214 resultados para 226-3-10


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研究了空间实用背场Si太阳电池和GaAs/Ge太阳电池性能随质子辐照注量1 * 10~9 ~ 5 * 10~(13) cm~(-2)的变化。实验表明,两种太阳电池的电性能随辐照注量增加有不同的衰降趋势,背场Si太阳电池性能参数I_(sc)、V_(oc)和P_(max)衰降变化快,辐照注量为2 * 10~(10)cm~(-2)时,P_(max)就已衰降为原值的75%;而GaAs/Ge电池对应相同的衰降辐照注量达8 * 10~(11)cm~(-2), 且其I_(sc)、V_(oc)和P_(max)衰降变化起初缓慢,当辐照注量接近3 * 10~(12)~(-2)时才迅速下降。背场Si电池和GaAs/Ge电池性能衰降分别与擀子辐照引入的E_v + 0.14eV及E_v + 0.43eV和E_c - 0.41eV深能级有关。

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1987年大兴安岭北坡发生的特大森林火灾,过火面积达1.33×106ha,如何在如此大面积的火烧迹地上恢复森林资源,是森林经营管理者迫切需要回答和解决的问题。本文应用空间直观景观模型(LANDIS)设计不同的管理方案,模拟火后森林景观在不同自然干扰和人类干扰下的长期演替动态,以弥补这一不足。通过对比研究这些管理方案对森林景观的长期影响,不仅可以评价目前该区所采取的经营管理方案是否合理,还可以找到更合适的管理方案,为火后森林景观的定向恢复和加速恢复过程提供实际的指导意义。此外,通过对1987年火后十几年来森林植被的野外调查研究,可以弥补LANDIS只模拟树种不模拟草本和灌木,且以10年为步长的不足,加深人类活动对火后森林植被短期变化影响的理解。本文研究主要结论如下: 1)相对于轻度灭火方案而言,目前重度灭火方案可以增加针叶林(落叶松和樟子松)在该区所占的比例,相应地降低白桦等阔叶林在该区所占的比例。而且,目前重度灭火强度可以增加针叶树种成过熟林在该区所占的比例,减少幼龄林所占的比例,可见目前重度灭火方案有利于火后森林恢复。另外,目前重度灭火方案下的累计过火面积较少,火烧频率降低,但火干扰以重度火烧为主,这可能对于森林资源造成重大的损失。 2)种植强度越高,越有利于针叶林的更新。但考虑到经济以及劳动力等因素,中等种植强度(例如,种30%)已能很好地有利于火后森林恢复。相对于聚集种植而言,在整个重度火烧区进行随机种植可以增加针叶树种在该区所占的比例,降低白桦等阔叶树种所占的比例,因此随机种植更有利于火后森林恢复。进行人工造林时尽量不要种植单一物种。相对于其他种植比例而言,目前落叶松和樟子松的种植比例(7:3)有利于针叶树种的恢复。 3)相对于完全依靠天然更新而言,目前经营管理措施可以增加针叶树种在该区所占的比例,相应地降低阔叶树种的比重。在目前经营措施下,由于火后10年内进行大规模的森林采伐,使针叶树种的成过熟林及聚集程度等有较大幅度的下降,虽然随后逐渐增加,但也需要近100-150多年的时间才能恢复。总之,目前经营管理方案与完全依靠天然更新相比,有利于火后森林恢复,但在演替的前期(100-150多年)也存在一些问题。因此,大兴安岭林区发生特大森林火灾后,应禁止大规模的森林采伐,否则会发生森林年龄结构的锐变等一些问题,不利于森林景观的稳定。如果进行大规模的森林采伐,即使进行人工造林,也要很长时间才能得以恢复。 4)在火后完全依靠天然更新,无论是草本、灌木还是乔木树种在演替前期都发生了极大的变化。火后初始,阳性草本植物迅速增加,占据火烧迹地。但目前(火烧16年后)草本物种数开始下降,而且阳性草本逐渐减少,阴性草本逐渐增加。草本盖度的变化与物种变化呈明显的正相关,随着物种数的下降,草本盖度也逐渐下降。而灌木盖度与物种数则没有明显的相关性。目前喜阳灌木物种逐渐消失,而耐荫的逐渐增多,但总的灌木物种数只有少量减少。目前该区树种以白桦等阔叶林为主。在人工促进天然更新下,目前火烧迹地上的物种数仅稍高于天然更新。而由于人促更新使物种尤其是乔木更有利于更新,火烧迹地上的植被盖度却要高于天然更新。相对于天然更新而言,在人促更新下,目前在火烧迹地形成的针阔混交林中,针叶树种所占的比例明显提高。在人工更新下,目前火烧迹地上主要以针叶树种为主,而阔叶树种则较少。

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土壤碳循环过程是目前全球碳源碳汇研究的核心,目前对土壤碳循环过程和机制的研究还十分缺乏。杉木人工林约占我国人工林面积的1/4,由于近几十年经营管理措施不当,土壤有机碳的下降已经成为不争的事实,极大地影响了杉木人工林生产力的可持续发展。本研究通过对杉木人工林土壤有机碳来源、分解和释放动态的区分量化,结合13C标记示踪试验,开展了杉木凋落物分解对土壤有机碳平衡影响的研究,为土壤碳平衡和转化机理及杉木人工林的可持续经营提供了可靠的理论依据。通过系统的研究,得出以下结论: ⑴估算了典型杉木人工林土壤碳的周转状况,研究发现典型杉木人工林土壤碳更新较慢。土壤碳年输入量、形成量、转化量、输出量和贮存量分别为2.79 t hm-2、1.58 t hm-2、2.04 t hm-2、4.57 t hm-2、113.21 t hm-2。其中在土壤碳年排放量中矿质土层呼吸、根呼吸、凋落物层呼吸碳分别占土壤碳总排放量的50.6%、26.0%、23.1%。 ⑵计算了凋落物分解对土壤碳平衡的贡献。不同器官凋落物在土壤中的矿化释放碳量和进入土壤碳库量均随着凋落物易分解性的增大而增大,并且各器官凋落物分解以CO2-C释放最多,以微生物量碳存在的量次之,以可溶性碳存在的量最少。年均温16.5 ℃条件下培养100天,分别来自于叶、枝、细根、粗根有机碳的13.81%、9.26%、5.74%、4.62%被矿化释放,占总CO2-C释放量的比例分别为43.7%、37.2%、31.9%、29.0%。同时不同器官凋落物依次有3.05%、3.26%、2.24%、1.84%存在于土壤微生物碳库,占总微生物量碳的比例分别为12.9%、14.3%、10.5%、8.8%;不同器官凋落物依次有0.62%、0.62%、0.31%、0.24%存在于可溶性有机碳库,占总可溶性有机碳的比例分别为3.99%、4.10%、2.13%、1.73%。 ⑶不同器官凋落物进入土壤对土壤碳排放的激发效应不同,叶、枝、细根、粗根加入土壤产生了正激发效应,激发率依次为6.6%、7.0%、2.2%、2.8%。并且土壤风干-湿润过程影响了凋落物在土壤中的分解和转化过程。土壤风干-湿润使起始矿化底物库增大,培养初期凋落物分解速率上升,同时土壤原有机碳矿化速率降低,微生物对凋落物碳的利用以及凋落物对可溶性有机碳的贡献下降。 ⑷凋落物碳在不同轻组密度组分中的分布不同,但各器官凋落物间无明显差异,均为中等密度自由轻组最多,其次为最小密度自由轻组,最少为闭蓄轻组。室外培养224天,结果表明叶、枝、细根、粗根凋落物在各密度组分中的分配情况为:<1.0 g cm-3自由轻组中16.5~19.1%,1.0~1.8 g cm-3自由轻组中56.8~65.2%,闭蓄轻组中残留5.7~6.9%,其余的9.9~21.0%被矿化损失。研究还表明,凋落物粉碎添加方式能改变其在土壤组分中的分布比例,倾向于向较重的密度组分中分布而被保护起来利于有机碳的积累。

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单株树木CO2和H2O交换的研究对森林生态系统碳水循环的深入理解具有重要意义,而目前尚未有使用可靠、操作简便、商品化的成熟观测系统直接应用于单株尺度气体交换观测。 本研究基于国内外常用的美国LI-COR公司生产的Li-6400便携式光合仪,自行设计制作了两套箱式气体交换观测系统:闭路箱式气体交换观测系统和开路箱式气体交换观测系统。对这两套系统进行了调试和评价后,利用这两套系统,以长白山红松针阔叶林主要优势种水曲柳(Fraxinus mandshurica)为试验材料,探讨了单株CO2和H2O交换的日变化特征,并与单叶尺度气体交换结果进行了对比分析。主要结论有: 1)本研究设计制作的闭路和开路箱式气体交换观测系统具有经济实用,适用范围广、改造方便和操作简单等特点。实现了单株树木CO2和H2O气体浓度的同时观测,且能自动采集和存储数据,能够自动监测箱体空气温度、空气相对湿度、光合有效辐射和大气压等环境因子。 2)闭路箱式气体交换观测系统密闭性较好,但在测定过程中箱内气温和相对湿度会升高,其上升速率随着外界气温的升高而增加。基于仪器响应和环境控制等方面的考虑,该系统在应用时实际观测时间为200s,除去20s的混合响应时间,使用180s的数据。该系统环境控制标准为:箱内外温差 <3℃, 箱内外相对湿度差< 10%。 3)开路箱式气体交换观测系统在测定时箱内的环境因子与箱外接近,箱内外的气温和相对湿度差异都很小,与外界气温平均相差1℃以内,相对湿度的最大差异也仅为8.53%。确定开路系统的观测时间为600s,在数据处理过程中需要出气口气体浓度数据进行延迟处理。 4)冠层不同位置叶片的气体交换速率日变化特征为:垂直方向上,由下至上三个层次叶片的平均气体交换速率表现为第三层 >第一层 >第二层;水平方向上,东西南北四个方位叶片的平均净CO2交换速率表现为南向叶>西向叶>北向叶>东向叶,而平均H2O交换速率为西向叶> 南向叶>北向叶>东向叶。不同层次和不同方位叶片的气体交换日变化曲线的走势主要与光合有效辐射PAR和饱和水汽压差VPD的日变化有关,另外还与各叶片氮含量的差异也有关系。 5)闭路和开路箱式气体交换系统对水曲柳单株气体交换速率的日变化观测表明:两套系统内的环境因子基本得到了有效控制,但开路系统优于闭路系统。两套系统测定的单株尺度气体交换速率日变化趋势与各自当天的光合有效辐射变化相同,这与单叶尺度的气体交换表现一致。另外,单株尺度的CO2交换速率与光合有效辐射存在双曲线关系,而该尺度的H2O交换速率与PAR存在线性关系

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养分再吸收是植物保存养分的重要机制之一,对植物的生长、竞争和适应性等产生重要影响。国外对养分再吸收的研究集中于比较不同生活型或不同立地条件对养分再吸收的影响,且多为静态研究,而通过动态研究能较全面的认识植物养分再吸收特征。马尾松是我国南方主要造林树种之一,国内对马尾松林养分循环的研究主要集中于养分分布和养分外循环,而对养分内循环的认识还十分有限。本文以马尾松为研究对象,分析了马尾松的养分动态和养分回特征,并在试验研究和文献资料检索的基础上对养分再吸收的机制进行了讨论,结果表明: 1)10年生马尾松不同器官N、P、K含量表现为:叶>果>根>枝;枝的P、K养分再吸收效率和叶无显著差异,但N的再吸收效率叶>枝,由于枝的养分含量占全树养分含量较大比重,因此营林过程中利用自然整枝将有利于提高林分养分利用效率;成熟叶N、P养分含量随针叶衰老逐渐下降,落叶前后比叶质量平均下降20.5%,物质回收突出,反映了马尾松养分利用效率高;养分再吸收效率生长期比较稳定,落叶期达到最大值;根系和土壤养分在8月均有一低谷,这可能与该时期马尾松生长旺盛,养分需求较多有关;养分再吸收效率与土壤、根系、叶片养分之间缺乏相关性,马尾松新叶生长获得养分的两条途径(养分回收和根系吸收)没有表现出此消彼涨的现象,这可能与根系养分含量变化较小,还不足以通过统计分析表现出来有关。 2)由于针叶凋落前存在物质回收,3个林龄(10、23、45龄)马尾松针叶凋落后的平均质量、长度和单位长度质量分别下降了15.9%、4.6%和13.9%;不同林龄马尾松单叶N、P、K平均50%以上被回收,养分再吸收效率和转移度均随林龄先增后减,与生长规律密切相关,这是因为23龄马尾松生长旺盛,养分需求比较多,导致养分再吸收效率和转移度比其它林组高;各林龄阶段P转移度都较高,可能与该地区土壤P缺乏有关。以单位质量养分含量和单位长度养分含量所计算的养分再吸收效率偏低,但不显著,因此,对于类似于马尾松的针叶树种,在研究养分再吸收效率时,可以应用易于操作的基于质量浓度的养分再吸收效率。 3)通过绿叶N/P所反映的N、P养分的相对限制性影响了植物对N、P的利用特征,并以马尾松和樟子松为例证实了这种关系的存在;常绿植物和落叶植物随N的限制性增强,N的再吸收效率、转移度、利用效率随之升高,反之亦然;常绿植物随P的限制越强,P的再吸收效率反而降低,反之亦然,这可能与常绿植物P含量低有关;常绿植物P的再吸收水平和利用效率与P的限制性没有关系;落叶植物随P限制性增强,P的再吸收水平和利用效率随之升高,反之亦然,但P的限制性与P的再吸收效率没有关系;N/P与N和P利用特征的关系对于指导适地适树有实际意义,在土壤N含量比较低的立地,选择N/P高的植物,将有利于提高N的养分利用效率,反之,在P含量比较低的立地,选择N/P高的植物将有利于提高P的利用效率。

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用百喜草(Paspalum notatum)和水花(Alternanthera philoxeroides)等草本植物作对比,通过叶片离体实验、温室盆栽实验、田间小区实验和大田推广实验,并结合室内分析,较系统地研究了香根草(Vetiveria zizanioides)的抗热、抗冻和抗盐特性和对污水的净化效果。此外,还探讨了矮化香根草和促进香根草分蘖的可能性;提出了香根草生态工程的思想,阐述了香根草生态工程推广应用的价值与效果;通过对国内野生香根草资源的调查和标本鉴定,指出了过去对这个种的错误描述,提出了保护野生香根草资源和香根草湿地的紧迫性与重要意义。主要研究结果如下: 1.离体叶片电解质渗漏的测定结果表明,3种植物对高温、冻害、干旱的抵抗力依次为香根草 > 百喜草 > 水花生,特别是在胁迫程度高、幅度大或胁迫时间长时,香根草所表现出的强抗逆性更加明显。香根草有比百喜草和水花生更强的适应能力。2.叶片电导率的实验结果显示,香根草、水花生和百喜草对盐胁迫的反应相差不明显,但盆栽实验则显示出较大差异,抗盐能力明显表现为香根草 > 水花生 > 百喜草。导致3种植物生物量下降10%的EC_(se)值分别为6.4、5.1和4.3 dS m~(-1);导致生物量下降50%的EC_(se)分别为20.9、16.2和11.5 dS m~(-1)。在抗盐等级划分上,香根草和水花生属抗盐植物种类,百喜草属中度抗盐种类。总的来说,3种植物都表现出了相对较强的抗盐特性。以上结果还表明考察植物的抗盐性时必须用整株做为实验材料,离体叶片或组织培养所得到的结果不能作为植物抗盐能力的标准。3.植物体内Na~+和Cl~-含量随土壤盐度水平升高而升高,而茎叶中的Na~+和Cl~-又直接影响到植物的生物量、叶面积、株高等。这表明盐度对3种植物生长发育的影响相当明显,且植物体的Na~+和Cl~-很可能都是影响植物生长发育的直接因子。然而,叶片光合色素受Na~+或Cl~-的影响不甚明显,而且在Na~+和Cl~-的浓度不高时色素含量还随茎叶中Na~+和Cl~-的浓度升高而显现增加趋势,即使Na~+和Cl~-的浓度较高时,光合色素下降的幅度也远不及生物量的大。这可能由于光合作用是被“反馈抑制”,而不是直接被Na~+或Cl~-抑制。4.3种植物表现出完全不同抗盐机理。香根草表现出拒盐特性,而且将所吸收的盐分的大部分(尤其是Na~+)滞留在根系内:水花生表现为稀盐特性,即当植株体内含盐量增加时,其水分含量亦增加,并趋向肉质化;百喜草有较强的吸盐能力,并可能通过盐腺泌出体内高浓度的盐分且通过加速老叶死亡来排除过多的盐。5.广州市李坑垃圾卫生填埋场的渗滤污水含有高浓度的污染物,经过人工净化后仍未 达到排放标准,对植物产生毒害并带来严重的环境污染,须作进一步净化,并建议开展生物净化来辅助物理和化学净化。6.在被观测的4种植物中,风眼莲(Eichhornia crassipes)在高浓度和低浓度2种污水中均被毒害致死;百喜草在高浓度的渗滤液中不能存活,在低浓度中受严重伤害;水花生在高浓度污水中受较重伤害,但在低浓度形成庞大生物体,这可能是污水的“富营养化”所致;香根草在这2种污水中亦受伤害,但受害程度为4种植物中最轻。总的来说,它们的抗污能力和去污效果表现为香根草 > 水花生 > 百喜草 > 风眼莲。7.在污水中表现相对较好的2种植物中,水花生对低浓度污水的净化效果总体上好于香根草,尤其对总氮和硝态氮的净化效果明显好于香根草,但香根草对高浓度污水中的7种“污物”的净化效果均优于水花生,且对低浓度污水中的磷与COD的净化亦优于水花生。在被观测的7种水质指标中,植物对氨氮的净化效果最好,净化率在77%~91%之间。此外,香根草对磷也表现出了较强的净化能力,净化率高达70%以上。香根草和水花生可分别作为高、低2种浓度垃圾污水的净化植物来辅助净化污水。8.香根草虽不是水生植物,但能在水中生长。用香根草作为污水的净化植物时须用支撑物将其固定;香根草和水花生都生长迅速,生物体高大,因此用它们净化被污染的环境时,还应适时对其地上部分进行剪割以保证新生的植株体能不断地吸收水中“污物”,使它们都能成为“超级生物累积器”。但是,任何单一植物对污水或污物的净化能力都是有限的,要想对垃圾污水产生好的净化效果,最好的办法也许是将香根草、水花生等多种有良好净化效果的植物有机结合起来,同时种植在污水中。9.植物通过吸收来去除“污物”的能力是很有限的。香根草和水花生对污水中N、P、Cl~-的吸收量只占净化量的一部分,和原液中N、P、Cl~-的含量相比,吸收量所占的比例更低。植物净化系统中的去污方式除根系的吸收作用外,还有根系的吸附、元素的沉降、固结和挥发、水体中微小动物和微生物的作用等,即是通过根系微生态系统的综合作用来达到净化目的。10.植物生长延缓剂对香根草的株高生长、分蘖速度和抽穗开花等方面都产生影响,但不同的药剂种类和浓度所产生的影响相差甚远。低浓度的延缓剂不仅不抑制香根草的株高生长,而且还有显著地促进作用,高浓度虽有抑制作用,但这种抑制也只是短期的,一般不超过2个月。延缓剂对分蘖的形成具有较好的促进作用,而且这种促进作用持续3个月左右。3种延缓剂中,以低浓度的B9促进分蘖的效果最显著,比对照高出50%。不同的延缓剂对香根草抽穗扬花的影响表现不同,PP333具有一定的促进效果,而CCC和B9-尤其是B9-表现出明显的抑制作用。总的来说,B9对香根草矮化、促进分蘖和抑制开花方面产生的效果要好于CCC和PP333。11.植物生长延缓剂对香根草的作用效果与对一般作物的作用效果相差较远,这可能是香根草的抗性较强,延缓剂对它的影响不明显所致。总的来说,植物生长延缓剂对香根草株高生长的抑制效果不理想。有关这方面的研究还有待进一步开展。12.公路滑坡不仅带来严重的交通阻塞,而且危及到行车与行人的安全。常规治理公路滑坡的手段是采取砌石墙的工程措施,这不仅费用昂贵,而且缺乏生态效益,也难以达到根治效果。应用香根草生态工程(The Vetiver Eco-engineering)对滑坡路段进行综合治理,能产生良好护坡固土效果,而且所需成本仅为机械工程的12%~18%。香根草生态工程是指以香根草为主要或核心草种,同时与一些适合当地生长的植物—包括乔木、灌木、草本、藤本一进行有机搭配,并在需要时辅以一定的工程措施,用于水土流失治理和退化生态系统的恢复的植物生态工程措施。13.为了使香根草生态工程尽快生效,应采取一定的栽培管理措施。香根草应等高密植,注意施肥,前期不要被遮光;所搭配的植物应该是抗逆性强,乔、灌、草、藤结合起来,并注意在香根草带中间适当种植一些生长迅速、抗瘠能力强、覆盖效果好的草本植物,这不仅能使坡面更稳固,而且能变得更美观。总之,香根草生态工程在公路护坡方面所产生的经济效益、社会效益和生态效益都是相当明显的,在我国南方地区有着广阔的应用前景。14.一般认为,香根草原产印度,然而,中国亦有天然的香根草群落分布。早在70多年前就在海南发现野生的香根草种,1957年又在广东吴川发现一片面积达6000多hm~2的湿生性的天然香根草群落。40年来,这片珍贵的热带湿地遭到严重破坏,香根草的面积和密度都大幅度下降。对此,笔者建议尽快在当地划一块自然保护区,这不仅是为了保护珍贵的野生香根草资源,保护当地的生物多样性和生态环境,而且能为研究热带湿地和草原提供理想基地,并为研究香根草的起源、系统演化和分类提供理想素材。15.过去的文献一直把广东吴川这片湿地中的野生香根草种认为是V. nigritana,但本文的标本鉴定认为它并不是V. nigritana或其它种,而是V. zizanioides。不过,引种栽培观测和RAPD技术研究都表明,这一野生种和普通的栽培种属于同一个种的不同生态型或基因型,而导致形成这种差异的原因是由于野生种生长在长年渍水或干湿交替的环境所致。16.目前对香根草的起源和系统演化知之甚少,香根草属的系统分类还很不完善,有 关香根草对重金属、污染物的抗性机理等诸多方面都还不太清楚或很不清楚。因此,对 香根草这一神奇植物的研究还有待继续深入地开展下去。总之,香根草这一多年生的禾本科植物对盐、碱、酸、瘦、冷、热、早、涝都表现出了较强抗性,在水土流失防治、退化生境恢复、污染环境净化、贫瘠土壤改良、农田小气候改善等方面都表现出了较好效果。香根草无愧是一种神奇之草。然而,要真正将香根草生态工程在我国南方地区大规模推广开来,还需要做较多的工作,这包括更深一步的科学研究、更广泛的宣传、培训与示范、更充分的资源利用与经济创收等。

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辽东山区的天然次生林是辽宁的森林资源宝库和辽中城市群的天然屏障,在辽宁的经济建设和生态建设中发挥着不可替代的重要作用。辽东山区的天然次生林是原生植被阔叶红松林遭破坏后形成的次生群落,现大部分为低产、低质、低效的“三低”林分,因此天然次生林的恢复具有重要意义。本文对辽东天然次生林的演替动态、干扰对天然次生林的影响、恢复目标林分主要树种的生理生态学特性、恢复的生态过程及恢复技术等进行了系统研究,得出以下主要结论:(1)辽东山区的天然次生林,经聚类分析,分成四种主要类型即:柞木林、阔叶混交林、硬阔叶林和杨桦林。杨桦林在演替序列中的定位应属原生群落遭破坏后初级阶段即软阔混交林阶段。阔叶混交林主要是以锻属、榆属、械属、柞属等阔叶树种组成的群落,在演替序列中的定位应为软硬阔混交林阶段。硬阔叶林系指以辽东山区三大硬阔叶树种水曲柳、、黄菠萝、核桃揪等为主要树种组成的群落,在演替序列中的定位应为硬阔叶林阶段。柞木林是以栋属树种为优势树种的森林群落,它与阔叶红松林同时存在,是长白植物区系的一个亚顶极群落;(2)通过放牧对不同林分类型林木生长、森林环境以及部分生态功能的影响研究表明,天然次生林与其它林分类型比较,其抵御外来干扰的缓冲能力较强,具有一定稳定性。因此在天然次生林中可以适当放牧。科学地解决了辽东山区林牧矛盾问题。试验结果证明:不同采伐方式对天然次生林环境因子有明显影响。择伐是天然次生林较好的恢复途径,既不使森林环境发生大变化,同时择伐后还可以在林冠下引进针叶树,形成针阔混交林;(3)对天然次生林恢复所涉及到的主要树种红松、云杉、水曲柳、花曲柳、黄菠萝、蒙古柞、紫锻等进行了生理生态学特性与光环境关系的研究。红松是阳性树种,具有喜光的特性,但同时幼年又有一定的耐荫性。在透光10%条件下最大净光合速率为5.743μmofco2.m-2.s-1,全光条件下为8.233μmolco2.m-2.s-1。随树龄的增长趋于喜光。利用红松等针叶树的幼年耐荫特性,进行林冠下更新,使人工恢复阔叶红松林成为可能:在一定的光照范围内,水曲柳、花曲柳、黄菠萝、蒙古柞、紫锻这五种阔叶树的最大净光合速率随光照强度的增加而提高,在光照极弱的条件下生长不良,多数树种在透光70%条件下净光合速率最大;光饱和点、暗呼吸速率这五种阔叶树有所差异,蒙古柞和黄菠萝相对喜光,花曲柳和水曲柳居中,紫极相对耐荫;(4)天然次生林的人工恢复是多途径的。人工恢复阔叶红松林组成类型主要有:红松杂木林、红松花曲柳和蒙古柞林、红松水曲柳林、红松核桃揪林4种类型。各类型中红松重要值(相对密度+相对频度十相对优势度)均超过100;在天然次生林下人工栽植红松,经过20年大部分林分已形成三层垂直结构;人工恢复过程中林木的生长,上层保留木随着林冠的伐开,生长加快,迅速郁闭,这对林冠下栽植红松的成活有利。因光照条件改善,林下阔叶树生长迅速,并大量萌生新的个体。林冠下红松的初期高生长与全光条件下比较几乎无差异,巧年后开始低于全光条件下的生长。红松径生长,栽植10年后明显低于全光条件下的;(5)根据辽东山区天然次生林的形成、现状、在群落演替中的定位以及功能定位等确定辽东天然次生林主要恢复目标为:阔叶红松林、柞树林和阔叶混交林,面积比例分别以30%、65%和5%为宜;以对天然次生林现状、人为干扰对其影响、恢复目标群落所需要的引进种和天然次生林中的主要建群种的生理生态学特性以及人工诱导过程中,系统所发生的变化的研究为基础,并结合林龄、密度、立地条件等确定恢复途径,采取人工诱导、抚育间伐、人工营造针阔棍交林以及封育保护等技术措施完成恢复过程,达到恢复目的。天然林保护是我国正在实施的重大生态建设工程,辽宁省也出台了天然次生林禁止商业性采伐的措施,使辽东天然次生林的保护得到了政策保障。本文研究成果将为辽东天然次生林的保护、恢复以及可持续经营提供可靠的理论依据和技术支撑。

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土壤水动力学参数的推导和土壤水分运动的数值模拟是研究土壤水分运动规律的两个重要部分,是农田节水灌溉自动化控制工程设计的理论依据。本文以曰光温室草甸棕壤的三种质地为研究对象,应用土壤转换函数理论和有限元法,通过RETC软件由土壤机械组成和容重两个基本物理性质指标推导其土壤水动力学参数;运用HYDRUS-2D软件对同一渗灌管埋深〔30cm)、3种管径、10种供水压力、6种初始土壤水势条件下的土壤水分运动进行了数值模拟;并对土壤水动力学参数推导和土壤水分运动数值模拟结果进行了实测验证。结果表明:(1)RETC和HYDRUS-2D是进行土壤水动力学参数推导和土壤水分运动数值模拟的有力工具。(2)土壤水动力学性质对渗灌条件下土壤水分运动速度具有显著的作用,最适宜渗灌的土壤是壤土,偏砂、偏虱质地次之。(3)渗灌的供水压力对三种质地土壤水分运动具有显著的影响。壤砂土、壤土和戮土三种质地土壤的适宜供水压力应分别不小于500cmH2O、700cmH2O、400cmH2O。(4)就内径为10mm、15mm和20mm渗灌管而言,渗灌管管径越大越有利于渗灌水向渗灌管四周土壤入渗,三种质地土壤渗灌均宜采用20mm管径渗管。(5)在壤砂质土和在较干燥的(土壤水势值<-1000cmH2O)壤质土和赫质土中,土壤初始水势值对渗灌土壤水分运动数值模拟结果的影响较小,而在较湿润的(土壤水势值>-1000cmH2O)壤质土和载土中,随着土壤初始水势值的降低,渗灌土壤水分运动速度(模拟)加快。

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LUCC是全球变化研究的核心主题之一,也是社会经济可持续发展的关键问题。改革开放后四川的社会经济发展非常快,在各种因素的驱动下,土地利用/覆盖发生了深刻变化。目前四川省缺乏基于实际调查数据的、全域性的、具有连续时间序列的LUCC和驱动力分析及土地可持续利用研究成果,这对我们从全局上把握全省土地利用现状、发展变化趋势,利用土地政策参与宏观调控,实现长期可持续发展目标,建设资源节约型、环境友好型社会极为不利。本研究针对这一问题,选取全川八大土地利用类型作为研究对象,研究了全省1996年到2006年的土地利用/覆盖格局和变化情况,分析了不同尺度的驱动因素,对全省农用地和建设用地的集约利用状况、潜力进行了分析评价,并提出相应的对策措施。 1.1996年-2006年10年来整个省域的土地利用/覆盖格局变化。 (1)1996年-2006年全省的土地利用/覆盖格局 1996年,全省是一个以农用地为主的土地利用/覆盖格局,林地和牧草地属于优势覆盖类型(合占69.17%),居民点及工矿用地和交通用地合占只有3%左右。 2000年的LUCC格局较为明显的特点是耕地所占比重下降0.4个百分点,水域和未利用土地所占比重有所下降,牧草地保持不变,其余地类所占比重有所上升。 与2000年相比,2004年林草地的优势格局进一步得到强化(合占比重达到70.23%)。耕地面积占幅员面积的比重下降0.83个百分点,略有下降的有未利用土地、水域和牧草地。值得关注的是在“退耕还林还草”的大背景下,牧草地占幅员面积的比重下降0.04个百分点。 到2006年,仍为林草地为主导优势的格局,二者合占上升0.15%。在城市化快速推进的背景下,居民点及工矿用地中的城市用地和建制镇用地占比重超过15%,农村居民点占比重降至76%。交通用地中农村道路占比重降至57.8%,公路用地占比重升至37.5%。五个地貌区的土地利用/覆盖格局与全省的变化基本一致。值得关注的是盆西平原区的交通用地上升幅度和盆地丘陵区的未利用土地的开发利用力度明显大于其它地貌区。 (2)1996-2006年10年间土地利用/覆盖格局的变化 1996-2000年4年间,耕地、水域和未利用地三个地类下降,年均减少0.75、0.19和0.32个百分点。其中耕地年均减少49229.0公顷,约一半流向林地,13.77%流向园地,约20%流向建设用地。另外5个地类面积增长,增长绝对量最大的是林地,年均增长40063.7公顷,交通用地增幅最大,4年年均增长达1.95%。 2001-2004年是西部大开发逐步推进、“退耕还林还草”项目全面展开和土地整理深入实施的关键期,LUCC更为深刻。耕地、未利用地、水域和牧草地四个地类面积下降,其余地类按增长幅度依次是园地、交通用地、居民点及工矿用地和林地。耕地加速下降,年均降幅达到1.59%,其减少去向主要是林地(占66.75%)和园地(占19.84%),其增加来源主要是未利用地、园地和水域。交通用地的增幅最大,为3.96%,其增加主要来源于耕地、未利用土地和林地,分别占49.96%、16.63%和13.09%。居民点及工矿用地增长幅度为3.12%。 从1996年到2006年的10年间,耕地、未利用地、水域和牧草地下降幅度分别为10.36%、3.61%、1.34%和0.26%。园地增幅达23.61%。绝对面积增长最大的则是林地,达630733.3公顷。交通用地和居民点及工矿用地增幅也较大,分别为15.00%和9.31%。 10年间年均总变化量为310326.6公顷,2000年-2004年之间变化最大(为356865.8公顷),高于平均变化量,而1996-2000年间和2004-2006年间都小于平均变化量。 (3)10年间不同地貌区的LUCC变化 盆西平原区的特点是园地大幅上升达77%,居民点及工矿用地和交通用地也大幅上升,耕地、未利用地下降幅度大,该区耕地、水域、未利用地的减少强度和园地、居民点及工矿用地、交通用地的上升强度均居五区第一;盆地丘陵区的特点是牧草地下降幅度大,为-36.89%,交通用地、园地和林地上升幅度较大,该区耕地减少、未利用地减少、林地增加、居民点及工矿用地和交通用地增加的变化强度均居五区相应地类增减的第二位;盆周山地区的特点是耕地减少较多,交通用地和园地增长较大,该区林地变化强度居各区第一位,牧草地和水域变化强度居各区第二位,耕地、居民点及工矿用地和未利用地居各区第三位;川西南山地区的特点是园地、耕地、交通用地和居民点及工矿用地变化幅度大,另外四个地类变化较小。该区减少的牧草地占全省牧草地减少的97.91%,变化强度居各个地貌区的第一位,园地相对变化强度居五区的第二位;川西北高山高原区的特点是耕地大幅下降、园地大幅上升,交通用地升幅也较大,其余地类变化不大。值得注意的是,该区牧草地和水域面积增加,与全省该地类的变化相反。其余地类的相对变化强度均是五个地貌区中最小的。 用变化强度分值考量变化强度,盆西平原区的变化强度最大,盆地丘陵区和盆周山地区的变化强度相当,川西北高山高原区的变化强度则要小得多。 (4)1996年及2006年全省土地利用/覆盖格局的景观生态学分析 全省是以自然景观占优势(占约70%)、农业景观为补充、建设用地景观居于从属地位的土地利用景观格局。景观多样性和均匀度不高。到2006年,全省总的景观格局并无大的改变。总体情况是随着时间的推移和人类活动的加强,区内景观优势度上升、多样性和均匀度变小。但斑块数减少,斑块面积和斑块孔隙度有所增大。斑块的形状指数和分维数均有所下降,表明受人为干扰有加剧的趋势。反映景观格局结构的破碎度指数有轻微下降。景观指数的变化表明全省土地利用有缓慢集中、规模聚集的趋势。 (5)三大生态建设工程对土地利用/覆盖变化的影响 1996-2006年间LUCC与三大生态建设工程实施的耦合分析,发现退耕工程对耕地、林地、牧草地等地类覆盖变化的影响最大,天保工程次之,长防工程最小。 2.四川省LUCC驱动力分析 (1)总体分析: 从整体上分析,人为因素对区域整体LUCC的影响从1996年的63.32%增加到2006年的66.99%,变得日益强烈。同时人为因素影响强度表现出明显的区域差异,地势平缓、经济区位条件好的区域其人为影响强度明显较高。 政策体制转变下的经济高速增长、快速的城市化、工业化过程和生态建设是四川省LUCC宏观尺度的驱动因素。区域的LUCC主要受到了由内向外(从城市到乡村)和由外向内(从山顶向平地)两种作用力的共同推动。局部尺度上,如距离交通线、水利线、中心城市的远近,地形凸起、大型独立项目落址、重污染项目的阻隔等,甚至一些乡规民俗等因素也会成为LUCC的驱动影响因素。在较小的尺度上,人类个体行为选择对LUCC的影响也是存在的。   根据驱动因子的特性作者将其划分为驱变、阻变、良性、惰性因子等类型。 (2)分地貌区的驱动因子分析 各地貌区都存在城市化、工业化、生态工程实施、自然灾害等驱动因子,但主次不一。对于盆西平原和盆地丘陵区,城市化、工业化是前两位的因子,而对另外三个地貌区,生态工程实施和产业结构调整则成为第第一、二位的驱动因子。 (3)分地类的驱动因子分析(以坡耕地为例) 分坡度的耕地变化分析发现,耕地减少主要集中在2°以下的平地、15°-25°和25°以上三个坡度级,是其它坡度级耕地减幅的三倍左右。这表明耕地减少受城市化进程和“退耕还林还草”工程驱动影响尤为巨大。 3.土地利用格局优化、集约利用评价和可持续利用及对策研究 (1)土地利用格局优化的战略选择及调整预测 土地利用格局调整的战略是农业生产用地、建设用地和生态及其他用地占幅员的比重分别稳定在13%、7%和80%左右,重点是三大类别内部二级和三级地类的合理调整。 (2)全省土地集约利用评价 全省农用地利用集约度为0.46,总体上集约度不高,处于较适度利用阶段。建设用地利用集约度为0.38,处于较适度利用阶段。集约利用提升空间较大。 农用地的潜力主要在于加强土地保育、完善利用制度、提高单产。城市建设用地的包括存量潜力、强度潜力、结构潜力,空间很大。农村居民点整理潜力可以逐步挖掘。 (3)新增建设用地集约利用的统筹安排 据测算,到2020年,四川省城市建设用地需求量在463850-492360hm2之间,城镇各业新增建设用地规模为361276.79hm2,占用耕地200565.94 hm2。2004-2020年间四川省农村居民点整理潜力33.86万hm2。农村居民点建设用地需求量为70.57万公顷。 (4)土地集约利用措施与坡耕地可持续利用战略 提出了土地集约利用的措施。在对坡耕地生态系统结构与功能分析的基础上,提出坡耕地可持续利用战略与生态恢复战略,并从技术和政策层面提出了坡耕地合理利用和生态退耕的措施和建议。 LUCC is one of the key questions of global change and sustainable development of society. After the opening and reform of China, the society and economy of Sichuan Province developed very fast ,the land-use/cover changed very strong droved by many factors .But nowadays we have no constant spatial-temporal study and driving force analysis about the whole province based on investigation. And it is lack of land sustainable utilization study based on correlative study. So we choose all the land resource in Sichuan, combine RS and GIS and field investigation, and take statistic-mathematic means and system analysis, to study the LUCC patterns and different scale driving force of different physiognomy regions, land cover types and periods; to analyze the current situation and potential of land resource intensive utilization, and gave out corresponding measurements. We found that forest and grassland are the dominant cover types of Sichuan provincial land –use/cover pattern, and becoming more and more stronger from 1996 to 2006,the natural landscape is the metric and occupy 70%,the diversity and evenness index are not high; the totally change quantity from 2000 to 2004 is the biggest; cultivated land especially steep cultivated land ,garden plot, forestry land ,settlement and industry land and traffic land changed relative stronger; among five physiognomy regions ,the changing intensity of PEN XI PING YUAN QU is the biggest, CHUAN XI BEI GAO SHAN GAO QU is smallest; under the background of policy system changing, the fast developing of economy, fast urbanization and industrialization and ecology construction are the macro-scale driving force of Sichuan provincial LUCC; to compare the impacts of “TUI GENG GONG CHENG” on LUCC especially to cultivated land ,forestry land and grassland is strongest, “TIAN BAO GONG CHENG ” is stronger,“ HANG FANG GONG CHENG” is smallest; the intensive utilization level of farmland and construction land of whole province is relative moderation, there is huge potential to excavate and fulfill the increasing demand of construction land;we must take synthetic measurements to accelerate the sustainable utilization of land resource, including administrative, economical ,technological and ecological policies.

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岷江柏(Cupressus chenggiana S. Y. Hu)是我国川甘地区特有的珍稀濒危乔木,一般生长在干旱的河谷区,在涵养水源和保护水 土等方面起着重要的作用。本文选择4个岷江柏种群,采用了野外调查和室内实验相结合的研究方法,调查岷江柏种群结实状况, 分析种子和球果形态特征,阐明种子发芽的基本特征,研究岷江柏种子贮藏过程中几个生理指标的动态变化特点,目的是为岷江柏 种苗繁育、自然更新能力评估以及珍稀濒危机制分析提供理论依据。研究得出如下结论:1.岷江柏球果呈椭球形,长为1.5~ 2.2cm,宽为1.5~1.9cm,质量为1.7~4.2g,球果鳞片数量为8~11片,球果内种子数量一般在40~70粒。岷江柏种子为椭圆形,长 为3.58~4.02mm,宽为3.10~3.15mm,厚为0.96~1.11mm,千粒重为3.1~3.5g。岷江柏的结实率很低,并且有显著的地理差异和 大小年差异。2. 岷江柏种子发芽温度范围是5℃~30℃,其中种子的适宜发芽温度范围是10℃~25℃。种子最适发芽温度随着贮藏 时间的增加而变化。在适宜温度范围内,种子发芽周期为20d。温度对种子的发芽势和T50有显著影响,对种子发芽率没有显著影响 ;光照有利于种子发芽;岷江柏种子的发芽特征是岷江柏保护种子资源、防止物种濒危的一种环境适应,有助于岷江柏种子提高发 芽率和幼苗的存活率。岷江柏种子是一种耐贮藏的正常性种子,在短期贮藏过程中,贮藏温度和种子含水量对于种子生理指标和种 子发芽没有显著影响。3. 岷江柏种子在短期贮藏过程中,千粒重没有显著变化;含水量都经历了先下降,再稳定的过程;粗脂肪 含量和可溶性糖含量逐渐降低;可溶性蛋白含量和丙二醛含量逐渐增加;脯氨酸含量在贮藏1~7个月时变化差异不明显,但是贮藏 7~10个月后显著增加。岷江柏种子的各个生理指标之间的相关性差异不显著。4. 岷江柏球果和种子的形态特征存在显著的地理差 异。岷江柏种子的发芽能力的地理性差异不大,种群间差异不大。岷江柏种群的地理差异由种群特征、生境特征和气候特征共同决 定。5. 在岷江柏的人工繁育中,对于刚刚采集的种子,发芽温度在15℃~25℃比较适合,其中以25℃最佳;而对于短期贮藏(4~ 10个月)后的种子,发芽温度在10℃~25℃均可,以15℃~20℃为最佳。野外播种的最适时间为4~6月,6~9月的间歇性干旱和降 水波动可能是限制岷江柏自然更新的因素之一。在短期贮藏过程中,种子可以采用常规室温贮藏,可以节约成本。Cupressus chenggiana is a specific and endangered plant in Sichuan and Gansu provinces of China, and it usually grows in dry valley and plays an important role in water supply and soil and water conservation in the dry valley of alpine and canyon region of southwest China. The research selected four Cupressus chenggiana populations and used the methods of the field investigation and the lab experiments. The fruiting characters of Cupressus chenggiana populations, the morphological characters of seeds and cones, the germination characters of seeds and the store physiological dymatics of several factors of seeds have been studied in order to give some theoretical advices on the artificial propagation and the ability of natural regeneration and the endangered principle of Cupressus chenggiana in the paper. The main results may be clarified as follows: 1. The cones of Cupressus chenggiana are ellipsoidal, length ranged from 1.5 to 2.2cm, with ranged from 1.5 to 1.9 cm, weight ranged from 1.7 to 4.2g, the number of cone squama ranged from 8 to 11, and the seed number of per cone ranged from 40 to 70. The seeds of Cupressus chenggiana are elliptical, length ranged from 3.58 to 4.02 mm, width ranged from 3.10 to 3.15 mm, thickness ranged from 0.96 to 1.11 mm, and the weight of 1000 seeds ranged from 3.1 to 3.5g. The fruiting rate of Cupressus chenggiana is very low, and the fruiting period of Cupressus chenggiana has the geographical differences and the big or small year differences. 2. Seed germination temperature is between 5℃ and 30℃, while the suited temperature is between 10℃ and 25℃. The optimum temperature of seed germination will change as the store time of seeds changes logner. The cycle of seed germination can persist 20 days in the range of the suited temperature. The germination temperatures have significant influences on the germination potential and T50, but have no significant infuluences on the germination rate. The photoperiod is in favor of seed germination. The characters of Cupressus chenggiana seed germination represent a kind of environmental adaptability to protect the seed sources and endangered species, and it can give help to increase the germination rate of seeds and the livability of seedings. The seeds of Cupressus chenggiana are a kind of orthodox seeds that can endure the long time storage. In the short time storage, the store temperatures and the moisture contents of seeds have no significant infuluences on the physiological factors and the germination of seeds, but the store time has significant influences on the physiological factors of seeds. 3. In the short store course of Cupressus chenggianna seeds, the 1000 seed weight has no significant variation; The moisture content descends at the beginning of the storage, but has no significant variation later; The crude fat content and the soluble sugar content descend gradually; The soluble protein content and MDA content increase gradually; The praline content has no significant variation after 1~7 months storage, but increase significantly after 7~10 months storage. The correlations of different physiological factors are not significant. 4. The morphological characters of cones and seeds of four populations exist significant differences. The germination of Cupressus chenggiana seeds has no significant geographical variation. The geographical variation of Cupressus chenggiana populations can be ascribed to the population characters, climate and environment. 5. In the course of artificial propagation of Cupressus chenggiana, it is favored that the germination temperature of newly collected seeds is between 15℃ and 25℃, while the optimum temperature is 25℃. After the short storage ranged from 4 months to 10 months, it is favored that the germination temperature is between 10℃ and 25℃, while the optimum temperature is ranged from 15℃ to 20℃. The field sowing optimum time is between April and June, and the interval drought and fallrain fluctuation between July and September may be one of the reasons that restrict natural regeneration of Cupressus chenggiana. In the short storage, seeds can be stored in the condition of room temperature.

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近年来,随着对作物重茬(连年种植)障碍原因的深入研究,植物的化感作用越来越受到国内外众多学者的重视。而作为重要调料和药用植物的生姜,其连作障碍也备受关注,系统地研究生姜化感作用将有助于理解和最终解决生姜连作障碍问题。本文通过研究生姜不同部位、不同浓度的水浸液对与其间作的两个物种(大豆和四季葱)种子的萌发及幼苗生长的影响,从而证明生姜化感作用的存在;并通过温室盆栽实验研究了生姜的自毒作用(即研究生姜不同部位、不同浓度的水浸液对其幼苗的形态、生理生化、光合作用、土壤酶、土壤微生物多样性及土壤养分的影响),从而揭示生姜退化和衰老的机制,并为生姜筛选出合适的间作物种提供科学依据,对生姜连作障碍提出科学的解决方法。主要研究结果如下: 1. 与对照相比,生姜所有部位(根茎、茎、叶)、所有浓度(10、20、40、 80 g l-1)的水浸液均抑制了大豆种子和葱籽的萌发率、幼苗生长、水分吸收和脂肪酶活性,并且其抑制程度随着水浸液浓度的增加而增强,其生姜各部位水浸液抑制效应的强弱顺序为茎>叶>根茎。这一结果表明生姜根茎、茎、叶含有能够抑制大豆种子和葱籽种子萌发和幼苗生长的水溶性化感物质。根茎是生姜的主要收获部位,而生姜的残株(主要是茎和叶)应该从大田中处理掉以减轻其抑制效应。生姜水浸液中主要化感成分包括:根茎水浸液中主要是丁香酸和伞花内脂;茎水浸液中主要是阿魏酸,且其含量最高为73.4 ug/g;叶水浸液中除了阿魏酸,其他六种物质均检测出来,但含量较高的主要有丁香酸、伞花内脂和香豆酸。 2. 生姜茎和叶不同浓度的水浸液均显著抑制了生姜幼苗的株高、每株叶片数和叶面积,其抑制程度随着水浸液浓度的增加而有所增强,而生姜幼苗每株分枝数差异不显著;同时生姜水浸液也极大程度地影响了生姜幼苗的生物量(包括地下生物量、地上生物量和总生物量,均为鲜重)。在同一浓度下,茎水浸液对生姜幼苗形态指标及生物量指标均显示出最强的抑制作用,叶水浸液次之,根茎水浸液最弱。与对照相比,低浓度的生姜根茎水浸液提高了生姜幼苗叶片内四种抗氧化酶(SOD、POD、CAT、APX)活性,高浓度的根茎水浸液抑制了四种抗氧化酶活性,而茎和叶水浸液均随着浓度的增加而抑制了四种抗氧化酶活性,三种水浸液均随着浓度的增加降低了生姜幼苗叶片内叶绿素的含量,而增加了生姜幼苗叶片的相对电导率和丙二醛含量。同时,三种水浸液均随着浓度的增加降低了生姜幼苗的光合参数(包括胞间CO2浓度、气孔导度、蒸腾速率及净光合速率)。 3. 三种生姜水浸液对所测六种土壤酶活性均产生了不同程度的影响,其中影响最大的是酸性磷酸酶和蔗糖酶,在10 g l-1 时就达到了显著水平,并且所有酶均有随着水浸液浓度增加而增大的趋势;相同部位的水浸液随着浓度的增加,细菌和真菌的数量呈增加趋势,而放线菌的数量呈减少趋势;三种生姜水浸液均随着浓度的增加降低了土壤中有机质的含量,加剧了土壤中硝态氮含量的积累,根茎水浸液对土壤有效磷、速效钾和铵态氮均显示出低浓度提高其含量而高浓度降低其含量的趋势,而茎和叶水浸液则随着浓度的增加均降低了其含量。 4. 与生姜单作相比,所有间作系统均在旺盛生长期和收获期不同程度地提高了土壤酶活性,同时也增加了土壤细菌数量及土壤微生物总数但不显著;所有间作系统在旺盛生长期和收获期均不同程度地影响了土壤真菌及放线菌数量(增加或减少),所有间作系统间的多样性指数差异不显著,除了旺盛生长期四种作物(生姜-大豆-四季葱-大蒜)的间作模式显著降低了多样性指数,其值仅为生姜单作的33.18%;生姜与大豆间作不仅提高了19.6%的生姜产量而且获得了较好的经济效益,并且,所有间作系统均显著抑制了生姜姜瘟病的发生。 5. 不同栽培模式不同程度地影响了收获期生姜的株高、分枝数、根茎产量及内在品质。其中处理2显著地促进了生姜的分枝(10.5%),同时处理2、3和4也促进了生姜的生长(株高分别增加了15.0%、11.4%和14.0%),并且这三个处理提高了生姜的产量;处理2和3能有效提高生姜块茎中维生素C(分别较单作生姜显著提高了3.29%和4.05%)、处理3显著提高了可溶性糖(8.2%)、姜辣素(4.6%)和蛋白质等有益物质的含量,降低硝酸盐有害物质的含量(处理2显著降低了14.0%),改善了姜块的外观和内在品质。并且,生姜与大豆间作具有最高的纯收入和产投比,分别较生姜单作提高了24.80%和8.8%。Recently, allelopathy has been more and more paid attentions by national and foreign scholars with profound research on reasons of crop replanted (continuous planted) obstacle. Ginger rhizome is valuable all over the world either as a spice or herbal medicine and ginger replanted obstacle is also paid attentions. Systematic research on ginger allelopathy will contribute to understanding and ultimate solving problem of ginger replanted obstacle. The effects of ginger aqueous extracts with different parts and concentrations on seed germination and early seedling growth of soybean and chive were studied in this article to testify that ginger existed allelopathy. Furthermore, ginger autotoxicity was also studied by pot experiment in greenhouse (namely research on effects of ginger aqueous extracts with different parts and concentrations on morphological indexes, physiological and biochemical indexes, photosynthesis, soil enzymes, soil microbial diversity and soil nutrients) to reveal mechanism of ginger degeneration and senescence, provide scientific basis for selecting appropriate intercropping species and put forward scientific resolvent for ginger replanted obstacle. The main results were as follows: 1. All aqueous extracts at all concentrations inhibited seed germination, seedling growth, water uptake and lipase activity of soybean and chive compared with the control, and the degree of inhibition increased with the incremental extracts concentration. The degree of toxicity of different ginger plant parts can be classified in order of decreasing inhibition as stem>leaf>rhizome. The results of this study suggested that rhizome, stem and leaf of ginger contained water soluble allelochemicals which could inhibit seed germination and seedling growth of soybean and chive. The rhizome is the main harvested part of ginger. The residue (mainly stems and leaves) of the ginger plant should be removed from the field so as to diminish its inhibitory effect. The main allelopathic components of three kind of aqueous extracts were as follows: Rhizome extract chiefly contained syringic acid and vmbelliferone and stem extract mainly contained frulic acid whose content was the highest (73.4 ug/g). The other six substances were detected except of frulic acid, but only contents of syringic acid, vmbelliferone and p-coumaric acid were higher. 2. Stem and leaf aqueous extracts of ginger with different concentrations significantly inhibited plant height, leaf numbers per plant and leaf area, and the degree of inhibition increased with the incremental extracts concentration. However, tiller number per plant of ginger seedling showed no significant difference. At the same time, ginger aqueous extracts also influenced biomass including under-ground biomass, above-ground biomass and total biomass (fresh weight) to a large extent. Under the same concentration, stem aqueous extract showed the mostly inhibitory effect on morphological indexes and biomass indexes of ginger seedling. Rhizome aqueous extract showed the leastly inhibitory effect and leaf aqueous extract was intervenient. Enhanced concentration of ginger aqueous extracts significantly reduced total chlorophyll content, accompanying with increases in memberane permeability (REL) and lipid peroxidation (MDA). Compared with the control, rhizome ginger aqueous extract of lower concentration (10 g l-1) increased the activities of major antioxidant enzymes (superoxide dismutase, SOD; peroxidase, POD; catalase, CAT; ascorbate peroxidase, APX) of ginger leaf tissue and higher concentration inhibited the activities of four antioxidant enzymes. However, stem and leaf aqueous extract inhibited the activities of four antioxidant enzymes with increase in concentration. Meanwhile, enhanced concentration of ginger aqueous extracts significantly reduced photo-parameters of ginger seedling (including CO2 concentration, stoma conductivity, net photosynthesis rate and transpiration rate). 3. Rhizome, stem and leaf ginger aqueous extract showed different effect on six soil enzyme activities, and acid phosphatase and invertase showed significant effect when aqueous extract concentration got 10 g l-1. Furthermore, six soil enzyme activities increased with increase in aqueous extract concentration. Bcterial and fungi number tended to increase while antinomyces tented to decrease with the increase in aqueous extract concentration of identical part. Ginger aqueous extracts reduced soil organic matter content with increased concentration, accompanying with NO3-—N accumulation in soil. Rhizome aqueous extract showed the same tendency for available P, available K and NH4+—N, namely lower concentration increased their contents in soil and higher concentration reduced their contents. While stem and leaf aqueous extracts reduced their contents with the increamental concentration. 4. All intercropping systems increased soil enzyme activities to different extent both at VGS and at HS compared to solo ginger. All intercropping systems increased the colony numbers of soil bacteria and total of soil microbe but not significantly either at VGS or at HS. All intercropping systems increased the colony numbers of soil fungi and actinomytes to a different extent (increase or decrease) both at VGS and at HS. For DI, difference between all cultivation patterns and S-G was not significant either at VGS or at HS except that G-S-C-G whose value was only 33.18% of S-G at VGS significantly decreased. G-S not only increased ginger yield by 19.6% but also obtained better economic benefit. Furthermore, all intercropping systems significantly inhibited occurrence of bacterial wilt of ginger. 5. Different cultivated pattern influenced plant height, tiller numbers, rhizome yields and intrinsic quality of ginger. Treatment 2 significantly facilitated tiller occurring (10.5%). Treatment 2, 3 and 4 promoted ginger growth (plant height respectively increased 15.0%、11.4% and 14.0%) and enhanced rhizome yields. Treatment 2 and 3 effectively increased vitamin C content (significantly increased 3.29% and 4.05% compared to solo ginger). Treatment 3 significantly increased contents of beneficial substances such as soluble sugar (8.2%), gingerols (4.6%) and protein. Treatment 2 significantly decreased contents of deleterious substance namely nitrate (14.0%) and improved appearance and intrinsic quality of ginger rhizome. Furthermore, treatment 2 (ginger/soybean intercropping) could obtain better economic benefit and showed the highest net income and ratio of benefit and cost whose values respectively increased by 24.80% and 8.8% compared to solo ginger.

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土壤是人类赖以生存的自然环境和农业生产的重要资源,目前土壤受到干旱和盐胁迫的危害越来越严重。杨树具有适应性强、生长快和丰产等特性,本论文以青杨组杨树为模式植物,研究杨树对土壤干旱和盐胁迫的生态生理及蛋白质组学反应,研究成果可为我国干旱半干旱地区营造人工林、防止沙漠化提供理论依据,也为恢复与重建盐污染地区退化生态系统提供科学指导。主要研究结果如下: 1 青杨不同种对逐步干旱胁迫的响应差异 将来自喜马拉雅山东缘高海拔的康定杨和低海拔的青杨枝条扦插在温室中,用来检测它们对逐步干旱胁迫的响应。研究结果表明来自不同海拔的杨树对逐步干旱胁迫的适应性反应是不一样的。株高、叶片发育、叶片相对含水量、丙二醛、过氧化氢等指标的显著性变化在青杨中比在康定杨中来得早些,而且随着干旱胁迫程度的增加,这些参数的变化越来越明显,尤其是当青杨受到严重干旱胁迫的时候;而可溶性蛋白、可溶性糖、游离脯氨酸、抗氧化酶活力变化在康定杨中来得早一些。与青杨相比,在干旱胁迫下,康定杨仍能保持较好的植株生长和叶片发育;康定杨也能在逐步干旱条件下积累更多的可溶性蛋白、可溶性糖、游离脯氨酸及抗氧化酶活力,但是在丙二醛和过氧化氢含量方面增加的更少些。而且,我们的研究结果表明高海拔的康定杨有更强的耐干旱能力,杨树对干旱胁迫的适应能力与干旱发生的速度、强度、持续时间及两种杨树的海拔有关。 2 干旱胁迫下青杨不同种的蛋白质组学分析 来自青杨和康定杨雌株的枝条扦插在温室中,用来研究它们对干旱胁迫的蛋白质组学反应。采用TCA-丙酮/酚提取法提取总蛋白,并进行双向电泳分析。在每个处理的重复图像中都能检测到1,000 个以上的蛋白点。在青杨中有58 个蛋白在干旱处理后发生显著变化,其中22 个蛋白通过肽指纹图谱成功鉴定。康定杨中有69 个蛋白的表达量发生了显著变化,其中有25 个蛋白通过肽指纹图谱成功鉴定。这些被鉴定的蛋白主要参与了光合作用、氧化还原平衡、信号传导、能量代谢、蛋白质合成等过程。尽管被鉴定的蛋白只占叶片总蛋白的很少一部分,但这些被鉴定的干旱响应蛋白可能对维持植株内部平衡方面有重要作用。 3 青杨的盐胁迫响应 青杨植株分别用 0、50 和100 mM NaCl 溶液进行处理。叶片相对含水量、叶绿素a、b 含量、CO2 同化速率和气孔导度的降低表明叶绿体受到了盐胁迫的影响。过氧化氢、丙二醛含量及电导率的升高表明细胞受到了伤害。可溶性糖、游离脯氨酸含量及抗氧化酶含量的上升增加了植株耐盐胁迫的能力。在每个处理的重复图像中都能检测到1,000 个以上的蛋白点。其中有38 个盐响应蛋白被成功鉴定,有16 个蛋白(点4、10、11、14、15、21、24、26、27、28、33、34、35、36、37 和38)出现在盐胁迫的植株中;3 个蛋白(点10、11 和35)只出现在重度盐胁迫处理中;而1 个蛋白(点1)只出现在对照处理中。2 个蛋白(点1 和2)表达量下降,其余蛋白点表达量都增加。被鉴定的蛋白一部分参与了生理生化反应,而另一部分则在信号传导、蛋白质合成等方面有重要作用。盐胁迫下的生理生化变化及蛋白质组学的联合研究有利于青杨对盐胁迫的适应性分析。 Soil is the indispensable environment for human survival and important resource for agriculture development. Nowadays soil is threatened by drought stress and salt stress. Poplars (Populus spp.) possess some characters such as strong acclimilation, fast growth and great production of biomass. In this study, different species of Populus section Tacamahaca spach were used as model plants to investigate the ecophysiological and proteomic responses to drought stress and salt stress. Our results can provide theoretical evidence for the afforestation and prevention of desertification in the arid and semi-arid areas, and also can supply scientific direction for the reconstruction and rehalibitation of ecosystems contaminated by salinity. The results are as follows: 1 Adaptive responses to progressive drought stress in two contrasting poplar species originating from different altitudes Cuttings of Populus kangdingensis C. Wang et Tung and Populus cathayana Rehd., originating from high and low altitudes in the eastern Himalaya, respectively, were examined during one growing season in a greenhouse to determine the effects of progressive drought stress. The results manifested that the adaptive responses to progressive drought stress were different in these two species from different altitudes. Significant changes in height increment, leaf development, relative water content (RWC), malondialdehyde (MDA) and hydrogen peroxide (H2O2) appeared earlier in P. cathayana than in P. kangdingensis, whereas changes in soluble protein, soluble sugar, free proline and antioxidant enzymes appeared earlier in P. kangdingensis. In addition, changes in these parameters became more and more significant when the drought stress progressed, especially under severe drought stress in P. cathayana. Compared with P. cathayana, P. kangdingensis was able to maintain a superior height increase and leaf development under drought stress. Also, P. kangdingensis possessed greater increments in soluble protein, soluble sugar, free proline and antioxidant enzymes, but lower increments in MDA and H2O2 than did P. cathayana when the cuttings were exposed to progressive drought stress. Our results suggest that P. kangdingensis originating from the high altitude has a better drought tolerance than does P. cathayana originating from the low altitude. Furthermore, this study manifested that acclimation to drought stress are related the rapidity, severity, duration of the drought event and the altitude of two contrasting species. 2 Proteomic responses to drought stress in two contrasting poplar species originating from different altitudes The cuttings from a female clone of P. kangdingensis and P. cathayana were used to determine proteomic response to drought stress, respectively. Total proteins of the leaves were extracted by a combination of TCA-acetone and phenol, and separated by two-dimensional gel electrophoresis. More than 1,000 protein spots were reproducibly detected on each gel. 58 differentially expressed spots were detected under drought stress in P. cathayana and 22 drought-responsive proteins were identified by peptide mass fingerprint. 69 differentially expressed spots were detected under drought stress in P. kangdingensiss and 25 drought-responsive proteins were identified by peptide mass fingerprint. The identified proteins are involved in several processes, i.e., signal transduction, protein processing, redox homeostasis, CO2 fixation and energy metabolism. Although the proteins identified in this investigation represent only a very small part of the poplar leaf proteins, some of the novel drought-responsive proteins identified here may be involved in the establishment of homeostasis in response to drought stress in the woody plants. 3 Responses to salt stress in P. cathayana Cuttings from a female clone of P. cathayana were treated by Hoagland’s solution: 0, 50, 100 mM NaCl, respectively. Salinity significantly decreased the relative water content of leaves, the contents of chlorophyll a and chlorophyll b, CO2 assimilation rate (A) and stomatal conductance (gs) in both salt stress treatments,which suggested the chloroplast was affected by salt stress. The observed increases of H2O2 and malondialdehyde contents and electrolyte leakage suggested that salinity caused cellular damage, whereas the increases in compatible solutes and in the activities of antioxidant enzymes enhanced the salt tolerance. More than 1,000 protein spots were reproducibly detected on each gel, and 38 salt-responsive proteins were successfully identified by peptide mass fingerprint (PMF). 16 spots (spot 4, 10, 11, 14, 15, 21, 24, 26, 27, 28, 33, 34, 35, 36, 37 and 38) absent in the control sample were induced by the salt treatment, and three spots (spot 10,11 and 35) were present only in the severely salt-stressed treatment. The %vol of the differentially expressed proteins generally increased with progressing salt stress, except for the decreased %vol of two proteins (spot 1 and 2) under salt stress and the presence of spot 1 only in the control sample. Some of the novel salt-responsive proteins identified here may be involved in physiological, biochemical response to salt stress in P. cathayana, the other identified proteins play a role in numerous cellular functions, including signal transduction and protein processing. An integrated physiological, biochemical and proteomic approach was used here to systematically investigate salt acclimation in poplar.

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揭示苔藓植株元素含量及其时空差异性是深入开展利用苔藓植物指示环境和筛选理想监测藓种的科学基础。采用微波消解(ICP-AES)方法对九寨沟自然遗产地原始林景点停车场周围三个采样带:I为停车场植被小岛(PS),向外约120 m半径为II带(D120),再向外距离约1,000 m为III带(D1000)和3个方向上的大羽藓和毛尖青藓2种苔藓中13种元素(A1, S, Ca, P, Cu, Fe, K, Mg, Mn, Pb, Ni,Zn和Cd)含量进行了测定和比较,并对采自边坡方向(PS-3)上2005和2007年的4种苔藓植物(南木藓、大羽藓、平藓和厚角絹藓)也进行了13种元素含量的测定和比较。同时对九寨沟自然遗产地、黄龙自然遗产地、夹金山和梦笔山的冷杉原始林4个地区的3种苔藓中(大羽藓、锦丝藓和塔藓)的A1、Ca、Cu、Fe、K、Mg、P、Zn、C和N 10种元素含量进行测定和比较。 对大羽藓和毛尖青藓2种苔藓植物内13种元素的测定发现:1)同种苔藓对不同元素的富集能力不同。A1、Ca、K、Mg和P的元素含量在苔藓中的富集较其他元素的要高。2)不同种苔藓植物对同种元素的富集能力不同,毛尖青藓较大羽藓能够监测出更多的元素;对于被检测出的元素,毛尖青藓监测出的累积量大于大羽藓,其中累积量最大的元素是Ca为10 874.286 μg.g-1.year-1,最小的是Cu元素为5.438 μg.g-1.year-1。对05年和07年的平藓、大羽藓、南木藓和厚角絹藓元素含量的测定表明:元素在两年中的积累量是不同的。综合分析表明,苔藓生物监测方法可有效监测景点停车场机动车尾气中排放出的典型元素(如Cu、Pb、Ni、Zn、Cd等)含量,而毛尖青藓较大羽藓能更可靠的监测九寨沟自然遗产地单景点汽车尾气金属元素种类及其排放量。 对4个地区3种苔藓10种元素监测发现:1)Ca、Mg、Zn、K和Cu元素在黄龙地区的含量高于在其它地区的含量;P元素在梦笔山地区的含量为最高;Fe和Al元素在夹金山地区的含量高于在其它地区的含量。2)C元素在其它因素一致的情况下,进行不同年龄间的元素含量比较,结果显示元素含量在各年龄间并不存在明显的差异性;N元素含量与年龄的差异出现在黄龙林下及林窗的塔藓、九寨沟林下的锦丝藓及塔藓和梦笔山的塔藓中,而在锦丝藓中未出现元素含量与年龄的差异性;塔藓能检测出更多的元素种类其含量与年龄间存在显著差异,锦丝藓检测到的元素种类次之;除锦丝藓(锦丝藓在林窗中几乎检测不到元素含量与年龄间的差异性)外,其他两种藓在林窗中能检测出的元素种类大于在林下的检测种类。3)元素含量与生境间存在差异性的元素分别有:黄龙大羽藓中的Ca、P和Mg元素;九寨锦丝藓中的Zn元素;夹金山塔藓中的Al、Fe和Zn元素;梦笔山大羽藓中的Al、Fe和Mg元素及锦丝藓中的Ca元素。4)区域、年龄和生境因素对苔藓植株元素含量均达到了显著水平,但两两之间及三者之间的交互作用由于元素种类的不同存在差异。综合分析表明,苔藓植物中的元素含量受年龄、区域的影响较生境的更大。 The revelation of mosses elements content and its spatiotemporal differences is the scientific foundation of moss monitoring. To determine the feasibility of moss monitoring metal depositions derived from travel bus emiss ions in scenic spot, we collected one year-growth samples of two mosses Brachythecim piligerum and Thuidium cymbifolium with different distance (island center, 120m,1000m ) and different direction (north, south and east) far from parking site island from Yuanshilin Spot at Jiuzhaigou World Nature Heritage in the Western Sichuan of China and determined thirteen element (A1, S, Ca, P, Cu, Fe, K, Mg, Mn, Pb, Ni, Zn, Cd)contents by ICP-AES analysis method. And picked 4 kinds of mosses (Macrothamnium macrocarpu m(Reinw. etHornsch.)Fleisch.,Thuidium cymbifolium,Entodon concinnus (De Not.) Par., Neckera pennata) from the direction PS-3 in 2005 and 2007, determined 13 element contents. Collected 3 kinds of moss (Thuidium cymbifo lium, Actinothuidium Hookeri (Mitt.) and Hyolcomium splendens (Hedw.) from Jiuzhaigou natural heritage, Huanglong natural heritage, Mt. Jiajin and Mt. Mengbi in primeval forest with two habitat (undergrowth and forest gap), determined element contents of A1, Ca, Cu, Fe, K, Mg, P, Zn, C and N. We found that, 1) The elements content are difference in same type of moss. Content of A1, Ca, K, Mg and P are higher than others. 2) While the contents of A1, S, Ca, P, Cu, Fe, K and Zn had significant correlation with the different distances from parking site, the nearer the distance was, the more accumulation was; 2) Comparing to Thuidium cymbifolium, Brachythecium piligerum can test more elements which contents show the significant correlation with distances. And Brachythecium piligerum can have greater element accumulation than Thuidium cymbifolium. The element contents in two years (2005 and 2007) are different. The present study found that moss can reliably bio-indicate metal deposition from traffic emissions in one scenic spot and Brachythecium piligerum is a good moss for bio-indicating element content from traffic emissions at Jiuzhaigou World natural Heritage. Determined the 10 element contents in 4 areas through 3 kinds of moss we found that, 1) Ca, Mg, Zn, K and Cu element content is higher in the Huanglong area than in other areas, The P element content in Mt. Jiajin is higher than other areas, Fe and Al element content is higher in the Mt. Jiajin than in other areas. 2) The content of C had no significant correlation with age. As for N, this significant correlation found in Hyolcomium splendens (Hedw.) with 2 habitat in Huanglong, Actinothuidium Hookeri (Mitt.) and Hyolcomium splendens (Hedw.) with undergrowth in Jiuzhai, Hyolcomium splendens (Hedw.) in Mt. Mengbi. The types of elements which content showt he significant correlation are most in Hyolcomium splendens (Hedw.) and least in Thuidium cymbifolium. Except Actinothuidium Hookeri (Mitt.), the types of elements that content had significant correlation with age in forest gap are more than in undergrowth. 3) The elements which content had significant correlation with habitat are P, Ca and Mg in Thuidium cymbifolium in Huanglong, Zn in Actinothuidium Hookeri (Mitt.) in Jiuzhai, Al, Fe and Zn in Hyolcomium splendens (Hedw.) in Mt. Jiajin, in Mt. Mengbi Al, Fe and Mg in Thuidium cymbifolium and Ca in Actinothuidium Hookeri (Mitt.). 4)The region, the age and the habitat factor has coeffect element content. The correlationship between element contents and the age, the region is closer than habitat.

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同源四倍体水稻(2N=4X=48,AAAA)是由二倍体水稻(2N=2X=24,AA)通过秋水仙素诱导染色体加倍后得到的新品系,具有优良的抗病性以及较高的蛋白质含量。因此,在四倍体水平上挖掘水稻的增产潜力成为水稻育种的新手段。同源四倍体水稻具有很强的遗传可塑性和很弱的遗传保守性,利用其作为水稻远缘杂交的桥梁,从野生物种中不断地引进有益的基因,这将有助于杂交水稻的多代利用和固定水稻的杂种优势。但是迄今为止,还没有关于同源四倍体水稻遗传多样性,遗传背景的报道。目前世界关于同源四倍体水稻的研究主要集中在中国,主要研究方向为培育、筛选结实正常的亲本材料,配置和筛选结实率正常或接近正常的组合。经过几十年研究,虽然在材料构建,细胞学研究等方面取得了较大进展,但同样由于结实率低的瓶颈问题未解决,而使多倍体水稻育种未能取得实质性进展。而近年来一些关于同源四倍体水稻低结实率机理的细胞学研究也由于缺乏统计学数据而缺乏说明性。本文用SSR标记,对选取的36个结实率正常同源四倍体水稻三系亲本和14个来源二倍体亲本,分析他们的遗传差异和群体遗传结构。本文还利用我们培育的高、低结实率的同源四倍体水稻恢复系、优良保持系和杂种F1及二倍体对照为材料,进行系统深入的细胞遗传学研究,进一步探讨同源四倍体水稻有性传递后代的发育过程,探索分裂期染色体行为特征与遗传性状稳定性的关系,为进一步选育多倍体水稻品种并将其应用于生产提供理论依据。同源四倍体水稻突变株D4063-1直链淀粉含量比来源二倍体明恢63下降一半,即其直链淀粉含量为5.23%,为研究其直链淀粉含量下降的原因,本文还根据普通水稻Wx基因设计引物,扩增测序获得了D4063-1Wx基因的全序列,与已报道Wx基因进行比对分析,并根据D4063-1和籼稻、粳稻的序列差异并根据D4063-1在该片段上的特征序列位点设计了用于识别D4063-1的寡核苷酸片段,为快速、准确的鉴别低直链淀粉的D4063-1创造了条件。 SSR标记具有基因组分布广泛、数量丰富、多态性高、容易检测、共显性、结果稳定可靠、实验重现性好、操作简单、经济、易于高通量分析等许多优点,被认为是用于遗传多样性、品种鉴定、物种的系统发育、亲缘关系及起源等研究的非常有效的分子标记。本研究选取了中国科学院成都生物所培育的同源四倍体和二倍体水稻亲本,并用36个微卫星标记进行了遗传差异和种群遗传结构分析。在50个品系中,我们观察到较高水平的多态性,每基因等位基因数(Ae)分布于2至6之间(平均值3.028),多态性信息含量(PIC)分布于0.04至0.76之间(平均值0.366);期望杂合度(He)分布于0.04至0.76之间(平均值0.370),Shannon指数(I)分布于0.098至1.613之间(平均值0.649)。同源四倍体品系的等位基因数,期望杂合性和Shannon指数都比二倍体品系高。在供试50个品系中,较多材料均发现Rare基因,根据SSR多态性指数我们构建了同源四倍体和二倍体水稻的核心指纹库。F-统计值表明遗传差异主要存在于同源四倍体品系中(Fst=0.066)。聚类分析结果表明50个品系可以分为4个组。I组包括所有的同源四倍体和二倍体籼稻保持系,以及一个同源四倍体籼稻雄性不育系及其来源二倍体。II组仅包括IR来源的品系。III组比II组和IV组更复杂,包括同源四倍体和二倍体籼稻恢复系品系。IV组包括同源四倍体和二倍体粳稻品系。此外,由于等位基因及配子的遗传差异,同源四倍体与二倍体品系中存在单位点和双位点的遗传差异。分析结果表明,二倍体和四倍体水稻基因库的不同,其中遗传变异可以区分四倍体与二倍体水稻。同源四倍体水稻具有长期而独立的遗传性,我们能够选育并得到与二倍体亲本相比有特殊优良农艺性状的品系。 本研究以高结实率的同源四倍体水稻恢复系DTP-4、D明恢63及优良保持系D46B为材料进行农艺性状及细胞遗传学比较研究。DTP-4、D明恢63及保持系D46B的的染色体组成均为2N=4X=48,花粉母细胞具有较为理想的减数分裂行为,配对染色体的比率在99%以上,这与理论染色体组构成相符。DTP-4和D明恢63PMC减数分裂各个时期单价体和三价体的比例都非常低,而在MI, PMC观察到较多的二价体和四价体且四价体多以环状形式出现,其最大频率的染色体构型分别为12II 6IV和10II 7IV。恢复系DTP-4和D明恢63在MI四价体频率分别为2.00/PMC和2.26/PMC,而保持系D46B在MI四价体频率为6.00/PMC,极显著地高于恢复系品系,表明保持系D46B具有更好的染色体配对性质;AI保持系D46B的染色体滞后频率为10.62%,远低于恢复系材料DTP-4和D明恢63的19.44%和23.14%,接近二倍体对照明恢63的7.30%水平;TI保持系D46B具有比恢复系更低频率的微核数。而在TII,D46B的正常四分小孢子比率不但高于恢复系品系甚至高于二倍体对照。对高低结实率的同源四倍体水稻恢复系和杂种F1代的花粉育性,结实率和细胞遗传学行为进行了比较研究。DTP-4, D明恢63, D46A´DTP-4和D46A´D明恢63的花粉育性和结实率比D什香和D46A´D什香显著提高。减数分裂分析的结果表明,DTP-4,D明恢63,D什香,D46A´DTP-4,D46A´D明恢63和D46A´D什香其减数分裂染色体构型分别为:0.05I +19.96 II (9.89棒状+10.07环状) +0.01III + 2.20 IV, 0.11I +19.17 II (8.90 棒状+10.37 环状) +0.09III + 2.26 IV + 0.01 VI, 1.33I +9.46 II (4.50 棒状+4.96 环状) +0.44III + 6.02 IV + 0.09VI + 0.09 VIII, 0.02I +14.36 II (6.44 棒状+7.91 环状) +0.01III + 4.80IV + 0.01VIII, 0.06 I +17.67 II (11.01 棒状+6.67 环状) +0.06 III + 3.10 IV + 0.01 VI and 1.11 I +11.31 II (5.80 棒状+5.51 环状) +0.41 III + 5.63 IV+0.03VI+0.03VIII。在同源四倍体水稻恢复系和杂种F1代材料中,最常见的染色体构型为16II +4IV和12II +6IV。在减数分裂过程中,结实率较高的材料染色体异常现象较少而结实率较低的材料染色体异常现象较严重。在杂种F1代中,二价体的比例要低于其相应的恢复系亲本,同样的,单价体,三价体和多价体的比例相比其恢复系亲本也偏低。然而,在减数分裂MI,杂种F1代中四价体的比例要显著高于其恢复系亲本。在中期I,每细胞单价体的比例和花粉育性呈现出极高的负相关(-0.996),当单价体数目升高时,花粉育性下降。其次是每细胞三价体的比例(-0.987),之后则是每细胞多价体的比例与花粉育性的负相关(-0.948)。但是统计分析表明,二价体和四价体的比例对花粉育性和结实率没有显著影响。这一结果表明出了花粉育性和细胞减数分裂行为的相关性,同源四倍体的减数分裂行为为筛选高结实率的同源四倍体种系提供了理论依据。 突变体是遗传学研究的基本材料。利用突变体克隆水稻基因,并进而研究基因的生物学功能是水稻功能基因组学的重要研究内容。本课题组在多年的四倍体水稻育种研究中已获得多个低直链淀粉含量突变体,其中一些突变体在直链淀粉含量下降的同时,胚乳外观也发生了显著改变,呈半透明或不透明。同源四倍体水稻突变株D4063-1直链淀粉含量比来源二倍体明恢63下降一半,即其直链淀粉含量为5.23%。为研究其直链淀粉含量下降的原因,我们根据普通水稻Wx基因设计引物,扩增测序获得了D4063-1Wx基因的全序列,与已报道Wx基因进行比对分析;同源四倍体水稻D4063-1Wx基因最显著变化为在外显子序列中发生了碱基缺失,导致移码突变,在第9外显子终止密码子提前出现。D4063-1Wx基因碱基位点的变化还导致了其序列上的酶切位点的变化,对常用限制性内切酶位点分析分析结果表明同源四倍体水稻相对于籼稻和粳稻多了2个sph1酶切位点,相对于粳稻减少了6个Acc1,增加了4个Xba1,1个Xho1,1个Pst1和1个Sal1酶切位点。聚类分析表明D4063-1Wx基因序列与籼稻亲源关系较近,由此推测D4063-1Wx基因来源于籼稻的Wxa基因型。另外,根据D4063-1Wx基因的碱基差异,我们推测D4063-1Wx基因外显子碱基变化导致的RNA加工障碍是其直链淀粉降低的主要原因,并可能与其米饭较软等品质相关。本文还根据D4063-1和籼稻、粳稻的序列差异并根据D4063-1在该片段上的特征序列位点设计了用于识别D4063-1的寡核苷酸片段,并作为PCR反应的引物命名为AUT4063-1,将该引物与我们设计的扩增普通籼稻、粳稻的Wx基因引物F5配合使用建立了识别D4063-1的显性和共显性两种检测方式的分子标记,为快速、准确的鉴别低直链淀粉的D4063-1创造了条件。 研究同源四倍体水稻基因组的遗传差异,探索同源四倍体水稻的遗传规律,研究分裂期染色体行为特征与遗传性状稳定性的关系,旨在揭示四倍体水稻中同源染色体配对能力的遗传差异,为进一步选育多倍体水稻品种并将其应用于生产提供理论依据。 Autotetraploid rice (2N=4X=48, AAAA) is a new germplasm developed from diploid rice (2N=2X=24, AA) through chromosomes doubling with colchicines and is an excellent resource for desirable resistance genes to the pathogens and high protein content. Therefore, heterosis utilization on polyploidy is becoming a new strategy in rice breeding. At present, the main research on autotetraploid rice centralizes in China. Breeding effort has been made to improve autotetraploid rice genetically, however, the progresses are limited due to higher degree of divergence between hybrid sterility and polygenic nature. But to date, almost nothing is reported about the genetic diversity, original and genetic background of autotetraploid rice. Despite several reports on cytological analysis of the mechanisms of low seed set in autotetraploid rice still the results are inconclusive due to lack the statistical evaluation. Therefore, the study on the mechanisms of low seed set in autotetraploid is a priority for rice breeding. Microsatellites or simple sequence repeats (SSRs) are the widely used marker for estimating genetic diversity in many species, including wild, weedy, and cultivated rice. In our research, genetic diversity and population genetic structure of autotetraploid and diploid populations collected from Chengdu Institute of Biology, Chinese Academy of Sciences were studied based on 36 microsatellite loci. For the total of 50 varieties, a moderate to high level of genetic diversity was observed at population levels with the number of alleles per locus (Ae) ranging from 2 to 6 (mean 3.028) and PIC ranging from 0.04 to 0.76 (mean 0.366). The expected heterozygosity (He) varied from 0.04 to 0.76 with the mean of 0.370 and Shannon’s index (I) ranging from 0.098 to 1.613 (mean 0.649). The autotetraploid populations showed a slightly higher level of effective alleles, the expected heterozygosity and Shannon’s index than that of diploid populations. Rare alleles were observed at most of the SSR loci in one or more of the 50 accessions and core fingerprint database of the autotetraploid and diploid rice was constructed. The F-statistics showed that genetic variability mainly existed among autotetraploid populations rather than among diploid populations (Fst=0.066). Cluster analysis of the 50 accessions showed four major groups. Group I contained all of the autotetraploid and diploid indica maintainer lines and a autotetraploid and its original diploid indica male sterile lines. Groups II contained only original of IR accessions. Group III was more diverse than either group II or IV and comprised of both autotetraploid and diploid indica restoring lines. Group IV included japonica cluster of the autotetraploid and diploid rices. Furthermore, genetic differences at the single-locus and two-locus levels, as well as components due to allelic and gametic differentiation, were revealed between autotetraploid and diploid varieties. This analysis indicated that the gene pools of diploid and autotetraploid rice are somewhat dissimilar, which made a variation that distinguishes autotetraploid from diploid rices. Using this variation, we can breed new autotetraploid varieties with some new important agricultural characters but the diploid rice has not. Cytogenetic characteristics in restorer lines DTP-4, DMinghui63 and maintainer line D46B of autotetraploid rices were studied. DTP-4, DMinghui63 and D46B showed the advantage of high seed set and biological yield. The meiotic chromosome behavior was slightly irregular in DTP-4, DMinghui63 and D46B. We observed less univalent, trivalent and multivalent at MI, but more bivalent and quadrivalent were observed. The most frequent chromosome configurations were 12II 6IVand 10II 7IV in restorer and maintainer lines, respectively. The quadrivalent frequency of DTP-4 and Dminghui63 at metaphase(MI) was respectively 2.00/PMC and 2.26/PMC. However that frequency of D46B was 6.00/PMC, which was greatly significantly higher than DTP-4 and Dminghui63. That indicates the maintainer D46B has better chromosome pairing capability in metaphase (MI). The frequency of lagging chromosomes of the maintainer D46B at anaphaseI (AI) was 10.62%, which was significantly lower than that of DTP-4(19.44%) and Dminghui63(23.14%) and nearly reaching the level of diploid CK(7.30%). In telophaseI (TI) maintainer D46B showed lower frequency of microkernel at TI and lower frequency of abnormal spores at telophaseII(TII). We also studied pollen fertility, seed set and cytogenetic characteristics of restorer lines and F1 hybrids of autotetraploid rice. DTP-4, DMinghui63, D46A´DTP-4 and D46A´DMinghui63 showed significantly higher pollen fertility and seed set than DShixiang and D46A´DShixiang. Pairing configurations in PMC of DTP-4, DMinghui63, DShixiang, D46A´DTP-4, D46A´DMinghui63 and D46A´DShixiang were 0.05 I+19.96 II (9.89 rod+10.07 ring)+0.01 III+2.20 IV, 0.11 I+19.17 II (8.90 rod+10.37 ring)+0.09 III+2.26 IV+0.01 VI, 1.33 I+9.46 II (4.50 rod+4.96 ring)+0.44 III+6.02 IV+0.09 VI+0.09 VIII, 0.02 I+14.36 II (6.44 rod+7.91 ring)+0.01 III+4.80 IV+0.01V III, 0.06 I+17.67 II (11.01 rod+6.67 ring)+0.06 III+3.10 IV+0.01 VI and 1.11 I+11.31 II (5.80 rod+5.51 ring)+0.41 III+5.63 IV+0.03 VI+0.03 VIII, respectively. Configuration 16 II+4 IV and 12 II+6 IV occurred in the highest frequency among the autotetraploid restorers and hybrids. Meiotic chromosome behaviors were less abnormal in the tetraploids with high seed set than those with low seed set. The hybrids had fewer frequencies of bivalents, univalents, trivalents and multivalents than the restorers, but higher frequency of quatrivalents than the restorers at MI. The frequency of univalents at M1 had the most impact on pollen fertility and seed set, i.e., pollen fertility decreased with the increase of univalents. The secondary impact factors were trivalents and multivalents, and bivalents and quatrivalents had no effect on pollen fertility and seed set. The correlative relationship between pollen fertility and cytogenetic behaviors could be utilized to improve seed set in autotetraploidy breeding. The amylose content of autotetraploid indica mutant Rice D4063-1 dropped by half than diploid Minghui 63, that is, its amylose content of 5.23%.The whole sequence of Waxy gene of D4063-1 is amplified and sequenced. And the discrepancy of bases is found comparing to the reported Waxy gene. The Waxy gene of autotetraploid Rice D4063-1 had a base deletion in exon sequence, which resulted frameshift mutation in exon 9 and termination codon occur early. The mutation of Wx also led to the change of some common restriction endonuclease sites. Results showed compared to indica and japonica, D4063-1 had two adding sph1 sites. Compared to japonica, D4063-1 had six decreasing Acc1, a adding Xho1, Pst1 and Sal1 restriction sites. Phylogeny analysis shows that the DNA sequence of Waxy gene of D4063-1 is closer to Indica, and we suppose that the Waxy gene of D4063-1 is origin from genotype Wxa. In addition, according to the base differences of Wx in D4063-1, we deduce that RNA processing obstacle led by base change of intron is the main cause to low the amylose content, and related to phenotype of its soft rice. Based on analysis of fragments of D4063-1, indica and japonica and according to the special point of the three species, primers as markers-AUT4063-I were designed for distinguishing the D4063-1 from other rice. Combining with primer pair F5, dominant and codominant ways were established for discriminating them., rapid and correct identification of D4063-1 from other rice could be done. The genetic analysis is important to ensure the original of autotetraploid rice, for maintaining the “distinctiveness” of autotetraploid varieties, and to differentiate between the various genetic background of autotetraploid rice. The autotetraploid breeding will benefit from detailed analysis of genetic diversity in the germplasm collections. Further investigation on mechanisms of meiotic stability should benefit polyploid breeding. These findings demonstrated opportunity to improve meiotic abnormalities as well as grain fertilities in autotetraploid rice.