防寒措施对冬季低温下移植香根草的影响研究

冬季低温条件下采用常规农艺防寒措施,旨在探索解决低温下种植香根草Vetiveria zizanioides难题的途径.试验结果表明:1)香根草移栽后采用覆膜措施比覆土壅根和对照春季存活率高,而且香根草春季返青、分蘖早,但最终存活率没有显著性差异;2)覆膜措施在各移栽期防寒效果较为稳定,而覆土壅根措施和对照的防寒效果因种植时间的不同而呈现差异;3)农田平地上种植的香根草春季存活率比在公路斜边坡上高,预示着香根草春季存活率高低与土壤水分、肥力等非温度因素有关;4)不同防寒措施对香根草分蘖影响不显著;5)从经济和技术角度来看,覆膜防寒措施是可行的.     

京郊果园种植几种优质果园草覆盖越冬技术研究

针对白三叶Trifolium repens、杂三叶T.hybridum、鸭茅Dactylis glomerata、百脉根Lotus corniculatus等几种优质果园草在京郊果园难以安全越冬的问题。试验采用覆膜、覆草、浅覆土3种覆盖越冬技术对果园草进行覆盖越冬效果的比较研究。结果表明,覆膜、覆草、浅覆土3种覆盖技术较对照均能显著提早各果园草品种的返青时间,显著提高越冬率和覆盖度。覆膜区的果园草品种较浅覆土和对照区分别提早返青13和20 d以上,越冬率平均分别提高21.8%和60.8%,返青生长到4月1日时草群覆盖度分别提高41%和51.3%,而覆草区的果园草品种较浅覆土和对照区分别提早返青4和8 d以上,越冬率平均分别提高16%和45.3%,返青生长到4月1日时草群覆盖度分别提高14%和22.7%。几种果园草品种覆盖越冬效果的具体表现为覆膜＞覆草＞浅覆土＞对照,但在具体实施中虽覆膜是一种效果最为明显的果园草品种覆盖技术,而覆草技术（干草535 g/m2、厚度约5 cm）更为环保、经济、实用。     

不同浓度海水灌溉对香根草生长的影响

模拟香根草在海边滩涂湿地上的生长环境,采用不同盐分浓度的海水浇灌移栽后的香根草,试验结果显示,不同浓度海水灌溉会影响香根草移栽后的成活率及其地上部和地下部器官的生长发育。不同浓度海水对香根草移栽后的成活率影响显著,0倍海水浓度处理香根草成活率1009,6,而2倍海水浓度处理移栽香根草则全部死亡,并且供试的4个处理,随着海水浓度升高抑制香根草生长发育的效应增强,0倍海水浓度灌溉对香根草生长发育没有抑制作用,0．5倍海水浓度和1倍海水浓度香根草生长受轻微影响,且两者之间没有显著差异,但2倍海水浓度浇灌香根草地上部的分蘖、绿叶数、株高、茎叶干重和地下部的最大根长、一级根条数、根体积、根干重及根茎比等性状指标都显著受到抑制。     

人工覆雪厚度对足球场草坪冬春季生长状况的影响

通过实地观测国家体育场冬季冰雪节人造雪覆盖条件下的草坪生长状况,研究了冬春季人工覆雪模式的影响及其可行性。结果表明,覆雪状态下草坪草比同时期未覆雪草坪草的可溶性糖含量、细胞膜透性都显著降低,根系活力相对增高,叶绿素含量在前期趋于一致、后期较高,覆雪对草坪草的冬季生长和返青有明显促进作用。但当雪层较薄低于30cm以下时,保温保湿作用大幅降低,同时还会因为雪融化结冰而对草坪产生负面影响。就草坪草冬春季的稳定性而言,无雪覆盖〉厚雪（60-70cm）覆盖〉薄雪覆盖（〈7cm）;对返青的促进作用而言,厚雪覆盖〉无雪覆盖〉薄雪覆盖。     

遮光对香根草生长发育的影响研究

香根草Vetiveria zizanioides移栽后采用不同遮光率的遮阳网遮盖,结果表明:1)移栽后约2个月香根草存活率才基本稳定,遮光对香根草成活率无显著影响;2)移栽后2个月内遮光对香根草分蘖影响不显著,但2个月后遮光对分蘖有显著影响;3)生长前期遮光对香根草株高无显著影响,但在生长后期,过度遮光会显著地影响株高的伸长;4)遮光会影响香根草根茎比,但这种影响比较复杂,会随生育时期的变化而改变。     

草铵膦在杂交狗牙根交播黑麦草草坪建植中的应用研究

研究了不同剂量草铵膦对杂交狗牙根(Cynodon dactylon)交播多年生黑麦草(Lolium perenne)草坪的质量调控效果。结果表明:低剂量草铵膦处理(225,450 g/hm2)对杂交狗牙根草坪的色泽没有显著的影响,但能够显著抑制杂交狗牙根的生长,而中、高剂量处理则对杂交狗牙根草坪的色泽有显著的负面影响;所有草铵膦处理对多年生黑麦草的萌发没有影响,且能够显著改善交播草坪的冬季色泽,450g/hm2剂量处理的冬季色泽均能维持在90%;低剂量草铵膦处理(225,450 g/hm2)对杂交狗牙根草坪的春季返青没有显著的影响,但中、高剂量的草铵膦处理则对杂交狗牙根的春季返青造成了严重的负面影响,显著延迟了杂交狗牙根的春季返青进程。试验表明450 g/hm2的草铵膦处理是交播草坪最适宜的应用剂量。     

红壤区坡耕地香根草篱对花生生长的空间影响

采用径流小区试验,分析了红壤坡耕地香根草（Veiveria zizanioides）篱对生育期内花生(Arachis hypogaea)植株高、叶绿素含量和花生产量的影响,探讨篱农间作最佳草篱间距。结果表明,与常耕相比,香根草篱处理苗期篱上第1行花生株高和叶绿素含量显著升高,开花期时株高显著升高（P＜0.05）,叶绿素含量却显著下降,结荚期株高和叶绿素含量都显著下降,其它各行无明显差异（P＞0.05）;香根草篱处理篱上第1、2行花生产量显著降低,第5、7、9行则显著升高,而第3、11行无明显差异。研究认为香根草篱与花生的安全距离≥66 cm,在此基础上,采用抛物线模型+直线平台分析得知香根草篱间距为8～12 m时,间作花生产量与常耕相比基本持平,间套优势明显.     

季节对母猪诱导发情效果的影响

应用PMSG制剂分别在不同季节对母猪进行了诱导发情研究。结果表明 :夏季母猪的情期受胎率显著 (P<0 .0 5 )低于春季、秋季和冬季 ;而冬季母猪的诱导发情率则极显著 (P <0 .0 1 )低于其它三个季节。因此 ,季节对母猪诱导发情效果影响较大 ,处理的最佳季节是春季和秋季     

狼尾草属种间杂交关键技术研究

在南京地区进行美洲狼尾草（Ｐｅｎｎｉｓｅｔｕｍａｍｅｒｉｃｕｎｕｍ）与象草（Ｐ．ｐｕｒｐｕｒｅｕｏｎ）的种间杂交，对象草作短日照处理，以诱导其抽穗，开花。通过对象不同移栽期，不同短日照处理天数的试验及对影响花粉量诸因子的综合分析表明，较早移栽植象草（５月５日移栽）覆膜２１ｄ能有效提高父本的花粉量。     

九种观赏草在南京地区的适应性评价

以香茅、红叶白茅、细叶芒、花叶芒、斑叶芒5种暖季型观赏草和蓝羊茅、花叶虉草、细茎针茅、金叶苔草4种冷季型观赏草为材料,观测其在南京地区不同季节的生长状况,对其基本形态特征、物候期及观赏价值进行了研究。结果表明:除红叶白茅、香茅不能正常抽穗开花外,其它7种观赏草在南京地区生长发育正常,适应性较好;冷季型草种在南京地区的适应性有所不同,部分观赏草种出现季节性休眠现象,如蓝羊茅夏季休眠,花叶虉草冬季短暂休眠,均降低了该季节的观赏价值;5种暖季型草种冬季休眠,其它季节观赏价值较高,适合用于南京地区的景观绿化。     

坡度对香根草护坡植物群落早期特征的影响

对不同坡度的相邻两边坡上香根草(Vetiveria zizanioides)护坡植物群落早期阶段连续2年的调查与分析,结果显示:(1)菊科(Compositae)、禾本科(Gramineae)、豆科(Lentil)3类物种最早在群落中定居,3类物种数占物种总数比例为56.00%～84.62%。(2)香根草种植两年后两坡面上植物群落开始出现分化。其中,1#坡面(坡度小)有利于香根草种群的发展,但也有利于乡土植物种在其中定居,植物群落保水效果也较好。(3)秋季植物群落特征规律明显,表现为:1#坡面(坡度小)植物群落丰富度指数R、多样性指数H′、均匀度指数J′随时间上升,植物群落优势度指数C′则呈现随时间下降;而2#坡面(坡度大)表现规律则相反。(4)植物群落丰富度指数R与群落中香根草物种优势度呈显著线性负相关;多样性指数H′和均匀度指数J′与群落中香根草物种优势度呈极显著线性负相关;优势度指数C′均与群落中香根草物种优势度呈极显著线性负相关。     

砷胁迫下老芒麦和香根草根茎叶砷吸收特征及抗氧化响应

采用盆栽试验,研究3种砷浓度下(0、10和100 mg·kg-1)老芒麦(Elymus sibiricus)和香根草(Vetiveria zizanioides)生长特征及根、茎、叶三部位砷含量变化及其细胞膜透性、抗氧化酶[超氧化物歧化酶(SOD)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)、过氧化氢酶(CAT)]响应特征。结果表明,低浓度砷对老芒麦和香根草株高和生物量抑制不明显,高浓度下抑制显著(P<0.05),二者相比香根草对重金属砷有更好的抗性。除老芒麦叶片变化不显著外,两种植物其余部位的砷含量均随着浓度的增加而显著增加;老芒麦地上部的砷积累量随浓度的增加显著降低,香根草则表现出随浓度的增加显著升高,高浓度条件下香根草地上部的砷积累量要高于老芒麦。老芒麦根、茎、叶三部位的细胞膜透性均表现出随砷浓度增加显著升高,香根草根、叶部位表现出相同的变化趋势,但茎部的差异不显著(P>0.05)。砷胁迫引起了老芒麦根、茎、叶三部位CAT、SOD和APX活性的显著增加,而香根草这3种酶的活性能够在10和100 mg·kg-1间维持。POD活性有所不同,表现为砷胁迫引起两种植物茎、叶部位降低,根系增加。综合而言,香根草对于重金属砷有更好的抗性、更强的富集能力,并且SOD与POD可能在其抗氧化体系中起关键作用。     

紫色土区香根草不同径级的根系特征与培肥效应

为探讨水土保持先锋物种香根草的培肥效应及其与各径级根系指标间的关系,以裸地为对照,定期分010 cm,1020 cm,2030 cm土层采集土壤和根系样品,常规方法测定土壤有机质、氮、磷、钾的全量和速效养分,WinRHIZO(Pro.2004c)根系分析系统分10个径级测定根系参数(根长、根表面积和根体积)。结果表明:香根草的培肥效应主要体现在有机质上,且此效应随香根草定植时间的延长而增强,其次是全氮,而有效磷和速效钾则出现亏损;香根草小区土壤有机质、有效磷、全钾、速效钾均表现出明显的土壤养分表聚现象,在010 cm土层的含量显著大于其他土层的(P<0.05);0.00 mm相似文献   

夏季高温条件下香根草耐旱性研究

夏季高温条件下香根草Vetiveria zizanioides耐旱能力很强,在高温干旱条件下停水可持续24～42 d之久.试验研究表明:高温条件下随着受旱时间的推移,地上部生长受到抑制,分蘖下降,株高降低,茎叶含水量下降,叶片受伤害程度变重,同时地下部根系生长也受到抑制,根体积和根生物量几乎不再增加;不同高温条件下香根草的耐旱能力不同,温度高,香根草受伤害就越重、越明显,持续耐旱时间变短,返青复活的可能性变小.     

Milk yield of primiparous beef cows from three calving systems and varied weaning ages

Primiparous beef cows produced in 3 calving systems were used in a 2-yr study with a completely random design to measure milk yield throughout a 190-d lactation (2002, n = 20; 2003, n = 24 per calving system). Calving occurred in late winter (average calving date = February 4 +/- 2 d), early spring (average calving date = March 30 +/- 2 d), and late spring (average calving date = May 26 +/- 1 d). Additionally, cows used in this study had been weaned at varied ages as calves, creating 6 dam treatments. Dam age at weaning was 140 (late spring), 190 (late winter, early spring, late spring), or 240 (late winter, early spring) d of age. Milk production was measured by using the weigh-suckle-weigh technique at an average of 20, 38, 55, 88, 125, 163, and 190 d in milk. Milk yield for the 190-d lactation period was calculated as area under the curve by trapezoidal summation. Data were analyzed with a model containing treatment, year, and their interaction. Orthogonal contrasts were used to separate effects when treatment was significant (P < 0.10). Total milk yield did not differ (P = 0.42) between cows in the late winter and early spring systems, but cows in the late spring system tended to differ (P = 0.09) from the average of the other 2 systems. Cows in the late spring calving system had increased milk yield in 2002 and lesser milk yield in 2003 compared with the other calving systems (treatment x year interaction, P < 0.001). Cows born in late spring that had been weaned at 140 d of age produced more (P = 0.05) total milk than those weaned at 190 d of age. Peak milk yield was affected (P < 0.001) by treatment and showed a treatment x year interaction (P = 0.006). Day of peak lactation differed among treatments (P = 0.002), with cows in the late winter system peaking later (P = 0.007) than early spring cows, and late spring cows peaking earlier (P = 0.004) than the average of late winter and early spring cows. The average date of peak lactation was May 4 for the late winter system, May 31 for the early spring system, and July 19 for the late spring system. Calf ADG differed (P < 0.001) for the late spring system compared with the average of the late winter and early spring systems, but the relationship interacted with year (P < 0.001). Cow BW and BW change differed among treatments (P < 0.004), with much of the difference associated with the amount of milk produced or the timing of peak lactation. Season of calving affects milk yield of primiparous cows grazing Northern Great Plains rangelands and ADG of their calves.     

三种常见边坡植物对模拟干旱环境抗旱性能的研究

香根草、紫花苜蓿和高羊茅是工程边坡常见绿化植被,通过探究干旱胁迫对3种植物种子萌发、光合及生理生化指标的影响,评价分析其抗旱性,为水电边坡生态修复中的物种筛选、植物群落的重建给予参考。采用聚乙二醇(PEG)模拟干旱胁迫对植物种子进行4个PEG浓度水平的胁迫处理(5%、10%、15%、20%),研究3种植物种子在PEG干旱胁迫下的萌发特性;采用盆栽控水法分别对3种植物的幼苗进行4组土壤水分处理:正常供水(土壤含水量为最大田间持水量的75%~80%)、轻度土壤干旱胁迫(65%~70%)、中度土壤干旱胁迫(50%~55%)和重度土壤干旱胁迫(35%~40%),分别测定不同土壤干旱胁迫下3种植物光合、生理生化指标,运用隶属函数法对3种植物的抗旱性综合评价。结果表明由于干旱胁迫导致3种植物种子萌发数量减少、种子萌发活力下降,且随着干旱程度的加剧,影响程度逐渐加大,低浓度PEG胁迫对香根草种子的萌发具有引发作用。干旱程度导致3种植物净光合速率、蒸腾速率、胞间CO₂浓度、气孔导度和水分利用效率有不同程度的下降,香根草的净光合速率、蒸腾速率和胞间CO₂浓度下降最为显著,高羊茅的气孔导度和水分利用效率下降最为显著。随着干旱程度的增加,3种植物的丙二醛、脯氨酸和可溶性糖均显著增加。综合分析3种植物种子萌发率、萌发指数、光合及生理生化等多个单项指标,运用隶属函数平均值法鉴定出3种边坡植物的抗旱性,比较得出紫花苜蓿的抗旱性最强,高羊茅次之,香根草的抗旱性相对较差。     

The growth of veld in response to defoliation by various means in late winter and spring

An experiment was conducted on Dohne Sourveld to determine the effect of mowing and burning during the late winter and spring on subsequent herbage yields. Mowing in spring and burning in late winter before rain gave the highest and lowest yields respectively. There was no difference between burning after the late winter and the spring rains. Mowing both before and after the late winter rains yielded less material than the previous two burning treatments. Reasons for these results are suggested and their implications discussed. Growth curves revealed that at no time did late winter burning before rain stimulate earlier grazing than mowing or burning after rain.     

植物生长调节剂对香根草定植缓苗期的影响

进行了香根草的土壤盆栽及营养液栽培试验,结果表明,几种植物生长调节剂浸根对香根草的地上部、根系生长及根系形态指标等方面都产生不同程度的影响.吲哚丁酸(IBA)能较好地增加新根数量,对地上部生长及根系形态指标有较好的促进作用.从总体来看,几种植物生长调节剂对香根草的作用效果与一般作物相比均不理想.     

香根草组织培养技术的研究

香根草常规的无性繁殖方式难以满足运用生物技术筛选香根草抗性种质对种苗的需求,更难以满足大规模的香根草生态工程对种苗的需求。因此,创建香根草的组织培养技术是很有必要的。以香根草的腋芽为外植体进行离体培养,以MS为基本培养基,对胚性愈伤组织的诱导和植株再生体系的建立进行了优化。结果表明,适宜的诱导愈伤培养基为MS 2.0 mg/L生长素(2,4-D) 1.0 mg/L细胞分裂素(6-BA),愈伤组织诱导率最高可达96.7%;适宜的分化培养基为MS 1.0 mg/L 6-BA;适宜的生根培养基为1/2 MS 0.1 mg/L吲哚丁酸(IBA) 0.1 mg/L多效唑(PP333)。不同品种在相同培养条件下的愈伤诱导率存在较大差异。香根草的胚性愈伤组织具有单子叶植物典型的胚胎结构,其植株再生能力在继代条件下可以长期保持,继代18次的愈伤组织植株再生能力仍高达92.0%,即使继代24次后仍可达89.6%。香根草高效再生系统的建立为香根草开展基因工程及遗传转化方面的研究奠定了基础,也为大规模繁殖香根草种苗提供了新的技术保障。     

Nuclear transplantation in bovine embryos

This study was conducted to develop a method for transplanting nuclei in bovine embryos and to test the development of several stages of donor nuclei transplanted to enucleated pronuclear recipient embryos. Pronuclear embryos were centrifuged to reveal nuclei. Nuclei were removed without penetrating the plasma membrane as membrane-bound karyoplasts, and were inserted into enucleated zygotes by electrically induced cell fusion. The highest rate of fusion (79%) occurred in Zimmerman Cell Fusion medium at 100 V for 20 to 40 microseconds with the fusion membranes oriented parallel to the electrodes. The effect of nuclear transplantation on development was tested in pronuclear embryos in which nuclei were removed and reinserted and the embryos were then transferred to sheep oviducts for 5 d. Of the intact nuclear transplant embryos recovered, 5/29 (17%) developed to morulae or blastocysts compared with 11/30 (37%) of the non-manipulated embryos. Two nuclear transplant embryos were transferred to a recipient cow, and both developed to normal offspring. When nuclei from two-, four-, or eight-cell embryos were transplanted to pronuclear recipient embryos, no development was observed.