大黍(Panicum maximum Jacq.)的胚珠附器

观察了大黍(PanicummaximumJacq.)胚珠附器的发生时间、位置和发育过程及其细胞化学特征。结果显示:(1)大孢子母细胞时期,珠孔端有一个或多个珠心表皮细胞开始伸长、膨大,特化为胚珠附器。(2)当胚珠附器伸长、膨大至最大程度时,胚珠附器细胞表现出显著的极性特征:细胞核位于细胞的珠孔端,大而清晰;细胞内同时形成了一个特大的液泡,几乎占据了整个细胞的合点端;细胞质则被挤到珠孔端一侧,集中分布在核的周围。(3)胚珠附器从开始出现到发育成熟,都没有淀粉粒的积累;但是,PAS反应显示胚珠附器细胞壁和细胞质都比普通珠心细胞的染色程度深,这说明其细胞壁和细胞内部富含可溶性多糖。

Phytoextraction of Trace Metals (Cd, Ni and Pb) by Panicum maximum Grown on Natural Soil

This study aims to assess the effective capacity of Panicum maximum to accumulate cadmium (Cd), nickel (Ni) and lead (Pb). P. maximum observed in a greenhouse was subjected to 2 ppm of Cd, 50 ppm of Ni, 100 ppm of Pb contaminated soil and uncontaminated soil, for 120 days. Plant growth and biomass produced concentration of trace metals in soil and plant, bioaccumulation and transfer factors, location of potentially toxic elements in tissues and cells of plant have been determined. Stem length and biomass produced by P. maximum were higher on the uncontaminated soil followed respectively by those of soil-contaminated by Pb, Cd and Ni. Bioaccumulation factors of trace metals were 8.93 (Pb), 8.47 (Ni) and 3.37 (Cd). Ni was more accumulated in shoot biomass (FT > 1), while Pb and Cd were concentrated in root biomass (FT < 1). Pb is accumulated preferentially in endodermis (roots) and epidermis (leaves). As for Ni and Cd, they are concentrated in central cylinder of roots and in conductive bundles of leaves. At cellular level, Ni and Cd are mainly concentrated in intracellular compartments of leaves and roots, while Pb is strongly detected at cell walls.

Antimalarial and analgesic activities of ethanolic leaf extract of Panicum maximum

Objective:To evaluate antiplasmodial and analgesic activities of ethanolic leaf extract/ fractions of Panicum maximum.Methods:The crude leaf extract(47-190 mg/kg) and fractions (chlor of orm,ethyl acqeous and methanol;96 mg/kg) of Panicum maximum were investigated for antiplasmodial activity against chloroquine sensitive Plasmodium berghei infections in mice and for analgesic activity against chemical and heat-induced pains.The antiplasmodial activity during early and established infections as well as prophylactic were investigated.Artesunate at 5 mg/kg and pyrimethamine at 1.2 mg/kg were used as positive controls.Analgesic activity of the crude extract/fractions was also evaluated against acetic acid,formalin and heat-induced pains.Results:The extract and its fractions dose-dependently reduced parasitaemia induced by chloroquine sensitive Plasmodium berghei infection in prophylactic,suppressive and curative models in mice.These reductions were statistically significant(P【0.001).They also improved the mean survival time from 13 to 28 days compared with control(P【0.001).The activities of extract/ fractions were incomparable to that of the standard drugs(Artesunate and pyrimethamine).On chemically and thermally-induced pains.the extract inhibited acetic acid and formalin-induced inflammation as well as hot plate-induced pain in mice.These inhibitions were statistically significant(P【0.001) and in a dose-dependent fashion.Condusions:Panicum maximum leaf extract has antiplasmodial and analgesic activities which may in part be mediated through the chemical constituents of the plant.

Influence of Lead and Cadmium Concentration on the Accumulation Capacity of Panicum maximum

The restoration of soils polluted by trace metals (Pb and Cd) by phytoremediation is an innovative and ecologically sustainable solution. The objective of the study was to develop a process of phytoaccumulation of trace metals (Pb and Cd) in soils with the species Panicum maximum. For this purpose, 30 buckets containing soil were used. These included six (06) buckets per dose of soil contamination by Pb and Cd (3 mg/kg and 9 mg/kg of Cd and 100 mg/kg and 300 mg/kg of Pb) and six (6) buckets containing uncontaminated soil (control). During a period of 90 days of experimentation, the concentrations of trace metals in the plant biomass and in the soils were measured. Also, the bioaccumulation (BF) and translocation (TF) factors, the mass of Pb and Cd taken up by the plant were determined. The results showed that the biomass produced was negatively influenced by increasing Pb and Cd concentration. The concentrations of Pb and Cd accumulated by P. maximum varied in the aboveground biomass from 6.48 ± 0.55 to 18.09 ± 0.71 mg/kg (Pb100);from 10.93 ± 0.38 to 23.04 ± 0.79 mg/kg (Pb300);from 0.91 ± 0.02 to 1.50 ± 0.03 mg/kg (Cd3);and from 3.05 ± 0.08 to 5.43 ± 0.09 mg/kg (Cd9) from day 30 to day 90. However, in the root biomass, trace metals (Pb and Cd) ranged from 8.09 ± 0.58 to 22.57 ± 0.86 mg/kg (Pb100);from 29.45 ± 0.49 to 62.35 ± 0.82 mg/kg (Pb300);from 0.66 ± 0.01 to 1.11 ± 0.07 mg/kg (Cd3);and from 2.22 ± 0.08 to 3, 97 ± 0.09 mg/kg (Cd9), from day 30 to day 90. Pb was concentrated in the root biomass and Cd in the aboveground biomass. Bioaccumulation factor values ranged from 0.26 ± 0.02 to 0.99 ± 0.04 (Pb100);from 0.21 ± 0.04 to 0.50 ± 0.06 (Pb300);from 0.83 ± 0.09 to 1.72 ± 0.18 (Cd3);and from 0.70 ± 0.08 to 1.54 ± 0.18 (Cd9). High concentrations of Pb and Cd show a negative effect on the accumulation potential of P. maximum.

Interactions Ticks, Hosts and Pastures： Case of the Girolando Dairy Cattle and the Artificial Pastures of Panicum maximum and Panicurn maximum var. C1

On the Kpinnou ranch in Benin, it was observed that the Girolando dairy cattle which graze Panieum maximum var. CI are more susceptible to infestation of ticks. The purpose of this study was to highlight the interactions between ticks and their bovine hosts and two types of artificial grazing pastures. Nineteen young Girolando dairy cattle were used during the big rainy season （March-June） 2009. All present ticks on the animals have been counted according to the body region. The bovine have been divided into two relatively homogeneous groups often and nine animals. The group I of 10 animals had been grazed on Panicum maximum whereas the group 2 of 9 animals had been grazed on Panicum maximum var. C 1. During the two months of grazing, a weekly monitoring of the evolution of the load in ticks has been achieved. Four genera of ticks were identified on the bovine Girolandos （Amblyomma, Hyalomma, Rhipicephalus and Boophilus）. The Boophilus genus is the most abundant （P 〈 0.05）. The animals having grazed Panicum maximum var. C I are more infested than those that have been grazed Panicum maximum. A variation of the rate of infestation of the animals has been observed in relation to the different body areas. The colour of the coat also has an effect on the load in tick of the bovine. The bovine of dark coat are in general more infested （P 〈 0.05） than those of clear colour.

外来植物坚尼草生态学研究

坚尼草 (PanicummaximumJacq .)是一种外来草本植物 ,已逸为野生 ,扩展迅速 ,对本地草本植物构成一定的影响。其扩展能力与其生长和繁殖特点有很大关系。研究表明 ,坚尼草对环境的适应能力较强 ;植株较高大 ,生长迅速 ,有较强的竞争能力 ;花期长 ,单丛坚尼草从始穗到终穗 ,花期可长达 6～ 7个月 ;同一穗的果实熟期不同 ,而且边熟边脱落 ,从抽穗的 5～ 7d起开始有果实脱落 ,脱落时间可持续 1个月左右 ,以抽穗 2～ 3周为脱落高峰 ;不同时间成熟的果实 ,种子萌发率也不同 ,7月份成熟的果实比 9月份成熟的果实萌发率高。同一穗中 ,以抽穗后 2～ 3周 (果实脱落的高峰期 )成熟的果实萌发率较高。果实成熟后 ,不能立即萌发 ,储存 1～ 6个月 ,种子萌发率较高。

刈割周期、施肥量对坚尼草产草量和质量的影响

16个月的研究结果表明 ,每次刈割后追施氮肥可显著提高坚尼草的干草产量和粗蛋白质含量。刈割周期以4 0～ 6 0 d为宜。刈次间干草产量差异不显著 ,但粗蛋白质含量随着刈割周期的延长而显著下降。参试的 3个坚尼草品种干草产量之间差异极显著 。

水稻与大黍不对称体细胞杂交再生植株

采用PEG(聚乙二醇)融合法,诱导水稻(Oryza sativa L.)原生质体与无融合生殖大黍(Panicummaximum Jacq.)原生质体融合,经过融合体筛选、培养,成功地获得了再生植株并移栽成活。在融合前,水稻原生质体经过2.5mmol/L碘乙酰胺(IOA)在室温(22～25℃)条件下处理15min,大黍原生质体经过60Kr软X射线照射处理。对获得的28株融合再生植株进行初步检查发现,在花器官形态、结构及生殖特性上与对照亲本水稻植株有显著的差异,出现多花药(一朵颖花具7～11枚甚至13枝花药)、多胚珠(1个子房内有2～3个胚珠)及“多胚囊”(1个胚珠内有2个以上类似胚囊的结构)等现象。雌、雄性育性显著降低或完全不育,仅有5株能够少量结实,I-KI溶液着色的花粉从0至68％不等。细胞胚胎学检查表明不能结实的植株雌性均不育,即不能分化出正常的胚囊结构。

添加剂对稻草调节水分的大黍青贮饲料品质影响

采用首次刈割鲜大黍 ,用稻草调节水分 ,设添加纤维素酶、糖蜜及不添加作对照的 3个组 ,青贮 60d,评定其营养价值。结果表明 :①各组间 pH值差异显著 ,以试验组为最低 ;粗蛋白质含量按对照组、纤维素酶组和糖蜜组显著提高 ,而粗纤维显著降低 ;挥发性碱基氮在原料中为 0 ,纤维素酶和糖蜜组青贮后显著低于对照组。②细胞内容物按对照组、纤维素酶组和糖蜜组显著提高 ,细胞壁成分则相反 ,依次显著降低 ;中性洗涤纤维、酸性洗涤纤维含量按对照组、纤维素酶组和糖蜜组显著降低。③乳酸含量按对照组、纤维素酶组和糖蜜组显著增加 ,而乙酸则相反 ;青贮饲料中丙酸产量很低 ;丁酸含量按纤维素酶组、对照组和糖蜜组显著减少。④鼠李糖只在纤维素酶组和糖蜜组产生 ,且糖蜜组比纤维素酶组高 6倍 ;甘露糖只产生于糖蜜组 ;糖蜜组青贮后果糖含量为 3 3 0 .3 μg·g-1,其他组为 0 ;葡萄糖经发酵后 ,对照组和纤维素酶组被消耗 ,而糖蜜组却增加 1 0倍 ;半乳糖含量以糖蜜组最高 ,其他两组很低 ;糖蜜组阿拉伯糖含量为 0 ,青贮后对照组为 0 ,而糖蜜组是纤维素酶组的 3倍 ;木糖含量在纤维素酶组和糖蜜组较对照组分别提高 2 8和 65倍。

热研9号坚尼草选育研究

热研 9号坚尼草是 1988年从哥伦比亚国际热带农业中心引进的新品系 ,经鉴定后于 1990年开始进行系列研究。结果表明 ,热研 9号坚尼草不但保持了该属牧草高产优质的特点 ,干草产量 180 0 0 kg/ hm2 · a,比对照增产40 %,干物质含粗蛋白质 7.90 %,种子产量 495 .8kg/ hm2 ,增产 93.9%,而且具有耐酸瘦土壤、耐低温干旱、较耐荫蔽等特点 ,适宜在我国热带及亚热带地区种植。

灌溉对柱花草和坚尼草产量与品质的影响

对柱花草(Stylosanthes guianensis)与坚尼草(Panicum maximum CIAT 9)2种热带牧草在旱季进行人工灌溉后刈割,测定灌溉和不灌溉对生物量的影响。分析了2种热带牧草在人工灌溉条件下生物量的变化,结果表明,在人工灌溉条件下生长的2种热带牧草,生长速率快,刈割周期短,其产量和营养价值也有所不同。坚尼草在灌溉条件下其鲜生物量为不灌溉的1.4倍,生长周期缩短34%;柱花草在灌溉条件下其鲜生物量为不灌溉的1.06倍,生长周期缩短27%。

重金属镉胁迫对热带牧草坚尼草生长及品质的影响

[目的]为在热带地区镉(Cd)污染土壤中种植坚尼草提供理论依据。[方法]以热研8号坚尼草(Panicum maximum)为供试植物,通过测定其株高、生物量、叶绿素和各营养成分的含量研究镉胁迫对坚尼草生长及品质的影响。[结果]收获时,镉浓度为0.3 mg/kg处理的热研8号的株高(91.40 cm)和平均干重(61.57 g/盆)分别比对照增加10.9%和27.4%,显著高于其他处理。各处理中叶绿素a和b的含量均先增加后减少。热研8号坚尼草中的粗纤维、粗脂肪、粗灰分、粗蛋白含量随Cd浓度的增加先降后升。镁和钙含量在0.3mg/kg处理中最低,镁含量的最高点出现在1.0 mg/kg处理中,钙含量的最高点出现在5.0 mg/kg处理中。[结论]当土壤中的Cd浓度约为0.3 mg/kg时,它对坚尼草的生长有一定的促进作用;当其浓度为约10 mg/kg时,它会明显抑制坚尼草的生长。

5个坚尼草品种在闽南地区的区域试验

对引进的5个坚尼草新品种在闽南地区进行了两年区域适应性试验,结果表明,参试的5个坚尼草品种在本地区均能正常越夏、越冬,耐旱耐瘦,其中8号坚尼草、9号坚尼草的平均年鲜草产量均极显著高于对照,粗蛋白质含量与对照相当或略高,是优良的刈牧兼水土保持植物,可在闽南地区繁殖推广。

6个坚尼草品种比较试验报告

对6个坚尼草品种进行比较试验,结果表明:坚尼草TD58、坚尼草Mombassa、热研8号坚尼草和热研9号坚尼草产量之间差异不显著,但显著高于坚尼草CIAT6299,其中,热研9号坚尼草年均产量18140.46kg/hm2;坚尼草TD58其年均干物质产量达到17402.42kg/hm2,仅次于热研9号坚尼草,两者产量均显著高于坚尼草CIAT6299和青绿黍。青绿黍年种子产量达640kg/hm2,坚尼草TD58仅次于热研9号坚尼草,种子成熟比较一致。

热研8号坚尼草选育及利用研究

热研8号坚尼草是1988年从哥伦比亚国际热带农业中心(CIAT)引进的新品系,经鉴定于1990年开始进行系列研究。研究结果表明,热研8号坚尼草既保持了该属牧草高产优质的特点,年干草产量22500kg/hm2,干物质粗蛋白质含量7.738%,又具有耐酸、耐瘦、耐荫等特点;花期晚,利用期比对照品种增加1个月,种子产量480kg/hm2,比对照品种提高87.8%,适宜我国热带及亚热带地区种植。

大黍的大小孢子发生、雌雄配子体发育及其淀粉动态

通过石蜡切片，在光学显微镜下系统观察了大黍有性生殖过程中大小孢子发生、雌雄配子体发育及其淀粉动态。大黍花药壁由表皮、药室内壁、中层和绒毡层４层细胞组成。在花药发育过程中，表皮细胞始终积累大、小不等的圆球状内含物，该内含物经ＰＡＳ、苏木精分别染色均呈负反应。表皮细胞外壁在花粉成熟时期略有增厚，且具小刺状突起。绒毡层细胞属腺质型。小孢子母细胞在减数分裂过程中胞质分裂属连续型。成熟花粉粒富含较大颗粒的淀粉。大孢子母细胞减数分裂形成线型四分体，合点端大孢子发育为单核胚囊。４核胚囊进一步发育为４游离核与４细胞共存的８核胚囊。成熟胚囊属蓼型。在胚囊发育过程中，合点珠心细胞中淀粉不明显，在胚囊中合点端淀粉亦少于珠孔端。

加勒比松林下坚尼草耐荫性试验报告

2年的试验结果表明 ,坚尼草在相对光照为 30 %～ 6 5 %的加勒比松林下种植均能成活生长 ,以品系CIAT6 2 99、CIAT6 90 1的耐荫性最强 ,年均干草产量分别达 110 4 4kg/hm2 、85 89kg/hm2 ,比推广品种分别增产 139.6 %、86 .4 %。

6个坚尼草品种在海南西南部半干旱地区品种比较试验

2004～2006年对6个坚尼草品系在海南西部半干旱地区品种比较试验,结果表明:坚尼草品系的花期比较长,历期1～2个月,个别品种花期2个月以上,对照4号坚尼草(Panicum.maximum Jacq.cv.Reyan No.9)开花最早,开花期在7月下旬,1号坚尼草(P.maximum Jacq.cv.TD58)开花最晚,开花期在9月下旬。参试坚尼草品系干草产量差异显著,2号坚尼草(P.maximum Jacq.cv.Mombassa)干草产量最高达17 224.58 kg/hm2.a,比对照品种4号坚尼草(11 857.05 kg/hm2.a)高45.27%,且差异显著;次高是6号坚尼草(P.maximum Jacq.cv.CIAT6299),干草产量为16 169.73kg/hm2.a,比对照品种高36.37%,5号坚尼草(P.maximum Jacq.cv.trichoglume)产量最低,干草产量仅为8 925.64 kg/hm2.a。参试坚尼草品系的粗蛋白含量介于10.30%～12.10%,以对照品种的粗蛋白含量最高,为12.06%,次高为2号坚尼草,为11.63%,3号坚尼草(P.maximum Jacq.cv.Reyan No.8)最低,为10.31%。

添加纤维素酶和糖蜜对大黍青贮饲料品质的影响

采用第一次刈割大黍为原料 ,设添加纤维素酶、糖蜜及对照的 3个组 ,青贮 6 0 d后 ,评定其营养价值。结果 :1常规成分 :添加组 p H较对照组显著降低 ;粗蛋白质在对照组、纤维素酶和糖蜜组的含量依次增加 ;粗纤维在添加组比对照组显著降低 ;挥发性碱基氮在纤维素酶组和糖蜜组分别比对照组显著、极显著降低。 2细胞成分 :细胞内容物在对照组显著低于两个添加组 ;OCW在对照组显著地高于两个添加组 ;Oa以添加纤维素酶组最低 ,糖蜜组显著高于纤维素酶组 ,与对照组间差异不显著 ;Ob以对照组最高 ,各组差异显著 ;ADF含量由于添加纤维素酶和糖蜜而降低 ;NDF由于添加纤维素酶和糖蜜分别显著、极显著降低。 3有机酸 :乳酸由于添加纤维素酶和糖蜜而显著高于对照组 ;乙酸在各组间差异显著 ;丙酸在对照组与两个添加组间差异显著 ;丁酸在对照组含量最高 ,并与两添加组间差异显著。 4糖组成 :甘露糖经青贮发酵 ,糖蜜组含量 10 0 .42 μg/ g青贮饲料 ,其他组为 0 ;糖蜜组使果糖含量增加到 472 .14μg/ g青贮饲料 ;葡萄糖在原料草为 16 2 μg/ g,经过青贮 ,对照组被消耗 ,添加组含量分别增加 5和 2 5倍 ;半乳糖在对照组为 0 ,添加组分别产生196 .91、5 18.2 1μg/ g青贮饲料 ,糖蜜组比纤维素酶组高近 3倍 ;在添加组产生阿?

热研8号坚尼草的光合特性研究

2006年9月上旬,在晴天用LI-6400便携式光合仪测定热研8号坚尼草的光合特性。结果显示,热研8号坚尼草的光合日变化呈“单峰型”,无“午休”现象,13:00时出现峰值(Pn为26.9μmol/m2.s),变化趋势与蒸腾速率(Tr)、气孔导度(Gs)等因子相同;叶片光饱和点(LSP)约为1 700μmol/m2.s,光补偿点(LCP)约为46μmol/m2.s,表观量子效率(AQY)为0.0535,CO2饱和点(CSP)为600μmol/mol,CO2补偿点(CCP)为3.49μmol/mol,羧化效率(CE)为0.1168。表明热研8号坚尼草是一种耐荫的C4型阳性植物。