Italian Ryegrass (Lolium perenne ssp. multiflorum) and Corn (Zea mays) Competition

Italian ryegrass is an annual/biennial grass that is typically used as a pasture crop or a cover crop along roadsides, rights-of-way, and industrial areas. Glyphosate-resistant (GR) Italian ryegrass populations have been documented around the world, mostly in orchard and vineyard situations. The first evidence of evolved GR Italian ryegrass in row/agronomic crops was reported from Washington County, Mississippi in 2005. GR Italian ryegrass populations can jeopardize preplant burndown options in reduced-tillage crop production systems, thereby, delaying planting operations. The effects of competition of Italian ryegrass on crop growth and yield are poorly understood. A field study was conducted in the 2012 growing season and repeated in the 2013 growing season. GR and susceptible (GS) Italian ryegrass populations were established in the greenhouse and transplanted in prepared corn row beds in the fall of 2011 and 2012 at 0, 1, 2, 3, and 4 plants·meter> of crop row. Italian ryegrass plants overwintered and developed over the following spring-summer. Glyphosate was applied at 1.26 kg·ae/ha (1.5× of labeled rate) in the spring to burndown the Italian ryegrass plants and corn was planted into the ryegrass residue 2 - 3 wk later. Current corn production practices were followed. Corn density (early and late season), height (early season), and yield and Italian ryegrass biomass (early-mid season) measurements were recorded during both years. Corn height was greater in 2012 than that in 2013 at comparable stages of the growing season, due to a cooler and wetter early season in 2013 than that in 2012. Averaged across weed densities, corn density (both early and late season) and yield were higher in the GS than those in the GR population, but Italian ryegrass biomass was similar for both populations. Averaged across Italian ryegrass populations, corn density (both early and late season), and yield were inversely proportional to Italian ryegrass density. In summary, Italian ryegrass significantly reduced corn density and yield and reduction was greater with the GR than that with the GS population. Studies are underway to study inter population competition in Italian ryegrass and investigate allelopathic effects of Italian ryegrass on selected crops.

Effects of Nitrogen Fertilization on Some Turfgrass Characteristics of Perennial Ryegrass (Lolium perenne L.)

The paper aimed to study the effects of nitrogen fertilization on the yield and some plant characteristics of perennial ryegrass (Lolium perenne L.). The study was conducted at Agricultural Research and Application Center of the Faculty of Agriculture in Igdir University in 2013. In the experiment, eight levels of fertilizers: 0, 10.0, 20.0, 30.0, 40.0, 50.0, 60.0 and 70.0 kg N/ha per month were applied in perennial ryegrass (Lolium perenne L.) during the sixth growing season. A randomized complete block with three replications was used as the experimental design. Nitrogen application affected plant height, green grass yield, plant covering rate, canopy color and turfgrass quality values of perennial ryegrass positively. In both monthly and as the average of nitrogen application, times of application (spring, summer and fall) caused the most uniform turfgrass quality and establishment. Results indicated that although a significant impact was on the character investigated, such as the leaf length, green grass yield, plant cover ratio, canopy color and turfgrass quality, the doses of nitrogen fertilizer have created close to each other in groups. In the stand point of view of all characters, N1, N2 and N3 were located in first group, N4 and N5 in the second group, N6 and N7 in the third group, expect for control (N0). It can be concluded that 40.0-50.0 kg N/ha per month may be more suitable to be used in ryegrass production in the landscape.

Cu^2＋胁迫对黑麦草(Lolium perenne L.)去除富营养化水体中氮、磷效果的影响

为探讨不同浓度Cu2+胁迫对黑麦草去除富营养化水体中N、P营养盐效果的影响,采用小试培养的方法,研究了Cu2+存在条件下黑麦草对水体中N、P去除的动力学过程及黑麦草植株对不同浓度Cu2+胁迫的生态响应.结果表明,0.1~2.0 mg/LCu2+胁迫均降低了黑麦草对水中N、P营养盐的去除速率,其去除过程符合二阶动力学模型.黑麦草对水体中Cu2+亦有良好的去除作用,根部是积累重金属Cu的主要部位,其对Cu2+的吸收速率符合米氏动力学方程.较低浓度Cu2+(≤0.2 mg/L)胁迫对黑麦草去除N、P的效果影响不大,并且能促进黑麦草生物量的增加,而较高浓度Cu2+(≥0.5 mg/L)胁迫虽有促进根系数量增加的趋势,但明显抑制了黑麦草根伸长和叶片生长等作用,因而严重影响了黑麦草对水体中N、P的去除.

Revegetation of Copper Mine Tailings with Ryegrass and Willow

To restore vegetation on metal mine tailings is very difficult because theyoften contain high concentrations of heavy metals, low nutrient content and low water retentioncapacity. This study involved 3 experiments that evaluated the effects of 4 treatment amendments:montmorillonite, rice straw, organic manure and chemical fertilizer on the growth of ryegrass(Lolium perenne L.) and willow (Salix viminalis L.) with Cu and Zn mine tailings from two miningareas. The results showed that ryegrass was the most tolerant of 4 crops to Cu toxicity. Also whenorganic manure, which contained high concentrations of inorganic salts, was added to the minetailings, it significantly hindered ryegrass growth (P = 0.05). Meanwhile, with ryegrass organicmanure significantly increased (P = 0.05) the extractable Cu concentration in both mine tailings.When montmorillonite was used as a mine tailings amendment with willow, the height and tress numberat the 1st cut were significantly greater (P = 0.05) than a control without montmorillonite. Howeverthere was no significant difference for height, tress number, dry weight or root dry weight at the2nd cut. So, amendment applications to reduce metal toxicity and increase nutrients retention inmine tailings were essential during revegetation of mine tailings.

Glomus intraradices对黑麦草生长和富集镉的影响

采用盆栽方法模拟不同镉污染状况,研究接种丛枝菌根真菌(AM)Glomus intraradices对黑麦草生长和富集、运转镉的影响。结果表明,土壤镉水平增加明显提高了黑麦草菌根侵染率,而显著降低了黑麦草的生长量,但对磷浓度无显著影响,表明Glomus intraradices对镉胁迫具有一定的耐性,并对黑麦草的磷营养和生长未表现出促进作用。Glomus intraradices的存在明显促进了黑麦草对镉的富集,菌根形成强化镉在根系的固持作用,减少镉向地上部运转,进而降低黑麦草地上部的镉浓度,减轻了镉对地上部的毒害,表现在根富集系数均大于1,运转系数远远小于1。这一结果对镉污染农田修复以及草坪草和牧草品质的改善都有重要意义。

Forage Species Suitability Mapping for China Using Topographic, Climatic and Soils Spatial Data and Quantitative Plant Tolerances

Selecting plants adapted to the climatic and soil conditions of specific locations is essential for environmental protection and economic sustainability of agricultural and pastoral systems. This is particularly true for countries like China with a diversity of climates and soils and intended uses. Currently, proper species selection is difficult due to the absence of computer-based selection tools. Climate and soil GIS layers, matched with a matrix of plant characteristics through rules describing species tolerances would greatly improve the selection process. Better matching will reduce environmental hazards and economic risks associated with sub-optimal plant selection and performance. GIS-based climate and soil maps have been developed for China. A matrix of quantitative species tolerances has been developed for example forage species and used in combination with an internet map server that allows customized map creation. A web-based decision support system has been developed to provide current information and links to original data sources, supplementary materials, and selection strategies.

黑麦草种子及幼苗对镉胁迫的生理响应

为了探明不同黑麦草品种对镉(Cd)富集能力的差异及其生理机制,以6个黑麦草品种为材料,研究镉胁迫对其种子萌发、生物量、镉吸收、色素含量、光合特性及抗逆特性的影响。结果表明,与正常生长条件相比,镉胁迫对不同黑麦草品种种子萌发和根芽生长具有低促高抑作用。镉胁迫增加了黑麦草光合色素含量;镉胁迫增加了维纳斯、奔驰、维多利亚叶片的气孔导度、胞间CO_(2)浓度、蒸腾速率;镉胁迫增加了奔驰、维多利亚、蓝标叶片的POD活性;镉胁迫增加了卡特、维多利亚叶片的SOD活性;镉胁迫增加了维多利亚、维纳斯叶片的CAT活性。奔驰、维多利亚、维纳斯可能较其他品种具有更强的耐镉性,从而减少镉对自身的危害;镉胁迫增加了所有品种可溶性糖含量及除卡特外的5个黑麦草品种脯氨酸含量,奔驰、蓝标、维多利亚能产生较多的渗透调节物质来减轻镉胁迫对其造成的伤害;在正常生长条件下,黑麦草地上部镉含量和镉累积量都较低,品种间差异较小。镉胁迫明显增加了黑麦草地上部镉含量和镉累积量,奔驰地上部镉含量和镉累积量最高,显著高于其他品种。综上,奔驰、维多利亚抗镉性及富镉能力较强,是镉污染土壤修复的优选品种。

Zn胁迫对黑麦草幼苗生长、生理生化及Zn吸收的影响

采用营养液培养法,研究了不同Zn浓度(0,0.25,0.50,1.00,2.00 mm o l/L)对黑麦草幼苗生长、过氧化物酶活性、脯氨酸、根系活力及Zn吸收的影响。结果表明,低锌胁迫对黑麦草幼苗生长无抑制,过度锌胁迫(Zn≥2 mm o l/L)将降低黑麦草地上部干质量。幼苗叶内游离脯氨酸含量随锌胁迫时间、锌浓度增加而增加。随Zn胁迫时间增加幼苗POD活性先降后升、根系活力先升后降,锌处理的植株地上部POD活性随锌浓度增加先降低,然后增加,而根系活力随锌浓度增加而增加。黑麦草幼苗地上部和根系Zn含量随Zn浓度的增加而增加,当Zn浓度为2.00 mm o l/L时,地上部Zn含量最大值为775.0 m g/kg。

利用流式细胞术鉴定黑麦草倍性方法的研究

为了测定几种不同倍性的黑麦草核DNA含量,利用流式细胞术(Flow Cytometry,FCM)检测黑麦草的染色体倍性,并通过传统的染色体制片的方法对其结果进行验证。结果表明不同品种间细胞核DNA含量差异显著,且随着倍性水平的增加,细胞核DNA相对含量随之成倍增加。流式细胞术检测结果与染色体制片检测结果一致。利用流式细胞仪测定黑麦草核DNA含量,具有样品制备简单,测量快速,精度高等优点,是进行倍性鉴定的理想方法。

海藻糖合酶基因转化黑麦草及耐旱性研究

以多年生黑麦草(Lolium perenne L.)种子成熟胚为外植体,在MS附加5mg/L2,4-D、500mg/L的L-脯氨酸、130mg/L天门冬酰氨、10mg/LAgNO3的诱导培养基(MSJ)上诱导胚性愈伤组织。用基因枪法将ubiqutin启动子驱动的海藻糖合酶基因(TPS基因)转入多年生黑麦草的胚性愈伤。在含有5mg/LBialaphos的选择培养基上经过2个月的抗性筛选,抗性愈伤组织在分化培养基上生成了898株再生植株,其中的220株检测为阳性株,检测的阳性率占供检株数的24.5%。PCR分析及PCR-Southern杂交鉴定表明,TPS基因已整合到黑麦草的基因组中。抗旱性鉴定表明,转基因黑麦草在干旱胁迫条件下的保水能力增强,电解质渗出率明显低于对照,耐旱性提高。

多年生黑麦草成熟胚再生体系的建立及基因枪转化

目的 :建立以多年生黑麦草成熟胚为起始材料的再生体系 ,用于基因枪转化。方法 :多年生黑麦草成熟种子在附加 5mg L 2 ,4 D的MS培养基上诱导愈伤组织 ,转至新继代培养基上产生胚性愈伤组织。分化培养基为无激素MS培养基。再生植株在培养基成分减半的无激素MS培养基生根 ,之后移栽至土壤。基于这一再生体系 ,用含有水稻几丁质酶基因RC2 4的质粒pARN6和含有草丁膦乙酰转移酶基因Bar的质粒pDB1 ,通过基因枪轰击胚性愈伤组织。用附加PPT的继代培养基进行转化植株的抗性筛选。结果 :共获得 2 4 3株再生植株。通过PCR进行检测 ,获得1 8株整合有RC2 4基因的植株 ,1 5株整合有Bar基因的植株 ,同时转入 2个基因的植株 2株。

植物油脂包膜尿素的氮素释放及其对黑麦草养分吸收利用的影响

以环境友好的植物油脂为包膜材料制得2种包膜尿素,连续溶出试验以商品包膜尿素(CCU)为对照,测定POU1、POU2的氮素释放状况,盆栽试验设不施肥处理(CK)、不施氮处理(PK)、普通尿素处理(NU)、商品包膜尿素处理(CCU)、自制包膜尿素处理(POU1、POU2),研究新型包膜尿素对多年生黑麦草养分吸收及氮素利用状况的影响。溶出试验结果表明,POU1、POU2的氮素累积溶出量显著低于CCU(P<0.05),且POU2显著低于POU1(P<0.05);在等氮处理条件下,施用POU2处理的黑麦草地上部含氮量明显高于NU处理,甚至达到显著水平(P<0.05),3次刈割后,POU1、POU2处理的黑麦草地上部总干物量和氮、磷、钾总积累量显著高于NU处理(P<0.05)。另外,POU1、POU2处理的黑麦草氮肥表观利用率明显高于NU处理(P<0.05)或CCU处理。植物油脂包膜尿素,尤其是POU2,能改善黑麦草氮素营养状况,增加黑麦草地上部氮、磷、钾的吸收,促进黑麦草生长。说明植物油脂可以作为包膜材料,植物油脂包膜尿素可视为新型缓释尿素。

多年生黑麦草高频再生体系的建立及优化

从外植体预处理方式、基本培养基、激素浓度等方面着手,对多年生黑麦草愈伤组织诱导、继代、不定芽分化及再生过程中的影响因素进行了研究,提高了再生频率。结果如下：切取胚端半粒种子,经75%乙醇处理1min,0.1%HgCl处理15min,在经无菌水清洗4～6次后接种方式较好;愈伤组织诱导培养基以MS＋2,4—D 8.0 mg/L（或另添加甘露醇25 g/L）为佳;愈伤组织接种于MS＋2,4—D 8.0mg/L＋甘露醇25 g/L上进行1～2次继代后于NB＋6—BA2.0 mg/L上进行分化;不定芽转接至MS＋6—BA2.0 mg/L上进行扩繁或于1/2MS＋NAA0.5mg/L＋IAA0.5mg/L上进行生根。

一氧化氮参与盐胁迫下黑麦草幼苗脯氨酸积累的调控

以黑麦草(Loliumperenne L.)幼苗为材料,采用溶液培养方法研究了150 mmol.L-1 NaCl胁迫下根尖和叶片中一氧化氮(NO)产生和脯氨酸(Pro)积累的关系,以探讨NO在盐胁迫下诱导Pro积累中的调节作用。结果表明:NaCl胁迫下黑麦草幼苗根尖和叶片中Pro和NO含量增加,Pro合成的关键酶吡咯啉-5-羧酸合成酶(P5CS)活性提高,而Pro降解的关键酶脯氨酸脱氢酶(ProDH)活性下降。100μmol.L-1外源NO供体硝普钠(SNP)促进了NaCl胁迫下幼苗根尖和叶片中Pro的积累及P5CS活性的提高,降低了ProDH活性;NO清除剂cPTIO和合成抑制剂L-NAME,NaN3逆转了NaCl胁迫和SNP对Pro积累的诱导作用及P5CS,ProDH活性的调节作用。因此,NO可能通过P5CS和ProDH活性参与盐胁迫下Pro积累的调控。

外源NO对渗透胁迫下多年生黑麦草幼苗生长和生理特性的影响

一氧化氮(Nitric oxide,NO)作为生物体广布的一种生理活性物质,可调节植物一系列生理生化反应,增强其对逆境的抵抗能力;为此,以15%PEG-6000模拟渗透胁迫,研究外源NO对多年生黑麦草(Lolium perenneL.)幼苗生长和生理特性的影响。结果表明:15%PEG-60000渗透胁迫下,0.1 mmol.L-1NO供体硝普钠(Sodium nitroprus-side,SNP)可显著减轻对幼苗生长的抑制;促进脯氨酸(Pro)的累积,延缓幼苗叶片的水分散失(P<0.05);可诱导超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)活性升高,减缓丙二醛(MDA)的积累,显著缓解因渗透胁迫诱导的细胞膜脂过氧化过程(P<0.05),增强其抗渗透胁迫能力,且随着胁迫程度的加剧效果越佳。0.5 mmol.L-1SNP处理对黑麦草幼苗生长影响不显著,促进保护酶活性及缓解氧化损伤的作用较0.1 mmol.L-1SNP处理显著减弱。外源NO诱导植物水分及抗氧化酶系活性的变化,是植物在渗透胁迫下维持正常生长的重要抗逆生理机制。

光强对黑麦草萌发生长、叶片叶绿素含量及光系统Ⅱ的影响

以常见景观植物黑麦草为试验材料,探究6种不同光照强度对水培黑麦草萌发生长、叶片叶绿素含量和光系统Ⅱ的影响。结果表明:光强为300μmol·m^(-2)·s^(-1)时水培黑麦草萌发及生长最好,发芽率、发芽势、发芽指数和活力指数分别为93%、23.67%、57.28和211.58,根长、芽长分别为3.04 cm和4.01 cm,该光强下叶片叶绿素含量显著高于其它光强处理(P<0.05),叶绿素a、b及总叶绿素含量分别为0.71、0.27 mg·g^(-1)和0.98 mg·g^(-1);随着光强的增强,最大荧光(Fm)、PSⅡ的最大光化学效率(Fv/Fm)和光化学性能指数(PIabs)呈现先升高后下降的趋势,300μmol·m^(-2)·s^(-1)光强下Fm、Fv/Fm和PIabs值都达到最大;叶绿素荧光快速诱导曲线(OJIP)受光强影响较大,以I点差异较显著,对OJIP曲线进行标准化后差异较小;OJIP曲线参数分析表明PSII供体侧在6组光强下无显著差异,随着光强增强,单位反应中心吸收(ABS/RC)、捕获(TRo/RC)和传递(ETo/RC)也随着增强,但单位反应中心热耗散(DIo/RC)减小,PSII受体侧在500μmol·m^(-2)·s^(-1)条件下电子传递受阻。

多年生黑麦草高频再生体系的建立及农杆菌介导PEPC基因的转化

以多年生黑麦草(Lolium perenne L.)成熟种子作为外植体,建立其高频再生体系,通过农杆菌介导法将磷酸烯醇式丙酮酸羧化酶(PEPC)基因转入,为多年生黑麦草的抗逆转基因工作奠定基础。结果表明:种子充分灭菌后在附加6.0mg·L-1 2,4-D的培养基中诱导愈伤组织,诱导率可达61.33%。愈伤组织在2,4-D浓度减半的培养基上继代培养长势良好,分化培养基为MS培养基附加1.0mg·L-16-BA,分化率最高达到61.33%,在1/2MS+0.5mg·L-1 NAA培养基中进行生根培养,生根率达100%。以该再生体系为基础,将获得的愈伤组织作为外植体进行遗传转化,经筛选培养后得到再生植株,通过PCR及实时荧光定量(Real-Time)PCR验证表明PEPC基因已成功转入,转化率为8.67%。试验结果将为多年生黑麦草抗性品种的研究奠定基础。

一年生四倍体黑麦草饲喂肥猪效果观察

利用一年生四倍体黑麦草(Lolium perenne L.)替代配合饲料饲喂肥猪,结果表明,用25%、30%、40%比例的黑麦草替代25%、30%、40%的配合饲料饲喂肥猪,日增重可分别降低3.0%、7.5%、8.6%,但饲粮消耗可分别减少22.75%、25.88%、35.69%,养猪成本分别降低16.12%、17.52%、24.53%。比较而言,一年生四倍体黑麦草替代配合饲料饲喂肥猪的适宜比例为25%。

多年生黑麦草转基因育种及其安全性的研究进展

多年生黑麦草是适应性很强的牧草和草坪草种,转基因技术的应用已成为其育种研究的重要途径。为此,概述了多年生黑麦草组织培养和遗传转化方面的研究进展,首次探讨了转基因多年生黑麦草的生物安全性。

铅胁迫对黑麦草叶绿素和可溶性糖含量的影响

研究了在不同浓度铅(500、1 000、1 500 mg/kg)及不同处理时间(5、10、15 d)的作用下,黑麦草(Lolium perenne L.)幼苗体内的可溶性糖及叶绿素含量的变化。结果表明,黑麦草叶片在遭受到了铅胁迫后其可溶性糖含量发生明显变化,在较高浓度及较长时间处理下其可溶性糖的含量有着明显的增加。叶绿素a、b含量在处理时间为10 d时达到最高值,显著高于5 d和15 d时的含量;但在同一时间下,随铅浓度的增加,黑麦草叶片叶绿素a、b含量绝大多数无显著变化。在不同时间及不同铅浓度处理下,类胡萝卜素含量变化均不一致,但均没有显著的差异。