海南野生禾本科牧草种质资源调查、收集与鉴定

2005年11月-2006年3月对海南省19个市县分布的禾本科牧草资源进行了调查、收集与整理,本次调查共收集到禾本科植物74个属、159种,分别占海南禾本科种质资源属数的73.27%和种数的77.56%,其中《海南植物志》未记载的有4个属、21个种。本文对调查和收集的资源种类、分布情况、营养价值进行了分析,并对牧草资源的保护进行了讨论。     

广西一些草场牧草营养成分的研究

<正> 广西草山草坡面积大,总面积约8767.14万亩,相当于现有耕地面积的两倍多。由于地处亚热带,天然条件优越,牧草种类多,生长茂盛,生长期长,有利于发展草食家畜畜牧业。牧草中的营养成分是形成畜产品的物质基础,它直接影响牲畜的产量和质量,是作为评定牧草质量的重要指标之一,也是草山资源评价指标之一。根据国家农委对草地资源调查要求及当前广西草山草坡发展畜牧业的需要,我们于1979—1982年先后对桂西、桂北、桂中和桂东南的各类草场和草山草坡进行调查研究,并采集部分天然牧草,进行营养成分测定,研究草场牧草的营养化学,揭示它的营养成分含量、类型及其变化规律。现将资料汇总撰写成文,供从事畜牧业工作的同志参考及广西草山草坡的合理开发利用提供科学依据。     

割草对牧草分蘖萌发的影响

对皇草（Ｐｎｎｉｓｅｔｕｍ ｐｕｒｐｕｒｅｕｍ ×Ｐ ｇｌａｕｃｕｍ）杂交狼尾草（ｐｅｎｎｉｓｅｔｕｍ ｇｌａｕｃｕｍ×Ｐ ｐｕｒｐｕｒｅｕｍ）、矮象草（Ｐｅｎｎｉｓｅｔｕｍ ｐｕｒｐｕｒｅｕｍ）和墨西哥玉米（Ｚｅａ ｍｎｙｓ ｓｕｂｓｐ．ｍｅｘｉｃａｎａ）等４种牧草在生长期进行了４次割草试验,探讨了不同割草次数对牧草单兜株数的影响。结果表明：１）在进行１次割草的情况下,４种牧草的营养生长时间分别为５３、９６、１５３和２０８ ｄ时,单兜株数分别为２０．２,８．５,１７．２,１１．７株,牧草的单兜株数随营养生长时间的增加而呈大小相间排列;２）在可靠性为９５％以上时,第二次割草时的单兜株数与第一次割草时有明显的差异,而多次割草后的差异性逐渐减小;３）营养生长的时间长短和前一次的单兜株数对牧草后一次的萌发和分蘖有显著的影响,在一定程度上决定了后一次的单兜株数;４）杂交狼尾草在多次连续割草后,单位面积上的株数变得不均匀,而皇草、矮象草和墨西哥玉米则逐渐均匀化,这个作用使得杂交狼尾草在退化坡地水土保持上的价值减少．     

四种禾本科牧草植物蒸腾速率与水分利用效率的比较

报道了４种热带亚热带禾本科牧草植物的蒸腾速率、水分利用效率的日变化图式,并就它们与叶面光强、叶面温度、气孔导度等参数之间的相关关系进行了分析．结果如下：（１）蒸腾速率因牧草种类不同而有差异,墨西哥玉米、矮象草．杂交狼尾草、皇草的日平均蒸腾速率分别为２．４７、１．３８、２．５３、２．９０ｍｍｏｌ ｍ－２ｓ－１;（２）正午前后（１０：００－１４：００）是４种牧草植物蒸腾耗水的主要时期;（３）虽然矮象草的净光合速率和蒸腾速率的日变化图式与其它３种牧草之间存在较大的差异,但水分利用效率日变化差异则很小;（４）不同牧草种类对正午前后高光强高温的适应策略存在差异,墨西哥玉米、杂交狼尾草、皇草采用了相同或相近的适应策略,即通过维持气孔扩张最大程度地蒸腾水分以降低叶温,矮象草则通过关闭气孔以减轻因水分过度消耗带来的伤害（５）４种禾本科牧草植物具有忍受或适应华南夏季炎热高温气候的能力或潜力,在热带亚热地区有推广价值和发展前景．     

对贵州少数民族地区农业生物资源保护和可持续利用的建议

通过"贵州农业生物资源调查"项目的调查,获得了大批农业生物种质资源,这些种质资源具有丰富的物种多样性和遗传多样性,它们是贵州少数民族世代相传的物质遗产,也是贵州少数民族生活和生产的物质基础。与此同时,通过调查说明,贵州少数民族地区农业生物资源还有很大的调查收集潜力。由此不难看出,有效保护和可持续利用贵州农业生物资源,不论对贵州还是对中国都具有重要的现实和长远意义。     

西藏自治区雀麦属种质资源考察与收集

为了摸清西藏自治区雀麦属种质资源,初步开展了西藏自治区中南部雀麦属种质资源的考察和收集工作。共收集到无芒雀麦、雀麦、旱雀麦、华雀麦、细雀麦、大序雀麦、篦齿雀麦、总状雀麦、大麦状雀麦等9种73份资源。其中,发现《西藏植物志》未记载的新记录种4个,分别是雀麦、篦齿雀麦、总状雀麦和大麦状雀麦,并发现了西藏特有种华雀麦。相较原有国家牧草种质资源库保存的西藏地区雀麦属1种1份,极大地丰富了国家牧草种质资源库,为深入研究西藏自治区野生牧草资源奠定了数据和物质基础,为下一步青藏高原野生牧草的驯化与育种提供了原始材料。     

中国苋科一新分布

发表了作者在皖北植物资源调查中采集到的1500余号标本,经研究鉴定发现,中国苋科一新分布,阿尔维长序苋(D. arvensis Forsk.)文中所及标本,存安徽大学资源植物标本室。     

不同盐分处理对狼尾草和大油芒发芽与幼苗生长的影响

为了解盐渍化生境中r对策者发芽与幼苗期的盐分适应特征,本研究选用狼尾草(Pennisetum alopecuroides)和大油芒(Spodipogon sibiricus),按照NaCl∶Na2SO4∶NaHCO3为1∶1∶3(mol)配制复盐溶液,分6个处理(0、0.1%、0.2%、0.4%、0.8%和1.6%),分别进行种子发芽和幼苗生长单因素实验,比较了两种植物的发芽能力、胚生长和幼苗生长状况以及生理生化指标。结果表明:种子萌发阶段,随盐分浓度增大,狼尾草和大油芒发芽率、发芽指数和发芽势等均显著下降,低浓度(≤0.4%)时狼尾草的发芽能力小于大油芒,高浓度(≥0.8%)时则相反;狼尾草和大油芒胚芽长、胚根长及胚鲜重均显著下降,但大油芒胚生长受抑制的程度高于狼尾草;幼苗阶段,盐分显著抑制狼尾草和大油芒的幼苗生长,但大油芒受抑制的程度低于狼尾草,且狼尾草体内生理活性钙和丙二醛含量高于大油芒;可见,两种植物的耐盐能力在种子萌发阶段狼尾草强于大油芒,而幼苗阶段狼尾草又弱于大油芒,这体现了r对策者风险分摊的对策。     

刈割频率对两种牧草越冬的影响

刈割频率对皇草和杂交狼尾草越冬影响的实验表明,两者的根系生物量、根系养分贮量、越冬返青率和越冬产量均随刈割次数的增加而减少,但影响程度两者略有不同。刈割次数对杂交狼尾草的越冬返青率的影响更大,皇草的根系生物量和越冬产量则随刈割次数的增加而明显下降,本文还就如何减低刈割对牧草越冬的影响进行了讨论．     

贵州农业生物资源的多样性

国家科技基础性工作专项"贵州农业生物资源调查"项目完成了对贵州42个县的普查和21个县的系统调查。调查的农业生物资源包括粮食作物、经济作物、蔬菜作物、果树作物和药用植物等。通过调查基本查清了贵州现有栽培的农业生物资源207类,采集了4800多份种质资源,其中3500多份是国家尚未编目、入库(圃)保存的新种质资源,并且这些种质资源呈现出丰富的物种多样性和遗传多样性。这充分说明我国少数民族的偏远地区农业生物资源还有很大的收集潜力,应继续调查收集。     

Ecophysiology of Pennisetum clandestinum: a valuable salt tolerant grass

High concentrations of sodium are toxic to most plant species, making soil salinity a major abiotic stress for plant productivity world-wide. Its salinity resistance makes the turf grass Pennisetum clandestinum Hochst (kikuyu grass) a candidate plant for utilization and reclamation of salinized areas. Kikuyu grass, a perennial native to the highlands of Central Africa now common in many areas, has recently become a valuable pasture and lawn plant because of its growth rate and well developed root system. However, its salt resistance has yet to be fully evaluated. The objective of this study was to identify the biochemical and physiological basis of salt resistance of kikuyu grass for the use of this grass as pasture, in phytoremediation, in controlling soil erosion and in biomass production for energy, in salt affected lands, where the growth of other species is markedly reduced. This study focused on the effect of salinity on germination, growth, metabolism, biochemistry, nutritive properties and root morphology of kikuyu grass. We compile evidence that kikuyu grass can germinate and grow in salinized areas. The use of this salt-tolerant grass may be an important part of a range of practices, such as recycling saline wastewater and reclaiming salt-affected soil in arid-zone irrigation districts.     

Composition and nutritive value of some grasses, plants and aquatic weeds tested as diets

The composition and nutritive value of different diets, namely the aquatic weeds— Hydrilla verticillata (L.f.) Presl., Lemna gibbs (L.) Pistia stratiotes (L.), grasses—Guinea grass Panicum maximum Jacq., Napier grass Pennisetum purpureum Schum. and plants—sweet potato leaves Ipomaea batatas L. and tapioca leaves Manihot utilissimus Pohl. were determined and compared. The diets contained 13.5 to 30.48% protein; 1.89 to 9.60% fat; 3.94 to 23.13% ash; 5.42 to 26.70% fibre and 24.87 to 46.27% carbohydrate. Most of the minerals determined in the aquatic weeds were higher than those in grasses and plants. The feeding of Hydrilla , Napier grass and tapioca leaves to grass carp Ctenopharyngodon ideltus (V.) showed a different growth rate and the results obtained indicated the superiority of Hydrilla diet over Napier grass and tapioca leaves.     

贵阳市10种观赏草基于AHP方法的观赏适应性综合评价

从观赏草观赏性出发,结合与适应性和生长繁殖相关的11个指标,通过层次分析法(AHP)对贵阳市引进的10个观赏草品种进行观赏适应性综合评价。结果表明,11个评价指标中,观赏草的株型、叶色、耐旱性所占权重均较大(＞0.1),是影响其观赏适应性的重要指标;通过建立评分标准后,得出10个品种的观赏性排名为火焰狼尾草、花叶蒲苇、紫叶狼尾草、矮蒲苇、新西兰亚麻、金叶苔草、粉黛乱子草、蓝羊茅、红巨人朱蕉、黄金苔草;生长适应性排名为矮蒲苇、花叶蒲苇、火焰狼尾草、紫叶狼尾草、新西兰亚麻、黄金苔草、粉黛乱子草、金叶苔草、红巨人朱蕉、蓝羊茅;最终综合评分观赏适应价值极好的(Ⅰ级＞4.30分)有花叶蒲苇、火焰狼尾草;观赏适应价值较好的(Ⅱ级3.56～4.30分)有矮蒲苇、紫叶狼尾草、新西兰亚麻、粉黛乱子草、金叶苔草;观赏适应价值一般的(Ⅲ级＜3.56分)有蓝羊茅、红巨人朱蕉、黄金苔草。     

巨菌草饲用价值研究现状及其对贵州喀斯特石漠化治理的启示

巨菌草(Pennisetum sp.)是一种多年生草本植物,具有适应性广、抗逆性强、产量高的特点,不仅可用作饲草,在生态环境治理中也具有其独特优势。综述了巨菌草作为饲草的优势、饲用价值及其在畜牧生产中的应用现状以及在石漠化治理的应用潜力,以期为巨菌草在畜牧生产及石漠化治理中的应用提供参考。     

Influence of Acidity on Growth and Biochemistry of Pennisetum clandestinum

Hydroponics were used to study the impact of acidity on growth, nutritive properties and metabolic changes in kikuyu grass (Pennisetum clandestinum Hochst). Four treatments (pH 6.0, 5.0, 4.0, and 3.0) were compared for effects on biomass, leaf and root length, crude protein, amino acid content and key enzymes of sugar metabolism. Reduction in biomass, root and leaf length, amino acid contents, glucose-6-phosphate dehydrogenase (G6PDH) and pyruvate kinase (PK) content was observed only at pH 3.0, in association with increased leaf proline content. Kikuyu grass is able to grow normally under mild acidity (down to at least pH 4.0).     

Proximate Composition of Freshwater Fish — Grass Carp,Puntius gonionotus and Tilapia

Summary The proximate analyses of freshwater fish — Grass carp (Ctenopharyngodon idellus), Puntius gonionotus and Tilapia (male hybrid) are compared. Dried meals from eviscerated freshwater fish contained 57.36–75.92% protein; 4.48–31.84% fat and 10.68–22.88% ash. The results indicate that Tilapia had a higher fat content than gonionotus and grass carp, the latter having the lowest fat content. The reverse is true for protein, ash and minerals like sodium, phosphorus and potassium. The composition of grass carp feeding on different diets, such as Hydrilla verticillata, Napier grass (Pennisetum purpureum) and tapioca leaves (Manihot utilissins) indicated only a slight difference in protein content but a significant difference in fat and ash. The tabulated results show that grass carp and goniotus were of higher nutritive value when compared to the Tilapia.     

Comparison of pasture types in the tropical Andes: Species composition,distribution, nutritive value and responses to environmental change

Pastoralism is the main land use in the humid tropical Andes of South America. Wide areas of mountain rainforest have been cleared for gaining pastureland. Due to the lack of indigenous useful grasses in the pristine forests, mainly exotic grass species have been used for establishing the pastures. In the Ecuadorian Andes, Axonopus compressus, Melinis minutiflora, Pennisetum clandestinum and Holcus lanatus are common pasture grass species. Their preference for certain microsites resulted in a mosaic of different pasture types, which reflect the differing ecological conditions on the undulating terrain of the mountain slopes. During the last decades, however, another exotic grass species, Setaria sphacelata has widely been introduced which, because of its fast growth on some of the sites could successfully suppress the formerly dominant plant species. With respect to the changing microclimate and cattle stocking rates the present study explored, whether planting Setaria is the best option for the common low-input type of pasture farming in these tropical mountains. In a study over twenty years, the development of four main pasture types, dominated by the above-mentioned grass species was investigated in areas with and without Setaria, and their topographical occurrence on the sloping terrain was analyzed. On forty-eight plots a pairwise (with or without Setaria) comparison of species composition and diversity, biomass production, forage quality and soil properties was performed. Although Setaria grows faster than the other grass species, its productivity was only higher on flat terrain. The nutritive value of the Setaria plots was at best equivalent to that of the former pastures, while species richness was consistently lower. Our results suggest the maintenance of a terrain-adapted diversification of the pastures and in particular the use of Setaria only on flat terrain.     

Bias when predicting crude protein,dry matter digestibility and voluntary intake of tropical grasses by near-infrared reflectance

A study was made of the bias (non-random error) of regressions for predicting crude protein (CP) content, dry matter digestibility (DMD) in vivo and voluntary intake (VI) of forage from its near-infrared reflectance (NIRR) properties measured at 19 wavelengths. The regression was derived from 97 samples including six tropical grasses, leaf and stem fractions, pelleted and chopped forms and regrowths varying from 28 to 150 days.Bias associated with differences in feed type was proved to exist in regression equations for predicting nutritive value when it was shown that the residual errors of these regressions were significantly reduced by including the combined effects of grass species, fraction, form and age. Measures of the bias which might be expected were calculated for two contrasting situations. The internal measure of bias (IMB) was ‘estimated’ as a possible average bias of a feed type when predicting nutritive value for samples of similar types to those used when deriving the calibration equation, while the extrapolation measure of bias (EMB) was ‘estimated’ as that associated with prediction of the nutritive value for feed types not included in the calibration equation.Crude protein was estimated with a residual standard deviation (RSD) of ± 0.77% when regressed against the 19 reflectance values, but when information on grass species, parts and regrowth was also included in the regression the RSD was reduced to ± 0.46%. The maximum difference in the IMB between grass species was 0.80% crude protein, while for EMB it was 3.35% crude protein. When separated leaf and stem were considered the differences were larger.Dry matter digestibility was estimated with an RSD of ± 2.7% which decreased to ± 1.8% when grass species, age, form and study were taken into account. Grass species had only a small effect on IMB but the maximum difference for EMB between species reached 5.6%. The EMB indicated that the largest differences between deviations were associated with age of regrowth but this effect was absent with the IMB.Voluntary intake was estimated with an RSD of ± 7.2 g/kg W^0.75/day, which decreased to ± 2.5 g/kg W^0.75/day when grass species, form, part and age were taken into account. The largest bias was for pelleted and chopped forage with mean differences of 14.5 for IMB and 28.8 g/kg W^0.75/day for EMB, respectively.It was concluded that when nutritive value is predicted by NIRR the estimates may often be biased according to the grass species, plant part or physical form of the sample tested and that the pattern of bias may be complicated. In order to obtain accurate predictions from NIRR full account must be taken of this bias. This might be achieved by correcting the nutritive value estimates made from an NIRR regression, based on a large number of feed types, by addition of the bias associated with the feed type being estimated.     

Can inconspicuous legumes facilitate alien grass invasions? Partridge peas and fountain grass in Hawai‘i

We investigated the potential role of a nitrogen-fixing legume in facilitating invasion by an alien grass, Pennisetum setaceum (fountain grass) into native Heteropogon contortus grasslands in Hawai'i. Both grasses are C₄ perennials. Many formerly extensive Heteropogon grasslands have been reduced to remnants surrounded by Pennisetum . An inconspicuous annual legume, Chamaecrista nictitans (partridge pea), was commonly associated with Pennisetum stands but was found at higher densities in Pennisetum-Heteropogon mixtures. In the field, we also found higher exchangeable soil nitrogen beneath Chamaecrista-Pennisetum-Heteropogon mixtures than beneath neighboring pure Heteropogon stands. We then used greenhouse experiments to test the hypothesis that increased nitrogen facilitates Pennisetum 's invasion of established Heteropogon . Under low nitrogen conditions, Pennisetum seedlings planted beneath established Heteropogon plants grew very little (<0.3 g biomass after 16 weeks), and their growth was not affected by high or low water treatments. In contrast, under high nitrogen conditions, in both low and high water treatments, Pennisetum seedlings grew rapidly, averaging 60 fold the biomass of seedlings in the low nitrogen treatment and exceeding the biomass of the established Heteropogon plants under which they were planted. We also compared Pennisetum - Heteropogon seedling competition in the presence and absence of live Chamaecrista . The growth of Pennisetum was not directly facilitated by live Chamaecrista in the greenhouse pots, but the Chamaecrista did not increase available soil nitrogen until after it had died. Our results suggest that increases in soil nitrogen, like those associated with an inconspicuous alien legume, can facilitate an alien grass' invasion of a native grassland.     

Biochemical and molecular analysis of plants derived from embryogenic tissue cultures of napier grass (Pennisetum purpureum K. Schum)

Summary We have investigated the extent of biochemical and molecular variation in 63 plants of napier grass (Pennisetum purpureum K. Schum.) regenerated from 3- to 24-week-old embryogenic callus cultures. The calli were derived from cultured basal segments of young leaves and immature inflorescences obtained from a single fieldgrown donor plant. The entire population was analyzed for the activity of 14 isozyme systems, but no qualitative variation was found at any of the loci examined. Similarly, no restriction fragment length polymorphisms (RFLPs) were detected in the mitochondrial, plastid and nuclear genomes in a representative sample of regenerated plants. Our results confirm earlier reports of the genetic uniformity of plants derived from somatic embryos and highlight their value both for clonal propagation and for genetic transformation.