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1.
假臭草根系分泌物化感作用初步研究 总被引：1，自引：0，他引：1
利用直接树脂吸收法来收集假臭草(Praxelis clematidea)根系分泌物,并对飞机草(Eupatorium odoratum)、胜红蓟(Ageratum conyzoides)、牛筋草(Eleusine indica)、三叶鬼针草(Bidens pilosa)、热研2号柱花草(Stylosanthes guianensis cv.Reyan No.2)和水稻(Oryza sativa)6种受体植物种子进行发芽试验和幼苗生长试验的测定。结果表明,假臭草根系分泌物对这6种受体植物均具有化感作用,但受体植物之间的作用表现差异显著。其中,胜红蓟发芽和水稻幼苗生长对假臭草根系分泌物最敏感。 相似文献
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大气CO2浓度升高条件下移栽水稻与不同出苗时间稗草竞争的响应差异 总被引：1，自引：1，他引：0
通过田间试验,研究了FACE（开放式空气CO2浓度升高）条件下,移栽稻田水稻（Oryza sativa）与不同发生时期稗草（Echinochloa crusgalli）生长和竞争的响应差异。结果显示,FACE条件下水稻与稗草比例为1∶1时,水稻分蘖、生物量和产量均增加,而稗草则减少。水稻与移栽稻田本田萌生稗草的生物量比率增加181.7%、产量比率增加259.7%、茎蘖比率增加24.2%、有效分蘖比率增加186.3%,水稻竞争优势增加,而移栽稻田本田萌生稗草竞争能力下降。水稻与秧田萌生稗草的竞争关系变化趋势在营养生长期与上述情况相同,但进入生殖生长后水稻竞争优势不再显著,FACE条件下与秧田萌生稗草竞争的水稻最终生物量和产量分别增加22.7%和8.2%,但秧田萌生稗草的最终生物量和产量也增加了11.9%和9.5%。水稻与秧田萌生稗草的生物量比率、茎蘖比率和产量比率增加均不显著。 可见,田间大气CO2浓度升高条件下水稻与稗草的竞争关系发生的变化与稗草发生时期有重要关系。 相似文献
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以云南省元谋干热河谷退化山地不同立地条件下种植的柱花草(Stylosanthes guianensis)为供试植物,研究柱花草的物候期、生长速率、生物量及覆盖效应。结果表明,在本区退化山地不同立地条件下,柱花草种植在台地及坡地均能完成其生长周期,有一定的生产力及覆盖效应。总体看,台地与坡地种植样地主要物候相差不大,台地由于保水作用强,能显著提高柱花草样地的整体生产力,草质好,柱花草的生物量、持水能力及生长量高于坡地。在改善小环境效应方面,台地和坡地柱花草种植样地由于作物覆盖地表,有效保持土壤水分,减少蒸发 相似文献
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为合理开发和利用热带牧草资源，研究热研2号柱花草和热研4号王草混合青贮对其营养成分及发酵品质的影响，以期筛选出适宜的混合青贮比例，为调制高品质的青贮饲料提供理论依据。本研究将热研4号王草和热研2号柱花草混合青贮比例分别设置为100∶0(CK)、85∶15(A1)、70∶30(A2)、55∶45(A3)4组，青贮30 d后开封取样检测。结果表明：A2组混合青贮感官评价最佳，随着热研2号柱花草比例的升高，pH和氨态氮/总氮（NH3-N/TN）值逐渐升高，A1、A2、A3组与CK组差异显著（P<0.05）；乳酸（LA）含量逐渐降低，A3组显著低于CK组（P<0.05）；各试验组乳酸/乙酸（LA/AA）值均大于2.6；且A2组丁酸（BA）显著低于其他各处理组（P<0.05）。随着热研2号柱花草比例升高，各处理组粗蛋白（CP）、干物质（DM）和粗脂肪（EE）含量随之升高，且显著高于CK组（P<0.05）；水溶性碳水化合物（WSC）含量呈上升趋势，且各试验组差异不显著（P>0.05）；中性洗涤纤维（NDF）逐渐降低，且各处理组间差异不显著（P>0.05）；各试验... 相似文献
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试验对6年龄桉树人工林间作禾本科及豆科牧草后的土壤微生物进行研究,结果表明：间作牧草可显著提高林地土壤微生物的生物量、呼吸强度、硝化作用强度及纤维素分解作用强度,且均随着土层深度的加深而降低;其中以间作热研6号珊状臂形草、热研2号柱花草、GC1581柱花草和Mineirao柱花草的土壤微生物生物量最高;热研15号刚果臂形草、热研6号珊状臂形草、杂交臂形草、热研10号柱花草、Mineirao和GC1581的呼吸强度高于CK;热研11号黑籽雀稗、热研10号柱花草、GC1581和热研2号柱花草的硝化作用强度强于CK;热研9号坚尼草、杂交臂形草和热研6号珊状臂形草、热研10号柱花草和热研2号柱花草的土壤纤维素分解作用强度较强。 相似文献
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以广东石质边坡14种常用植被为研究对象,设置15种组合,利用液压喷播优化基质,观测植被群落初期动态变化特征及基质硬度与基础呼吸特性,以期为高陡石质立面中后期植被群落生长提供合理的预测。结果显示,各指标主要受草本植物组合比例影响。初期呈现茂盛生长的草本植物群落组合,显著影响乔、灌木的成活率、生长高度和生物量(p<0.05)。随时间延长,基质基础呼吸值随草本植物比例增加及组合覆盖速率增长呈先上升后下降趋势,即过快的草本覆盖速度反而抑制了土壤呼吸。基质硬度随组合物种多样性及地下生物量的增加而降低,即在施工早期,根部初期生长较慢的植物种占据优势可有效提高基质硬度,增强坡体土壤稳固性。组合总生物量与物种多样性之间相关性不显著(p>0.05)。表明合理的草本植物喷播比例是影响高陡石质边坡生态修复草、灌、乔各目标植物在时空上逐步向稳定和合理的分布格局发展的关键因素。 相似文献
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试验设置4种玉米/黄顶菊混植比例,玉米单种(A1)、玉米/黄顶菊2∶1混种(A2)、玉米/黄顶菊4∶3混种(A3)、玉米/黄顶菊1∶1混种(A4),4种施氮梯度0(CK)、175(T1)、275(T2)、375 kg/hm^2(T3),采用甲基化敏感扩增多态性(Methylation Sensitive Amplification Polymorphism,MSAP)技术,研究不同处理下玉米叶片基因组DNA甲基化的变异特征。结果表明,筛选18对引物组合对各处理玉米叶片进行扩增,不同混植比例下各获得754条MSAP条带,在A1、A2、A3和A4混植比例下,对玉米表观遗传多样性贡献率最大的引物组合分别为EmHM21、EkHM17、EdHM21和EhHM17。A1混植比例下的未甲基化条带数、超甲基化条带数和总甲基化带数与其他3种混植比例条带数相比差异显著,4种混植比例下玉米叶片基因组DNA半甲基化和全甲基化条带数差异不显著,总甲基化条带数为79~93条,占比为10.84%~12.33%。与A1混植比例下相应施氮梯度相比,混植比例达到2∶1(A2)且施氮梯度达到175 kg/hm^2时,玉米叶片的半甲基化水平、全甲基化水平和总甲基化水平产生显著性差异。 相似文献
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《热带作物学报》2017,(10)
以6份柱花草(Stylosanthes guianensis)种质为材料,采用水培法,分析15%PEG-6000模拟干旱处理对柱花草生长的影响,并综合评价柱花草种质的抗旱性。结果表明:15%PEG处理显著抑制了柱花草的生物量、根系生长、叶绿素浓度(SPDA)及最大光化学效率(F_v/F_m),并显著增加了丙二醛(MDA)含量,但不同种质的抗旱性存在差异。运用隶属函数法对柱花草抗旱性进行综合分析,结果表明:种质TF227和TF210抗旱能力最强,为抗旱型柱花草,R~2和R5次之,TF226和TF244抗旱能力最弱。植株鲜重、地上部鲜重、丙二醛含量、叶绿素浓度和F_v/F_m可作为评价柱花草抗旱能力的指标。 相似文献
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农林复合系统中，各组分根系的空间分布决定了其对系统内资源的竞争能力，是复合系统设计的重要依据。本文采用带状分层挖掘法，对槟榔–象草复合系统中二者的根系密度和空间分布进行研究，并用Levins提出的生态位重叠公式计算槟榔与象草的地下竞争指数。结果显示，槟榔根系的生物量密度(1343.88 g/m3)是象草(558.53 g/m3)的2.41倍。在水平方向上，槟榔细根(0～2 mm)、中根(2～5 mm)和粗根(>5 mm)的生物量密度、根长密度及竞争指数随根系距槟榔树干基部距离的增加呈下降趋势；象草的根系生物量密度、根长密度及竞争指数则随距离的增加呈上升趋势，且分布相对均匀。水平方向上，在距槟榔树干80 cm内时槟榔的整体根系生物量密度显著大于象草，120～140 cm处时象草的根系生物量密度显著大于槟榔，其余距离内二者之间的差异不显著；20～40 cm处槟榔的根长密度大于象草，但差异不显著，其余水平距离内象草根系的根长密度均显著大于槟榔；除距离树干20～60 cm处，其余区域内象草的竞争指数均大于槟榔。垂直方向上，0～20 cm土层内槟... 相似文献
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研究刚果12号桉叶挥发油对植物、真菌和昆虫生长的影响,并对其化学成分作了分析。GC/MS分析结果表明,刚果12号桉叶挥发油的化学成分主要是萜类化合物,其相对含量超过90.0%,如对-伞花烃(6.84%)、β-桉叶油醇(16.12%)、α-桉叶油醇(11.17%)、β-蒎烯(8.99%)等。挥发油对植物、真菌和昆虫均具有生物活性,3种受体植物生菜、萝卜和热研2号柱花草幼苗初期生长受到抑制,叶绿素含量显著减少;对4种植物致病真菌菌落生长和有害昆虫斜纹夜蛾幼虫取食和化蛹的抑制活性尤其显著。 相似文献
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The effects on clover and grass growth of five levels of ammonium nitrogen (NH4-N) applied before sowing, at sowing and after nodule initiation have been investigated. A pot experiment in which S184 white clover was grown in a peat soil showed that NH4-N up to 688 mg N per pot (approx. equivalent to a field rate of 120 kg ha-1 N) applied before sowing and at sowing did not affect clover growth. N-fixing activity (C2H2-reduction), on the other hand, was reduced progressively up to the highest level (688 mg N per pot). Application after nodule initiation increased growth relative to the zero-N treatment at all levels of application. Maximum growth and N fixation occurred at 516 mg N per pot where the DM yield was 70% higher than in the absence of added N. A field trial in which S184 clover and S24 perennial ryegrass were surface sown on to a peat soil showed an increase in grass and clover growth in the first year in response to 120 kg ha-1 N applied at sowing. Grass growth alone was increased at 120 kg ha -1 N applied 40 d before sowing. Lower rates of application before sowing and at sowing did not affect clover or grass growth. The effect of the delayed application of NH4-N on legume growth was less marked than that in the pot experiment, 90 kg ha-1 N stimulating clover growth by 40% in the first year. The effect was however different from that in the pot experiment, in that, whilst 30kg ha-1 N increased N fixation relative to the zero-N treatment, plants exposed to higher levels showed a depression in N-fixing capacity. N-fixation was correlated with nodule numbers in the delayed NH4-N application, the closest correlation being with the number of multilobed nodules which was highest at 30 kg ha-1 N and lowest at 120 kg ha-1 N. It is suggested that circumstances exist when the use of a relatively low starter N dressing (20–60 kg ha-1 N) at sowing would not increase clover or grass growth in the early stages of the establishment of a hill reseed. Under such circumstances higher rates of application (100 kg ha -1 N), preferably delayed until the seedlings are in a position to take up the nitrogen rapidly, would have the greatest effect. 相似文献
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The effect of five cultivars of Festuca arundinacea on the botanical composition of mixed swards (with Dactylis glomerata and Trifolium repens singly and combined) at two soil fertility levels (moderate fertilizer application and no application) were examined. Shoot and root morphological characteristics of seedlings in each cultivar were also examined under pot conditions.
Although there was little difference in the total biomass of the three mixed swards between cultivars, the cultivars showed significant differences in their relative contribution to total biomass. The relative order of competitive ability between cultivars was maintained over the different soil fertility levels and different species associations.
Of the two yield components of a grass sward, tiller number and tiller size, number of tillers showed a larger response to the presence of neighbour species than mean tiller size, and thus success of F. arundinacea cultivars in mixed swards depended on the extent of reduction of number of tillers caused by the neighbour species of mixtures. The least competitive cultivar had the smallest seeds and shortest roots. 相似文献
Although there was little difference in the total biomass of the three mixed swards between cultivars, the cultivars showed significant differences in their relative contribution to total biomass. The relative order of competitive ability between cultivars was maintained over the different soil fertility levels and different species associations.
Of the two yield components of a grass sward, tiller number and tiller size, number of tillers showed a larger response to the presence of neighbour species than mean tiller size, and thus success of F. arundinacea cultivars in mixed swards depended on the extent of reduction of number of tillers caused by the neighbour species of mixtures. The least competitive cultivar had the smallest seeds and shortest roots. 相似文献
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研究柱花草菠萝皮不同比例混合青贮发酵品质。试验设4个处理，分别为100 %柱花草单独青贮(CK)、70 %柱花草+30 %菠萝皮(SP1)、60 %柱花草+40 %菠萝皮(SP2)、50 %柱花草+50 %菠萝皮(SP3)，青贮30 d后开窖取样，测定青贮饲料发酵品质。结果表明：与对照组相比，柱花草与菠萝皮混合青贮显著提高了乳酸含量，显著降低了pH值、丁酸和氨态氮/总氮，提高了发酵品质；各混合组随菠萝皮混合比例增大，乳酸增多，pH值和丁酸降低；SP2、SP3处理组pH值、乙酸、丙酸、挥发性脂肪酸和氨态氮/总氮无显著差异。从发酵品质和菠萝皮利用角度出发，50 %菠萝皮和柱花草混合青贮是可行的。 相似文献
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为探究播种方式和种植密度对冬小麦根系生长和产量的影响,以新冬22号为材料,采用二因素裂区试验设计,主区设条播（DR）和匀播（UN）2种播种方式,副区设150万粒·hm-2（D150）、225 万粒·hm-2（D225）、300万粒·hm-2（D300）和375万粒·hm-2（D375）4种种植密度,比较分析了不同播种方式和种植密度下冬小麦根系形态特征、根系伤流量和产量的差异。结果表明,随种植密度的增加,小麦总根干重、总根长呈先增后减趋势,单株次生根数、根系伤流量呈减小趋势。与条播相比,匀播下小麦总根干重、总根长显著增加,差异主要在0~30 cm土层;单株次生根数、根系伤流量增加,差异主要在生育中后期;产量显著提高（增幅9.89%）,其中以D225处理最大。综上,匀播能够促进小麦根系的生长,提高根系活性,有利于高产;在本试验条件下匀播小麦以225万粒·hm-2种植密度最佳。 相似文献
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采用盆栽法研究不同NaC(l盐)浓度胁迫对12个柱花草(Stylosanthes)品种幼苗生长的影响。测定叶片危害情况、植株生长高度、地上生物量、地下生物量等生物学指标,采用灰色局势决策模型法进行分析与综合评价。结果表明,随着盐处理浓度的增加,植株表现的萎蔫程度加强,植株的萎蔫速度加快;受胁迫植株的生长高度与对照相比呈下降趋势,受胁迫植株的生物量(茎叶、根)与对照的差异均达极显著。12个柱花草品种最终耐盐性排序为:有钩>热研5号>西卡>GC1480>GC1463>Mineiro>热研7号>GC1581>GC1517>热研2号>热研10号>热研13号。 相似文献
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Dactylis glomerata and Lolium perenne were grown in single-species stands and in mixed-species stands in boxes for 1 year. Plants were grown in paired rows in each box with full competition below ground, but aerial partitions prevented shoot competition. The rows were cut either frequently (six cuts) or infrequently (three cuts). In single-species stands, frequent defoliation reduced the root competitive ability of D. glomerata plants, when growing with infrequently defoliated plants, though this occurred only if no N fertilizer was applied. Frequent defoliation did not affect the root competitive ability of L. perenne plants, in single-species stands, whether or not N fertilizer was applied. In mixed-species stands, the root competitive ability of D. glomerata was always greater than that of L. perenne, though N fertilizer applications and frequent cutting both reduced the root competitive ability of D. glomerata relative to L. perenne. Mixtures of frequently cut and infrequently cut plants, in unfertilized single-species stands, always yielded more than the mean of the uniformly treated stands (frequently or infrequently cut); they usually yielded more than the highest-yielding uniformly treated stand. Mixtures of frequently and infrequently cut plants, in fertilized single-species stands, always yielded less than the mean of uniformly treated stands. Mixed-species stands usually yielded more than the mean yield of the component species, and sometimes yielded significantly more than the highest yielding component. This effect generally increased with time. Relative yield totals (RYT) were consistently greater than 1·0, in both single-species and mixed-species stands, when no N fertilizer was applied. RYT were greatest (1·2–1·6) when neither N nor P fertilizer was applied, and generally increased with time. The results are discussed in relation to the effects of cutting on root competition and the probable value of mixed-species stands. 相似文献