水稻稃壳结构和化学成分研究

水稻稃壳表面由整齐排列的双峰乳突、稃毛和纤细毛构成。双峰乳突群是一个整体的“甲片”,复盖在稃壳的“网状内胎”上。主要由硅元素构成,同时含有少量的钾、钙、铁、磷、硫、氛等元素。     

江淮丘陵地区水稻“颖壳不闭合”现象生理因素浅析

为水稻严重减产甚至出现绝收现象,以安徽省江淮丘陵地区发生的水稻“颖壳不闭合”现象为研究对象,简要介绍了水稻“颖壳不闭合”现象发生的症状与特点,从水稻“颖壳突变体”、雌雄性器官发育不全或成熟不一致、颖花雌雄性器官发育不全不能完成受精过程、穗部营养受到障碍致使子房或胚乳中途停止发育等生理因素对水稻“颖壳不闭合”现象的影响做了简要分析,并从高温、重金属毒害及土壤水肥条件不平衡等其他外界因素对水稻“颖壳不闭合”现象的影响做了简要分析。根据水稻“颖壳不闭合”现象的发生特点,从水稻品种选择、合理种植、科学施肥等方面提出相关建议。     

裂颖杂交稻种的特点及其应注意的问题

裂颖稻种是指水稻内外颖闭合不严密,颖壳开裂或有开裂痕迹的种子。杂交稻种常有裂颖现象,为确保杂交稻种子能够正常的发芽成苗,我们要掌握裂颖稻种的主要特点,并根据裂颖的轻重程度,采取不同的发芽方法。1　裂颖稻种的主要特点1.1　具有普遍性笔者随机对10个杂交稻组合连续三年进行了裂颖情况的调查,调查采用单粒标准和批样标准判定种子裂颖的轻重。单粒标准以种子内外颖闭合严密,无开裂痕迹为正常粒;以内外颖开裂,但看不见米粒为开裂轻粒;以内外颖开裂,又能看见米粒为开裂重粒。批样标准以开裂20%以下,开裂重粒10%以下为裂颖轻;以开裂20%~50%,开裂重粒……     

用药防病对水稻颖壳色泽及其稻米品质的影响

水稻生长后期在其叶面上喷施不同种类不同浓度的药剂,对水稻颖壳色泽和稻米品质均有一定的影响。实验主要就用药防病对水稻颖壳色泽及其稻米品质的影响进行了一系列的研究和分析。研究结果表明:水稻后期用药方法对颖壳色泽有一定的影响,大量用药尤其是粉剂农药使颖壳色泽显著变暗。穗期适当减少用药次数和用量,在孕穗期和破口期喷施适量三唑酮,颖壳色泽较好。药剂施用对稻米碾米品质无显著影响,但能改善稻米的蒸煮、食用品质,同时一定浓度的药剂施用能提高直链淀粉含量。     

不同镉积累类型小麦各器官镉积累分布规律及机理分析

探讨镉(Cd)低积累小麦不同器官Cd积累分配特性,有助于明晰其籽粒Cd低积累机制,对培育Cd安全小麦品种具有重要意义。通过盆栽试验,研究了不同Cd积累类型小麦生育后期不同器官Cd积累分配特征,并探讨节点I和颖壳滞留Cd的部分生理机制。结果表明,不同Cd积累类型小麦成熟期不同部位Cd积累分配存在较大差异,绵麦37节点I和颖壳Cd含量显著高于抗锈3816,灌浆期到成熟期是绵麦37节点I和颖壳Cd积累的关键时期。Cd处理下,不同Cd积累类型小麦节点I和颖壳亚细胞Cd分配比例均是细胞壁最大,占70%～80%。绵麦37节点I可溶部分分配比例为18%,抗锈3816为15%;而绵麦37颖壳可溶部分分配比例为19%,是抗锈3816的2.7倍,绵麦37节点I和颖壳将更多的Cd分配在可溶部分。灌浆期,两类小麦节点I谷胱甘肽(GSH)含量无显著差异,Cd处理下绵麦37节点I中植物螯合肽(PC)1和PC2的含量显著低于抗锈3816,PC3和PC4的含量显著高于抗锈3816,而绵麦37颖壳中GSH、PC1、PC2、PC3、PC4含量均显著高于抗锈3816。节点I和颖壳的细胞可溶部分对Cd的固定作用和非蛋白巯基的...     

裂颖与去壳对水稻种子萌发生理的初步研究

利用3个在四川生产应用比较普遍的杂交水稻品种为材料,将试验种子做裂颖、去壳处理,以正常颖壳种子为对照,研究颖壳对种子萌芽生长的影响.结果表明,萌芽速度、物质运转效率和贮藏物质消耗率为:去壳＞裂颖＞完整;随萌发时间的延长,α-淀粉酶活性下降速率为:去壳＞裂颖＞完整;根冠比为:去壳＜裂颖＜完整;叶绿素含量为:完整处理为最高,裂颖与去壳偏低.表明颖壳对水稻种子正常萌芽至关重要,是水稻幼苗健康生长的保障,是培育优质稻苗的基础.     

白三叶种质资源主要数量性状的变异与相关性研究

为了探讨白三叶(Trifolium repens L.)种质资源农艺性状变异和相关性,揭示各种质材料的特征特性和种质资源群间的遗传关系,本研究对78份白三叶种质的12个主要数量性状的变异和相关性进行了分析。结果表明：这些种质材料存在着丰富的遗传多样性,各个数量性状间均呈正相关,植株高度与小叶长度、小叶宽度、小叶大小、叶柄长度呈显著正相关;小叶长度与小叶宽度、小叶大小呈极显著正相关,与叶柄长度、叶柄直径呈显著正相关;小叶宽度与小叶大小呈极显著正相关,与叶柄长度、花柄直径呈显著正相关;小叶大小与叶柄长度、叶柄直径、花柄直径呈显著正相关。该批种质材料能为各类白三叶育种和遗传研究提供较为丰富的亲本材料。     

利用程氏指数法对173份水稻材料籼粳属性的鉴别

为提高鉴定水稻籼粳属性的准确性,用程氏指数法从稃毛,酚反应,第1.2穗节间长度,抽穗时壳色,叶毛和粒形等6项指标对173分水稻材料的籼粳属性进行分析,各项指标的分数加起来后,0～8分为籼(H),9～13分为偏籼(H'),14～17分为偏粳(K'),18～24分为粳(K),以典型籼稻冈46为对照,将供试材料分为籼、偏籼、粳、偏粳四类.     

水稻穗上发芽生理生化及颖壳扫描电镜观察

对易萌和不易萌水稻（Oryza sativa ssp.japonica）品种进行扫描电镜观察、穗上发芽1~4d水稻的α-淀粉酶活性和内源激素含量测定。结果表明：易萌品种穗上发芽过程中α-淀粉酶活性较高;IAA、GA1+3、ZR含量也高于不易萌的品种;而ABA含量低于不易萌品种。GA1+3/ABA比值含量的变化与GA1+3含量变化基本一致。扫描电镜观察显示：易萌品种水稻颖壳外表面细胞排列疏松,茸毛较多且孔洞大,萌发孔也大,体现其机械阻力小,易吸水。说明水稻穗上发芽与α-淀粉酶活性,内源激素含量及颖壳结构有关。     

转Trxs基因大麦品系Y002麦芽品质分析

对转Trxs基因大麦品系Y002种子的发芽特性、麦芽品质及其相关指标进行了研究,结果表明:(1)转基因品系Y002的发芽势、发芽率、发芽指数和活力指数等项指标分别比对照TrankgLin增加了9.70%、11.11%、10.37%和7.20%;(2)品系Y002的麦芽品质优于对照,其叶芽长度、糖化力、a-氨基氮、可溶性氮和库尔巴哈值分别为对照的1.03倍、1.03倍、1.11倍、1.09倍和1.13倍;(3)品系Y002种子发芽期淀粉酶和蛋白酶活性显著高于对照;(4)品系Y002种子的B组醇溶蛋白聚合程度加剧,萌发期降解速率显著快于对照,并且出现特异的蛋白条带。综上所述,转基因大麦品系Y002的酿酒品质显著优于对照,可作为培育优质啤酒大麦品种的理想材料。     

Production and genetic characterization of the co-isogenic lines of a common wheat Triticum aestivum CV. S-615 for ten major genes

Summary Co-isogenic lines of a common wheat, Triticum aestivum, cv. S-615 with each of the following ten major genes were produced by repeated backcrosses; The gene C on 2D chromosome for the compactum character, s on 3D for the sphaerococcum character, Hd on 4B, B1 on 5A, and B2 on 6B for awn suppression, Hg on 1A for glume hairiness, Hp on 4A for peduncle hairiness, Ne1 on 5B and Ne2 on 2B for hybrid necrosis, and v1 on 3B for virescence. Seven of them showed the typical mendelian fashion of inheritance, while three others (C, s and v1) were transmitted at lower frequencies than their corresponding normal alleles.The effects of those major genes on 24 characters of cv. S-615 were investigated, which are summarized as follows: C: Increased node diameter, number of spikelets per ear and spike density, but decreased lengths of all ear rachis, awn, anther, empty and outer glumes, and grain, and grain index. s: Increased culm diameter and thickness, and spike density, reduced lengths of all 1st and 2nd internodes, culm, flag leaf, rachis, awn, anther, empty and outer glumes, and grain, and grain index, and accelerated heading. Hd: Increased number of spikelets per ear and anther length, while decreased length of awn, and empty and outer glumes. B1: Increased 1st internode, rachis, and anther lengths, and grain index, but decreased spike density, awn length and grain thickness. B2: Increased rachis length, number of spikelets per ear, empty and outer glume lengths and grain index, but reduced awn length and grain thickness. Hg: No effects. Hp: Increased number of spikelets per ear. Ne1: Accelerated heading, and increased empty glume length. Ne2: Increased node and culm diameters. v1: No effects.Two species-specific genes, C and s, affected a large number of characters expressed in various developmental stages. These genes were found to have pleiotropic effects, namely, they influenced, at least, two groups of interdependent characters. Three awn suppressors influenced a limited number of characters, but no evidence of their pleiotropic effects was obtained.Contribution from the Laboratory of Genetics, Faculty of Agriculture, Kyoto University, Japan, No. 422. The work was supported in part by a Grant-in-Aid (No. 148,004) from the Ministry of Education, Japan.     

Pleiotropic effects of the elongated glume gene P1 on grain and spikelet shape-related traits in tetraploid wheat

Wheat grain size and shape are associated not only with yield but also with product and milling quality. A subspecies of cultivated tetraploid wheat, Triticum turgidum ssp. polonicum, is characterized by elongated glumes. To elucidate morphological effects of the subspecies differentiation-related gene, we conducted QTL analysis for grain and spikelet shape using a mapping population between two tetraploid wheat subspecies, polonicum and durum. P1, the gene controlling the elongated glumes, was located on chromosome 7A, and the polonicum-type allele acted in an incomplete dominance manner to express the elongated glume phenotype. The polonicum allele of the P1 locus significantly affected not only glume length but also grain shape, spike shape, awn length and seed fertility in tetraploid wheat. The elongated glume phenotype was correlated with an increase in spike length, grain length and grain weight, and with a decrease in fertility, grain number and awn length. Thus, the subspecies differentiation-related gene in subspecies polonicum dramatically affects grain shape accompanied by alteration of spikelet shape in tetraploid wheat.     

小麦花发育MADS-box基因的表达模式分析

为解析小麦花发育的分子机制,构建了MADS-box基因系统进化树,发现小麦中存在花发育ABCDE模型的各类基因。半定量RT-PCR和定量RT-PCR分析结果显示,A类基因AP1/FUL小麦中的同源基因TaFUL在所有花器官中都表达,在外稃和內稃中表达水平最高。B类基因TaAP3和C类基因TaAG的表达模式保守,TaAP3在浆片和雄蕊中表达,TaAG在雄蕊和雌蕊中表达。D类基因OsMADS13的同源基因除了在雌蕊表达外,在浆片也有较高的表达,暗示该基因可能同时影响胚珠和浆片的发育。E类基因TaSEP在内稃和内三轮器官表达,在外稃和护颖中不表达。LHS1是禾本科特有的MADS-box基因亚家族,发挥E类基因的功能。TaLHS1除了在內稃和外稃表达,在护颖中也有表达。水稻中控制心皮发育的DROOPING LEAF(DL)基因的同源基因TaDL除了在外稃和心皮表达外,在护颖中也有表达。根据这些结果,我们认为控制小麦花发育的分子机制比较保守,但部分基因功能在进化过程中可能发生了分化。另外,结合小麦外稃和护颖形态结构分析,TaLHS1以及TaDL的表达模式暗示小麦的护颖和外稃这两个器官可能有共同的起源。     

氮肥水平和栽插密度对杂交稻茎秆理化特性与抗倒伏性的影响

以杂交稻金优527为材料,分别在中低海拔地区雅安(600 m)和高海拔地区西昌(1 590 m)进行了以氮肥水平为主区,栽插密度为副区的田间裂区试验。结果表明,随施氮量和栽插密度的增加,茎秆基部节间变细长,茎壁变薄,秆型指数降低,茎鞘中淀粉、纤维素、木质素含量降低,充实度变差;氮肥水平和栽插密度还影响茎秆中氮、钾、硅、钙、镁、铁、锌、铜、锰等矿质元素的含量,从而影响茎秆的倒伏指数和抗倒伏能力。水稻基部茎秆的倒伏指数与株高、重心高度和基部各伸长节间的长度及氮、镁含量正相关,与茎粗、茎壁厚、比茎重、秆型指数及淀粉、纤维素、木质素和钾、钙含量负相关,与茎秆硅含量呈二次函数关系,适宜的硅含量为4.5~4.8 mg kg^-1。由于生态条件不同,两试点水稻茎秆抗倒能力和受氮肥水平与栽插密度影响的程度存在一定差异,高产、抗倒栽培要因地制宜。金优527基部节间的临界倒伏指数为200。     

Senescence of Flag Leaf and Glume in Rice: Role of Grains during Source-Sink Modification by Physical and Chemical Means

Senescence of flag leaf and glume of rice ( Oryza sativa L. cv. Ratna ) at different source sink ratios, through manipulating the plants by physical and chemical means, were analyzed. As judged from the chlorophyll retention capacity, induction of sterility deferred senescence of flag leaf and glume at both grain filling and post grain maturation period. Senescence of the glumes was promoted in the plants whose panicles were darkened. The time needed for achieving maximum 1000 grain dry weight was quickened, the harvest index (HI) was lowered and the flag leaf senescence was delayed by such manipulation. Spraying of urea deferred senescence of the flag leaf as well as increased 1000 grain dry weight and HI. The time taken for achieving maximum 1000 grain dry weight was, however, delayed. Senescence of glumes was promoted by α-HPMS spray, while the same was delayed by PMA spray on the whole plant. Both the chemicals deferred flag leaf senescence and decreased 1000 grain dry weight and HI. Senescence of the flag leaf at post grain filling period was also delayed by the above physical and chemical manipulations compared to that of control, the highest delaying effect was recorded in the flag leaf of sterile plant.
It is concluded that nutrient drainage is the primary cause of nonsequential senescence of the flag leaf of rice (cv. Ratna ). The involvement of senescence signal if any, is perhaps of secondary importance.     

Near-isogenic lines of durum wheat: their development and plant characteristics

Summary The effect of specific plant characteristics on the grain and biomass yield of durum wheat can be accurately determined by using isogenic lines, which, however, were not usually available. This study reported the effects of long glume, glaucousness, glume pubescence, black glume and purple culm on the yield and its associated characteristics in near-isogenic lines of durum wheat cv. LD222, which were developed by continuous backcrossing. The long glume trait which resulted in a large photosynthetic area did not enhance yield. Increased glume size associated with the P gene tended to increase the main culm dominance, characterized such as vigorous main culm and weak tillers, and plant height, but to reduce tillering and spike number. Consequently, grain yield and harvest index declined. Under the adequate water supplying condition of the present study, the glaucous trait was beneficial for grain yield. The trait of glume pubescence did not excert any significant effect on the yield related characteristics in the LD222 background. The traits of black glume and purple culm reduced the number of spikes per unit area and the number of kernels per unit area.     

Relationship between Quality, Colour of Glume and Gliadin Electrophoregrams in Durum Wheat

Gliadin electrophoregrams, protein content and SDS-sedimentation values from the modified SDS-sedimentation test were obtained from six Greek cultivars of Triticum durum and 98 biotypes (78 with white glumes, 20 with red glumes). Our results provide wheat breeders with the tool TO predict the cooking quality of durum wheat from early generation breeding lines, since we were able to correlate the colour of the glume with the presence or absence of gliadin bands 42/45. All red glume biotypes lacked gliadin band 45 and possessed gliadin band 42. Furthermore, their SDS sedimentation values were around 27 (weak gluten), indicating poor cooking quality. Yet, the electrophoregrams of the gliadin proteins allowed an identification of the wheat cultivars examined, since for each cultivars the pattern was different. No correlation was found between the colour of the glume and the amount of total gram protein.     

外源Si对水稻生长状况及稻瘟病抗性的影响

外源Si对提高水稻对病害的抗性有显著影响,但水稻应激防御系统对外源Si的响应机制尚缺乏深入研究。为探究不同浓度外源Si对稻瘟病胁迫下水稻的生长状况、产量及抗性的影响,在人工接种稻瘟病菌的条件下进行水稻盆栽试验。测算了水稻株高、穗数、穗长、地上部生物量和千粒重等生长数据,同时测量了水稻稻穗中MDA的含量和防御相关酶(PPO、CAT、SOD、POD)的活性。结果表明,施Si处理使水稻的稻瘟病病情指数下降了44.47%;显著提高了稻穗中PPO、CAT和SOD的活性,降低了POD的活性和MDA含量,缓解了稻瘟病引起的氧化胁迫;显著增加水稻株高,使其茎叶更加挺直,降低病菌的感染和传播;最终提高地上部干物质量积累,相比染病组的产量提高61.2%。因此,Si能够通过参与植物生理代谢过程,有效增强水稻抵御稻瘟病的抗性,提高植株活力,有效减少植株损伤。     

硅对镉和锌复合胁迫下水稻幼苗生长及重金属吸收的影响

通过盆栽试验研究了镉(Cd)、锌(Zn)复合胁迫下,外源施加不同浓度的硅(0,1.5,2.0,2.5 mmoL/kg)对水稻幼苗生物量及地上部和地下部Cd和Zn含量的影响.结果表明,无论是在Cd和Zn单一或者复合污染条件下,不同浓度的硅处理均能显著提高水稻幼苗地上部和根系的生物量,其中以硅浓度为1.5 mmol/kg时...