神农架地区米心水青冈林和锐齿槲栎林的格局与过程

本文对神农架地区广泛分布的米心水青冈林和锐齿槲栎林的种群和群落学特征、干扰历史、更新策略、生物量、生产量及元素循环特征进行了研究。得到如下结论： 1 米心水青冈林是神农架地区山地垂直分布的地带性植被类型，主要群落学特征为：（1）建群种明显，该区域主要有2种类型，即米心水青冈林和米心水青冈、锐齿槲栎林;（2）群落结构简单，但物种组成丰富，在6600m~2样地中出现高等植物（不含苔藓植物）77科150属271种，组成种类以蔷薇科、百合科、忍冬科、虎耳草科、樟科、杜鹃花科和壳斗科为主;（3）群落乔木层（占重要值的12％）和灌木层（占盖度的15％）中含有一定比例的常绿树种;（4）群落生活型以高位芽植物（70.89%）占绝对优势，其次为地面芽植物（15.50%）和地下芽植物(12.92%)。 2 米心水青冈是多主干的树种，萌枝现象普遍，但萌枝数量不同地点差异较大。通过萌枝产生的枝群体平均密度为257 ± 99.3n•hm~(-2)。枝群体的年龄结构表现为“幼龄个体数目较多型”和“中国年龄阶段数目较多型”，并且有较多的枝群体表现出一致的年龄结构。从整个群落米心水青冈的年龄结构来看，表现出发展型种群的特点。枝群体的分布格局为随机分布。9丛米心水青冈完整的年轮分析结果表明，它们萌枝的时间不是边疆的，而与森林的受干扰有关。根据83个圆盘和生长锥芯资料，米心水青冈在萌枝后成长为乔木层或林冠层的过程中，径向生长表现为5种模式。这是丛株内竞争的结果。萌枝在米心水青冈林的维持和发展过程中，具有重要的生态学作用。 3 锐齿槲栎林是神农架地区山地垂地分布的地带性植被类型，主要群落学特征为：（1）建群种明显，该区域主要有2种类型，即锐齿槲栎林和锐齿槲栎、米心水青冈林;（2）群落乔木层和灌木层中含有一定比例的常绿树种，和暖温带的落叶栎林有较大差异;（3）群落物种组成丰富，不仅具有典型的温带科属，还有典型亚热带分布的科属，组成种类主要以蔷薇科、百合科、忍冬科、虎耳草科、山茱萸科、杜鹃花科、壳斗科和樟科;（4）生活型以高位芽植物（66.32%）占绝对优势，其次为地面芽（23.51%）和地下芽（9.47%）植物。 4 通过样地调查、树干解析及直径分析法，对米心水青冈林和锐齿槲栎林受压和释压历史及更新策略进行了研究。米心水青冈直径生长表现为5种模式。而锐齿槲栎只表现为2种模式。85.9 ± 6.9%的米心水青冈有过受压过程，平均受压2.1 ± 0.8次，平均受压时间为47 ± 24.1a，最长受压时间73a，平均释压次数为1.6 ± 0.7次，平均释压时间为23 ± 21.5a，而60.83%的锐齿槲栎都均有1次受压。平均受压时间为19 ± 14a，受压后没有表现出释压过程。结合高生长和径向生长，认为米心水青冈是耐阴树种，它的更新策略是在林下形成苗性萌枝，在有林窗形成时释压生长进入乔木层;而锐齿槲栎是不耐阴树种，它的更新策略是通过产生大量种子，当有大的林窗时，幼苗在林窗内生长逐步进入乔木层。 5 神农架地区102-130a成熟米心水青冈林的生物量在251.31-358.63T•hm~(-2)之间，平均为288.70 ± 48.30T•~(-2)，20-60a锐齿槲栎林群落生物量在134.85-301.20T•hm~(-2)，平均为231.60 ± 78.10T•hm~(-2)。虽然米心水青冈林和锐齿槲栎林灌木层草本层及藤本植物组成很丰富，但二种类型森林生物量的95％以上集中在乔木层。乔木层生物量主要集中在少数优势种中。在米心水青冈林生物量从大到小的序列中，前5种植物分别占乔木层总生物量58.67%-96.37%不等，同样锐齿槲栎林前5种植物占群落生物量的68.13%-95.26%。常绿植物占乔木层生物量的比例变化较大，米心水青冈林中占2.85-18.70%，锐齿槲栎林中一般常绿植物占0.8-9.98%，只有1个锐齿槲栎林样地常绿植物（主要是粉白杜鹃）占乔木层生物量的44.04%。米心水青冈林生物量根冠比为0.27 ± 0.05，锐齿槲栎林为0.21 ± 0.06。神农架地区米心水青冈林的生物量，在成熟的欧洲水青冈林及日本的水青冈林生物量范围之内，而锐齿槲栎林生物量远远大于我国温带落叶栎林的生物量。 6 神农架地区102-130a米心水青冈林生产量范围在1857-2786g•m~(-2)•a~(-1)，平均为2330 ± 397 g•m~(-2)•a~(-1)。20-60a锐齿槲栎林的生产量范围在1319-2521 g•m~(-2)•a~(-1)，平均为1930 ± 498 g•m~(-2)•a~(-1)。米心水青冈林和锐齿槲栎林乔木层生产量占群落总生产量的95％以上，乔木层各器官生产量大小顺序为叶> 树干> 枝和根，其中叶生产量占乔木层的一半以上，达53.87 ± 2.72%（米心水青冈林）和57.31 ± 6.23%（锐齿槲栎林）。在乔木层生产量从大到小的序列中，前5种植物平均占乔木层总生产量的81.03 ± 13.94%（米心水青冈林，范围在62.75%-92.66%）和84.23 ± 9.68%（锐齿槲栎林，范围在68.54-95.11%）。米心水青冈林和锐齿槲栎林群落地下部分生产量占总生产量的比例分别为11.29 ± 1.02%和9.22 ± 2.72。和我国其它地区地带性植被类型相比。米心水青冈林和锐齿槲栎生产量是较高的，和亚热带绿阔叶林生产量接近，但在器官分配上两者差异较大。 7 米心水青冈林和锐齿槲栎林土壤均呈酸性。其中锐齿槲栎林地土壤酸性更强。土壤元素特征表现为Al>C>K>Mg>Ca>N>S、P的特点，富铝化作用明显。8种元素在群落优势植物不同部位含量差异较大，N、P、K、Ca、Mg基本上是以叶片含量最高，树干或根中最低。仅从叶片来看，元素特征表现为C>Ca、N>K>Mg>S>P、Al。优势植物的C/N和C/P显著高于暖温带落叶阔叶林优势植物。8种元素在米心水青冈林和锐齿槲栎林中积累量分别为147.09 ± 25.60和116.00 ± 37.63 Mg hm~(-2)a~(-1)，其中97％以上积累在群落乔木层。两种森林类型各元素的积累量都表现为C>Ca, N> K> Mg> P> S> Al的特点。米心水青风林和锐齿槲栎林8种元素的年存留量分别为6263 ± 90.8和5946 ±246 kg hm~(-2)a~(-1),其中N、P、K、Ca、Mg 5种主要营养元素的存留量分别为179.7 ± 18.2和169.4 ± 23.5kg hm~(-2) a~(-1)。两种森林类型各元素的存留量都表现为C> N> Ca> K> Mg> S> P> Al。

古田山大样地木本植物根萌现状及优势种群根萌空间格局分析

　　已有研究表明，萌生现象对森林恢复和植被演替等生态过程中具有及其重要的意义，作为一种可以和种子繁殖“抗衡”的直接的再生方式，森林萌生更新已受到越来越多的关注。近年来萌生生态学的研究主要针对于萌生的生态功能如对个体生活史策略的影响、在植被演替中的作用、对物种多样性影响等方面，研究的切入点大多注重相关的环境因子、遗传因子或自然和人为干扰如砍伐、火烧、大风等引起的萌生现象，针对原始森林演替的研究相对较少，针对“长期动态监测样地”的萌生现象则更少。由于长期动态观测样地具有固定和长期观察的特有优点，这对物种共存、格局及维持机制、植被演替等生物多样性热点问题的研究带来了难得的机遇和条件。 我国是地球上亚热带常绿阔叶林分布面积最广，发育最为典型的区域，我国亚热带常绿阔叶林的生物多样性极高,仅次于热带雨林。目前对亚热带常绿阔叶林物种共存、分布格局、群落演替等的研究相对较少。参照美国史密森热带研究所的热带森林研究中心(Center for tropical forest science，CTFS)森林动态样地的操作规范，中国森林生物多样性研究网络在中国从南到北按主要森林类型建立了5块20～25hm2的森林大样地。作为中国森林生物多样性长期监测网络的重要组成部分，古田山样地分布着典型的中亚热带常绿阔叶林。本论文在24hm2古田山中亚热带常绿阔林长期监测样地调查的基础上，重点从古田山大样地木本植物根萌现状及优势种群根萌空间格局等方面进行具体分析，试图了解古田山大样地根萌植物的种类组成、个体大小、数量、地理区系成分特点等基础特征，同时选择大样地乔灌木层的优势树种，重点分析优势种群根萌的空间分布格局及其特点，以便加深了解优势物种根萌的种内、种间的共存关系，也将对优势植物根萌植物的分布和样地生境的关系作出有益尝试。本文最后通过比较优势物种的主干和根萌空间分布格局等方面的相关性进一步揭示根萌在群落组成中的地位和作用。本研究将为亚热带常绿阔叶林根萌植物的长期动态研究积累基础资料，对了解常绿阔叶林根萌植物现状以及空间分布格局等方面起到积极的探索意义，同时对揭示根萌现象在亚热带常绿阔叶林物种多样性维持机制中的地位和作用也将起到一定的推动作用。

A laboratory study on risk assessment of microcystin-RR in cropland

The persistence time and risk of microcystin-RR (MC-RR) in cropland via irrigation were investigated under laboratory conditions. In order to evaluate the efficiency of the potential adsorption and biodegradation of MC-RR in cropland and the persistence time of MC-RR for crop irrigation, high performance liquid chromatography (HPLC) was used to quantify the amount of MC-RR in solutions. Our study indicated that MC-RR could be adsorbed and biodegraded in cropland soils. MC-RR at 6.5 mg/L could be completely degraded within 6 days with a lag phase of 1 - 2 days. In the presence of humic acid, the same amount of MC-RR could be degraded within 4 days without a lag phase. Accordingly, the persistence time of MC-RR in cropland soils should be about 6 days. This result also suggested the beneficial effects of the organic fertilizer utilization for the biodegradation of MC-RR in cropland soils. Our studies also demonstrated that MC-RR at low concentration (< 10 mu g/L) could accelerate the growth of plants, while high concentration of MC-RR (> 100 mu g/L) significantly inhibited the growth of plants. High sensitivity of the sprouting stage plants to MC-RR treatments as well as the strong inhibitory effects resulting from prolonged irrigation further indicated that this MC-RR growth-inhibition may vary with the duration of irrigation and life stage of the plants. (c) 2007 Published by Elsevier Ltd.

在盐胁迫下外源维生素浸种对小麦发芽及幼苗生长的影响

维生素(Vitamin)又称维他命，为“万年青”产品，是维持人体生命健康必需的一类低分子有机化合物质。维生素对人体健康的作用人们研究很多, 维生素可以增强人体对感染的抵抗力，降低出生缺陷及降低癌症和心脏病发病率等，一旦缺乏，肌体代谢就会失去平衡，免疫力下降，各种疾病，病毒就会趁虚而入；而维生素对作物影响的研究却很少。目前为止，尚无对用维生素浸种的方法来研究外源维生素是否对小麦种子萌发及幼苗生长起调节作用的报道，且对其在小麦抗逆性方面影响的研究甚少，对盐的胁迫抗性研究尚未有人报道。小麦（Triticum aestivum L.）属于拒盐的淡土性作物。盐害不利于小麦生长，严重影响小麦的产量和品质。本研究采用4 种不同维生素VB1、VC、VB6、VPP，分别对供试小麦品种川育12（红皮）、川育16（白皮）小麦浸种后，在一般自然条件下和逆境（盐胁迫条件）下，进行试验。探讨在正常情况下与在不同盐浓度条件下，各维生素及盐浓度对小麦发芽及幼苗生长的影响，并且比较两种不同皮色的小麦在相同盐胁迫条件下的差异表现，同时研究维生素处理的特异性，且哪种维生素对盐害缓解作用最佳。研究结果表明：在无盐胁迫（自然）条件下，对用4 种不同维生素VB1、VC、VB6、VPP 浸种小麦川育12、川育16 后的种子萌发及幼苗生长（幼苗的根长、根重、苗高、苗鲜重）的研究结果表明：4 种外源维生素浸种均对小麦发芽有调节作用，都能提高其最终发芽率。但是提高幅度有所差异。用VB6 浸种后的小麦提高幅度最多，VC 次之，VPP 提高幅度最小。同时，4 种外源维生素浸种对小麦种子的出芽速度及芽后长势也有一定的影响。VB6、VC 处理的小麦种子出芽速度最快，萌发后长势最好；VB1 出芽速度相对较慢，VPP 最慢,但都大于对照；VB1 处理长势略高于对照，VPP 处理的小麦长势则低于对照。从整体来看，VB6、VC处理促进效应明显， VB1 次之，而VPP 在某些方面无效甚至产生负效应。此外，相同的维生素处理对不同的品种的种子萌发、生长效果也存在差异，各种维生素作用于川育12 的效应均强于对川育16。进一步对幼苗根系TTC 还原力及幼苗叶片中硝酸还原酶活性进行测定、分析。研究发现：并非所有种类的维生素对幼苗根系TTC 还原力及幼苗叶片中硝酸还原酶活性的提高都有帮助。幼苗根系TTC 还原力在不同维生素处理下存在显著差异，而与小麦品种关系甚微。经VB6、VC 处理后，根系TTC 还原力测定值均显著高于对照，VB1 不明显，VPP 则略低于对照。VB6、VC 处理的幼苗叶片中硝酸还原酶的含量大于对照，VB1 与对照相差无几，而VPP 处理的川育12 幼苗叶片中的硝酸还原酶活性比对照CK 略高，而在川育16 中则略比对照CK 有所下降，呈现出抑制效应。综上结果表明：VB6、VC 具有促进种子发芽，幼苗生长及根系生长的作用，是较好的促生长剂；VPP 具有抑制作用，是较好的抑制剂，可进一步研究、开发利用。在盐胁迫条件下，对用4 种不同维生素VB1、VC、VB6、VPP 浸种川育12、川育16 后的种子萌发及幼苗生长（幼苗的根长、根重、苗高、苗鲜重）的研究结果表明：在不同盐浓度胁迫条件下， 各处理的种子萌发及幼苗生长均受到不同程度的抑制。随着盐浓度的增加, 发芽率、发芽指数和活力指数成下降趋势；幼苗的根长、根重、苗高、苗鲜重不断降低。4 种维生素处理间也表现出较大差异。VB6、VC 在每个处理中均保持对盐害的缓解作用，VB6 较VC 更易于促进发芽及幼苗生长。最终发芽率高，根系多、长、重，苗高高、重。而VB1、VPP 则表现出抑制作用。在高盐浓度150mM 时，4 种维生素浸种后的种子，其最终发芽率均不能达到40％，但VB6、VC 处理最终发芽率、苗重、根重均高于对照，VPP 最终发芽率、苗重、根重均低于对照。进一步对幼苗根系TTC 还原力及幼苗叶片中脯氨酸含量进行测定、分析。研究发现：不同盐浓度，不同维生素处理、不同品种间存在差异。随着盐浓度的增加（75mM，100mM，150mM），幼苗根系TTC 还原力活性成下降趋势，幼苗叶片中脯氨酸的积累量成上升趋势。VB6 处理脯氨酸含量增加最为明显，VC 次之，VPP 与对照接近，其变化幅度最小。经VB6、VC 处理后的幼苗根系还原强度，在不同盐浓度下，测定值均显著高于对照，VB1 不明显，VPP 则低于对照，产生负效应。此外，品种间表现不尽相同，相同的维生素处理，相同的盐浓度对不同的品种的种子萌发、生长效果也存在差异， 4 种维生素对川育16 的作用均强于川育12，但其影响趋势是一致的。说明VB6、VC 具有耐（抗）盐性，可以促进种子发芽和幼苗生长，是较好的耐（抗）盐拌种剂。 Vitamin is one kind of necessary low molecular compound for humans tosustain health and life. Lots of Studies have been done on the effectc of the vitaminsfor people. Vitamin can help people improve the body's natural resistance to disease,Drop the rate of birth defects、cacers and the incidence of the heart diseases. Ifpeople have less of them, the metabolism of the organism may throw off balance,immunity may drop off, and catch disease; Though the effects for Vitamin to thecrops are limited. up to now, there’s no one use soking seeds of wheats with vitaminsas a method, to study on how the effects will happen on the wheat seed germinationand seedling growth, and there are only few reserches on antireversion force forwheats ,none for the antireversion force in Sault stress condition.Wheat（Triticum aestivum L.）is sensitive to the salt, so the salt damage will doharm to wheat’s growth, it will have an unfavorable impact on the output and thequality of wheat.On this reaserch, we Soaking CHY12(red)、CHY16 (white) wheat seeds withVitamin C, B1, PP, B6 (50mg/L) as a pretreatment first. Then under two condition: one is in the normal environment the other is in different Salinity, we begin ourexperiments. Then disscuss on if the vitamin and salinity affect the wheat seedgermination and seedling growth, and what is the different between the two of them,the result shows that:Under the normal condition, after soaking seeds with VB1、VC、VB6、Vpp，we study on the their seed germination and the seeding growth(the root length andweights, The seedling heights and weights), it shows that all of those four kinds ofvitamin can adjust the seed germination, but different in The growth rate. VB6 isbest for increase, VC comes second,VPP is the worst. Meanwhile, those four vitaminalso have effect on the speed of the sprouting of the wheat. VB6、Vc can faster theseed germination most, and the seedlings are all doing well; VB1 do little effects onthe budding, Vpp is the worst, but all treatments are better than CK; but in Vi, VB1some what above the CK, while VPP lower than that. On the whole, the acceleratingeffect of VB6、VC are obvious, VB1 takes second place, but VPP in some aspects arenoneffective even have negative effect. Furthermore, different kind of seeds with thesame vitamin may different in seed germination and seedling growth, four vitaminson CHY16 is better than CHY12.More studies on TTC reductive capacity of roots and the activity of nitratereductase in the leaves, the reasult shows not all the vitamin can help the seedlings toimprove the TTC reductive capacity and the activity of nitrate reductase. TTCreductive capacity in different treatments shows significant differences,but notcorrelate to the variety of the wheat. The TTC reductive capacity of VB6、Vctreatments are all higher than CK, VB1 is nearly the same as CK, VPP is a littlelower than CK. Through the study of acivity of nitrate reductase, it shows that,VB6、VC are higher than CK ,VB1 is nearly the same as CK also, VPP is a little higher inthe CK of CHY12 but lower in CHY16. Through all the results above: VB6、Vc helpthe wheat seed germination, seedling growth and the growth of roots, is theperfectable factor of stimulating the growth; Vpp is a inhibition, that’ll be furtherreserch,and well develop and utilize in the future.Under the different Salinity condition, after soaking seeds with VB1、VC、VB6、Vpp，we study on the their seed germination and the seeding growth(the root lengthand weights, The seedling heights and weights), it shows that: under differentsalinity, the seed germination and the seedling growth of any treatment are inhibited.With the increase of the concentration, the germination rate, Vi、Gi all had fallen; theroot length and weight, the seedling heights and weights steadily sank down. There are also have pronounced difference between all treatments with four differentvitamins.VB6、VC in all treatments are alleviative the salt damage, VB6 is easier tocause to put forth buds than VC, and it’s quantitative value is the highest in theultimate germination rate, in root and seedlings’ hight and weight. Though the VPP、VB1 are seems to inhibite its growth. Under the high concentration150mM Nacl, theultimate germination rate in all treatments are below the 40%, but VB6、VC’squantitative values in any experiments are higher than CK,while VPP lower thanCK.Then we study on the TTC reductive capacity of roots and the content of Polinein leaves, the result shows that between the different salinity, different vitamintreatments, different varieties of the wheat have discrepancy.along with theincreasing concentraion of the salinity（75mM，100mM，150mM），TTC reductivecapacity of roots decreases, the accumulation of the content of Poline in leaves havean upward trend. The increase of VB6’s treatment are obviously, VC comessecond,VPP is nearly come up with CK, changes a little. In TTC reductive capacity of roots’s reserch, VB6、VC are higher than CK at any time,VB1 is not palpable,VPP is lower than CK, makes negative affect on wheat. In addition, varieties of thewheats are remain different, no matter it shows promoting or inhibiting, all fourvitamins have moreobvious effects on CHY16 than CHY12, but the tendency of theeffection are the same. It is say that VB6、VC can help wheat to standwith the saultwell, and promot in growth，they are the better reagent to mix with the seed.

中国青藏高原青稞抗穗发芽资源评价与α-淀粉酶基因的克隆及表达

穗发芽（PHS，preharvest sprouting）是影响禾本科作物生产的重要的灾害之一。收获时期如遇潮湿天气容易导致穗发芽发生。发生穗发芽的种子内部水解酶（主要是α-淀粉酶）活性急剧升高，胚乳贮藏物质开始降解，造成作物产量和品质严重降低。因此，选育低穗发芽风险的品种是当前作物育种工作中面临的重要任务。 青稞(Hordeum vulgare ssp. vulgare)主要分布于青藏高原，自古以来就是青藏高原人民的主要粮食。近年来，由于青稞丰富的营养成分和特有的保健品质、在燃料工业中的潜力以及在啤酒酿造工业中的利用前景，在发达国家日趋受到重视，掀起综合研究利用的热潮。我国拥有占全世界2/3 以上的青稞资源，具有发展青稞产业的得天独厚的条件。然而，由于青稞收获期间恰逢青藏高原雨季来临，常有穗发芽灾害发生，使青稞生产损失巨大。目前对青稞穗发芽研究很少，适用于育种的穗发芽抗性材料相对缺乏，不能很好的满足青稞穗发芽抗性育种的需要。本研究以青藏高原青稞为材料，对其穗发芽抗性的评价指标和体系进行构建，同时筛选青稞抗穗发芽品种并对其抗性进行评价，还利用分子生物学手段对青稞穗发芽抗性的分子机理进行了初步探讨。主要研究结果如下： 1. 本试验以来自于我国青藏高原地区的青稞为材料，对休眠性测定的温度范围进行探讨，并对各种穗发芽抗性测定方法的对青稞的适用性进行评测。通过探讨温度对13 个不同基因型的青稞籽粒发芽和休眠性表达的影响，对筛选青稞抗穗发芽资源的温度条件进行探索，并初步分析了其休眠性表达的机理。在10，15，20，25，30℃的黑暗条件下，选用新收获的13 个青稞品种为材料进行籽粒发芽实验，以发芽指数（GI）评价其休眠性。结果发现，不同品种对温度敏感性不同，其中温度不敏感品种，在各温度条件下均表现很低的休眠性；而温度敏感品种，其休眠性表达受低温抑制，受高温诱导。15℃至25℃是进行青稞休眠性鉴定的较适宜的温度范围。通过对供试材料发芽后的α-淀粉酶活性，发现温度对青稞种子的休眠性表达的影响至少在一定程度上表现在对α-淀粉酶活性的调控上。随后，对分别在马尔康和成都进行种植的34 份青稞穗发芽指数（SI），穗发芽率（SR），籽粒发芽指数（GI）和α-淀粉酶活性（AA）进行了测定和分析，发现它们均受基因型×栽培地点的极显著影响，且四个参数之间具有一定相关性。GI 参数由于其变异系数较低，在不同栽培地点稳定性好，且操作简便，是较可靠和理想的穗发芽评价参数。SI 参数可作为辅助，区别籽粒休眠性相似的材料（基因型）或全面评价材料（基因型）的穗发芽抗性特征。AA 参数稳定性较差，并且检测方法复杂，因此不建议在育种及大量材料筛选和评价时使用。此外，青稞穗发芽抗性受环境影响较大，评价时应考虑到尽可能多的抗性影响因素及其在不同栽培条件下的变异。 2. 对来自青藏高原的青稞穗发芽抗性特征及其与其它农艺性状间的关系进行研究。通过测定穗发芽指数（SI）、籽粒发芽指数（GI）和α-淀粉酶活性（AA），表明113 份青稞材料的穗发芽抗性具有显著差异。SI、GI 和AA 参数的变幅分别为1.00~8.86、0.01~0.97 和0.00~2.76，其均值分别为4.72、0.63 和1.22。根据SI 参数，六个基因型，包括‘XQ9-5’，‘XQ33-9’，‘XQ37-5’，‘XQ42-9’，‘XQ45-7’和‘JCL’被鉴定为抗性品种。综合SI、GI 和AA 参数，可以发现青稞的穗发芽抗性机制包含颖壳等穗部结构的抗性和种子自身的抗性（即种子休眠性），且供试材料中未发现较强的胚休眠品种，除‘XQ45-7’外，所有品种在发芽第四天均能检测出α-淀粉酶活性。穗部结构和种子休眠的抗性机制因基因型不同而不同，在穗发芽抗性中可单独作用或共同作用。农家品种和西藏群体分别比栽培品种和四川群体的穗发芽抗性强，而在不同籽粒颜色的青稞中未发现明显差异。相关性检验发现，青稞的穗发芽抗性，主要是种子休眠性，与百粒重、开花期、成熟期、穗长、芒长和剑叶长呈显著负相关关系，与株高相关性不显著。农艺性状可以作为穗发芽抗性材料选育中的辅助指标。本试验为青稞穗发芽抗性育种研究提供了必要的理论基础和可供使用的亲本材料。 3. α-淀粉酶是由多基因家族编码的蛋白质，在植物种子萌发时高度表达，与植物种子的萌发能力密切相关。在大麦种子发芽时，高等电点α-淀粉酶的活性远大于低等电点的α-淀粉酶。为了研究不同穗发芽抗性青稞品种中编码高等电点α-淀粉酶Amy1 基因结构与抗性间的关系，我们以筛选得到的抗性品种‘XQ32-5’（TR1）、‘XQ37-5’（TR2）、‘XQ45-7’（TR3），易感品种‘97-15’（TS1）、‘9657’（TS2）以及强休眠大麦品种‘SAMSON’（SAM）为材料，对其Amy1 基因的编码区序列进行克隆和结构分析，并对它们推导的氨基酸序列进行比较。结果显示，青稞Amy1 基因具有三个外显子、两个内含子，编码区中有13 个核苷酸变异位点，均位于2、3 号外显子，2 个变异位点位于2 号外显子。SAM 和TS1 分别在2 号外显子相应位置有5 个相同的碱基(GAACT)的插入片段。相应α-淀粉酶氨基酸序列推导发现，所有核苷酸变异中有8 个导致相应氨基酸残基的改变，其余位点为同义突变。青稞Amy1 基因编码区序列品种间相似度高达99%以上，部分序列变异可能与其穗发芽抗性有关。随后，我们又通过SYBR Green 荧光定量技术对该基因在不同发芽时间（1d~7d）的相对表达水平进行了差异性检测。结果发现，7 天内不能检测到SAM 的Amy1 基因表达，5 个青稞品种间的Amy1 基因的相对表达量均随着发芽时间延长而上升，但上升方式有所不同。弱抗品种该基因表达更早，转录本增加速率更大，且在4~5 天可达到平台期。发芽7 天中，抗性品种总转录水平明显低于易感品种。本研究结果表明，青稞Amy1 基因的转录水平是与其穗发芽抗性高度相关。 我国青藏高原青稞，尤其是农家品种的穗发芽抗性具有丰富的变异，蕴藏着穗发芽抗性育种的宝贵资源。本研究为青稞穗发芽抗性育种建立了合理抗性评价体系，筛选出可供育种使用的特殊材料，阐明了农艺性状可辅助穗发芽抗性育种，同时还对穗发芽抗性与α-淀粉酶基因的结构和表达关系进行分析，为青稞穗发芽抗性资源筛选奠定了基础。 Preharvest sprouting (PHS) is a serious problem in crop production. It often takes place when encountering damp, cold conditions at harvest time and results in the decrease of grain quality and great loss of yield by triggering the synthesis of endosperm degrading enzymes (mostly the α-amylase). Therefore, PHS is regarded as an important criterion for crop breeding. In order to minimize the risk of PHS, resistant genotypes are highly required. Hulless barley (Hordeum vulgare ssp. vulgare) is the staple food crop in Qinghai-Tibetan Plateau from of old, where is one of the origin and genetic diversity centers of hulless barley. Recently, interest in hulless barley has been sparked throughout the world due to the demonstrations of its great potential in health food industry and fuel alcohol production. Indeed, hulless barley can also be utilized to produce good quality malt if the appropriate malting conditions are used. In China, overcast and rainy conditions often occur at maturity of hulless barley and cause an adverse on its production and application. PHS resistant genotypes, therefore, are highly required for the hulless barley breeding programs. However, few investigations have been made so far on this issue. The objectives of this study were: 1) to assessment of methods used in testing preharvest sprouting resistance in hulless barley; 2) to evaluate the variability and characteristics of PHS resistance of hulless barley from Qinghai-Tibet Plateau in China; 3) to select potential parents for PHS resistance breeding; 4) to primarily study on the molecular mechanism of PHS resistance of hulless barley. Our results are as followed: 1. We investigated the temperature effects on seed germination and seed dormancy expression of hulless barley, discussed appropriate temperature range for screening of PHS resistant varieties, and analyzed the mechanism of seed dormancy expression of hulless barley. The dormancy level of 13 hulless barley were evaluated by GI (germination index) values calculating by seed germination tests at temperature of 10，15，20，25，30℃ in darkness. There were great differences in temperature sensitivity among these accessions. The insensitive accessions showed low dormancy at any temperature while the dormancy expression of sensitive accessions could be restrained by low temperature and induced by high temperature. The temperature range of 15℃ to 25℃ was workable for estimating of dormancy level of hulless barley according to our data. Analysis of α-amylase activity showed that the temperature effects on seed germination and the expression of seed dormancy be achieved probable via regulating of α-amylase activity. Furthermore, we evaluated the differences in sprouting index (SI), sprouting rate (SR), germination index (GI) and α-amylase activity (AA) between Maerkang and Chengdu among 34 accessions of hulless barley from Qinghai-Tibetan Plateau in China. These PHS sprouting parameters were significantly affected by accession×location, and they had correlation between each other. GI was the most reliable parameter because of its low CV value, good repeatability and simple operation. SI could assist in differentiating between accessions of similar dormancy or overall evaluation of the resistance. AA was bad in repeatability and had relatively complex testing method, therefore, not appropriate for breeding and evaluation and screening of PHS resistant materials. Besides, since PHS resistance of hulless barley was greatly influenced by its growth environment, possibly much influencing factors and variations between cultivated conditions should be considered. 2. In this study, large variation was found among 113 genotypes of hulless barley (Hordeum vulgare ssp.vulgare) from Qinghai-Tibetan Plateau in China, based on the sprouting index (SI), germination index (GI) and α-amylase activity (AA) which derived from sprouting test of intact spikes, germination test of threshed seeds and determination of α-amylase activity, respectively. The range of SI, GI and AA was 1.00~8.86, 0.01~0.97 and 0.00~2.76，the mean was 4.72, 0.63 and 1.22 espectively. Six resistant genotypes, including ‘XQ9-5’, ‘XQ33-9’, ‘XQ37-5’, ‘XQ42-9’, ‘XQ45-7’ and ‘JCL’, were identified based on SI. Integrating the three parameters, it was clear that both hulls and seeds involved in PHS resistance in intact spikes of hulless barley and there was no long-existent embryo dormancy found among the test genotypes. All the genotypes, except ‘XQ45-7’, had detectable α-amylase activity on the 4th day after germination. There was PHS resistance imposed by the hull and seed per se and the two factors can act together or independent of each other. Besides, landraces or Tibet hulless barley had a wider variation and relatively more PHS resistance when compared with cultivars or Sichuan hulless barley. No significant difference was found among hulless barley of different seed colors. The correlation analysis showed PHS resistance was negatively related to hundred grain weight, days to flowering, days to maturity, spike length, awn length and flag length but not related to plant height. This study provides essential information and several donor parents for breeding of resistance to PHS. 3. Alpha-amylase isozymes are encoded by a family of multigenes. They highly express in germinating seeds and is closely related to seed germination ability. In barley germinating seeds, the activity of high pI α-amylase is much higher than low pI α-amylase. The aim of this study was to determine the relationship between preharvest sprouting resistance of hulless barley and the gene structure of Amy1 gene which encodes high pI α-amylase. The coding region and cDNA of Amy1 gene of three resistant accessions, including ‘XQ32-5’ (TR1), ‘XQ37-5’ (TR2), ‘XQ45-7’ (TR3), two susceptible accessions ‘97-15’ (TS1), ‘9657’ (TS2) and one highly dormant barley accession ‘SAMSON’ (SAM) was cloned. Analysis of their DNA sequences revealed there were three exons and two introns in Amy1 gene. Thirteen variable sites were in exon2 and exon3, 2 variable sites were in intron2. SAM and TS1 had a GAACT insert segment in the same site in intron2. Only 8 variable sites caused the change of amino acid residues. There were 99% of similarity between the tested hulless barley and some of the variable sites might be related with preharvest sprouting resistance. Then, we investigated the expression level of Amy1 gene in the 7-day germination test. Results of quantitative real-time PCR indicated that the relative expression trends of Amy1 gene were the same but had significant differences in the increase fashion between hulless barleys and no detectable expression was found in SAM. Susceptible accessions had earlier expression and faster increase and reached the maximum on day 4 ~ day 5. Besides, total transcripts level was found lower in resistant accessions than susceptible accessions. This study indicated that α-amylase activity was highly related to the transcription level of Amy1 gene which not correlated to missense mutation sites. In conclusion, hulless barley, especially the landraces from Qinghai-Tibetan Plateau in China possesses high degree of variation in PHS performance, which indicates the potential of Tibetan hulless barley as a good source for breeding of resistance to PHS. This study provides several donor parents for breeding of resistance to PHS. Our results also demonstrate that agronomic traits may be used as assistants for PHS resistance selection in hulless barley. Besides, analysis of high pI α-amylase coding gene Amy1 revealed the relative high expression of was Amy1 one of the mainly reason of different PHS resistance level in hulless barley.