Study on the Degradation Trend of Ryegrass-White Clover Artificial Grassland

[Objective] The study aimed to explore the degradation law and trend of artificial grassland. [Method] Taking the ryegrass （Lolium perenne） - white clover （ Trifolium repens） artificial grassland in Maiping Township, Guizhou Province as the research object, the grassland vegetation of 40 quadrate from different areas （area around the sheep shed, hilltop, hillside, flatland at the foot of the hill） were analyzed by comparing the dominance and richness index. [ Result] Degradation of different degrees appeared in various areas of this artificial grassland. To be specific, the degradation of grassland around the sheep shed was not serious for less consumption by the sheep; however, the areas on the hilltop and hillside degenerated to the grassland types of dallis grass （ Paspalum dilatatum Poir. ） -Indian lovegrass （ Eragrostis pilosa） and dallis grass - cogongrass [ Imperata cylindrica （ Linn. ） Beauv. ], respectively, and the area at the foot of the hill degenerated to the grassland type dominated by garland chrysanthetnum （ Chrysanthemum coronarium L. ） and knotgrass （ Paspalum distichum L. ）. [ Conclusion ] This study provided a basis for grassland improvement as well as the efficient and sustainable utilization of grazing-type artificial grassland in South China.

Removal of Pyrene from Contaminated Soils by White Clover

Phytoremediation has been used as an emerging technology for remediation of soil contamination with polycyclic aromatic hydrocarbons(PAHs),ubiquitous persistent environmental pollutants derived from natural and anthropogenic processes,in the last decade.In this study,a pot experiment was conducted to investigate the potential of phytoremediation of pyrene from spiked soils planted with white clover(Trifolium repens)in the greenhouse with a series of pyrene concentrations ranging from 4.22 to 365.38 mg kg-1.The results showed that growth of white clover on pyrenecontaminated soils was not affected.The removal of pyrene from the spiked soils planted with white clover was obviously higher than that from the unplanted soils.At the end of the experiment(60 d),the average removal ratio of pyrene in the spiked soils with white clover was 77%,which was 31%and 57%higher than those of the controls with or without micobes, respectively.Both roots and shoots of white clover took up pyrene from the spiked soils and pyrene uptake increased with the soil pyrene concentration.However,the plant-enhanced dissipation of soil pyrene may be the result of plant-promoted microbial degradation and direct uptake and accumulation of pyrene by white clover were only a small part of the pyrene dissipation.Bioconcentration factors of pyrene(BCFs,ratio of pyrene,on a dry weight basis,in the plant to that in the soil)tended to decrease with increase in the residual soil pyrene concentration.Therefore,removal of pyrene in the contaminated soils was feasible using white clove.

Effect of Chilling Stress on Synthesis of Antioxidant Enzymes, Osmotic Adjustment Substances and Membrane Lipid Peroxide Levels in Two White Clover Cultivars

Although white clover has been widely studied and applied,less is known about its physiological responses to chilling stress in northern China.The effects of acclimation time of chilling stress in the two white clover cultivars,Rivendel and Haifa,after exposure to 4℃for 0,4,8,12,24 and 48 h were investigated.Seven physiological indexes were measured in shoots of the two cultivars.It was found that Rivendel had a strong ability to maintain the stability of cells,cope with oxidative damage and accumulate osmotic adjustment substances compared with Haifa.In addition,a comprehensive evaluation on the chilling tolerance of the two cultivars based on subordinate function value analysis showed a stronger chilling tolerance of Rivendel than Haifa.

White (<i>Trifolium repens</i>L.) and Arrowleaf (<i>Trifolium vesiculosum</i>Savi) Clover Emergence in Varying Loblolly Pine (<i>Pinus taeda</i>L.) Tree Alley Spacings

Agroforestry systems have the potential to provide year-long income opportunities via the integrated forage or crop, timber, and livestock. Legumes are an attractive alternative option during the growing season when more traditional forages may not be as productive. The objective of this study was to test the establishment of arrowleaf and white clover grown under varying pine tree alley widths. In 2011, existing forage was removed in 15-yr old loblolly pine tree row alleys of different widths (3.7, 4.9, 7.3, and 9.8 m), including an open area. Arrowleaf, as an annual, was replanted in 2012. Seedlings were counted twice/year, while dry matter was measured three times/year. Photosynthetically active radiation (PAR) was measured in all alley widths to compare light penetration through the canopy. Hot and dry conditions occurred throughout 2012, affecting results. In 2012 and 2013, the greatest PAR for most treatments was observed in June. Seedling counts for all treatments were greatest immediately after establishment, and gradually declined throughout the course of the study. Dry matter yields increased throughout the growing season, and were greatest in arrowleaf clover in the open area on all measurement dates;however, increased weed pressure and repeated flooding affected yields. This study demonstrated that clover establishment in shady wooded areas is possible, but only under suitable environmental conditions.

Resource Sharing by the Different Clonal White Clover Plant(Trifolium repens L.)

Resource sharing in the different parts of the clonal white clover plant (Trifolium repens L.) was investigated in this study. The results showed that the integration of water and nitrogen metabolism occured among parental, young and old branches of a plant when water passed through its stolons. Under the sufficient supply of light, water and nutrients from soil the newly developed branches showed similar capacity in taking in sufficient water and nitrogen to that of old branches. The development of the new branches did not affect the growth of the old and parental branches attached. The results also indicated that energy values in roots was significantly related with plant age, however, the energy values were various in the different parts of a plant.

几种栽培豆科牧草生物量与结构的研究——兼论Ladino白三叶的栽培密度

牧草生物学特性差异导致牧草生物量和结构的差异，结构的差异表现出品种间对时空的利用各不相同。Ｌａｄｉｎｏ白三叶（Ｔｒｉｆｏｌｉｕｍｒｅｐｅｎｓ）密度试验，其生物量表现出株行距小的窄行定植ａ大于株行距大的窄行定植ｃ，中行定植ｃ的生物量介于二者之间，同密度试验的雅安白三叶（Ｔ．ｒｅｐｅｎｓ），其生物量和抗草害的能力较低。１８０天的不同物候期的盖度与密度的大小为正相关。且经三年的盆栽封闭性试验得以证实。几种豆科牧草地上部的倒“”字结构和地下部的半“Ｔ”字型结构中：无性繁殖的Ｌａｄｉｎｏ白三叶生物量大于雅安白三叶；种子直播的金花菜（Ｍｅｄｉｃａｇｏｈｉｓｐｉｄａ）。

Genetic Diversity of Clover by SRAP

In the present study,genetic diversity and genetic relationship of 11materials including red clover ( Trifolium pretense L.),white clover ( T.repen L.) and alsike clover ( T.hybridum L.) and leaf-type variants of white clover were investigated by SRAP (sequence related amplified polymorphism).Forty SRAP primers were screened,and 792 reliable bands were amplified,among which 426 (53.8%) were polymorphic.The number of polymorphic bands per pair of primers ranged from 3 to 38 with an average of 10.6.SRAP cluster analysis showed that the similarity coefficients between white clover materials were from 0.465 to 0.997 with an average of 0.812,indicating that there was certain genetic diversity among white clover.Specific bands appeared in white clover variants,indicating that there were certain differences in DNA sequence between normal while clover plants and their leaf-type variants.The similarity coefficients between red clover materials were from 0.457 to 0.827 with an average of 0.597,indicating that the different red clover germplasms had genetic diversity at the DNA molecular level.The results also showed that the genetic relationship of the alsike clover with the red clover was closer than that with the white clover.This study shows that SRAP technique can be effectively used for the analysis on interspecific and intraspecific relationship,germplasm resource identification and genetic diversity of clover.

白三叶种质资源耐酸铝性综合评价

白三叶(Trifolium repens)是一种世界性优质的蛋白饲草,在我国长江流域及以南地区被广泛栽培,而南方地区多为酸性土壤。研究发现,白三叶具有一定的耐酸铝性,因此筛选耐酸铝种质对于开发白三叶优异资源、培育耐酸铝新品种具有重要意义。以30份国内外白三叶种质为对象,研究不同酸铝浓度下的白三叶萌发特性,并采用隶属函数法进行耐酸铝性综合评价。随Al3+胁迫浓度的增加,白三叶发芽率逐渐降低,发芽势和发芽指数下降,胚根变短、变粗;Al3+浓度≥1.0 mmol·L^(-1)时白三叶种质发芽率和胚根长度受到显著抑制(P<0.05)。除胚根直径外,白三叶萌发性状不同胁迫浓度间差异显著(P<0.05),且萌发期每个胁迫处理下同一性状不同白三叶材料间亦存在极显著差异(P<0.01)。在2 mmol·L^(-1)处理下白三叶多数性状具有更大的变异系数指标差异,可作为白三叶耐酸铝性综合评价的适宜胁迫浓度。聚类分析将30份白三叶划分为3个耐酸铝能力不同的类群,其种质耐酸铝性强弱与综合评价值基本一致。来自荷兰的种质‘EM196’和来自澳大利亚的种质‘EM085’具有较高的酸铝胁迫耐受性。

白三叶花色遗传规律及对光温的响应

为明确白三叶红花突变体花色性状的遗传规律,探究光温对花色表达的影响,以白三叶红花突变体和白花品种为材料进行杂交、回交、自交和测交试验,研究杂交后代花色性状分离规律,并分析不同温度和光照处理下白三叶突变体花色的色度差异。白三叶红花突变体与白花品种杂交F1代花瓣均显白色,突变体自交一代(S_(1))花瓣均显红色;F_(2)代和回交一代(BC_(1))花色分离符合孟德尔遗传规律,红花与白花比例分别为49:699和96:279,基本符合1:15和1:3的预期比例。相对于暖温环境(28℃8 h,34℃16 h),低温处理(12℃8 h,18℃16 h)显著降低花瓣亮度值(L值),红色度(a值)增加但差异不显著;温度骤降显著提高花瓣红色度,降低花瓣亮度。遮光2 d后突变体花瓣颜色由红转白,恢复光照1 d后又转为红色。白三叶红花突变体花色性状受双隐性基因控制,光是白三叶红花突变体花瓣颜色调控的关键因素。

营养元素对豆科牧草-根瘤菌共生系统牧草生长及结瘤能力的影响

为了探究营养元素对豆科牧草-根瘤菌共生系统牧草生长及结瘤能力的影响,试验选用贵州天然豆科牧草红三叶(Trifolium pratense L.)、白三叶(Trifolium repens L.)分别与根瘤菌伯克氏菌(Burkholderia phytofirmans)R63-1、拉格雷根瘤菌(Rhizobium laguerreae)R87-4共生,设不同浓度(100,200,300,500 mg/L)的氮肥、磷肥、钾肥3种肥料,另设不配施根瘤菌液、不配施肥料在自然状态下生长的牧草作为空白对照(CK1、CK2),同时设只配施根瘤菌液、不配施肥料的牧草作为对照(CK3~6),共60个处理,每个处理3个重复,测定牧草农艺性状和结瘤能力,解析营养元素对固氮共生体系的影响。结果表明:红三叶+根瘤菌的株高、根际直径及单株鲜重与CK1、CK2相比,分别最高增加了90.93%、242.55%、714.47%,白三叶+根瘤菌分别最高增加了65.92%、69.06%、334.21%。红三叶+R63-1+200 mg/L氮肥处理的根长、干物质含量均最高,根瘤数最多,分别为29.03 cm、22.94%、202.78颗/株,比CK3分别增加63.92%(P<0.05)、41.17%(P<0.05)、87.85%(P<0.05)。红三叶+R63-1+500 mg/L磷肥处理的根际直径、单株鲜重均最高,根瘤数最多,分别为10.01 mm、16.13 g、271.67颗/株,比CK3分别高24.35%(P>0.05)、67.50%(P>0.05)、151.66%(P>0.05)。红三叶+R87-4+300 mg/L钾肥处理的株高、单株鲜重、鲜重冠根比均最高,分别为23.70 cm、16.16 g、1.51,但与CK4相比均差异不显著(P>0.05),且根瘤数最多,达424.11颗/株,比CK4高485.87%(P<0.05)。白三叶+R87-4+100 mg/L氮肥处理的株高、根长、根际直径、单株鲜重均最高,根瘤数最多,分别为39.28 cm、26.25 cm、5.96 mm、13.13 g、121.33颗/株,比CK6分别高14.75%(P<0.05)、12.32%(P>0.05)、33.04%(P<0.05)、13.68%(P>0.05)、6.18%(P>0.05)。白三叶+R87-4+300 mg/L磷肥处理的株高、根长、单株鲜重均最大,分别为56.64 cm、27.67 cm、23.73 g,比CK6分别高65.47%(P<0.05)、18.40%(P>0.05)、105.45%(P<0.05),且根瘤数为508.67颗/株,比CK0高345.15%(P<0.05),但较大根瘤体积比CK6低62.70%(P<0.05)。白三叶+R87-4+500 mg/L钾肥处理的根长、根际直径、单株鲜重均最大,根瘤数最多,分别为24.67 cm、6.82 mm、33.34 g、375.33颗/株,比CK6分别高5.56%(P>0.05)、52.23%(P<0.05)、188.66%(P<0.05)、228.46%(P<0.05)。红三叶、白三叶在氮磷钾肥各浓度处理下,除结瘤率外,红三叶、白三叶在各指标变异系数分别在15.75%~99.32%、17.83%~90.43%之间。说明加施菌液可以让两种牧草形成根瘤,且促使两种牧草的株高、根际直径、单株鲜重增加;以单株鲜重为主进行分析,R87-4的促进作用强于R63-1,菌液对红三叶的促进作用强于白三叶。对两种牧草分别加施氮、磷、钾肥后,部分浓度对红三叶、白三叶的农艺性状和结瘤能力有抑制作用,部分浓度有促进作用,以变异系数为主进行分析,肥料对白三叶的影响大于红三叶。

不同融雪剂对三种草坪草种子萌发特性的影响

融雪剂对植物种子萌发影响是国家标准中一项重要指标。本文采用种子萌发实验方法,以2号氯盐融雪剂和3号混合型融雪剂为对照,比较新研发的1号生态环保融雪剂对禾本科黑麦草(Lolium perenne cv.Green Emerald)和早熟禾(Poa pratensis cv.Merit)豆科白三叶(Trifolium repens cv.Riverdel)3种草坪草种子萌发特征影响,结合材料的环保性与经济性,评价不同融雪剂对草坪种子萌发特性的影响。结果表明:3种融雪剂对草坪草种子萌发均表现为低促高抑效应;相同浓度时,融雪剂对3种草坪草种子萌发50%抑制的临界值表现为:2号氯盐融雪剂>1号生态融雪剂>3号混合型融雪剂;随着融雪剂浓度增长,3种种子萌发受到抑制作用随之增强。3种草坪种子对融雪剂耐受性表现为早熟禾>黑麦草>白三叶草。发芽率、发芽指数、活力指数、根长、种子相对受害率间呈显著相关。研究结果从多维度评价分析不同融雪剂对种子萌发特性的影响,为不同融雪剂使用的浓度限制范围,以及生态环保融雪剂推广应用提供参考。

紫花苜蓿、白三叶硒蛋白的提取方法筛选及工艺优化

硒蛋白是微量元素硒(Se)在生物体内发挥生物学作用的主要形式,对宿主在抗氧化、抗炎、提高免疫力等方面有重要意义。为探究不同豆科牧草硒蛋白提取方法筛选及其工艺优化,本研究以紫花苜蓿(Medicago sativa)和白三叶(Trifolium repens)为原材料,采用碱提法(NaOH)、盐提法(NaCl)、酸提法(HCl)和水提法(H2O)4种溶剂提取法获得牧草硒蛋白,并在单因素试验基础上进行正交试验优化硒蛋白提取工艺。结果表明:碱提法提取紫花苜蓿和白三叶硒蛋白效果最好。紫花苜蓿最佳工艺条件为温度40℃、料液比1∶20 g·mL^(-1)、碱浓度0.15 mol·L^(-1),硒蛋白提取率为35.39%。白三叶最佳工艺条件为温度50℃、料液比1∶40 g·mL^(-1)、碱浓度0.15 mol·L^(-1),硒蛋白提取率为35.52%。本研究可为从豆科牧草中提取硒蛋白提供重要的技术支持和实践指导。

高加索三叶草与白三叶杂种F_(1)代表型遗传变异研究

对高加索三叶草(♀)、白三叶(♂)及其远缘杂交育成的8个F_(1)代株系的13个数量性状和7个质量性状进行调查,研究杂交F_(1)代表型的相对遗传力与杂种优势。结果表明:13个数量性状表型遗传多样性丰富,11个性状的变异系数超过10%;7个质量性状遗传多样性指数较低;F_(1)代表型遗传多为正向显性,相对遗传力a1最高可达1.92,母本对F_(1)代的相对遗传力较父本高;F_(1)代杂种优势最明显的是小花数与结实小花数,杂种优势率达65.03%和80.96%;聚类分析表明,8个F_(1)代与高加索三叶草距离较近,与白三叶距离较远。

丘陵地苹果园生草对根际土壤理化性状及微生物的影响

以白三叶草和黑麦草为试材,清耕区为对照,采用田间和室内试验相结合的方法,研究了生草对丘陵地苹果园0~60 cm土层土壤物理性状、土壤肥力及土壤微生物的影响,以期为通过生草改善丘陵地苹果园土壤环境提供参考依据。结果表明:生草提高了丘陵地苹果园土壤含水量、孔隙度、有机质含量、pH、全氮、速效氮、速效磷、速效钾含量及细菌、真菌、放线菌的数量,降低了土壤容重,影响主要集中在0~40 cm土层,不同草种对果园土壤环境的影响存在一定差异。综合分析可知,生草改善了丘陵地苹果园土壤微域环境,尤其是对0~40 cm土层效果显著,种植白三叶草的效果好于黑麦草。

豆科牧草化感作用初探

采用培养皿滤纸的生物检测方法对红三叶、白三叶和紫花苜蓿 3种常用豆科牧草的化感作用进行了初步研究。结果表明 :3种豆科牧草在一定的播量下 ,对萝卜、青菜、番茄等受体植物生长表现出明显的抑制作用 ,使发芽率、苗长、根长、苗干重、根干重明显比对照降低 ,且抑制作用的强弱与豆科牧草种子播量有关 ,说明 3种豆科牧草均存在较大的化感作用潜势。

亚热带丘陵茶园间作白三叶草的生态效应

在亚热带丘陵区1a生幼龄茶园通过连续4a的大田对比试验，研究了茶园间作白三叶草的生态效应，结果发现：茶园间作白三叶草降低了土壤容重，提高了土壤孔隙度、有机质、全N、水解N的含量、K的活性、蚯蚓的数量和生物量，消耗了部分有效P；增加了土壤关键层次（0—20cm）和关键时期（4～6月）的水分含量，延缓和缩短了夏季高温干旱与秋季持续干旱时间；获得了土壤降温时增温、保温与升温时降温的双向动态调控效果，增加了同一层次土壤温度的稳定性，延缓了高温和低温的出现时间，缩短了过度高温时间，减少了高温对茶树生长产生的影响；抑制了杂草生长，增加了天敌的种类和种群数量，减少了虫害发生率。从而形成了立地环境．茶树．伴生生物群落系统自我调节的动态平衡，促进了茶树生长，改善了茶叶品质，显著增加了茶叶产量。与清耕茶园相比，茶园间作白三叶草后，春秋茶的酚氨比分别下降了17．10％和30．90％，产量提高了32．65％。

白三叶转基因及其生态适应性研究进展

牧草基因工程是近年来国内国际研究的热点之一 ,白三叶作为温带地区优良的豆科牧草 ,是人工草地建植的首选草种 ,也是各类观赏性草坪和绿地的主要组分。但白三叶的生态幅较窄 ,适宜在温暖 (适宜生长温度为 19～ 2 4℃ )湿润、年降雨量 70 0～10 0 0 mm的地区生长 ,对土壤酸碱度的要求比较严 ,适宜的土壤 p H为 6～ 7,耐酸性和耐盐碱能力都比较差 ,从而限制了其在许多地区的应用。利用转基因手段提高其抗逆性和生态适应性 ,培育抗性强、适应性广的白三叶新品种 ,对我国尤其是北方畜牧业、草坪业和生态建设都具有重要意义。在提高其对生物胁迫和非生物胁迫的抗性和生态适应性方面 ,白三叶的转基因研究已经取得了较大进展。结合国内外白三叶基因工程及生态适应性研究动态 ,系统介绍了白三叶转基因研究的主要内容和方法 ,在对已有成果进行综合分析的基础上 ,就目前白三叶转基因和生态适应性研究中亟待解决的一些问题进行了探讨。

通过农杆菌介导法获得耐盐转甜菜碱醛脱氢酶基因白三叶草

通过农杆菌介导法将耐盐植物山菠菜甜菜碱醛脱氢酶 (BetaineAldehydeDehydrogenase ,BADH)基因成功地转化了白三叶草。转基因植株在经过 4 8h 1%NaCl胁迫后相对电导率为 2 0 %左右 ,而非转基因植株高达 4 0 % ,表明转基因植株细胞膜在盐胁迫下受到的伤害较非转基因的轻 ,并且转基因植株能够在含有 0 5 %NaCl的水培养中正常生长两周以上 ,而非转基因植株则呈现不正常生长。

三种三叶草幼苗期抗旱性差异的研究

在模拟干旱条件下测定了高加索三叶草、白三叶和红三叶幼苗期的抗旱生理指标。结果表明,随干旱时间的延续,三种三叶草都表现出相对含水量下降、细胞膜透性升高、游离脯氨酸含量增加、相对生长率下降等特征,但三种三叶草的反应速度及复水后各指标的恢复能力各不相同。综合评价后初步认为,高加索三叶草的抗旱性强于白三叶和红三叶。

丛枝菌根真菌对铜尾矿上植物生长和矿质营养的影响

通过温室盆栽试验研究了白三叶草(TrifoliumrepensLinn.)和黑麦草(LoliumperenneL.)在单独和混合种植情况下单独或混合接种丛枝菌根真菌Glomusmosseae和Glomusversiforme对铜尾矿砂中植物生长和矿质营养的影响.试验结果表明,不同接种处理下均以单独种植白三叶草菌根侵染率较高,平均为25%.在单种和混种情况下,接种处理均显著提高了白三叶草地上部的干物重,但对黑麦草生长影响不明显.同时,接种处理显著提高了三叶草植株中的磷含量,同时降低了植株铜含量,但对黑麦草植株体内元素含量影响不明显.两种植物混合种植情况下黑麦草显示了相对竞争优势,而菌根共生体能够提高三叶草的竞争能力.试验初步证明丛枝菌根真菌对于豆科植物适应铜尾矿复合逆境(养分贫瘠和重金属污染),以及在尾矿上重建具有物种多样性的植被具有潜在作用,但有必要进一步筛选耐性菌株,并验证自然条件下菌根真菌的作用潜力.