defoliation causes an immediate loss of leaf area and photosynthetic capacity,leading to reduced root growth,with hypothesised implications for nutrient uptake and nitrogen use efficiency.Methods:In Experiment 1,we grew single plants in split root boxes with N supplied equally or unequally,with half the plants subject to repeated defoliation to quantify the impact of each treatment.In Experiment 2,we grew pairs of Poa annua plants in three‐chamber split root boxes,with N supplied either to the outer chambers(no competition)or to a shared centre chamber(competition),to quantify the influence of defoliation on root competition.Results:In Experiment 1,defoliation caused a significant decrease in root mass but did not affect root distribution between chambers,while differential N supply led to an 11%increase in shoot mass.In Experiment 2,strong root competition was seen in undefoliated plants under competitive conditions.Where one plant was defoliated,the other exhibited increased shoot mass and N content in competitive,but not noncompetitive conditions.Conclusions:Our data suggest that plant belowground competitive success following defoliation may be strongly influenced by the spatial distribution of soil resources.

一年生早熟禾种子萌发适宜温度研究

【目的】探究一年生早熟禾(Poa annua)种子萌发适宜温度。【方法】试验以甘肃省16个不同地区的野生一年生早熟禾种子为材料,设4、8、12、16、20、24、28和32℃8个恒温处理,研究温度对一年生早熟禾种子萌发的影响。【结果】随着温度的升高,一年生早熟禾种子的发芽率、发芽势、发芽指数、胚根长、苗鲜重、活力指数均呈先增后减趋势,胚芽长呈逐渐增大趋势。结论隶属函数综合评价表明,光照周期为16 h光照/8 h黑暗,相对湿度55%的恒温条件下,野生一年生早熟禾种子适宜萌发温度范围为16~24℃,最适萌发温度为24℃。

不同种源一年生早熟禾种子质量和幼苗生长特性与生态因子的相关性

【目的】研究不同种源一年生早熟禾(Poa annua)种子质量和幼苗生长特性与生态因子的相关性,为野生一年生早熟禾种质资源收集和良种选育提供基础数据和理论依据。【方法】以9个野生一年生早熟禾种子为试验材料,比较不同种源种子质量和萌发特性,并采用隶属函数法对其种子质量进行综合评价。【结果】一年生早熟禾种子和幼苗生长性状在不同种源间存在显著差异(P<0.05)。种长、长/宽、胚芽长和幼苗鲜重与经度、年均温度和无霜期呈正相关。种子发芽率、发芽势、发芽指数和千粒质量与年均降水量和海拔呈正相关,且生态因子对种子和萌发性状的影响大小为:海拔>年均降水量>经度>年均温度>无霜期>纬度。隶属函数综合评价显示,9个野生一年生早熟禾种子质量排序依次为:甘州>湟中>平安>永昌>天祝>安宁>榆中>凉州>秦州。【结论】种源为甘州和湟中的一年生早熟禾种子种质优良,具有推广潜力。

盐胁迫对早熟禾种子萌发的影响

设置NaCl溶液浓度为0.2%、0.4%、0.8%、1.4%,研究不同浓度盐胁迫对早熟禾种子出芽率、叶绿素的影响。结果表明,0.2%NaCl、0.4%NaCl溶液有利于早熟禾种子萌发及幼芽生长,其发芽率分别为30%、48%,幼芽高度分别为5.0 cm、6.2 cm。早熟禾种子在小于0.4%浓度NaCl胁迫下可以正常发芽,在大于0.4%浓度NaCl胁迫下发芽情况较差。从幼芽叶绿素含量来看,不同浓度NaCl胁迫下,早熟禾种子幼苗叶绿素含量均低于对照,且叶绿素含量随NaCl溶液浓度的升高而降低。

若尔盖高寒草地优势牧草植物根际促生菌的筛选及特性

通过探究若尔盖高寒草地优势牧草根际促生菌的分布特征,筛选植物根际促生菌(PGPR),为研制适宜高寒草地的微生物菌剂提供菌种资源。本研究在低温条件下,采用选择性培养基,从若尔盖高寒草地中的早熟禾(Poa annua)、老芒麦(Elymus sibiricus)根际筛选PGPR。通过钼锑抗比色法测定菌株的溶磷能力,利用乙炔还原法测定菌株的固氮能力,通过16S rRNA基因扩增与系统发育分析确定菌株的分类地位。结果表明,共分离筛选出49株PGPR,其中,溶磷菌28株、固氮菌21株。溶磷菌中17株菌能够溶解无机磷,溶磷量介于290.32~457.77μg·mL^(-1),菌株PBRS2溶无机磷量最大,达457.77μg·mL^(-1);11株菌能够溶解有机磷,溶磷量介于1.64~6.95μg·mL^(-1),菌株MBRS15溶有机磷量最大,达6.95μg·mL^(-1)。21株固氮菌的固氮酶活性介于93.33~234.35 nmol·(h·mL)^(-1),菌株NARS10固氮酶活性最高,达234.35 nmol·(h·mL)^(-1)。从老芒麦根际筛选的PGPR最多。根表土(RS)区域菌株的促生特性较强。通过灰色关联分析,筛选出9株促生特性优良的PGPR,经16S rRNA鉴定,7株属于假单胞菌属(Pseudomonas),1株属于红育菌属(Rhodoferax),1株属于马赛菌属(Massilia),以假单胞菌属为优势菌属。这9株促生特性优良的PGPR可为后续研制适宜若尔盖高寒草地的微生物菌剂提供优良菌种资源。

不同盐分类型对一年生早熟禾种子萌发和幼苗生长的影响

采用培养皿法,研究不同盐分类型和盐浓度对一年生早熟禾种子萌发特性的影响,测定其相对萌发率、相对发芽势、相对萌发指数、相对活力指数、相对胚芽长、相对胚根长和相对盐害率等指标,分析一年生早熟禾种子萌发和幼苗生长对不同盐分类型的响应。结果表明:(1)永昌种源一年生早熟禾的种子萌发和幼苗生长特性均高于其他3个种源。(2)在不同盐分类型、盐浓度及主要因素交互作用下一年生早熟禾的种子萌发和萌发期幼苗生长均受到显著抑制,碱性盐毒害强于中性盐,与萌发期幼苗的胚芽相比,胚根的响应更为敏感。(3)不同盐分类型对一年生早熟禾种子萌发期的盐害性强弱依次为:Na_(2)CO_(3)>NaHCO_(3)>Na_(2)SO_(4)>NaCl。研究结果可为种植一年生早熟禾生态修复不同类型盐碱地提供科学依据。

葡萄行间早熟禾生物量分布及其与土壤物理性质的关系

[目的]定量分析果园人工草地的生长状况及其环境响应规律,为果园生草的技术应用和可持续经营提供依据。[方法]采用样方调查法和环刀取样法,研究了设施条件下葡萄行间早熟禾(Poa annua)的地上、地下生物量的空间分布及其与土壤容重、饱和持水率等土壤物理性质的相关关系。[结果]早熟禾生物量平均为395.8 g/m~2,地上部分占79.6%,地下部分占20.4%;行间正中部位显著高于两端部位(P<0.05),0~10 cm土层显著高于10~20、20~30 cm土层(P<0.05)。土壤饱和持水率、毛管持水率、田间持水率分别为46.3%、38.4%、35.7%,其空间变化与生物量分布一致;土壤容重平均为1.40 g/cm~3,其空间变化与生物量相反。地下部分生物量空间分布与土壤物理性质有较强相关性,在水平分布上与田间持水率呈极显著正相关(P<0.01),与毛管持水率、自然含水率、容重呈显著相关(P<0.05);在垂直分布上与田间持水率、毛管持水率呈极显著正相关(P<0.01)。[结论]葡萄行间草地生物量受土壤物理性质显著影响,在水平方向上呈中间高、两端低的单峰型格局,在垂直方向上随土层深入而逐渐降低。

青藏高原5种牧草木质素含量及其体外消化率研究

在海拔高度3200m的中国科学院海北高寒草甸生态系统定位站选取羊茅 Festucaovina 、早熟禾 Poaannua 、艹洽草 Koeoeriacristata 以及莎草科的矮嵩草 Kobresiahumilis 、黑褐苔草 Carexalrofusca 5种青藏高原重要牧草品种,分别测定羊茅、早熟禾、艹洽草、矮嵩草茎、矮嵩草叶、黑褐苔草茎和黑褐苔草叶的木质素含量,并采用二级离体培养法测定其体外消化率,比较不同牧草间木质素含量及消化率差异.1999和2000年两年的实验结果表明,牧草木质素含量与其体外消化率之间为极显著负相关 P<0.01 ;就同种牧草不同器官而言,牧草茎的木质素含量明显高于叶,其降解率较低;3种禾本科牧草及2种莎草科牧草不同牧草品种间木质素含量和体外消化率差异不显著.

青藏高原不同海拔高度对禾本科牧草体外消化率的影响

利用大板山北坡 32 0 0 m～ 380 0 m的海拔梯度 ,分别在 32 0 0 m、340 0 m、36 0 0 m和 380 0 m处选取羊茅、一年生早熟禾和 艹洽 草用二级离体培养法测定其体外消化率。 1999和 2 0 0 0年测定结果表明 ,随着海拔的升高 ,3种牧草的体外消化率呈增加趋势 ,海拔从 32 0 0 m升到 380 0 m,羊茅、早熟禾、艹洽 草的体外消化率分别增加 6 .4 2、6 .35、8.6 9和4 .89、9.8和 5 .1个百分点。显著性分析结果表明 ,供试牧草的体外消化率与其生长的海拔高度之间的正相关关系差异显著 (P<0 .0 5 )。

3种常见草原植物水浸液对冰草和早熟禾种子萌发的影响

【目的】研究百里香(Thymus mongolicus)、星毛委陵菜(Potentilla acaulis)、糙隐子草(Cleistogenes squarrosa)水浸液对冰草(Agropyron cristatum)和早熟禾(Poa annua)2种牧草种子萌发的影响,为放牧地补播牧草选择和人工草地配置等提供参考依据。【方法】以内蒙古锡林浩特典型草原植物百里香、星毛委陵菜和糙隐子草地上部分为供体,以蒸馏水为对照,分析3种植物不同质量浓度(0.5,5,10,20和50g/L)水浸液对冰草和早熟禾种子萌发的影响。【结果】水浸液质量浓度小于50g/L时,3种植物水浸液对早熟禾和冰草种子萌发的影响均不显著。当水浸液质量浓度达到50g/L时,百里香水浸液对冰草发芽率、发芽指数均无影响,但对早熟禾的发芽率和发芽指数有显著抑制作用;星毛委陵菜水浸液对冰草发芽率、发芽指数均无影响,对早熟禾发芽率也无影响,但对其发芽指数有极显著抑制作用;糙隐子草水浸液对冰草和早熟禾的发芽率、发芽指数均有显著抑制作用,冰草与早熟禾发芽率分别较对照减少了80.97%和68.11%;糙隐子草水浸液对冰草与早熟禾的综合效应指数绝对值均大于百里香和星毛委陵菜水浸液。【结论】糙隐子草对冰草和早熟禾种子萌发抑制作用较大,百里香、星毛委陵菜对早熟禾种子萌发的影响大于冰草。

污泥复混肥对早熟禾草坪草生长性状及土壤酶活性的影响

为使城市生活污泥得以无害化、资源化综合利用,通过盆栽试验,研究了经无害化处理的生活污泥辅以化肥配制的污泥复混肥对早熟禾草坪草生长以及土壤酶活性的影响。结果表明：在氮、磷、钾施用总量相同的条件下,随复混肥中污泥含量的增加,草坪土壤脲酶、蛋白酶、转化酶活性显著提高,草坪草的颜色明显改善,剪草量、分蘖数显著增加,特别在生长中后期草坪颜色提高两个等级,剪草量鲜重增加10-15 g.盆^-1,分蘖数增加30-50个.盆^-1,细胞膜透性降低40%。但污泥提供氮素养分占总氮量的60%以上时,其肥料效应的增加不再显著,故在配制污泥复混肥时,以污泥提供氮素养分占总氮量的60%左右为宜。

2种肥料对早熟禾生长及叶绿素含量的影响

[目的]研究氮肥和磷钾肥对早熟禾生长影响的差异。[方法]以城市环境下正常生长的早熟禾为试材,研究了硝酸铵、磷钾配施对生长季节内早熟禾叶片加长和加宽生长以及干物质积累、叶绿素含量的影响。[结果]施肥可以促进早熟禾叶片的加长生长,2种肥料间差异不显著;6～8月硝酸铵可以在0.05水平显著降低早熟禾叶片宽度,磷钾肥影响效果不明显;施肥可以在0.05水平显著促进早熟禾植株的干物质积累,硝酸铵促进作用优于磷钾肥;施肥可以改变早熟禾叶片含水量,不同月份表现不同;硝酸铵对促进早熟禾叶绿素含量增加的效果优于磷钾肥。[结论]施肥可以促进早熟禾生长和观赏价值的提高,硝酸铵优于磷钾肥。

园林植物刺桐对早熟禾的化感作用

用生物测定法研究刺桐茎、叶浸提液对早熟禾萌发的化感作用,结果表明,刺桐的化感作用和供体植物的器官以及浸提液浓度密切相关.刺桐的化感作用总趋势为叶>茎.随浸提液浓度的加大,刺桐的化感作用增强.在实验设计的浸提液浓度范围内,0.100 g/ml的茎、叶浸提液对早熟禾种子萌发的化感作用最强.刺桐化感作用的研究为园林植物的选择提供了一定的理论依据.

早熟禾育种的研究进展与现状

对早熟禾的种利品种、生殖方式、染色体数目及倍性水平、遗传育种等方面的国内外研究进展与现状作了较系统的论述，重点介绍了草地早熟术和一年牛早熟禾的育种方法及有成品种，指出草地早熟禾是二倍体无孢子生殖，染色体数目变化很大，可以用单株选择法及种内和种间杂交等方法培育有性生殖品种利无融合品种，并介绍了目前早熟术育种的研究方向和内容。

大气硫氧化物污染对早熟禾种群遗传结构的影响

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4种除草剂防除保护性耕作麦田早熟禾效果及其对作物的安全性

通过田间试验,比较4种除草剂药后不同时期对保护性耕作麦田早熟禾的防效及其增产效果,进而比较7.5%啶磺草胺WG、3.6%甲基二磺隆·甲基碘磺隆钠盐WG、15%炔草酸WP、6.9%精唑禾草灵EW 4种除草剂防除早熟禾效果和对小麦的安全性。采用田间药效试验方法,对麦田早熟禾采用喷雾处理,进行4种除草剂防除麦田早熟禾效果及其对作物的安全性试验。7.5%啶磺草胺WG 187.50 g/hm2和3.6%甲基二磺隆·甲基碘磺隆钠盐WG 450.00 g/hm2对早熟禾鲜质量防效分别为83.58%、84.87%。3.6%甲基二磺隆·甲基碘磺隆钠盐WG对春小麦通麦1号品种有一定的药害,药害程度:甲基二磺隆·甲基碘磺隆钠盐>啶磺草胺。6.9%精唑禾草灵EW、15%炔草酸WP对早熟禾达未到防治要求。187.50 g/hm27.5%啶磺草胺WG,安全性好、防效高、持续期长,可进一步示范推广使用。